Next time you make yourself a berry smoothie, you might want to skip the banana.
Sure, this fruit is full of potassium and makes a deliciously thick and creamy drink, but according to researchers at the University of California Davis (UCD), there’s something in bananas that might surpass the antioxidants found in the berries .
The antioxidants in this case are called flavonols. They are found in plant foods like berries, tea, cocoa, apples, pears and peaches, and many of us don’t get enough of them in our diet.
When a person consumes foods rich in flavonols, the compounds are quickly absorbed into the bloodstream, where they are processed.
The resulting metabolites have been linked to benefits such as improved cardiovascular health and cognitive function.
But new experiments suggest that when a single banana is added to a berry mix, these metabolites are not as abundant.
In a controlled, blinded study, UCD researchers gave a small group of eight participants either a flavonol-rich berry smoothie or a simple flavonol capsule. Tests later showed increased levels of flavonol metabolites in their blood.
However, when volunteers consumed a banana-berry smoothie, the metabolites in their blood were 84 percent lower than after a pure dose of flavonol.
“We were really surprised to see how quickly adding just one banana decreased the level of flavonols in the smoothie and the levels of flavanols absorbed in the body,” says nutritionist Javier Ottaviani from UCD.
“This highlights how food preparation and combinations can affect the absorption of dietary compounds from foods.”
The reason bananas have this effect on flavonols likely has to do with an enzyme. called polyphenol oxidase (PPO), which is involved in the oxidation process that causes bananas to turn brown when peeled.
Exposed to banana, the antioxidants “mop up” the PPOs, preventing them from doing all that good work inside our bodies.
When a high-PPO banana-berry smoothie was left at room temperature in experiments, researchers found that it contained fewer flavonols than a purely berry smoothie after sitting for an hour.
However, when the PPO in bananas was inhibited, the flavonols persisted.
This suggests that PPO may limit the availability of flavonols before they enter the human body.
To see if bananas can also “disarm” antioxidants in the stomach, researchers asked 11 participants to consume two separate drinks at the same time: a banana drink and a berry drink.
This prevented the PPO from interacting with the flavonols before ingestion. Even so, the researchers found that flavonol metabolites weren’t as present in the participants’ blood after drinking the two smoothies separately, compared to when they didn’t drink the banana drink.
The research was conducted only with a small number of male participants. However, the UCD researchers believe their initial findings deserve further scientific attention.
“(T)his study highlights that it is necessary to consider not only the types of fruits and vegetables and plant-based products to be recommended to increase their consumption, but also the way in which they are prepared, stored and consumed in the part of a regular meal. in order to maximize their potential to support health”, conclude the researchers.
The study was published in Power and function.
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