Recent claims suggest that combining bananas with blueberries in smoothies may undermine the berries’ health benefits, sparking debate amongst experts. Dr Rhonda Patrick, a biomedical scientist, highlighted on the Mel Robbins Podcast that bananas could potentially reduce the nutritional value of blueberry smoothies due to an enzyme called polyphenol oxidase found in bananas.
Understanding the Banana-Blueberry Enzyme Interaction
Dr Patrick expressed that polyphenol oxidase impacts polyphenols, a group of antioxidants found in plant foods, including blueberries. Her assertions are reportedly based on research published in 2023 which investigated the enzyme’s influence on the absorption of flavanols, a type of polyphenol. This study observed that participants consuming banana smoothies with flavanol supplementation had lower bloodstream levels of these antioxidants compared to those who drank mixed-berry flavanol smoothies.
Examining the Research Limitations
While the study’s findings might support the enzyme interaction theory, Dr Joe Schwarcz, director of McGill University’s Office for Science and Society, noted significant limitations. The research did not actually involve a banana-blueberry blend and only examined eight subjects, which Schwarcz argues is insufficient for a definitive conclusion. Furthermore, he stressed that the study focused on flavanols rather than anthocyanins, a more prevalent type of polyphenol in blueberries linked to many health benefits.
It’s also important to note that the study was financed by Mars, a company that manufactures flavanol products, which may influence the interpretation of results.
Understanding Nutrient Interactions
Registered dietitian Alyssa Northrop, based in Minneapolis, suggested that while nutrient interactions are common, they should not be a significant concern in daily dietary planning. She emphasised maintaining a balanced diet rich in diverse fruits, vegetables, and whole foods over micromanaging nutrient combinations. Most importantly, Northrop warned that the bigger issue is the general public’s underconsumption of recommended fruit and vegetable servings.
Sheri Gaw, a dietitian nutritionist in the San Francisco Bay Area, highlighted bananas’ wholesome attributes, including their vitamins, minerals, and fibres, providing natural sweetness and texture to smoothies without necessitating concern over nutrient interference.
Evaluating Polyphenol Needs
Polyphenol-rich foods, although beneficial, do not have a stipulated daily intake requirement like vitamins and minerals do, according to Northrop. While they can support cardiovascular and metabolic health, the direct impact of inadequate polyphenol consumption on health is not yet clearly defined. Alternative fruit options lower in polyphenol oxidase, like mango or pineapple, can replace bananas for those concerned about flavanol absorption.
Ultimately, Schwarcz and other experts suggest focusing on a varied diet rather than worrying excessively about specifics like banana and berry combinations. The overall dietary diversity and nutrient intake are what truly contribute to health and wellbeing.
Reporting based on coverage first published by theguardian.com.