Here's why you might not want to put those bananas in your smoothie

Flavanols have been tied to many positive health benefits, such as improved brain function and decreased risk of cardiovascular disease.

A recent study by the University of California, Davis published in the Royal Society of Chemistry’s journal Food and Function looked at how smoothie consumption can impact flavanol levels.

The study found when a banana is blended into a smoothie with berries,  it could reduce flavanol level in the body.  UC Davis researchers said those who drank the banana smoothie had 84% lower levels of flavanols in their body compared to those who had smoothies made with just mixed berries. The researchers noted that foods like apples, pears, blueberries, blackberries, grapes and cocoa are considered great sources of flavanols.

"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," said lead author Javier Ottaviani, an adjunct researcher with the UC Davis department of nutrition. "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."

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Ottaviani stressed that bananas are still healthy and should be consumed, including in smoothies. But he recommends not combining bananas with berries as the bananas can negate the flavanols in the mixture.