Why Shouldn't You Eat Bananas and Berries Together?

October 7, 2025 •

4 min read

According to a 2023 study from UC Davis and the University of Reading, blending bananas and berries together can reduce the absorption of beneficial flavanols by as much as 84%. This groundbreaking research explains why you shouldn't eat bananas and berries together if you want to maximize your nutrient intake.

Quick Summary

This article explores the enzymatic reaction that occurs when bananas and berries are combined, hindering the absorption of key nutrients known as flavanols. It discusses the science behind this common smoothie mistake and offers practical advice on alternative fruit pairings and food preparation methods to optimize your health benefits.

Key Points

Enzymatic Conflict: Bananas contain high levels of the enzyme polyphenol oxidase (PPO).
Flavanol Destruction: The PPO in bananas destroys beneficial flavanols found in berries, especially when blended.
Reduced Absorption: A study showed up to an 84% reduction in flavanol bioavailability when bananas were blended with berries.
Nutrient Loss: This interaction means you get significantly fewer heart-healthy and cognitive-boosting flavanols.
Smoothie Alternative: For optimal benefits, combine berries with low-PPO fruits like pineapple or mango.
Digestive Comfort: Some food-combining theories suggest that mixing sweet and acidic fruits can also lead to digestive issues.
Simple Solution: Enjoy bananas and berries separately to get the maximum health benefits from each fruit.

The Unseen Enzyme: How Bananas Impact Berries

For years, a banana and berry smoothie has been a staple of healthy breakfasts and post-workout fuel. However, new research reveals a surprising interaction that can dramatically reduce the nutritional benefits you thought you were getting. The key player in this biochemical drama is an enzyme called polyphenol oxidase, or PPO.

PPO is naturally present in many fruits and vegetables and is responsible for the browning effect you see when an apple or avocado is exposed to air. Bananas, in particular, have a very high concentration of this enzyme. Berries, on the other hand, are loaded with beneficial plant compounds known as flavanols, which are linked to improved cardiovascular and cognitive health. When you blend these two ingredients, the PPO from the banana destroys a significant portion of the flavanols from the berries before your body can absorb them.

The Science of Reduced Bioavailability

A study published in the journal Food & Function showed a staggering reduction in flavanol absorption. Participants who consumed a smoothie with bananas and berries had 84% lower levels of flavanols in their bloodstream compared to a control group who received a flavanol capsule. The researchers were surprised by the extent of this effect, highlighting how food preparation and combinations can significantly impact the bioavailability of nutrients. This isn't a theory; it's a measurable chemical reaction with documented results.

How to Maximize Your Smoothie's Potential

Just because bananas and berries don't mix perfectly doesn't mean you have to stop enjoying smoothies. The solution is to use fruits with low PPO activity when combining them with berries. Here are some effective strategies to get the most out of your ingredients:

Pair berries with low-PPO fruits: Choose fruits like pineapple, oranges, or mangoes, which have low levels of polyphenol oxidase, to blend with your berries. This allows the flavanols to remain intact and available for absorption.
Eat bananas and berries separately: If you love both fruits, simply enjoy them at different times. Eat your banana as a snack on its own, and have a berry smoothie later in the day to get the full nutritional benefit of each.
Consider alternative creamy bases: For that desired creamy texture in your smoothie, swap the banana for other low-PPO options. Avocado provides healthy fats and a smooth consistency, while yogurt adds probiotics and creaminess without compromising flavanol content.
Drink your smoothie immediately: The destructive effect of PPO on flavanols begins as soon as the fruits are blended and exposed to oxygen. Drinking your smoothie right away can help mitigate some of the nutrient loss compared to letting it sit for a long period.

Comparison Table: High PPO vs. Low PPO Fruits

To help you make smarter smoothie choices, here's a quick comparison of fruits based on their polyphenol oxidase levels.


Feature	High PPO Fruits	Low PPO Fruits
Examples	Bananas, pears, apples, avocados	Berries, oranges, mangoes, pineapple
Effect on Flavanols	Significantly reduces flavanol absorption when blended with berries	Preserves flavanol bioavailability when blended with berries
Best Use	Best eaten whole or separate from high-flavanol foods	Ideal for combining with berries in smoothies to maximize nutrient intake
Impact on Smoothies	Can lead to nutrient loss and browning	Helps maintain antioxidant levels and bright color

Other Food Combining Considerations

While the banana-berry interaction is a specific, scientifically-backed example of how certain food pairings can affect nutrient absorption, the broader concept of food combining has other facets as well. Some traditional nutritional systems, like Ayurveda, and anecdotal evidence suggest that combining fruits with different digestion times can cause issues like bloating, gas, or indigestion. For example, mixing acidic fruits (like berries) with sweet fruits (like bananas) is sometimes cited as a potential cause of digestive discomfort due to fermentation. While these effects are not universally experienced and can vary by individual, they are worth considering if you have a sensitive digestive system. The main takeaway from the scientific research, however, is a clear and measurable impact on your body's ability to absorb heart-healthy flavanols.

Conclusion: Maximize Your Nutrient Absorption

Understanding the science behind why you shouldn't eat bananas and berries together, particularly in a blended form, is key to optimizing your nutrition. The high concentration of the enzyme PPO in bananas can substantially decrease the bioavailability of heart-healthy flavanols from berries. By being mindful of your food combinations, you can ensure your body gets the full benefit of these antioxidant-rich foods. Consider swapping out bananas for low-PPO alternatives like pineapple or simply enjoy your favorite fruits separately to unlock their full nutritional potential.

Food & Function journal article

Frequently Asked Questions

Yes, eating bananas and berries separately is the best way to ensure you get the full nutritional benefits from each fruit. The enzymatic reaction that causes the flavanol destruction primarily occurs when the ingredients are blended together.

Polyphenol oxidase (PPO) is an enzyme found in many fruits and vegetables that causes them to brown when exposed to oxygen. Bananas have a particularly high concentration of this enzyme.

Yes, you can still add bananas to smoothies, but it is best to pair them with ingredients that don't contain high levels of flavanols. If your goal is to maximize flavanol intake, blend berries with low-PPO fruits instead.

For a delicious and nutrient-rich berry smoothie, try low-PPO alternatives such as pineapple, mango, or oranges. You can also use avocado or yogurt for creaminess without impacting flavanol absorption.

While the flavanol destruction is most pronounced in blended drinks, where the enzymes and compounds are fully mixed, some reaction may still occur in a fruit salad, though to a much lesser extent. The primary concern, and the focus of the research, is with smoothies.

Flavanols are a type of antioxidant found in berries, apples, and cocoa. They are important for cardiovascular health and cognitive function, with recommended daily intakes for adults.

Some alternative health practices, like Ayurveda, and anecdotal reports suggest that mixing acidic and sweet fruits can cause digestive discomfort. However, the scientific evidence for digestive problems from fruit combining is limited and varies among individuals.