Bananas and the Slippery Science of Flavanols
Bananas are a staple in many breakfast bowls and post-workout blends, prized for their creaminess, natural sweetness, and potassium boost. But a recent study in the Royal Society of Chemistry’s journal Food and Function suggests that the way we blend bananas with other fruits could quietly undermine the very health benefits many smoothie lovers seek. The culprit isn’t the banana itself, but an enzyme called polyphenol oxidase (PPO), naturally present in many fruits. PPO can influence how well our bodies absorb flavanols, a family of bioactive compounds linked to heart and brain health.
What Are Flavanols and Why Do They Matter?
Flavanols are plant-based polyphenols found in foods such as apples, pears, berries, grapes, and cocoa. They’re associated with improved blood flow, anti-inflammatory effects, and potential cognitive benefits when consumed regularly. While the foods above are enjoyed in smoothies across kitchens worldwide, the body’s ability to absorb these flavanols depends on how the foods are prepared and combined.
The Banana Experiment: What the Researchers Did
Lead author Javier Ottaviani and colleagues conducted a practical test to see how a common smoothie ingredient affects flavanol availability. They compared two smoothie versions: one built around a banana, the other featuring mixed berries. The banana smoothie has higher PPO activity, while the berry blend presents lower PPO activity. For comparison, participants also took a flavanol capsule. After consumption, researchers measured flavanol levels in blood and urine to gauge absorption.
Key Findings: A Surprising 84% Drop
The results were striking. Those who drank the banana-forward smoothie showed about 84% lower flavanol levels in their bloodstream than those who took the flavanol capsule alone. In contrast, the berry-based smoothie did not exhibit the same drop. The team’s interpretation was clear: the presence of banana—and its PPO activity—can rapidly alter the amount of flavanols that become available for absorption when blended with other ingredients.
Why This Matters for Everyday Eating
These findings highlight a broader principle: nutrient absorption is not just about what we eat, but also how we prepare and combine foods. If flavanols are a goal, pairings matter. The researchers suggest that the practical impact of a single ingredient like banana can ripple through a smoothie’s nutritional value, especially for individuals targeting specific cardiometabolic benefits tied to flavanols.
<h2 Practical Guidance: How to Maximize Flavanol Intake in Smoothies
For people aiming to meet daily flavanol targets recommended by nutrition authorities, the study offers actionable tips. The Academy of Nutrition and Dietetics has suggested a daily range of 400–600 milligrams of flavanols for cardiometabolic health. Ottaviani advises choosing berry-rich ingredients with low PPO activity or pairing flavanol-heavy fruits with other components that don’t amplify PPO activity.
Suggestions include:
– Use berries, grapes, apples, or cocoa-rich ingredients as the primary flavanol source in smoothies.
– Pair with pineapple, oranges, mango, or yogurt—foods with relatively low PPO activity—to reduce antagonistic effects.
– If you love banana smoothies, consider keeping bananas as a secondary ingredient or separating their consumption from flavanol-dense blends.
<h2 Beyond Fruits: A Wider Implication for Nutrition Research
The study’s authors emphasize that this is an emerging field with broader implications. Tea, another major flavanol source, could be influenced by brewing methods in ways similar to blending strategies. The work invites researchers to explore how everyday food preparation affects the bioavailability of bioactive compounds across the diet, not just in isolated capsules.
<h2 Looking Ahead
Ottaviani notes that the findings open avenues for more nuanced dietary guidance and product development. As science uncovers how preparation alters nutrient absorption, dietary recommendations can become more precise—helping people enjoy their favorite foods while preserving their health benefits. The study, funded by Mars, Inc., adds to a growing body of knowledge about how the foods on our plates interact with our bodies in real time.
<h2 About the Researchers and Funding
The work was conducted by a team including researchers affiliated with UC Davis, the University of Reading, King Saud University, and Mars, Inc. While funded by Mars, Inc., the study is part of a broader effort to better understand how cocoa flavanols and other polyphenols interact with everyday diets to influence health outcomes.
