Researchers from the University of California-Davis found that adding this tropical fruit may interfere with the absorption of powerful compounds known as flavanols, which are linked to brain and heart health. "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," the study's lead author, Dr Javier Ottaviani, said in a news release. What are flavanols? Flavanols - also known as flavan-3-ols or catechins- are a type of compound found in many fruits, vegetables, tea, and cocoa. They are powerful antioxidants that help protect cells from damage and have potential benefits for heart health, brain function, and reducing inflammation. According to researchers, bananas are a powerhouse of flavanols along with an enzyme known as polyphenol oxidase or PPO. In experiments, banana-based smoothies dramatically cut flavanol absorption as compared to berry-based ones. The study, published in the journal Food and Function, says that flavanols protect against oxidative stress and inflammation, which are linked to various chronic diseases. They also lower blood pressure, which reduces the risk of deadly heart diseases. Flavanols are also beneficial in improving memory, focus, and cognitive function, especially in the frontal cortex. It also has a major role in protecting against cancer, diabetes, and other diseases. How do bananas lower the effect of flavanols? According to researchers, polyphenol oxidase, which causes the bananas to quickly turn brown when peeled, affects how much of these beneficial flavanols the body absorbs when the fruits are combined in a smoothie. "We sought to understand, on a very practical level, how common food and food preparation, like a banana-based smoothie, could affect the availability of flavanols to be absorbed after intake," Ottaviani said. The study was conducted with participants enjoying two different smoothies for breakfast - one made with a banana, with a high PPO activity, and the other made with mixed berries, which have low PPO. Participants also took a flavanol capsule for comparison. Later, flavanol levels in their blood and urine were measured. The results clearly showed that those who had the banana smoothie had 84 per cent lower flavanol levels than those who swallowed the control capsule. According to the Academy of Nutrition and Dietetics, you must consume 400 to 600 milligrams of flavanols daily for cardiometabolic health. However, if you are shooting to reach that level, make sure to go heavy on the berries when your smoothie is made of ingredients like pineapple, oranges, mango, or yogurt, and skip the banana! What healthy ingredients can you add to smoothies? To make your smoothies healthy, you can add nutritious superfoods like:

• Tofu
• Strawberries
• Spinach
• Raspberries
• Avocado
• Coconut water
• Tomatoes
• Celery
• Kale
• Mango
• Papaya
• Pineapple