Do Bananas Reduce Flavanol Absorption? Unpacking the Smoothie Dilemma

November 16, 2025 •

4 min read

Recent studies have revealed that blending bananas with flavanol-rich foods can reduce the absorption of beneficial flavanols by as much as 84%. This surprising discovery raises an important question for health enthusiasts: do bananas reduce flavanol absorption, and what can we do about it?

Quick Summary

Yes, bananas significantly reduce flavanol absorption due to the high levels of polyphenol oxidase (PPO). This enzyme degrades flavanols during preparation and digestion, hindering bioavailability.

Key Points

High PPO in Bananas: The enzyme polyphenol oxidase (PPO) in bananas is the main reason they reduce flavanol absorption.
Significant Absorption Reduction: A single banana blended with flavanol-rich berries can reduce flavanol bioavailability by up to 84%.
Separate Consumption is Best: To maximize flavanol intake, consume bananas separately from foods like berries, grapes, or cocoa.
Low-PPO Alternatives Exist: Use low-PPO fruits like pineapple, mango, or oranges in your smoothies to preserve flavanol content.
PPO Remains Active Post-Ingestion: Even when consumed separately, banana PPO can degrade flavanols in the stomach, though the effect is less pronounced than when blended.
Other Nutrients Unaffected: The PPO in bananas only impacts flavanol absorption, not the absorption of other valuable nutrients like potassium or fiber.

The Surprising Science Behind Your Smoothie

For years, the banana has been a staple of healthy smoothies, prized for its potassium content and ability to add a creamy texture. However, a landmark 2023 study published in the journal Food and Function challenged this long-held practice by revealing a significant nutrient interaction at play. The study demonstrated that adding a single banana to a berry smoothie drastically reduced the amount of flavanols absorbed by the body. This effect wasn't limited to smoothies, as even co-ingesting bananas and flavanols separately diminished absorption, suggesting that the interaction continues in the stomach. The key to this nutritional puzzle lies in an enzyme called polyphenol oxidase (PPO), which is abundant in bananas.

What is Polyphenol Oxidase (PPO)?

Polyphenol oxidase is the same enzyme that causes fruits and vegetables to turn brown when they are cut or bruised and exposed to air. When bananas are blended or consumed with flavanol-rich foods, their PPO content interacts with and breaks down the flavanols, turning them into compounds that the body cannot easily absorb. Research showed that after preparing a banana-based smoothie, a key flavanol called (-)-epicatechin had largely degraded within an hour, a process inhibited by PPO blockers. This reveals the powerful impact that food preparation and combinations can have on the bioavailability of dietary compounds.

The Health Benefits of Flavanols

Before adjusting your smoothie routine, it's important to understand why flavanols are so beneficial. As a subclass of flavonoids, flavanols are powerful antioxidants linked to numerous health benefits. They are known for their role in supporting cardiovascular and cognitive health, and recommended daily intakes have been established by bodies like the Academy of Nutrition and Dietetics. By maximizing your flavanol absorption, you can help protect your cells from oxidative damage, improve blood vessel function, and support brain health as you age.

Optimizing Your Flavanol Intake

To reap the full benefits of flavanol-rich foods, consider these strategies:

Eat separately: The simplest solution is to enjoy bananas and flavanol-rich foods at different times. Eat your banana as a standalone snack at least an hour before or after your flavanol-focused meal or drink.
Choose low-PPO ingredients: If a creamy smoothie is what you crave, swap out high-PPO bananas for fruits and ingredients with lower levels of the enzyme. Good options include pineapple, oranges, mango, or yogurt.
Add inhibitors: Certain foods can naturally inhibit PPO activity. For instance, the vitamin C found in lemon juice can help stabilize flavanols and boost their absorption.

High-PPO vs. Low-PPO Smoothie Ingredients

Understanding which foods contain high or low levels of PPO can help you make smarter choices for your smoothie recipes. Here is a helpful guide to some common ingredients:

High-PPO foods to be cautious of when mixing with flavanols:

Bananas
Apples
Pears
Beet greens
Eggplant

Low-PPO foods ideal for flavanol-rich smoothies:

Berries (blueberries, raspberries, strawberries)
Pineapple
Oranges
Mango
Spinach
Kale
Yogurt

Food Synergy: When to Combine, and When Not To

The phenomenon of how certain food combinations can either enhance or inhibit nutrient absorption is known as food synergy. The banana-flavanol interaction is a classic example of a combination that works against your nutritional goals. On the other hand, a squeeze of lemon juice in green tea can enhance the absorption of its beneficial catechins, showcasing a positive synergistic effect. Making a conscious effort to understand these interactions allows for a more intentional and effective approach to nutrition.


Feature	Banana-Berry Smoothie (High PPO)	Berry-Mango Smoothie (Low PPO)
PPO Level	High	Low
Flavanol Bioavailability	Significantly reduced (~84%)	High (similar to supplement)
Key Benefit to Maximize	Potassium, Fiber, Gut Health	Antioxidant Power, Heart & Brain Health
Primary Goal of Drink	Creamy texture, quick energy	Maximize flavanol intake for health
Recommended Use	Standalone snack, or with low-flavanol ingredients	High-flavanol blend for antioxidant boost

Conclusion: Navigating Your Diet with Intention

The discovery that bananas can dramatically inhibit flavanol absorption due to the PPO enzyme has prompted a reevaluation of common dietary practices. While this doesn't mean you should abandon bananas—which are excellent sources of other nutrients like potassium and fiber—it does mean reconsidering how you combine them with flavanol-rich foods such as berries, grapes, and cocoa. For those aiming to maximize the cardiovascular and cognitive benefits of flavanols, opting for low-PPO fruits or enjoying bananas separately is the smarter strategy. By understanding the intricacies of food synergy, we can make small, informed adjustments that have a significant impact on our long-term health and well-being.

For more detailed information on flavanols and related nutrition research, you can explore scientific journals like Food & Function which regularly publish on the topic.

Frequently Asked Questions

Bananas contain high levels of an enzyme called polyphenol oxidase (PPO), which breaks down flavanols into less absorbable compounds, both when blended and after ingestion.

Studies have shown that adding a banana to a flavanol-rich berry smoothie can slash the absorption of flavanols by approximately 84% compared to a capsule.

Use fruits with low polyphenol oxidase (PPO) activity, such as berries, pineapple, oranges, or mango, and combine them with other low-PPO ingredients like yogurt or spinach.

Yes, but to maximize flavanol benefits, it is recommended to eat bananas and flavanol-rich foods at separate times. Have your banana as a snack at least an hour before or after your flavanol-containing meal.

Flavanol-rich foods include berries, cocoa, apples, pears, grapes, green tea, and dark chocolate.

Absolutely. Bananas are excellent sources of other nutrients like potassium, vitamin B6, vitamin C, and fiber. The issue is only with their interaction with flavanols.

Yes, blending causes a rapid release of the PPO enzyme, allowing it to interact with and degrade flavanols more quickly and extensively than if the foods were just consumed together.