After reading this, you'll never put bananas in your smoothie again 🍌

Fruit smoothies are often considered a healthy way to consume essential nutrients. However, a recent study reveals that certain ingredients could significantly reduce their benefits.

Researchers discovered that adding banana to a smoothie decreases the absorption of flavanols, compounds beneficial for heart and cognitive health. This reduction can reach 84%, according to a study published in Food and Function. The responsible enzyme, polyphenol oxidase, abundant in bananas, alters the availability of these nutrients.


Flavanols, found in berries, apples, and cocoa, play a key role in preventing cardiovascular diseases. The study suggests their absorption is optimal when these fruits are consumed alone or with foods low in polyphenol oxidase. Participants who consumed a banana-free smoothie showed significantly higher flavanol levels.

The research team, led by Javier Ottaviani, explored food interactions and their impact on nutrient absorption. Their work highlights the importance of carefully choosing smoothie ingredients to maximize health benefits.

Co-author Gunter Kuhnle emphasizes that while bananas are nutritious, they're not ideal for maximizing flavanol intake. He recommends combinations with fruits like pineapple or mango instead, which don't affect absorption of these compounds.

This research opens new perspectives on food interactions and their influence on nutrition. It reminds us that food preparation can alter nutritional value, an aspect often overlooked in dietary recommendations.

What is polyphenol oxidase?

Polyphenol oxidase is an enzyme present in many fruits and vegetables. It's responsible for the browning that occurs when these foods are cut or bruised.

This enzyme catalyzes the conversion of polyphenols into quinones, compounds that then react to form brown pigments. This process is a natural defense reaction of plants against damage.

In smoothies, polyphenol oxidase can degrade flavanols, reducing their bioavailability. Bananas in particular contain high levels of this enzyme.

Understanding polyphenol oxidase's role can help optimize food preparation to preserve nutrients. Methods like adding ascorbic acid can inhibit its activity.

Why are flavanols important for health?

Flavanols are phytochemical compounds with antioxidant and anti-inflammatory properties. They play a protective role against cardiovascular and neurodegenerative diseases.

These molecules improve endothelial function, thereby reducing atherosclerosis risk. They also promote blood circulation and cognitive health by protecting neurons.

Dietary sources of flavanols include cocoa, berries, apples, and tea. Regular consumption is associated with better metabolic and cognitive health.

Despite their benefits, flavanols are sensitive to food processing. Their absorption can be affected by enzymes like polyphenol oxidase, highlighting the importance of proper food combinations.