Frustrated!

[Daibell]

I remain astounded by all these ignorant dieticians trotting out the mantra they have been told at training. A professional is supposed to acquire knowledge, analyse it and proffer intelligent knowledgeable solutions as output. Any fool can just repeat what they have been told on a training course. Well done for sticking to what you know is the right diet. I'd like to see the data that says the brain needs 130gm carbs (glucose?) per day and if it does it can get that from the fat and protein you eat.

 

[NoCrbs4Me]

I remain astounded by all these ignorant dieticians trotting out the mantra they have been told at training. A professional is supposed to acquire knowledge, analyse it and proffer intelligent knowledgeable solutions as output. Any fool can just repeat what they have been told on a training course. Well done for sticking to what you know is the right diet. I'd like to see the data that says the brain needs 130gm carbs (glucose?) per day and if it does it can get that from the fat and protein you eat.

From the Canadian Diabetes Association:
"The current recommended minimum intake for CHO is not less than 130 g/day, to provide glucose to the brain (32)."

The reference is:
32. Institute of Medicine, Food and Nutrition Board. Dietary Reference Intakes for
Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino
Acids. Washington, DC: National Academies Press; 2002.

Here's a link to the referenced report: http://www.nal.usda.gov/fnic/DRI/DRI_Energy/energy_full_report.pdf

From the 2002 report: "The Recommended Dietary Allowance (RDA) for carbohydrate is set at 130 g/d for adults and children."

There's an entire chapter on carbs: "6. Dietary Carbohydrates: Sugars and Starches".

On page 277 there's an interesting section called "EVIDENCE CONSIDERED FOR ESTIMATING THE AVERAGE REQUIREMENT FOR CARBOHYDRATE".

From page 277: "The requirement for glucose has been reported to be approximately 110 to 140 g/d in adults (Cahill et al., 1968). Nevertheless, even the brain can adapt to a carbohydrate-free, energy-sufficient diet, or to starvation, by utilizing ketoacids for part of its fuel requirements."

 

[tim2000s]

Unfortunately this is where the start of the "lies" arises. The Cahill report has been taken as gospel by many groups and modified to state that you must eat that amount of carbs per day, which has since been proven inaccurate. I'll try and dig out the research that backs this up.

 

[Daibell]

From the Canadian Diabetes Association:
"The current recommended minimum intake for CHO is not less than 130 g/day, to provide glucose to the brain (32)."

The reference is:
32. Institute of Medicine, Food and Nutrition Board. Dietary Reference Intakes for
Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino
Acids. Washington, DC: National Academies Press; 2002.

Here's a link to the referenced report: http://www.nal.usda.gov/fnic/DRI/DRI_Energy/energy_full_report.pdf

From the 2002 report: "The Recommended Dietary Allowance (RDA) for carbohydrate is set at 130 g/d for adults and children."

There's an entire chapter on carbs: "6. Dietary Carbohydrates: Sugars and Starches".

On page 277 there's an interesting section called "EVIDENCE CONSIDERED FOR ESTIMATING THE AVERAGE REQUIREMENT FOR CARBOHYDRATE".

From page 277: "The requirement for glucose has been reported to be approximately 110 to 140 g/d in adults (Cahill et al., 1968). Nevertheless, even the brain can adapt to a carbohydrate-free, energy-sufficient diet, or to starvation, by utilizing ketoacids for part of its fuel requirements."

Thanks for these links; interesting

 

[tim2000s]

So, this paper describes an estimate of the glucose requirement for the brain to run exclusively on Glucose: http://books.nap.edu/openbook.php?record_id=10490&page=277

However, the key point of the paper in reference to this discussion is that it states that the brain runs perfectly efficiently on ketone bodies, glycerol, and protein-derived glucose.

This paper published in the FASEB Journal in October 2008 details research into the brain's use of Lactate as a primary energy source during strenuous exercise when muscles require glucose. http://www.fasebj.org/content/22/10/3443.full

@NoCrbs4Me, Page 277 onwards of your originally referenced document fromdiscusses estimating carbohydrate requirements. It includes the statement:

In individuals fully adapted to starvation [or low carbohydrate diets], ketoacid oxidation can account for approximately 80 percent of the brain’s energy requirements (Cahill et al., 1973). Thus, only 22 to 28 g/d of glucose are required to fuel the brain. This is similar to the total glucose oxidation rate integrated over 24 hours determined by isotope-dilution studies in these starving individuals (Carlson et al., 1994; Owen et al., 1998).

Or in other words, even this study mentions that the 130g of glucose isn't actually necessary for brain functioning and that less than 30g will suffice.

When you put these (and other studies that can be found with a bit of googling), it becomes clear that:

a) The brain does not operate solely on a glucose metabolism
b) The brain does not require 130g of glucose per day to operate
c) The value of 130g is an estimate derived from a number of assumptions, the keymost being that the brain operates solely on a glucose metabolism
d) The majority of papers discussing the brain and glucose metabolism describe multiple sources from which the brain can obtain glucose including protein and fat derived glucose which means that the "130g of glucose required from an external source" is a myth.