Why Adding Bananas To Your Smoothies Might Make Them Less Nutritious

It's easy to go bananas for bananas — they're cheap, available year-round, and boast an irresistibly-creamy texture. They're also a popular smoothie add-in. You showcase the flavorful yellow fruit as the star of the beverage or blend them frozen to thicken smoothies in a pinch. Unfortunately, bananas might actually have a negative impact on your drink's nutritional value, according to a 2023 study published in the journal Food and Function.

The study found that bananas can interfere with the absorption of certain beneficial compounds when paired with other fruits. Notably, when combined with flavanol-rich foods like berries (as in our strawberry banana oatmeal smoothie), the circulation of flavan-3-ols are significantly reduced in the body. Flavanols are naturally-occurring compounds found in many fruits, and they have some pretty valuable health benefits. They're antioxidants, anti-inflammatory, and support your heart health, just to name a few. So, it's not ideal that their effects are negated when bananas are in the mix.

But why does this happen? Well, when bananas come into contact with air, they release an enzyme called polyphenol oxidase (PPO). This chemical is responsible for bananas (plus some other fruits, like apples and pears) turning brown when cut open. It might seem like a superficial detail, but the enzyme impacts much more than just the fruit's appearance. The study found that PPO degrades flavanol compounds, reducing how much your body absorbs in the end.

If your post-workout regiment calls for a nutritiously-dense fruit smoothie, or you're looking to extract the most health benefits from your homemade drinks, it's alright if you want to nix bananas (or other PPO-rich fruits) from your next smoothie. Luckily, there are plenty of ways to substitute bananas in your smoothie. For example, you could use silken tofu, which provides protein and a creamy texture. Or, you could try adding in a handful of dates, which we consider to be the secret to nutritiously sweetened smoothies. They're rich in flavor, with a luxurious, caramel-like taste that we're sure you'll love.

All that being said, the study does come with a couple of limitations. For one, the researchers only observed male participants. While it's unclear if the tests would yield very different results in women, it does present a void in the research. In addition, the researchers added flavan-3-ols to the participants' smoothies in hopes of creating a standardized level of bioactivity across each drink. The researchers believe that the extra flavanols might interact differently with the PPO than the naturally-occurring compounds in fruit.

Smoothie fans might also want to consider the possibility of nutritional trade-offs. Even with a potential degradation of flavanols, bananas are still a great source of potassium, fiber, and vitamin C, alongside a plethora of other nutrients. Not to mention, if you're simply bananas for the taste, there's no reason to not enjoy your favorite smoothie flavors.