Do Bananas Stop Absorption of Nutrients? The Truth About PPO and Flavanols

November 1, 2025 •

5 min read

A 2023 study found that bananas can drastically reduce the absorption of certain antioxidants called flavanols from berries by over 80% when blended in a smoothie. This surprising finding has prompted many to ask: do bananas stop absorption of nutrients more broadly, or is this a specific interaction to be mindful of?

Quick Summary

A specific enzyme in bananas, polyphenol oxidase (PPO), interferes with flavanol absorption from other fruits like berries, particularly in smoothies. However, bananas contain nutrients and fiber that support nutrient uptake, making this a specific food pairing issue, not a general nutritional problem.

Key Points

The PPO Effect: An enzyme in bananas, polyphenol oxidase (PPO), significantly reduces the absorption of flavanols from other fruits like berries, particularly when blended together.
Enhances Iron Absorption: The high vitamin C content in bananas actively promotes the absorption of non-heme iron from other plant-based foods.
Supports Calcium Absorption: Prebiotic fibers like FOS in bananas improve gut acidity, which can indirectly aid the absorption of calcium from other dietary sources.
Boosts Gut Health: Unripe bananas contain resistant starch, a prebiotic that nourishes beneficial gut bacteria and supports a healthy digestive system.
Low Antinutrient Content: Compared to grains and legumes, the edible flesh of bananas has very low levels of antinutrients like phytates and oxalates.
Expert Perspective: Dietitians emphasize that the PPO effect is a specific interaction and not a reason to avoid bananas, stressing the importance of overall dietary diversity.
Strategic Pairing: To maximize flavanol intake, eat bananas and berries separately or pair berries with low-PPO fruits like pineapple or oranges.

The PPO Problem: A Specific Case of Nutrient Inhibition

The idea that bananas could hinder nutrient absorption came to prominence following a study published in the journal Food & Function. The research focused on the effects of polyphenol oxidase (PPO), an enzyme found in high concentrations in bananas, particularly when they are unripe. PPO is the same enzyme responsible for the browning of fruit after it's been cut and exposed to air.

The study found that when flavanol-rich fruits, like berries, were blended with high-PPO fruits, like bananas, the PPO activity drastically reduced the bioavailability of flavanols. The results showed that the flavanol metabolite levels in participants' blood were significantly lower after consuming a banana-based smoothie compared to a control capsule. This is because PPO interacts with flavanols and causes them to degrade before they can be absorbed into the bloodstream. While the results were certainly striking (an 84% reduction was reported), it’s crucial to understand the context. This effect is not a universal truth about bananas blocking all nutrients but a specific interaction between PPO and flavanols, exacerbated by the blending process.

Putting the Finding into Perspective

Many nutrition experts advise against overreacting to this study's findings for several reasons. First, the study had a small sample size, and it focused on a specific nutrient-enzyme interaction. Second, flavanols are just one of many health-promoting compounds, and people rarely consume enough fruits and vegetables in the first place. Focusing on minor nutrient interactions at the expense of overall fruit and vegetable intake is counterproductive. The simple takeaway is that if maximizing flavanol absorption from berries is your primary goal, it might be better to enjoy your bananas separately or pair your berries with low-PPO fruits like pineapple, mango, or oranges.

Bananas as a Nutrient Enhancer

While some specific interactions can reduce the absorption of other nutrients, bananas themselves contain beneficial properties that actively support the absorption of essential vitamins and minerals, as well as general gut health.

Support for Iron Absorption

Contrary to blocking, bananas actually help with iron absorption. The reason is their significant vitamin C content. Vitamin C is known to enhance the absorption of non-heme iron (the type found in plant-based foods). So, consuming a banana alongside other iron-rich, plant-based foods like spinach or lentils can actually boost your body's ability to utilize that iron.

Aid in Calcium Uptake

Bananas aren't a high source of calcium, but they contain fructooligosaccharides (FOS), a prebiotic fiber. FOS works in the colon to increase gut acidity, which allows the body to absorb more calcium from the foods you eat. Additionally, FOS feeds the beneficial probiotic bacteria in your gut, which further supports overall nutrient absorption.

The Role of Bananas in Digestive Health

Beyond specific nutrient interactions, the fiber content in bananas plays a major, overarching role in promoting a healthy digestive system, which is the foundation for efficient nutrient absorption.

Resistant Starch: Unripe (green) bananas contain high levels of resistant starch, which is not digested in the small intestine. Instead, it travels to the large intestine, where it acts as a prebiotic, feeding the good bacteria in your gut. These bacteria ferment the resistant starch, producing short-chain fatty acids that nourish the cells lining your colon and support overall gut health.
Pectin: Both unripe and ripe bananas contain pectin, a soluble fiber that aids digestion. In unripe bananas, pectin and resistant starch can help with issues like diarrhea by regulating bowel movements. In ripe bananas, the soluble fiber can help alleviate constipation.

Clarifying Concerns About Antinutrients

Some might wonder about the presence of antinutrients, such as phytates, which can bind to minerals and hinder absorption. Research shows that while banana peels contain some antinutritional factors, the edible flesh contains very low levels of phytates and oxalates compared to many other plant-based foods like whole grains, legumes, and nuts. Therefore, antinutrient content is not a significant concern when consuming banana flesh.

Nutrient Absorption Interactions: Bananas and Food Pairings

To better understand the complex nature of nutrient absorption, let's compare some of the interactions mentioned above.


Interaction Type	Nutrient Affected	Banana's Role	Context	Overall Impact
PPO-Flavanol	Flavanols (e.g., from berries)	Inhibits absorption due to PPO enzyme	Blending high-PPO bananas with high-flavanol fruits, like in a smoothie	Significantly reduces absorption of these specific antioxidants
Vitamin C-Iron	Non-heme iron (from plants)	Enhances absorption due to vitamin C content	Consumed alongside iron-rich, plant-based foods (e.g., spinach, lentils)	Improves the body's ability to absorb plant-based iron
FOS-Calcium	Calcium (from other foods)	Enhances absorption via prebiotic FOS	FOS ferments in the colon, increasing acidity and aiding calcium absorption	Indirectly supports bone health by improving calcium uptake from other dietary sources
Prebiotic Fiber-General Absorption	Gut microbiota	Promotes overall gut health and efficiency	Resistant starch and pectin feed beneficial bacteria, improving the gut environment	Creates a healthier environment for the absorption of a wide range of nutrients

Conclusion: A Balanced Perspective on Nutrition

The question of whether bananas stop nutrient absorption is not a simple "yes" or "no" but rather a testament to the complex interactions within food science. While a specific enzyme, PPO, can significantly reduce the absorption of flavanols when bananas and berries are blended, this does not define the banana's overall nutritional impact. In fact, bananas are powerhouses of nutrition that promote the absorption of other vital nutrients, like iron and calcium, while their high fiber content is crucial for maintaining a healthy and efficient digestive system. Rather than eliminating bananas from your diet or smoothies, a better approach is to be mindful of how you combine them. To get the maximum benefit from both bananas and flavanol-rich fruits, consider eating them at different times or combining flavanol-rich fruits with low-PPO alternatives. As nutrition experts suggest, the bigger picture of a diverse and balanced diet remains the most important factor for optimal health.

Authoritative Source

Taylor & Francis Online: Bioactive profile and functional food applications of banana in health promotion

Disclaimer

Please consult a healthcare professional or registered dietitian before making significant changes to your diet, especially if you have existing health conditions or concerns.

Image

A close-up, high-quality image of bananas, a bowl of mixed berries, and a blender, visually representing the topic of the article. Caption: "The enzyme in bananas can inhibit flavanol absorption from berries, but proper pairing can prevent this." (Image needs to be sourced and added manually).

Frequently Asked Questions

If your primary goal is to maximize the absorption of flavanols from your berries, you may want to avoid blending them with bananas. A better strategy is to eat bananas at a different time or combine your berries with low-PPO fruits like pineapple or mango.

No, there is no evidence that bananas cause overall nutrient deficiencies. The flavanol-PPO interaction is very specific and doesn't affect all nutrients. In fact, bananas contain vitamin C which enhances the absorption of non-heme iron.

Unripe bananas contain more resistant starch, a prebiotic fiber that feeds beneficial gut bacteria. Ripe bananas have more simple sugars and are easier to digest. The best choice depends on your specific health goals.

No, bananas do not block iron absorption. Their vitamin C content actually helps your body absorb non-heme iron from plant-based foods more efficiently.

PPO, or polyphenol oxidase, is an enzyme that causes browning in cut fruits and vegetables. In the context of blending, it can degrade flavanols, a type of antioxidant, before your body can absorb them.

Some traditional and alternative health perspectives suggest avoiding this pairing, but scientific evidence is limited. Combining bananas with protein-rich yogurt may slow digestion for some, but many people tolerate it well. Listening to your body is key.

You can get the full benefits by enjoying them separately. For instance, have a banana as a snack and then have a berry smoothie later, or mix your berries with a low-PPO fruit like pineapple.