Hold off on the banana.
Sure. It makes the drink thick. Creamy even. Loaded with potassium, which is fine. But here’s the catch: that sweet slice might be quietly stealing the nutrients you paid for.
Research from UC Davis suggests bananas can overpower the antioxidants in berries. Specifically, the good stuff called flavonols.
These compounds live in tea, apples, cocoa, and berries. We usually don’t get enough. When eaten alone, flavonols hit the bloodstream fast, turning into metabolites that help your heart and brain. Win-win.
But mix in one banana?
The benefits crash.
In a 2023 study, volunteers drank berry smoothies with and without fruit. The results were stark. With just a single banana, blood levels of beneficial flavonol metabolites dropped by 84% compared to taking a pure flavonol dose.
“We were really surprised to see how quickly… [the banana] decreased the level of flavonol”
— Javier Ottaviani, nutritionist at UC Davis
Why? An enzyme named polyphenol oxidase (PPO). It’s the same chemical reaction that turns banana peels brown when you leave them on the counter. The antioxidants in berries “mop up” the PPO. They burn themselves out fighting the enzyme before they can help your body.
You might think separating them saves you. Did the researchers try that? They gave people a berry drink and a banana drink at the same time to prevent PPO contact before ingestion. Still. The flavonol levels in the blood remained low. The stomach doesn’t seem to be safe either.
Is this the end of the banana?
Maybe not. But the study involved only eight men, and later, eleven more. It’s a small group. The researchers aren’t telling you to ban the fruit. Just be aware.
Food preparation matters. Storage matters. What you combine matters. If you want those berry antioxidants to do their job, you have to look closer at how you build your meal.
The data is just a beginning. But it’s enough to make you pause next time the blender runs.
What else in your routine might be canceling out the good stuff?
