These microorganisms, which include bacteria, viruses, and fungus, are critical to our general health and wellbeing.

Recent research has revealed the complicated ways in which the microbiome interacts with human bodies, as well as how microbiome imbalances may contribute to a range of health concerns.

Microbiome and gut health

One of the most important roles of the microbiome is in maintaining the health of our gut.

The bulk of our bacteria live in our gut, which is responsible for breaking down food, absorbing nutrients, and protecting us from hazardous diseases. Dybiosis, or an imbalance in the gut microbiome, has been related to a number of health disorders, including inflammatory bowel disease, irritable bowel syndrome, and even obesity.

• Meditation associated with good gut health
• Cranberry extract can boost microbiota and help to prevent chronic diseases
• Small changes in sleep patterns linked to harmful gut bacteria

The microbiome is extremely important in our immune system. Our gut microbes assist in training our immune system to identify and respond to hazardous invaders.

Individuals with a broad and healthy microbiome have stronger immune systems and are less prone to illnesses and allergies, according to research.

The microbiome influences our entire metabolism in addition to its work in the stomach and immune system.

The microbes in our gut aid in digestion and nutrition absorption, and microbiome abnormalities have been related to metabolic disorders such as type 2 diabetes and obesity.

Microbiome and diabetes

The relationship between the microbiome and diabetes, both type 1 and type 2 diabetes, is an active area of research.

Studies have shown that changes in the gut microbiome may contribute to the development of type 2 diabetes.

One of the ways in which the microbiome may affect diabetes is through its role in metabolism.

• Body microbiota combined with obesity and diabetes increases COVID-19 severity
• Gut microbes could pave the way for type 2 diabetes preventative treatments

The gut microbiome plays a significant role in the metabolism of carbohydrates and fats, and can influence the body’s ability to regulate blood sugar levels. Studies have found that individuals with type 2 diabetes have a less diverse and less balanced gut microbiome compared to healthy individuals.

Another way in which the microbiome may affect diabetes is through its impact on inflammation. Studies have suggested that an imbalance in the gut microbiome, known as dysbiosis, can lead to chronic low-grade inflammation, which is a known risk factor for type 2 diabetes.

Microbiome and mental health

Recent research has also shown that the microbiome plays a role in our mental health.

Studies have shown that individuals with depression and anxiety have different gut microbiomes compared to those without these conditions. The gut-brain axis, the complex communication network between the gut and the brain, plays a role in how the microbiome affects our mental health.

One of the most promising areas of research in the microbiome is its potential to be used as a therapeutic tool. The use of probiotics, or beneficial bacteria, has been shown to be effective in treating a variety of health conditions including inflammatory bowel disease, irritable bowel syndrome, and even certain types of cancer.

The use of fecal microbiota transplantation, which involves transplanting healthy gut microbiome from a donor, has also been shown to be effective in treating certain conditions such as Clostridium difficile infection.

• Gut bacteria may be linked to brain damage in premature babies, research suggests
• Extra microbiome variations and reduced inflammation triggered by fermented foods, study reports

Effect of antibiotics on the microbiome

The use of antibiotics, which are designed to kill harmful bacteria, can also have a significant impact on the microbiome. Antibiotics can disrupt the delicate balance of bacteria in the gut, leading to an overgrowth of harmful pathogens. This can lead to a number of health problems, including diarrhea and other gastrointestinal issues.

Research also suggests that the use of antibiotics, which can disrupt the delicate balance of bacteria in the gut, may also contribute to the development of type 2 diabetes.

How can I improve my microbiome health?

While the microbiome is still not fully understood, it is clear that it plays a crucial role in our overall health and wellbeing.

There are several ways to improve gut health and promote a diverse and balanced gut microbiome:

1. Diet: A diet that is high in fibre, low in sugar, and rich in fermented foods can help to promote a healthy gut microbiome. Consuming a variety of fruits, vegetables, whole grains, and fermented foods such as yogurt, kefir, and sauerkraut can help to support the growth of beneficial bacteria in the gut.
2. Avoid processed foods: Processed foods are often high in sugar and low in fibre, which can contribute to an imbalance in the gut microbiome. Limiting the intake of processed foods can help to improve gut health.
3. Limit the use of antibiotics: Antibiotics can disrupt the delicate balance of bacteria in the gut, leading to an overgrowth of harmful pathogens.
4. Reduce stress: Stress has been linked to changes in the gut microbiome, so finding ways to manage stress such as yoga, meditation, or therapy can help to improve gut health.
5. Exercise regularly: Regular exercise has been shown to have a positive impact on the gut microbiome, so incorporating physical activity into daily routine can help to support gut health.
6. Take probiotics: Probiotics are live microorganisms that can help to restore the balance of bacteria in the gut. They can be found in supplement form or in fermented foods like yogurt, kefir, sauerkraut, kimchi, and kombucha.

Some people may have specific gut related conditions that require a tailored approach.

The microbiome is an essential component of human health, playing a critical role in digestion, immune function, and metabolism.

As we continue to learn more about the microbiome, it is becoming increasingly clear that it is a vital component of our overall health.

Testosterone is a steroid hormone and is frequently referred to as the male sex hormone as men have significantly higher levels of the hormone than women.

Research has shown a significant link exists between low levels of testosterone and

type 2 diabetes
in men whilst showing associations between high testosterone levels in women with type 2 diabetes.

What is the functional role of testosterone?

Testosterone is in a family of steroid hormones known as androgens.

Testosterone in males is important for the development of masculine features including the male genitals and other male characteristics including facial hair, deepening of the voice and muscle development.

In females, testosterone is associated with maintaining

libido
after the menopause and women with significantly high levels of testosterone may experience irregular periods and increased body hair and muscle mass.

Testosterone also plays an important part in other functions of the body including how fat is deposited on the body, the maintenance of bone mineral density, regulating metabolism, maintaining

libido

How is testosterone linked with diabetes?

Testosterone has been shown to influence how our body deposits fat. Body fat can be stored either as subcutaneous fat, that is fat is stored just underneath the skin or as visceral fat, which is stored around the abdominal organs.

Visceral fat has been shown to be closely associated with increased risks of type 2 diabetes as well as heart disease,

Alzheimer’s disease
and cancer.

Research has shown that low testosterone levels in men are linked with increased deposition of visceral fat, leading to insulin resistance and type 2 diabetes.

Conversely, it is higher than normal levels of testosterone that is linked with increased visceral fat storage in women.

Whilst research has shown links between testosterone and insulin resistance, researchers still need to unravel more about the part which testosterone levels play in the development of type 2 diabetes.

Low testosterone in men with diabetes

Low levels of testosterone in men have been shown to lead to increased storage of this more dangerous form of fat and greater incidence of

insulin resistance
and type 2 diabetes.

The NHS records that around 1 in 6 men with type 2 diabetes also have low levels of testosterone, which can lead to decreased libido and motivation, loss of muscle mass and increased body fat around the waist.

• Read more about
  
  low testosterone in men

Testosterone levels in women with diabetes

Testosterone levels in women with type 2 diabetes show a different pattern than in men, with higher than normal levels of testosterone in women being more commonly associated with insulin resistance and type 2 diabetes.

Women with a condition called

PCOS (polycystic ovaries syndrome)
have high levels of testosterone and are at significantly higher risk of developing type 2 diabetes.

How can I help maintain normal testosterone levels?

There are a number of natural ways which can help to promote or maintain normal levels of testosterone.

High intensity exercise and

strength training
have been shown to increase levels of testosterone as well as being beneficial towards insulin sensitivity.

Low levels of vitamin D have been associated with lower levels of testosterone and studies on rodents have found vitamin D supplementation to improve testosterone levels.

The stress hormone cortisol has been shown to block testosterone from taking effect.

Lowering stress
has also been shown to be beneficial in people with diabetes.

The respiratory system is the system of organs that allow the body to take in oxygen and expel carbon dioxide, this process is known as gaseous exchange.

We generally breathe between 12 and 20 times a minute. There are a number of

complications of diabetes
that can negatively affect our breathing.

Parts of the respiratory system

The following parts of the body make up the respiratory system:

• Mouth and nose
• Trachea (windpipe)
• Lungs
• Diaphragm

How the respiratory system works

Breathing is usually initiated by contraction of the diaphragm, a muscle which separates the chest cavity from the abdomen.

As the diaphragm contracts, more space is made available in the chest cavity and this has the effect of creating suction as the lungs expand to fill the space.

The lungs draw in air through the nose and/or mouth which then travels down the trachea (windpipe) before reaching the lungs.

Within the lungs are tiny air sacs called alveoli which allow oxygen from the air we breathe to be absorbed into the many tiny blood vessels contained with the alveoli.

As this happens, the alveoli take in carbon dioxide from the

blood vessels
and this completes gaseous exchange.

With gaseous exchange complete, the diaphragm relaxes and the carbon dioxide rich air in the lungs is expelled via the trachea out of the mouth and/or nose.

The lungs

As noted above, it is within the lungs that the gaseous exchange of oxygen and carbon dioxide takes place. The lungs are filled with a branched structure of airways called bronchi and smaller airways called bronchioles. Located at the end of the bronchioles are the alveoli in which the exchange of gases takes place.

The average capacity of human lungs is between 4 and 6 litres of air. The capacity of lungs may be reduced if the lungs become diseased or damaged. A common risk of lung damage is

smoking

How diabetes can affect the respiratory system

Diabetes can adversely affect our breathing in a number of different ways. Breathing difficulties don’t affect everyone with diabetes and the risk of having difficulty breathing can be reduced by maintaining good diabetes control and a

healthy body weight

Ketoacidosis and Kussmaul breathing

Rapid or laboured breathing, known as Kussmaul breathing, can be a symptom of diabetic ketoacidosis (DKA). Ketoacidosis is a short term complication of diabetes caused by very high blood glucose levels accompanied by a high level of ketones in the blood. Ketoacidosis will only usually affect people with diabetes if they haven’t taken sufficient insulin.

Ketoacidosis is a very dangerous condition and should be treated as an emergency.

• Read more about
  
  diabetic ketoacidosis

Kidney failure and shortness of breath

Becoming very short of breath, say whilst climbing the stairs, can be a result of kidney failure. Chronic kidney disease can lead to anemia which leaves the blood short of red blood cells with which to carry oxygen. If we have anemia and need to be more active, this can lead to our body struggling to get enough oxygen for our muscles and can leave us out of breath.

Kidney disease is one of the more common complications of diabetes, affecting about 40% of people with diabetes.

• Read more about
  
  diabetic kidney disease

Obstructive sleep apnea (OSA)

Obstructive sleep apnea (OSA) is a condition that results in difficulty breathing whilst sleeping. This can happen if the muscles in the throat collapse inwards and block your airway. This may happen partially or completely and can therefore disturb sleep.

Being overweight is the main risk factor of sleep apnea and the NHS notes that people with diabetes have a 3 times higher risk of developing sleep apnea.

• Read more about
  
  obstructive sleep apnea

The skeletal system is the organ system which includes all the bones of the body. Adults have 206 bones with the smallest bone being found in the ear and the largest being the femur (thigh bone).

Some of our bones do more than keeping us upright, they are also able to produce our blood cells and even release hormones which play roles in blood glucose regulation and fat storage.

Role of the skeletal system

The main roles of the skeleton are:

• Providing support for muscles, tendons and our internal organs
• Allowing the body to move
• Protecting organs, including the
  
  brain, heart and lungs
• Producing blood cells
• Storing minerals, such as calcium

Bone immune system

A number of bones in the body, including the thigh bones and the sternum contain

bone marrow
which produces red and white blood cells. White blood cells play an important part in the

immune system
as it these cells which recognise and destroy invading pathogens.

Bone and blood glucose levels

A less well known role of the skeletal system is its effect on our blood glucose levels. Bone cells can release a hormone called osteocalcin which helps in the regulation of blood sugar levels.

Osteocalcin has been found to increase the secretion and sensitivity of insulin and reduces fat storage. Lower levels of osteocalcin have been found in people with a higher BMI.

How diabetes affects the bones

People with diabetes mellitus, types 1 and 2, have an increased risk of osteoporosis, a condition which causes bones to weaken.

Risk factors for osteoporosis include the duration of diabetes and how well controlled

blood glucose levels
are.

Charcot foot

Charcot foot is disorder which can cause fractures to be sustained in the foot.

The condition can develop in people with

neuropathy
because the nerve damage masks pain which would otherwise be felt from a foot fracture.

It is therefore important that people with diabetes check their feet (or have them checked) daily so that any signs of damage such as swelling or changes in colour of the foot can be acted upon quickly to prevent more serious injury.

• Read more on
  
  Charcot foot

The urinary system, also known as the excretory system, allows the body to remove waste or unneeded products from the body through the urine.

The urinary system can also help the body to remove excess glucose from the blood. As a result, though, high blood sugar levels can present problems for the urinary system in the short term as well as in the longer term.

Role of the excretory system

The role of the excretory system is to remove waste products such as urea, uric acid, and creatinine from the blood to be passed out of the

body
as urine.

The urinary system also helps us to regulate the amount of glucose, salts and water in the blood.

Components of the urinary system

The following organs and vessels make up the excretory system:

• 
  Kidneys
• Ureters
• 
  Bladder
• Urethra

The kidneys are the filters which remove waste products and water from the blood. The resulting urine passes out of the kidneys through muscular tubes called the ureters which drain into the bladder.

The bladder gradually collects and stores urine until it can be conveniently emptied. Upon emptying, the bladder’s sphincter opens and urine travel down a tube called the urethra which empties out of the body via the genitals.

The urinary system and blood sugar levels

If the blood has an excess of glucose, the kidneys will remove glucose from the blood to be excreted in the urine.

A number of diabetes drugs, known as SGLT2 inhibitors, have been developed which reduces the amount of glucose that is reabsorbed by the kidneys, therefore more glucose is passed out of the urine.

How diabetes can affect the urinary system

Diabetes can have short term and long term effects on the urinary system. In the short term,

high blood glucose levels
can promote bacterial growth which can raise the risk of urinary tract infections or thrush developing.

Long term effects of diabetes on the urinary system can include

kidney damage
and damage to nerves controlling the bladder can result in difficulty urinating or

urinary incontinence

Urinary tract infections

Urinary tract infections (UTIs)
are bacterial infections which start in the genitals which can affect any part of the urinary system but are particularly dangerous, and even life threatening, if they affect the kidneys.

UTIs are therefore best treated early and this be done by taking antobiotics.

Yeast infections (thrush)

Yeast infections
are fungal infections that can affect different parts of the body. Yeast infections that affect the genitals are a common type of yeast infection that is more likely to affect people with diabetes that have glucose present in their urine.

The glucose in urine provides a fertile environment for fungal infections to grow. Thrush can be treated by taking anti-fungal creams.

White blood cells are the cells that help the body fight

infection
There are a number of different types and sub-types of white blood cells which each have different roles to play.

The three major types of white blood cells are:

• Granulocytes
• Monocytes
• Lymphocytes

Granulocytes

There are three different forms of granulocytes:

• Neutrophils
• Eosinophils
• Basophils

Granulocytes are phagocytes, that is they are able to ingest foreign cells such as bacteria, viruses and other parasites.

Granulocytes are so called because these cells have granules of enzymes which help to digest the invading microbes. Granulocytes account for about 60% of our white blood cells.

Neutrophils are by far the most prevalent of these cells. Each neutrophil cell can ingest up to between around 5 and 20 bacteria in its lifetime.

Eosinophils are involved in allergic reactions and can attack multicellular parasites such as worms.

Basophils are also involved in allergic reactions and are able to release histamine, which helps to trigger inflammation, and hepari, which prevents blood from clotting.

Monocytes

Monocytes can develop into two types of cell:

• 
  Dendritic cells
  
  are antigen-presenting cells which are able to mark out cells that are antigens (foreign bodies) that need to be destroyed by lymphocytes.
• 
  Macrophages
  
  are phagocyte cells which are larger and live longer than neutrophils. Macrophages are also able to act as antigen-presenting cells.

Lymphocytes

Lymphocytes are cells which help to regulate the body’s immune system.

The main types of lymphocytes are:

• B lymphocytes (B cells)
• T lymphocytes (T cells)

B lymphocytes

B lymphocytes are able to release antibodies which are Y shaped proteins that bind to infected microbes or cells of the body that have become infected.

Antibodies can either neutralize the target microbe or can mark it out for attack by T lymphocytes.

T lymphocytes

There are a number of different T lymphocytes:

• 
  Helper T cells
  
  release a protein called cytokines which help to further direct the response of other white blood cells.
• 
  Cytotoxic T cells
  
  (also known as natural killer T cells) are able to release molecules which kill viruses and other antigens.
• 
  Memory T cells
  
  will be present after the body has fought off an infection and help the body to deal more easily with any future infection of the same type.
• 
  Regulatory T cells
  
  (also known as suppressor T cells) help to regulate other T cells to prevent them targeting the body’s own cells.

T lymphocytes and Type 1 Diabetes

In type 1 diabetes, the killer T cells target and kill the body’s own insulin producing cells. Even if new insulin producing islet cells are transplanted, the T cells will still try these cells off.

As a result people who have had

islet cell transplants
need to take strong anti-immune drugs to preserve the transplanted cells.

Researchers have therefore been investigating ways to regulate the immune response in type 1 diabetes.

Bone marrow transplants have had some success in modulating the immune system, however, bone marrow transplants introduce a

risk of complications
developing.

• Read more about
  
  bone marrow transplants for diabetes

Anti-type 1 diabetes vaccines are being developed by a number of research teams around the world. The vaccines have been successful in curing mice but the level of success has yet to be replicated in humans.

• Read more about
  
  diabetes vaccines

The brain is key to the nervous system and provides the processing power to make sense of information provided by the nerves and gives instruction back through the nerves to guide our physical responses.

Role of the nervous system

The nervous system allows the body to take in and process information on what is happening around and inside us and take appropriate action.

Some of these actions will be automatic or reflex responses, whereas other actions will come directly from our own choice.

What are the components of the nervous system?

The nervous system is made up of the central nervous system and the peripheral nervous system.

The central nervous system encompasses the brain and the spine. The brain is the processing centre of the nervous system.

The spinal cord is like the trunk of a tree, extends from the brain down our back and branching off into the many different nerves which make up the peripheral nervous system.

The peripheral nervous system is made up of all the nerves outside of the brain and spinal cord.

The peripheral nervous system includes the autonomic nervous system, which controls involuntary functions such as our heart rate and perspiratio, and also includes the enteric nervous system which governs our gastrointestinal response.

The brain

The brain is a key organ enabling us to understand and interact with our surroundings. The brain communicates with the rest of our body via the nerves.

The skull keeps the brain intact from the outside and the blood-brain barrier helps to allow certain nutrients into the brain whilst keeping any harmful substances in the blood away from the brain.

• 
  Diabetes and the brain

Spine

The spine acts as a nerve highway from the brain out to the periphery nervous system. The bones of the spine play an important role helping to protect the nerves travelling through the spine from damage.

Damage to the spinal nerves is often very serious and can sometimes result in paralysis.

Nerves

There are different types of nerves. Sensory nerves carry impulses from out sensory organs, such as our eyes and

skin, to the brain for processing allowing us to see, feel and experience other senses.

Motor nerves carry impulses away from the brain to organs and muscles allowing our muscles and organs to move and respond as appropriate.

• 
  Diabetes and the nerves

How diabetes can affect the nervous system

If blood glucose levels remain high for extended periods of time over a number of years, the blood vessels which feed the nerves can become damaged and can lead to the nerves themselves becoming damaged.

Damage to the nerves
can lead to loss of feeling in extremities such as the hands and lower legs.

If damage is sustained to nerves leading to organs such as our digestive organs, this can affect the functioning of these organs.

What is diabetic neuropathy?

Neuropathy is the name for nerve damage. Nerve damage can take the form of sensory neuropathy,

motor neuropathy
or autonomic neuropathy.

Neuropathy
is understood to be present in up to 50% of people with diabetes.

Nerve damage in the feet is particularly dangerous for people with diabetes, putting us at a higher risk of foot damage which could lead to

amputation

As neuropathy is common in diabetes, we are advised to check our feet regularly.

The human eye is a small but complex organ that enables us to see the world around us. However, damage to the eyes can put our sight at risk.

The most common cause of blindness among people in the UK is a condition called

retinopathy, which is caused by damage to the retina – the ‘seeing’ part at the back of the eye.

Most people affected by this are those who have diabetes, as retina damage can be caused by

high levels of blood glucose, among other things.

About the eyes

The eye is a slightly irregular shaped sphere that consists of the following:

• 
  The iris
  
  – the pigmented part of the eye
• 
  The pupil
  
  – the black circular opening in the iris that lets light in
• 
  The lens
  
  – the part behind the iris that helps to focus light on the back of the eye
• 
  The cornea
  
  – a clear dome over the iris
• 
  The conjunctiva
  
  – an invisible, clear layer of tissue covering the front of the eye, except the cornea
• 
  The retina
  
  – delicate light-sensitive tissue at the back of your eye
• 
  The sclera
  
  – the white part of your eye

How your eye works

When we look at something, a number of processes take place before we are able to actually “see”. Firstly, light passes through the pupil and is focused by the cornea and lens onto the retina.

The retina converts the light into electrical signals, which are then carried to the

brain
via the optic nerve. The brain then interprets these signals to produce the images that you see.

Another important part of the human eye is the

macula
It is a small, sensitive area within the retina that provides our central vision, i.e. allows us to focus for activities such as reading and writing, and to recognise colours. It is also essential for clear, detailed vision.

How diabetes affects the eyes

Diabetes can lead to the development of a number of eye conditions, which can affect your sight. These include:

• 
  Diabetic retinopathy
  – Retinopathy is a common complication of diabetes and the most serious of all diabetes-related eye conditions. It occurs when persistent
  
  high levels of blood glucose
  cause leaks or blockages in the capillaries (small blood vessels) that provide the retina with a constant supply of blood. This damages the retina and stops it from working, thus affecting your vision. If left untreated, it an lead to total loss of sight.
• Temporary blurring – the abnormal changes in blood sugar levels caused by diabetes can affect the lens inside the eye, which can lead to short spells of
  Fergus
  throughout the day.
• 
  Cataracts
  – a cataract is an eye condition that is more commonly associated with older diabetics. It occurs when the lens becomes cloudy, causing vision to become blurred or dim as light struggles to pass through to the back of the eye.

Types of Diabetic Retinopathy

There are different types of diabetic retinopathy, which are based on the extent of the damage to the blood vessels in the retina caused by uncontrolled blood glucose.

Background diabetic retinopathy

This is early stage retinopathy that affects many people who have had diabetes for some time. It can cause the capillaries in the retina to bulge slightly (
microaneurysm
) and leak blood (haemorrhages) or fluid (exudates).Most people with this very mild form of retinopathy are unaware of their condition as it does not cause any noticeable symptoms. Eyesight remains unaffected but problems can occur if the condition progresses.

Annual

retinal screening
tests are offered to diabetics in England and Wales to help keep a close check on retinopathy during the initial stages and ensure that any signs of progression to more serious stages are detected early, and treated effectively.

Maculopathy

More common in people with type 2 diabetes,

maculopathy
is a more serious type of retinopathy that affects the macula, the most used part of the retina. Fluid leaking around this area from the blood vessels causes swelling (oedema). This can affect your central vision, making it extremely difficult for you to read or see fine details. The amount of central vision that is lost varies from person to person, but if left untreated, it can cause blindness.

Proliferative diabetic retinopathy

Progression of background retinopathy can lead to more severe problems. The larger blood vessels in the retina can become blocked and damaged, starving the larger areas of the retina of vital oxygen (ischaemia).

This triggers a damage repair process called neo-vascularisatio, which stimulates the eye into growing new vessels to replace the blocked ones.

However, these newly formed blood vessels are very delicate, bleed easily and grow in the wrong place (on the surface of the retina and into the vitreous gel – a clear jelly-like substance inside your eye). The bleeding can lead to large haemorrhages that totally obscure vision in the affected eye.

Extensive haemorrhages can lead to scar tissue forming, which pulls and distorts the retina, causing it to become detached. This often leads to total sight loss. Fortunately, proliferative retinopathy is quite rare, affecting just 5 to 10% of all diabetics.

Looking after your eyes

Keeping your eyes in good health is vital for preventing conditions such as

diabetic retinopathy
and maintaining your eyesight. If you have diabetes, it is very important to

control your blood sugar
and

cholesterol, and keep your

blood pressure
as close to normal as possible. Effective management of diabetes will reduce your risk of having problems.

Other steps you can take to help prevent retinopathy include:

• Informing your GP or diabetes care team of any changes to your vision
• Losing weight (if you’re overweight) and maintaining a healthy weight
• Eating a healthy, balanced diet and keeping fit through regular exercise
• Quitting smoking (if you smoke)
• Sticking to your prescribed medication plan

Diabetic eye screening

One of the most effective ways to prevent retinopathy-caused sight loss is to attend your

diabetic eye (or retinal) screening
appointments.

Each annual appointment involves a detailed examination of the eyes and is designed to help reduce the risk of vision loss in people with diabetes by identifying retinopathy at an early stage – research shows that early detection of retinopathy and appropriate treatment can prevent 90% of all those at risk from losing their eyesight.

Nerves are a collection of neurons, which are the individual nerve cells. Nerves can be damaged by diabetes – known as neuropathy.

A neuron has a soma (the cell body) which includes the cell nucleus, dendrites which conduct stimulation of the nerve, one or more axons which provide nerves with their length and axon terminals which transmit impulses to other nerves.

Where are the nerves located?

Our nerves are located throughout our bodies from our skin, through and round our organs and towards their centre, the brain.

In biology, the nervous system is divided into the central nervous system, which includes the nerves of the brain and the spine, and the peripheral nervous system which includes the rest of the nerves.

The peripheral nervous system encompasses, as a subcategory, the autonomic nervous system which helps the body to control involuntary functions including the movements of our heart, stomach, intestines, bladder and sweating.

Which types of nerves exist?

The main

2 types of nerves

are sensory nerves and motor nerves.

• 
  Sensory nerves
  
  also known as afferent nerves, carry impulses from sensory receptors towards the brain.
• 
  Motor nerves
  
  also known as efferent nerves, carry impulses away from the brain to muscles and glands.

How diabetes affects the nerves

Just as other cells do, the nerves need to be kept fuelled by the blood vessels which supply them with oxygen and other nutrients.

If blood vessels feeding the nerves become damaged by high blood glucose levels over extended periods of time, the nerves can become damaged and unable to function properly.

The term for nerve damage as a result of diabetes is

diabetic neuropathy
and can be categorised in different forms:

• 
  Sensory neuropathy
• 
  Motor neuropathy
• 
  Autonomic neuropathy

Sensory neuropathy is when the nerves that sense touch and heat are affected. This typically affects the extremities, such as the hands, feet and lower legs, and affects our ability to feel pain from these parts of our body.

This can be dangerous as it means we can sustain injury without knowing it. Sensory neuropathy can also cause us to feel unexplained tingling or burning sensations.

Motor neuropathy is when the nerves controlling muscular movement are affected. If the feet are affected, it can affect how we distribute our body weight on our feet and could lead to a foot complication known as

Charcot foot

Autonomic neuropathy can affect the nerves which control involuntary functions including stomach emptying, bowel movements, our ability to pass urine and sweat and can affect functioning of the heart.

Looking after your nerves

People with diabetes can reduce their risk of developing neuropathy by keeping

blood glucose within the target blood glucose level guidelines

The US National Institutes of Health state that vitamin B12 is an important nutrient for neurological function.

People with vitamin B12 deficiencies may have an increased risk of neuropathy.

Dietary sources of vitamin B12 come from animal products such as:

• Meat
• Fish
• Poultry
• Egg and
• Dairy products

The Mayo Clinic advises

regular exercise
and avoiding alcohol and smoking can help to reduce neuropathy risk.

The male and female reproductive systems have different roles but together allow the combination of DNA of the egg and sperm that results in the development of new life.

Diabetes can affect both the male and female reproductive systems but this should not necessarily prevent reproduction.

Female reproductive system

The female reproductive includes the following components:

• Ovaries
• Fallopian tubes
• Uterus
• Cervix
• Vagina

The ovaries produce ova (egg cells) which are released into the fallopian tubes. An egg is produced once a month by either of the ovaries.

The egg will take about 5 days to travel through the fallopian tube before it reaches the uterus. If fertilised, the ovum becomes implanted in the wall of the uterus and development of the foetus commences.

The cervix is the opening to the uterus which allows sperm to enter the uterus and either releases the baby into the vagina when ready or, if fertilisation has not occurred, opens to release the uterine lining.

Male reproductive system

The components of the male reproductive system include:

• Testes
• Prostate gland
• Urethra
• Penis

The testes produce the sperm for fertilisation. The prostate gland is responsible for commencing ejaculation as well as secreting fluid which helps to protect sperm from the acidic environment of the vaginal tract.

During ejaculatio, sperm is propelled through the urethra and out of the penis and into the vagina during

sexual intercourse

The penis becomes hard and erect for intercourse enabling it to penetrate into the woman’s vagina. The dense collection of nerve endings in the penis helps to stimulate the prostate to trigger ejaculation.

Diabetes and female sexual dysfunction

In the long term diabetes can affect the blood vessels and nerves of the female genitals. This can result in difficulties in arousal and lubrication. Diabetes is not the only cause of sexual dysfunction; psychological factors can also diminish arousal for instance. Your health team can help to identify the cause of the problem and provide appropriate treatment or therapy.

• Read more on
  
  female sexual dysfunction

Erectile dysfunction and male sexual dysfunction

In men, damage to nerves and or blood supply of the penis can make it difficult to achieve or maintain an erection. Depending on the cause, a number of treatments may be prescribed, including sexual therapy, tablets (such as Viagra, Cialis and Levitra) and vacuum pumps.

• Read more on
  
  erectile dysfunction

Diabetes and pregnancy

It is important that expectant mothers maintain good blood glucose level control through pregnancy to ensure a healthy birth.

Preparation for pregnancy is highly recommended for women with diabetes to allow you to have a health assessment and adjust to keeping your sugar levels stable before commencing pregnancy.

Mothers with diabetes have a greater chance of having a larger baby and, as a result, there’s an increased chance you may need to have a caesarean section birth.

• Read more on
  
  diabetes and pregnancy

Oestrogen is a group of steroid hormones which are often referred to as the female sex hormones because women have higher levels of these hormones than men.

Phthalates are chemicals found in a number of day to day items including plastics and have become a hotly discussed topic as these chemicals have been found to behave like oestrogen and shown to disrupt the body’s

endocrine system
as well as being linked with low fertility.

Role of oestrogen

Oestrogen plays a number of roles in the female body, being involved in ovulatio, pregnancy, childbirth itself and the development of female characteristics, such as the development of breasts, wider hips and female genitals. Oestrogen is also ovulatio, pregnancy and childbirth.

In males, oestrogen is also produced and is involved in the production of sperm and fertility.

Oestrogen and health

Deficiency of oestrogen linked with

cardiovascular disease
and problems affecting the brain such as

Alzheimer’s disease, Parkinson’s disease and schizophrenia.

Oestrogen also plays an important role in bone formation and lower oestrogen levels have been linked with weaker bones and

osteoporosis

Too high a ratio of oestrogen to testosterone is linked with faster progression of autoimmune diseases, which include rheumatoid arthritis and

type 1 diabetes

Oestrogen is also linked with the development of breast cancer. Some breast cancers can be treated with an antibody medication called trastuzumab (trade name: Herceptin) that blocks oestrogen receptors to help prevent the

cancer
growing.

Oestrogen and type 2 diabetes

Many research studies have investigated whether there is a clear link between oestrogen and insulin resistance.

The research has given differing conclusions with some researchers noting that higher than normal oestrogen appears to be linked with increased insulin resistance, yet other studies have shown that low oestrogen levels, are linked with greater insulin resistance and other effects of

metabolic syndrome, such as the development of fatty liver disease.

The research indicates that the balance achieved in nature is a finely balanced one. Significantly high or low levels of oestrogen could both be involved in the development of

insulin resistance
but researchers still need to gain a better understanding of the mechanics of the hormones before clear conclusions can be drawn.

Oestrogen in the environment

Concerns about high levels of oestrogen-like compounds in the environment are relatively commonly reported in the media and have been linked with increases in breast cancer in women, reduced fertility, a lower sperm count in men and undescended testicles in boys (cryptorchidism).

Phthalates are a group of chemicals which can behave like oestrogen if taken into the body and are commonly found in many items within our daily environment including:

• Plastics
• Food cans
• Beauty products
• Cleaning products
• Industrial chemicals
• Tap water
• Pesticides
• Soya and certain other legumes

The European Union has placed a ban on plastic toys containing more than 0.1% phthalates but other sources remain free of legislation regarding concentrations of phthalates.

The circulatory system is responsible for the delivery of blood, and therefore glucose in the blood, round the body.

The different complications of diabetes are a consequence of damage to

blood vessels

in different parts of the circulatory system.

What is the circulatory system?

The circulatory system is essentially the body infrastructure, providing the route ways for the blood to transport oxygen,

nutrients

and hormones to and from the cells and organs.

The heart plays a key role in the circulatory system, helping to pump blood around all the body.

Blood vessels range in size, from larger arteries into very small blood vessels called capillaries.

Capillaries feed into the veins which carry blood back to the heart.

The role of the circulatory system

The circulatory system performs a number of roles, including:

• Delivering oxygen and nutrients, including glucose, to the body’s cells
• Carrying carbon dioxide and waste products away from the cells
• Transporting hormones and therefore helping the body communicate with its organs
• Transport white blood cells to fight off infection
• Regulating body temperature

The circulatory system and diabetes

The circulatory system allows

blood glucose levels

to be regulated.

The hormone glucagon, carried in the blood, signals the liver to release glucose into the blood and the presence of insulin in the blood instructs the cells to take in glucose from the blood.

If blood glucose levels become too high for extended periods of time, damage can be sustained by the blood vessels.

If significant numbers of blood vessels are damaged, this can have a negative effect on the functioning of the body.

Circulatory complications in diabetes

Where damage is sustained to a significant number of blood vessels in a certain area of the body,

diabetic complications

will develop.

Neuropathy (nerve damage) results from damage to the blood vessels that feed the nerves. Damage to circulation and the nerves in the foot and legs can increase the risks of developing foot ulcers and could lead to amputation.

When blood vessels feeding organs are damaged, this can affect performance of the organ. When the kidneys are damaged in this way, they lose their effectiveness in filtering the blood. If the damage continues, it can lead to kidney failure.

Each of the complications in diabetes is related to damage to the circulatory system.

Cholesterol is an organic chemical substance that is essential for the function of the human body.

It forms part of the outer membrane that surrounds every cell in our bodies and is used to insulate nerve fibres and produce hormones, which carry chemical signals around the body.

However, too much cholesterol in the blood is dangerous as it increases the risk of

coronary heart disease

and disease of the arteries.

Lipoprotein levels

Lipoproteins are special molecules that carry or transport cholesterol around the body.

There are 3 main types (see below) and knowing how much of each is in your system, in addition to your cholesterol level, will give you a better idea of your personal risk of heart disease.

• 
  Low-density lipoprotein
  
  (LDL) – Often referred to as ‘bad cholesterol’, LDL carries cholesterol from the liver to the cells and can cause harmful build-up of cholesterol if there is excess supply.
• 
  High-density lipoprotein
  
  (HDL) – This so-called ‘good cholesterol’ removes cholesterol from the cells puts it back in the liver, where it’s either broken down or excreted.
• 
  Triglycerides
  
  – Your risk of cardiovascular disease is likely to be high if you have high levels of LDL cholesterol and trigylcerides, and low levels of HDL cholesterol.

Healthy cholesterol levels

In the UK, the average total cholesterol level for men is 5.5mmol/l and 5.6mmol/l for women, which is higher than the normal levels recommended by various health groups and organisations.

While total cholesterol readings are important, more attention should be paid to the balance of the different types of lipoproteins in your body as this has a greater influence on your cardiovascular risk.

Your overall risk of heart disease is based on a combination of factors, including age, gender, weight, smoking status, family history of heart disease, blood pressure and diabetes.

For example, a male smoker who has

high blood pressure

and/or suffers from diabetes will be at much greater risk of heart disease, and will therefore have a greater need to lower their cholesterol to a ‘healthy’ level.

The National Institute for Health and Clinical Excellence (NICE) and Department of Health recommend that cholesterol levels for UK adults should be:

• 
  Total cholesterol
  
  – less than 5.0mmol/l
• 
  LDL cholesterol
  
  – less than 3.0mmol/l

However, these national policy guidelines are being reviewed due to pressure from the Joint British Societies (a group of the main UK expert societies involved in cardiovascular disease), which has more stringent cholesterol limits for people who have, or are at risk of, coronary heart disease:

• 
  Total cholesterol
  
  – less than 4.0mmol/l
• 
  LDL cholesterol
  
  – less than 2.0mmol/l

Low cholesterol

Another controversial health topic in the UK is the efforts people who have little risk of heart disease should go to keep their cholesterol levels healthy – below 5mmol/l.

Some health experts believe the lower the cholesterol level, the better the chances are of preventing heart disease.

They are also strongly in favour of cholesterol-lowering drugs being offered over-the-counter to everyone, regardless of whether they have high cholesterol, as they appear to have minimal side-effects.

But others say there is research to prove that anti-cholesterol drugs,

such as statins

, can cause damage to muscles or the kidneys, and argue there is no evidence to suggest these drugs can benefit certain low-risk groups, such as women who don’t have a history of heart disease.

Treatments for high cholesterol

If you have high cholesterol, your GP will usually recommend:

• A healthy, balanced daily diet
• Regular exercise/physical activity

Eating healthily means including more fruit and vegetables in your meals, cutting down on red meat and replacing sugary snacks and drinks with healthy, natural alternatives.

The key is to not only cut down on fats, but also to replace saturated fats with unsaturated alternatives.

Some foods can help

to lower cholesterol levels and you may be advised to add these to your diet. These include:

• Garlic
• Soya
• Oats
• Corn and
• Selenium-enriched cereals

If your cholesterol level is still high after taking these steps, your GP may put you on a course of lipid-lowering medication.

The vascular system is made up of arteries and veins that carry oxygenated blood around the body and oxygen depleted blood to the lungs to remove carbon dioxide from the blood and replenish the oxygen.

People with diabetes commonly experience problems with their vascular system and charity Diabetes UK notes that diabetes is associated with a 5 times higher risk of developing cardiovascular disease.

What are the problems that can arise with the vascular system?

Arteriosclerosis

Arteriosclerosis is the thickening and stiffening of the arteries this means that they become less flexible and create resistance for the blood that is moving inside them.

Arteriosclerosis is thought to be caused by excess fat in the diet and high cholesterol. There are some schools of thought that have hypothesised that it is refined food and food rich in omega-6 fatty acids that leads to an inflammation of the endothelial cells that line the veins and arteries in the entire circulatory system.

It is thought that this inflammation means that excess fat and

cholesterol

consumed binds easier to the artery walls forming hard plaque structures which result in the stiffening and in some severe cases blockages of veins and arteries.

Coronary Heart Disease

Coronary heart disease results if the build up of plaque on the inside of the arteries and veins that supply oxygen to and take away carbon dioxide from

the heart

This causes the narrowing of the arteries and veins which means the heart isn’t receiving enough oxygen as it is needed and it is being poisoned by excess carbon dioxide.

High blood pressure

High blood pressure can result from the heart trying to pump blood through narrowed arteries, although is has also been attributed to a diet high in salt, obesity, alcoholism and high stress levels. Individuals with diabetes are reported to have

high blood pressure

if their blood pressure is 130/80 mmHg or higher.

Peripheral Arterial Disease (PAD)

Peripheral arterial disease is a vascular problem that arises if arteries are narrowed and subsequently restricted in areas of the body other than the heart, most frequently the legs. People who have PAD are 6 times more likely to also have coronary heart disease. PAD has also been highlighted as a cause of problems with the

kidneys

, spleen and the pancreas, particularly in individuals with diabetes.

Diabetes and vascular problems

Many people with diabetes also suffer from vascular system problems. There remains to be debate as to whether the pathology of type 2 diabetes is causing these problems or whether these problems may also arise as a result of the same physical

causes of diabetes

People with diabetes are at a greater risk of having high blood pressure, peripheral arterial disease, and coronary heart disease.

What can be done to reduce the risk of vascular problems

Diet

Having a balanced diet with high levels of omega-3 fatty acids reduces inflammation of the arteries in the body.

If the arteries are not inflamed there is less for bad cholesterol to bind with and subsequently veins and arteries remain supple and healthy, meaning that blood can flow through with little resistance.

Reducing your intake of omega 6 in the form of refined foods can also help reduce inflammation within the body.

Keeping

alcohol

intake to a minimum has been shown to help lower blood pressure and therefore put less pressure on your heart and the vascular system.

Lowering your intake of salt particularly table salt which is highly refined has been found to lower both the levels of bad cholesterol and reduce blood pressure.

Weight Management and Exercise

It has been found that having excess body fat puts extra strain on the vascular system. Regular cardiovascular exercise including brisk walking, jogging, swimming and cycling burns fat stores within the body reducing the pressure on the vascular system.

Additionally,

exercise

decreases the amounts of bad LDL cholesterol and improves the strength and health of the vascular system. Finally, cardiovascular exercise has been found to reduce stress levels, improve stamina and increase your metabolic activity rate all of which have been linked to enhanced vascular health.

Mindfulness Meditation

Mindfulness meditation is becoming aware of the present moment in a state of non-judgemental acceptance. It has been shown in numerous studies to have a direct impact on high blood pressure. Practicing mindfulness daily can reduce stress levels. If stress levels are under control, the fight or flight response does not occur to the same extent, therefore, blood pressure, blood glucose levels and rates of digestion all remain stable throughout the day.

• Read more about
  
  diabetes and mindfulness
  

When we think about digestion, one of the first organs to spring to mind is the stomach.

Diabetes can affect the stomach if the nerves controlling the stomach are damaged by

high blood glucose levels

The stomach may also be involved in bariatric surgery, used to tackle obesity.

The role of the stomach

The role of the stomach is to break down food from its chewed state into a form that can be passed through the

small intestine

Carbohydrates are broken down quickly and spend the least time in the stomach, followed by

proteins

and then

fats

The stomach can absorb certain nutrients, such as
Fergus
and drugs such as

aspirin

, although most of the absorption of nutrients takes place within the small intestine.

Gastroparesis

Gastroparesis

is a complication that affects the vagus nerve that controls the functioning of the stomach.

Gastroparesis causes delayed emptying of the stomach, which can make control of blood glucose levels more difficult, particularly for people taking

rapid acting insulin

at meal times.

Damage to the vagus nerve may occur if blood glucose levels are frequently too high for a number of years.

• Read more about
  
  diabetes and the nerves
  

Diabetes and stomach surgery

People with a large BMI may be offered, or may opt to have,

weight loss

surgery.

A number of bariatric surgery options involve the stomach.

Gastric band surgery effectively decreases the size of the stomach decreasing the size of meals that can be eaten.

Gastric bypass surgery is a more invasive procedure involving joining the top of the stomach with jejunum, therefore bypassing the lower part of the stomach and the duodenum.

• Read more about
  
  diabetes and bariatric surgery
  

Glycogen is a stored form of glucose. It is a large multi-branched polymer of glucose which is accumulated in response to

insulin

and broken down into glucose in response to

glucagon

Glycogen is mainly stored in the

liver

and the

muscles

and provides the

body

with a readily available source of energy if blood glucose levels decrease.

The role of glycogen

Energy can be stored by the body in different forms.

One form of stored energy is fat and glycogen is another. Fatty acids are more energy rich but glucose is the preferred energy source for the brain and glucose also can provide energy for cells in the absence of oxygen, for instance during anaerobic exercise.

Glycogen is therefore useful for providing a readily available source of glucose for the body.

Glycogen storage in diabetes

In a healthy body, the pancreas will respond to

higher levels of blood glucose

, such as in response to eating, by releasing insulin which will lower blood glucose levels by prompting the liver and muscles to take up glucose from the blood and store it as glycogen.

People with diabetes either do not make enough of their own insulin and/or their insulin does not work effectively enough.

As a result, the

pancreas

may not be able to respond effectively enough to rises in blood glucose.

Glycogen release

Glycogen may be released by the liver for a number of reasons, including:

• In response to
  
  stressful situations
  
• Upon waking (this process is known as the
  
  dawn phenomenon
  
  )
• In response to
  
  low blood sugar
  
• To aid digestion

In these situations, when the body feels extra glucose is needed in the blood, the pancreas will release the hormone glucagon which triggers the conversion of glycogen into glucose for release into the bloodstream.

Glycogen and exercise

Glycogen plays an important role in keeping our muscles fuelled for exercise. When we exercise, our muscles will take advantage of their stored glycogen. Glucose in our blood and glycogen stored in the liver can also be used to keep our muscles fuelled.

Once we complete our exercise session, our muscles will replenish their glycogen stores. The time it takes to fully replenish glycogen stores can depend on how hard and how long we exercise and can vary from a few hours to several days.

Exercise can therefore be a useful way to reduce blood glucose levels and can be particularly useful in people with

type 2 diabetes

Following exercise, the muscles will try to replenish their stores of glycogen and will therefore take in available glucose from the blood to do so, helping to lower blood glucose over this period.

• Read more on
  
  exercise and blood sugar levels
  

Visceral fat is body fat that is stored within the abdominal cavity and is therefore stored around a number of important internal organs such as the liver, pancreas and intestines.

Visceral fat is sometimes referred to as ‘active fat’ because research has shown that this type of fat plays a distinctive and potentially dangerous role affecting how our hormones function.

Storing higher amounts of visceral fat is associated with increased risks of a number of health problems including

type 2 diabetes

What types of fat do we store?

It is important to define the difference between visceral fat and subcutaneous fat. Subcutaneous fat is the fat that we store just under our skin. The fat we may be able to feel on our arms and legs is subcutaneous fat.

A growing belly can be the result of both types of fat. The fat we can feel just under the skin is subcutaneous fat but we may also be storing significant extra fat within our abdomen where our organs reside. This intra-abdominal fat is our visceral fat.

Visceral fat and insulin resistance

Carrying a high amount of visceral fat is known to be associated with insulin resistance, which can lead to

glucose intolerance

and type 2 diabetes. Researchers have found that visceral secretes a protein called retinol-binding protein 4 (RBP4) which has been shown to increase resistance to insulin.

• Read more on
  
  insulin resistance
  

What are the health risks associated with visceral fat?

All of us will have a certain amount of visceral fat but those of us with a larger quantity of visceral fat may be exposed to increased risks of the following health conditions.

• Type 2 diabetes
• 
  Heart disease
  
• Breast cancer
• 
  Colorectal cancer
  
• 
  Alzheimer’s disease
  

How can I tell if I have too much visceral fat?

The most certain way to tell if you are storing excess visceral fat is to undergo an MRI scan (Magnetic Resonance Imaging scan). However, MRI scans are not a cheap procedure and is therefore not recommended as a diagnosis tool for

diabetes risk

A relatively good indicator of visceral fat is to take a waistline measurement. Harvard University note around 10% of our total fat is likely to be stored as visceral fat, therefore if you are carrying higher amounts of body fat than is recommended, it is therefore more likely that you are also storing more visceral fat than is healthy.

Research has shown that the size of our belly is a relatively reliable indicator of the health risks linked to visceral fat.

Read our

guide to waist measurements

to see whether you may be at an increased risk of diabetes and other associated health issues.

Link to new ‘waist measurement and diabetes risk’ content

Why does the body store fat around the organs?

Scientists are looking to find answers as to why visceral fat is stored by the body. To date, it is known that stress has a significant effect on where fat is stored on our body. Researchers have found that the stress hormone, cortisol, significantly increases the storage of visceral fat.

How can I prevent fat being stored around my organs?

Harvard University states that diet and

exercise

have been to be more effective at reducing visceral fat than the fat around our hips and thighs. So don’t be too disheartened if diet and exercise is not reducing your clothing sizes as much as you’d like as your work could well be paying off through unseen benefits inside your body.

The following recommendations have been recognised as being helpful in reducing levels of visceral fat.

• Take part in regular exercise
• 
  Eat a healthy, balanced diet
  
• Ensure you regularly get a good night’s sleep
• 
  Reduce your levels of stress
  
• Limit alcohol intake
• Quit smoking

It should come as no surprise that these are the same

lifestyle recommendations

for reducing the risk and effect of

type 2 diabetes

Should I consider liposuction?

Liposuction only removes subcutaneous fat and therefore should not be undertaken as a procedure for improving health.

As with any form of surgery, liposuction carries the risk of infection which can negatively affect our health.

The Newcastle Diet and decreased visceral fat

A research study, published in 2011 by Newcastle University, showed that a very low calorie diet can significantly reduce levels of visceral fat in people with type 2 diabetes.

Along with the reduction in visceral fat, the study participants recorded improved blood glucose levels and a number of them were able to reduce or come off their diabetes medication.

Note that a very low calorie diet is regarded as an extreme diet and should only be undertaken with supervision from your doctor.

• Read more on the
  
  Newcastle diet
  

Bone marrow is found in the middle of longer bones in the body. Bone marrow is a soft spongy tissue which is able to produce red and

white blood cells

and platelets.

The red blood cells carry oxygen round our body, white blood cells help to fight infection and platelets help the blood to clot when we suffer cuts or wounds.

Location of bone marrow

Bone marrow is mainly found in the following bones:

• The sternum (breast bone)
• The pelvis
• The femur (upper leg bone)
• The humerus (upper arm)

The bone marrow, within these bones, is fed by blood vessels which deliver oxygen and enable the marrow to release new blood cells into the bloodstream.

Bone marrow’s role in the immune system

Bone marrow plays an important role in the
Fergus
as it produces and releases the white blood cells. Some of these white blood cells will develop the properties of mature white blood cells in the thymus, an organ found in front of the heart, which will enable these cells to identify and attack infectious cells such as bacteria and viruses.

Bone marrow transplantation and type 1 diabetes

Type 1 diabetes

is an autoimmune disease in which a form of white blood cells, T lymphocytes, attacks the beta cells in the pancreas which produce insulin.

Bone marrow transplantation has had success in helping people with type 1 diabetes to come off insulin for up to a number of years.

Procedures carried out in Brazil allowed around half of 23 bone marrow transplant recipients to go injection free for over 3 years whilst around a third needed only intermittent

insulin injections

The

NHS

notes that a bone marrow transplant is a complicated procedure that carries significant risks.

Preparation before a bone marrow transplant involves radiotherapy to remove the existing characteristics of the immune system and complications may develop as a result of the transplant.

The brain is a hugely important organ which helps to be aware of, understand and interact with our surroundings and others.

As with many of our organs, the brain is susceptible to damage as a result of diabetes.

What are the parts of the brain comprised of?

The brain is a very complex orga, housed in our skull, which is made up of a number of different areas:

• 
  Frontal lobe:
  
  responsible for thought, learning and behaviour
• 
  Parietal lobe:
  
  responsible for processing sensory experiences and understanding
• 
  Temporal lobe:
  
  responsible for memory and certain emotions
• 
  Occipital lobe:
  
  responsible for processing visual information
• 
  Cerebellum:
  
  responsible for coordination of movement, balance and some reflex actions
• 
  Brain stem:
  
  responsible for regulating breathing, heart rate, blood pressure and body temperature

The skull helps to protect us from external blows which could damage brain cells.

The blood-brain barrier is a membrane which protects the brain from any harmful pathogens that may be present in the blood.

The brain requires nutrients, however, such as oxygen and glucose, so the blood-brain plays an important role in enabling good nutrients in and keeping harmful cells away.

Role of the brain

The brain helps us to makes sense of what we see, hear, smell, taste and touch, and helps us to think, learn and understand.

What’s more, our brains allow us to develop and exert our personality.

Cognitive function

Cognitive function is the process of perceiving or comprehending ideas. Research studies indicate that type 1 diabetes and type 2 diabetes are associated with cognitive impairment.

This doesn’t mean that everyone with diabetes will have reduced cognitive ability but statistically, the risk of cognitive impairment is higher.

A meta-analysis of studies carried out in the Netherlands showed that

type 1 diabetes

is associated with slower mental speed and reduced mental flexibility but not learning or memory. No clear link was found between cognitive ability and control or duration of type 1 diabetes.

However, presence of

neuropathy

and

retinopathy

was associated with impaired cognitive ability.


^[54]

In

type 2 diabetes

, memory deficiencies are more common, along with reduced mental speed and executive function (the ability to organise and manage tasks).

Better diabetes control and fewer complications are linked with lower cognitive impairment.


^[55]

Hypoglycemia and cognitive dysfunction

The impact of

hypoglycemia

on cognitive dysfunction has been studied but the Dutch meta-analysis found no clear association between long term cognitive impairment and episodes of

severe hypoglycemia

^[54]

In the short term, such as during or straight after a period of hypoglycemia, low blood glucose can have a pronounced effect on our ability to carry out tasks.

For this reason, people with low blood glucose levels should not carry out potentially dangerous activities such as driving or operating certain machinery.

Diabetes and Alzheimer’s Disease

Alzheimer’s is caused by damage to the nerves, brain cells and neurotransmitters in the outer layer of the brain, cerebral cortex.

The fact that outer layer of the brain is affected first draws some parallels to neuropathy which initially affects the extremities such as the hands and the feet.

Alzheimer’s has in fact been dubbed as ‘diabetes of the brain’ as a higher risk of

Alzheimer’s

has been found in people with insulin resistance.

Alzheimer’s can be treated with medications such as:

• Donepezil
• Galantamine
• Rivastigmine

These medications help to slow down deterioration of the brain.

The NHS encourages people with Alzheimer’s to exercise their brain and cognitive stimulation programmes involving problem solving may be prescribed.

Glucose is the key source of energy for the human body. Supply of this vital nutrient is carried through the bloodstream to many of the body’s cells.

The liver produces, stores and releases glucose depending on the body’s need for glucose, a monosaccharide.

This is primarily indicated by the hormones insulin – the main regulator of sugar in the blood – and glucagon.

In fact, the liver acts as the body’s glucose reservoir and helps to keep your circulating blood sugar levels and other body fuels steady and constant.

How the liver regulates blood glucose

During absorption and digestion, the

carbohydrates

in the food you eat are reduced to their simplest form, glucose.

Excess glucose is then removed from the blood, with the majority of it being converted into glycoge, the storage form of glucose, by the liver’s hepatic cells via a process called glycogenesis.

Glycogenolysis

When blood glucose concentration declines, the liver initiates

glycogenolysis

The hepatic cells reconvert their glycogen stores into glucose, and continually release them into the blood until levels approach normal range.

However, when

blood glucose levels

fall during a long fast, the body’s glycogen stores dwindle and additional sources of blood sugar are required.

To help make up this shortfall, the liver, along with the kidneys, uses amino acids, lactic acid and glycerol to produce glucose.

This process is known as gluconeogenesis.

The liver may also convert other sugars such as sucrose, fructose, and galactose into glucose if your body’s glucose needs not being met by your diet.

Ketones

Ketones are alternative fuels that are produced by the liver from fats when sugar is in short supply.

When your body’s glycogen storage runs low, the body starts conserving the sugar supplies for the organs that always require sugar, including the brain, red blood cells and parts of the kidney. To supplement the limited sugar supply, the liver makes ketones in a process called

ketogenesis

Ketones

are burned as fuel by muscle and other organs in the body, and the sugar is saved for the organs that need it.

Like glucose, the production of ketones in the liver is controlled by the hormone glucagon.

Dawn Phenomenon and Rebound Hyperglycemia

Blood glucose levels rise sharply in the early morning due to the release of certain hormones in the middle of the night.

These counter-regulatory hormones, which include glucagon, growth hormone, epinephrine and cortisol, increase the level of blood glucose by signalling the liver to release more glucose and by hindering glucose utilisation throughout the body.

Overnight, the surge in the amount of growth hormone and cortisol released by the body effectively increases glucose production in the liver to prepare the body for activity during the day.

For individuals without diabetes, these processes are balanced out by increased

insulin

secretion by the pancreas, which keeps blood glucose levels relatively stable.

But in people with

type 1 diabetes

, whose bodies are unable to produce insulin, and

type 2 diabetes

, where the liver’s response to insulin may not be sufficient to stop glucose production, changes in glucose metabolism during sleep can have a big impact on morning blood glucose levels.

In addition to the

dawn phenomenon

, there is another process that can cause high blood sugar in the early hours of the day.

Rebound hyperglycemia

Rebound hyperglycemia, the body’s rebound from low blood glucose levels at night, is also caused by the release of counter-regulatory hormones and represents the body’s defence mechanism against low blood sugar.

The only way to tell the two phenomena apart is to check your blood glucose level in the middle of the night (around 3am) – a high level indicates you are experiencing the dawn phenomeno, while a low reading suggests rebound hyperglycemia.

Another name for rebound hyperglycemia is the

Somogyi effect