Every day during the summer months, I have a post workout smoothie. 1 Cup of Juice, 1 Banana, 1 Cup Frozen Blueberries, 1 Cup Frozen Spinach, ½ Cup yogurt, & 2 Tbsp peanut butter. This smoothie has tons of carbs to refill my energy stores, protein to start muscle synthesis, vitamins and minerals to improve bodily function, and what I thought were antioxidants from the blueberries. Then, my fiance sent me an instagram post with an influencer citing a recent study that bananas destroy all the antioxidants from blueberries. The influencer was right. According to the study, bananas contain a high amount of an enzyme that destroys the antioxidants from blueberries.
This sucks since bananas are so delicious in smoothies. I will not drink a smoothie without it. Normally, avocados could be a substitute because of their similar thickening properties but they are also high in the same enzyme that breaks down antioxidants. Fortunately, for all of us this situation is a bit more complicated than bananas are “bad”.
In one cup of blueberries you are getting 4g of fiber, 2% iron, 2% potassium, 15% vit C, 20% Manganese, and 25% Vit K. As for the antioxidant content in one cup of wild blueberries you could get upwards of 13,000 antioxidants and for cultivated blueberries 9,000.
Blueberries are high in a compound called polyphenols which acts like an antioxidant. Polyphenols have shown to help with lipid profiles, blood pressure, insulin resistance, systemic inflammation, and cardiovascular health. Polyphenols have made the news before but by a different name. Remember when everyone started drinking red wine? That was because a study showed a polyphenol called Resveratrol had heart protective effects. Unfortunately, the amount you would need to drink in order to get a therapeutic dose would be too much for it to be worth it.
Now back to bananas. Bananas have an enzyme called polyphenol oxidase which “destroys” polyphenols or antioxidants. If you were making a fruit smoothie specifically for its antioxidants then according to the study you should not put bananas in it. In the grand scheme of things, adding a banana to your smoothie is not really a big deal.
First, a smoothie is just one meal in your day and you should be including foods that are nutrient dense and colorful at every meal. This will ensure you get plenty of vitamins, minerals, and antioxidants throughout the day. If you drink coffee then you are getting antioxidants which is actually the leading food or beverage in the American diet contributing antioxidants.
Second, the smoothie is still providing tons of other nutritional value. Taste is the most important factor in determining the adherence to any diet. If the smoothie loses the banana, in my opinion, it sucks. The consistency of getting the other nutrients on a daily basis outweighs the loss of the antioxidants. Especially if you are having antioxidants at other meals, which you should.
Lastly, what does the rest of your life look like? Are you worried about losing antioxidants because of “bad” bananas when instead you should be focusing on getting more sleep, exercising, moving consistently throughout the day, having meaningful relationships, and challenging yourself mentally?
According to the study, you should not put bananas with blueberries because it destroys the antioxidants. There is a hierarchy, or pyramid, of things to focus on to improve your health. Sleep is at the base of the pyramid while things like nutrient combinations (bananas and blueberries), nutrient timing, and supplementation are way at the top of the pyramid. Focus on the basics. Once you master the basics then you can worry about “bad” bananas hurting your cute blueberries.