Here’s why you might want to skip adding bananas to your smoothies
Bananas are great. They're a fantastic addition to any diet, being a good source of potassium, fibre and natural energy. Not only that, but they are a thick fruit, not like a watery orange. So, it seems like a banana would be the perfect ingredient to any smoothie. But research says that if you’re adding berries – it's better to stay away from a banana. Why? (Picture: Getty)
A joint study between the University of California, Davis and the University of Reading, found that blending together berries and bananas can influence whether you are getting a nutritional boost. The study looked into how levels of polyphenol oxidase, an enzyme found in many fruits and vegetables, altered the levels of flavanols in food which is absorbed by the body (Picture: Getty)
Flavanols are important, and are a group of bioactive compounds which help heart and cognitive health. They occur naturally in apples, pears, blueberries, grapes and cocoa. But the researchers found that adding banana to a berry smoothie reduces the levels of flavanol by 84% (Picture: Getty)
Gunter Kuhnle, Professor of Nutrition and Food Science at the University of Reading and co-investigator of the study said: ‘We still know very little about food-food and food-nutrient interactions, even though they can have a huge impact on the uptake of nutrients and bioactives like flavanols. Here, we could show that the uptake of flavanols can vary by more than five-fold depending on the combination of foods. Bananas are a great ingredient in smoothies to provide a nicer texture - but they can affect flavanol uptake’ (Picture: Getty)
The study, which was published in the Royal Society of Chemistry’s journal Food and Function, saw participants drink a smoothie made with banana and berries, one with mixed berries, or a flavanol capsule. Then, the researchers took blood and urine samples to measure the flavanols which were present in the participant’s body (Picture: Getty)
They found that levels of flavanol were reduced both in the smoothie and absorbed by the body. Professor Kuhnle said: ‘Smoothies are a popular way to pack fruit and vegetables into our morning routines. We know from previous studies that flavanols can be broken down by polyphenol oxidase. The extent of the effect from adding a single banana was still very surprising – it had enough polyphenol oxidase to destroy the vast majority of flavanols found in the berries. Bananas may be ruled out of the morning smoothie if you want to boost your flavanol intake, but on their own, they are still great fruits and can play an important role in many healthy diets’ (Picture: Getty)
The recommended intake of flavanols per day is 400-600 milligrams, according to the Academy of Nutrition and Dietetics in the USA. So, what do you do if you love smoothies, but still want to gain all the nutrients your body needs to function? Professor Kuhnle recommends: ‘If you want to boost your flavanol intake with a smoothie, you should combine flavanol-rich fruits like berries with foods that have a low polyphenol oxidase activity like pineapple, oranges, mango or yoghurt’ (Picture: Getty)
