Banana And Blueberry Smoothie: It’s A Bad Food Combo!

If you’re making smoothies, do not combine bananas with flavanol-rich fruits such as berries, grapes and cocoa.

Smoothies are a healthy breakfast option, and an easy way to increase your consumption of fruits and vegetables. But knowing the right combo is important to get the most health benefits from smoothies. Blending certain ingredients in smoothies can affect the abortion of nutrients by the body. For example, a banana and blueberry smoothie may be a bad combination. According to a new study, adding a banana to fruit smoothies can decrease the level of flavanols in the smoothie as well as its absorption in the body.

The study by researchers at the University of California, Davis, found that polyphenol oxidase (PPO), an enzyme found in banana and many other fruits and vegetables, affects the levels of flavanols in smoothies to be absorbed by the body. Flavanols are bioactive compounds naturally found in apples, pears, blueberries, blackberries, grapes and cocoa (common smoothie ingredients) and are known to be beneficial for the heart and cognitive health.

Polyphenol oxidase is also found in apples and berries, but in low quantity. After you slice an apple or peel a banana, the fruit will quickly turn brown. This occurs when polyphenol oxidase present in those foods is exposed to air.

Should we avoid banana-based smoothies?

The researchers wanted to know how drinking smoothies made with different PPO-containing fruits impacted the amount of flavanols available for absorption by the body. They found that participants who drank the banana smoothie, which has naturally high PPO activity, had 84 per cent lower levels of flavanols in their body compared to the those who had a smoothie made with mixed berries (which have naturally low PPO activity). The participants also took a flavanol capsule along with the smoothie samples.

Lead author Javier Ottaviani stated that adding a single banana can quickly decrease the level of flavanols in the smoothie and the levels of flavanol absorbed in the body. This shows that the combination of certain ingredients can affect the absorption of dietary compounds in foods.

If you like smoothies with bananas, do not combine it with flavanol-rich fruits such as berries, grapes and cocoa. The same goes for other high PPO activity fruits and vegetables such as beet greens, the researchers said.

This means blending fruits with high PPO activity (like banana) with flavanol-rich fruits (berries, grapes and cocoa) in smoothies may be a bad combo.

How to boost levels of flavanols in the body?

The Academy of Nutrition and Dietetics recommends consuming 400 to 600 milligrams of flavanols daily for cardiometabolic health. To increase intake of flavanols, Ottaviani suggests preparing smoothies by combining flavanol-rich fruits like berries with ingredients like pineapple, oranges, mango or yogurt that also have a low PPO activity.

Tea is also a good source of flavanols, but how much flavanols would be available for absorption depends on how it is prepared, Ottaviani added.