Are Bananas bad for you?

Bananas: Good or bad?

By Gabrielle Finora and the Team at LCWNS 

If you are like me and have scrolled through Instagram or TikTok recently, you may have heard that you should avoid bananas. Even I was surprised to see that one of my favorite fruits is under attack on social media. 

The claims are rooted in a recent study from the University of Califonia, Davis, studying the effects of an enzyme found in bananas called polyphenol oxidase, or PPO. You can see this enzyme at work when you leave a cut or bruised fruit or vegetable out on the counter, and it browns (like in bananas). Many fruits and vegetables have PPO, such as apples, pears, peaches, potatoes, lettuce, and mushrooms This study was about one of PPO’s unique properties. It is a known inhibitor of flavonoids. 

Flavonoids are bioactive molecules that are good for heart and brain health, acting as antioxidants and removing free radicals in the body. They are found naturally in blackberries, blueberries, cocoa, kale, and others. Unsurprisingly, these are very common (and delicious) smoothie ingredients. 

With bananas being a popular addition to smoothies, we need to understand how a high concentration of a naturally occurring enzyme can affect the absorption of nutrients. This study performed by UCD measured the subjects’ blood and urine flavonoid levels after drinking a smoothie with either bananas or berries. The researchers reported that the group that had the smoothies with bananas had decreased levels of flavonoids due to the high PPO activity in bananas.

This study is a great starting point to investigate how food preparation can change its nutritional composition. But what does that mean for us? Should we stop eating bananas?

The short answer is no. Bananas are still a great source of potassium, fiber, and starch to feed your gut microbiome. “Poor bananas are always in the spotlight in the nutrition field: ‘too many carbs,’ ‘too much sugar,’ ‘high-calorie fruit,’ etc. Now they will say they also have no nutrients,” says Paige Mandel, MS, RD, CDN. “It is important to extrapolate the real message – bananas are NOT bad, and having bananas in your smoothie is NOT harmful to your health.” 

If you like to add bananas to your smoothies, add them! We eat for more reasons than to get nutrients. Still, you may not receive the most nutrition out of your smoothies. “If your main source of fruits and vegetables in your diet comes from smoothies or other blended foods, then you are losing a significant source of nutrition by blending these foods together,” recommends Rebecca Jaspan, MPH, RD, CDCES, CEDS.  

In the end, research provides us with new information. Just like all news, however, it matters who interprets it. Bananas have so many great nutritional qualities that cannot be overlooked, like their high amounts of potassium. So, if you love bananas in your smoothies, feel free to keep doing what you love. Just add another serving of fruit on the side for your antioxidants.

Looking for something new to try? Check out these delicious smoothie recipes for an antioxidant boost!

Blueberry and Spinach Brain Boosting Smoothie 

Antioxidant Smoothie with Dragon Fruit, Blueberries, Strawberries, Pineapple Juice, and Beets

Antioxidant Berry Smoothie




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