Adding a banana to a smoothie impacts how much nutrition from other foods your body absorbs, new research has shown.
The study authors say their findings highlights how food combinations can affect the absorption of dietary compounds in foods.
Flavanols are bioactive compounds which have been linked to improved heart and brain health and can be found in foods including apples, pears, blueberries, blackberries and grapes.
However, the presence of polyphenol oxidase (PPO), an enzyme found naturally in many fruits and vegetables, affects the body’s ability to take in flavanols.
Some fruit turns brown when it is cut open due to PPO reacting with oxygen. Researchers set out to investigate if this same enzyme activity impacts the extent to which flavanols are absorbed by the body when fruits are blended together to make smoothies.
Lead author Javier Ottaviani, director of the Core Laboratory of Mars Edge, part of Mars, Inc., and adjunct researcher at the University of California, Davis, explained: “We sought to understand, on a very practical level, how a common food and food preparation like a banana-based smoothie could affect the availability of flavanols to be absorbed after intake.”
The study participants drank two different smoothies, one made with banana, a fruit with a high PPO activity, and another smoothie made with mixed berries, which have low PPO activity, and participants also took a flavanol capsule to compare. Flavanol levels were measured with blood and urine samples.
Researchers were struck by the results – those who had the banana smoothie had 84% lower flavanol levels compared to those who took the control capsule.
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Ottaviani said: “We were really surprised to see how quickly adding a single banana decreased the level of flavanols in the smoothie and the levels of flavanol absorbed in the body.
“This highlights how food preparation and combinations can affect the absorption of dietary compounds in foods.”
The team say bananas are still a nutritionally valuable fruit to eat but advised not to mix them, or other foods with high PPO activity, with flavanol-heavy foods like berries and grapes.
Ottaviani added: “This is certainly an area that deserves more attention in the field of polyphenols and bioactive compounds in general.”
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