Adding a banana to your morning smoothie may be undermining its health benefits. Researchers at the University of California, Davis, have discovered that bananas significantly reduce the body's absorption of flavanols, bioactive compounds critical for heart and cognitive health.
The study, published in Food and Function, examined how polyphenol oxidase (PPO), an enzyme abundant in bananas, interacts with other ingredients. Participants consumed smoothies containing either high-PPO bananas or low-PPO mixed berries, alongside a control group taking flavanol capsules.
Results were stark: those drinking banana smoothies exhibited flavanol levels 84% lower than the control group. Lead author Javier Ottaviani noted the team was "really surprised" by the speed and magnitude of this reduction, highlighting how food combinations directly impact nutrient absorption.
To maximize daily flavanol intake-recommended between 400 and 600 milligrams-the researchers suggest avoiding bananas when blending with flavanol-rich foods like berries, grapes, or cocoa. Instead, opt for low-PPO alternatives such as pineapple, orange, mango, or yogurt.
Ottaviani clarified that bananas remain a healthy fruit; the issue lies specifically in their combination with certain high-flavanol ingredients. For optimal results, separate your banana consumption from your berry-based antioxidant sources.