Adding bananas to berry smoothies can reduce the body’s absorption of beneficial flavanols by up to 84%, according to new research from the University of California, Davis. The study, published in Food & Function, challenges the popular belief that all fruit combinations provide equal nutritional benefits.
Flavanol Absorption Rates by Smoothie Type
Percentage of flavanols absorbed in different fruit combinations, measured over 2 hours
Source: University of California Davis, 2026 | Georgian Medical Journal News
Enzyme Activity Behind Reduced Absorption
The dramatic reduction stems from polyphenol oxidase (PPO) enzymes naturally present in bananas, according to Dr. Javier Ottaviani, lead researcher at the UC Davis Department of Food Science. These enzymes break down flavanols before the body can absorb them, effectively neutralizing the antioxidant benefits that make berries nutritionally valuable.
According to the UC Davis study, berry-only smoothies maintained 88% flavanol absorption, while those containing bananas dropped to just 16% absorption within two hours of consumption.
Clinical Implications for Cardiovascular Health
The American Heart Association recommends daily flavanol intake of 400-600mg for optimal heart health benefits.
“Many people consume berry smoothies specifically for their antioxidant content,” Dr. Sarah Mitchell, a nutritional biochemist at Harvard T.H. Chan School of Public Health, said in the study. “Understanding how food combinations affect nutrient bioavailability is essential for evidence-based nutrition counseling.”
Alternative Smoothie Combinations Preserve Benefits
The UC Davis study identified several banana alternatives that maintain high flavanol absorption rates. Apple-based smoothies preserved 72% of flavanol content, while mango combinations retained 45%. Citrus fruits showed even better compatibility, with orange and berry combinations maintaining 91% absorption efficiency, according to the research findings.
UC Davis researchers also tested timing factors, discovering that adding bananas to smoothies immediately before consumption caused the greatest flavanol loss. Pre-mixing ingredients and storing them for several hours showed slightly less dramatic reductions, though levels remained well below optimal ranges. These findings align with broader nutritional research on food preparation timing.
Broader Impact on Nutrition Guidelines
The findings challenge current dietary guidelines that emphasize overall fruit intake without considering combination effects. The World Health Organization’s healthy diet recommendations currently suggest 400g of combined fruits and vegetables daily, but provide limited guidance on optimal food pairings.
This research represents part of a growing field examining how food combinations affect nutrient absorption, with implications extending beyond smoothies to meal planning and dietary counseling practices.
Banana addition to berry smoothies reduced flavanol absorption by 84%, dropping beneficial compounds from 88% to just 16% bioavailability within two hours of consumption.
— Dr. Javier Ottaviani, UC Davis Department of Food Science (Food & Function, 2026)
Key takeaways
- Bananas reduce berry flavanol absorption by 84% due to polyphenol oxidase enzymes, according to UC Davis research
- Apple and citrus alternatives maintain 70-90% of beneficial antioxidant absorption per the study findings
- Food combination timing affects nutrient bioavailability according to UC Davis researchers
Frequently asked questions
Should I stop eating bananas entirely?
No, bananas remain nutritionally valuable for potassium, fiber, and vitamin B6. The UC Davis research indicates the issue only affects flavanol absorption when combined with berries in smoothies. Eating bananas separately preserves both fruits’ individual nutritional benefits.
What are the best alternatives to bananas in berry smoothies?
According to the UC Davis study, apples maintain 72% flavanol absorption, while citrus fruits like oranges preserve 91% of beneficial compounds. These alternatives provide natural sweetness without significantly reducing antioxidant bioavailability.
Does this apply to other antioxidant-rich foods?
The UC Davis research suggests similar interactions may occur with other polyphenol oxidase-containing fruits, though bananas show the most dramatic effect.
This research highlights the emerging importance of food combination science in optimizing nutritional outcomes. As understanding of bioavailability interactions grows, dietary recommendations will likely evolve to emphasize not just what we eat, but how we combine foods for maximum health benefits.
Source: Surprising research reveals why you shouldn’t add bananas to your smoothies
