Key Takeaways
- Bananas contain an enzyme called polyphenol oxidase (PPO) that can break down beneficial polyphenols in other fruits
- A recent study found that adding bananas to a blueberry smoothie may reduce the absorption of beneficial polyphenols
- Experts argue that the findings are 'interesting' but don't tell the whole story, and that bananas still provide fiber and other nutrients
Dr. Rhonda Patrick, a biomedical scientist, recently demonstrated how she makes her smoothies without bananas, citing the enzyme polyphenol oxidase (PPO) as the reason. PPO is responsible for breaking down polyphenols, which are beneficial for gut, heart, and brain health. Recent studies suggest that when bananas are added to a blueberry smoothie, fewer beneficial polyphenols are absorbed from the berries.
Instead of using bananas, Dr. Patrick uses avocado to give her smoothies a creamy texture with 95% less sugar. Avocado also adds monounsaturated fat, which can increase the absorption of carotenoids, like lutein and zeaxanthin, from kale in the smoothie. This opinion sparked debate among dietitians and nutritionists, with some arguing that bananas should not be villainized based on a small body of research.
The Study
The study Dr. Patrick referenced analyzed food absorption in eight healthy men. Participants drank either a banana smoothie, a mixed berry smoothie, or took flavan-3-ol capsules with milk. Blood tests showed that people absorbed about 84% fewer beneficial plant compounds after drinking the banana smoothie than after taking the flavan-3-ol capsules.
While the study's findings are interesting, experts like Los Angeles-based registered dietitian nutritionist Ilana Muhlstein argue that they don't tell the whole story. Muhlstein pointed out that the study included only eight participants and has not yet been replicated. She also noted that researchers used a standardized cocoa-derived flavanol supplement instead of whole fruits, such as berries, which may be absorbed differently by the body.
Expert Opinions
Dr. Patrick responded to the backlash from her original post, saying, 'You can add bananas to your blueberry smoothies. However, you should know that you are going to degrade some of the polyphenols in those blueberries.' She added that not every beneficial compound in blueberries will be eliminated by bananas, as the fruit contains many other polyphenols, including anthocyanins.
New York-based certified Robin DeCicco agreed that the findings don't mean everyone should avoid bananas. She noted that nutrition advice should be individualized, and that someone who eats mostly processed foods should focus on replacing them with fruits and vegetables, while someone with a more advanced nutrition plan may benefit from limiting high-carb, high-sugar fruits like bananas.
Why This Matters
The debate surrounding bananas in smoothies highlights the importance of considering the nuances of nutrition and individualized health needs. While the study's findings are intriguing, they should not be taken as a blanket statement to avoid bananas altogether. Instead, experts recommend focusing on whole, nutrient-rich foods, like fruits and vegetables, and consulting with a healthcare professional for personalized nutrition advice.