Banana Smoothies May Diminish Health Benefits of Berries, Research Finds
A recent study conducted by scientists at the University of California, Davis, has revealed that adding bananas to berry smoothies could significantly reduce the absorption of heart- and brain-boosting flavanols. The research, published this month in the journal Food & Function, highlights the role of polyphenol oxidase (PPO), an enzyme commonly found in bananas, as a key factor in this reduction. While bananas are often considered a healthy addition to smoothies, this study suggests that their presence might inadvertently limit the benefits of other fruits, such as berries, grapes, and apples.
The findings were based on a clinical study where volunteers consumed two types of smoothies: one with banana and one with mixed berries, which have lower levels of PPO. Blood and urine samples showed that the banana smoothie resulted in significantly reduced flavanol absorption, compared to the berry version or a flavanol capsule. Lead researcher Javier Ottaviani, an adjunct professor at UC Davis, explained that the study aimed to understand how a common food preparation method could affect the availability of flavanols to the body. “We sought to understand, on a very practical level, how a common food preparation like a banana-based smoothie could affect the availability of flavanols to be absorbed after intake,” Ottaviani told Fox News Digital.
The study further revealed that even when bananas and flavanol-containing foods are consumed at different times, the PPO enzyme can still reduce flavanol levels in the body. This process is similar to the browning of fruit after it is cut, where PPO interacts with oxygen and breaks down flavanols. The researchers emphasize that while bananas are a nutritious fruit and a great option for smoothie preparation, they should be used carefully to preserve the health benefits of other ingredients.
“It is important to avoid combining flavanol-containing foods with ones that quickly turn brown after they are cut, like bananas, avocados, and beet greens,” Ottaviani added. He recommended combining flavanol-rich fruits, such as berries, with low-PPO ingredients like pineapple, oranges, mangoes, or yogurt. However, he acknowledged that bananas still have their place in a balanced diet, provided they are used in moderation and paired with other nutrient-dense foods.
The study, conducted in collaboration with scientists from the University of Reading in England and King Saud University in Saudi Arabia, was funded by a research grant from Mars, Inc., a company known for its involvement in cocoa flavanol research. The research has potential implications for understanding how food preparation methods affect nutrient absorption and could lead to new strategies for enhancing the bioavailability of beneficial compounds in diets.
Other experts have echoed the importance of dietary diversity and moderation. Dr. Parth Bhavsar, a board-certified family medicine physician, emphasized that while the study highlights the need to be mindful of food pairings, it is not necessary to eliminate bananas from the diet. Instead, he advised rotating between different types of smoothies to ensure a balanced intake of nutrients. He also noted that other common food combinations, such as tea or coffee with iron-rich foods, can similarly impact nutrient absorption. “Although small in each instance, these interactions can add up in patterns over time,” Bhavsar said.
This research opens the door for further exploration into how food processing and preparation techniques influence the nutrient content and absorption of fruits and vegetables. As scientists continue to uncover the complex interactions between food components, consumers can use this knowledge to optimize their diets and maximize the health benefits of their meals.