Bananas in Smoothies May Block Key Nutrient Absorption, Study Finds
A new study highlights a surprising interaction in your morning smoothie: combining bananas with flavonoid-rich berries could significantly reduce the health benefits.
The Key Finding
A study published in Food & Function found that bananas, due to their high levels of the enzyme polyphenol oxidase (PPO), can sharply reduce the amount of flavanols absorbed from a smoothie. Flavanols are plant compounds linked to improved heart and cognitive health.
The Research
Researchers gave participants three options: banana-based smoothies, mixed berry smoothies, and flavanol capsules.
- Those who drank banana smoothies had 84% lower flavanol levels in their blood compared to the control group.
- In contrast, low-PPO mixed berry smoothies showed flavanol absorption similar to the capsules.
A second test suggested that PPO activity may continue even after the smoothie is consumed.
Important Caveats
- The study was small, involving just 8 and 11 participants in two tests.
- It was funded by Mars, Inc., a company with interests in flavanol research.
Expert Recommendations
The Academy of Nutrition and Dietetics recommends 400–600 mg of flavanols daily. The study authors suggest pairing flavanol-rich ingredients like berries with low-PPO alternatives such as pineapple, orange, mango, or yogurt. They note that bananas can still be part of a healthy diet, just not necessarily in the same smoothie as high-flavanol fruits.