UK surgeon debunks the claim that bananas destroy berry smoothie nutrition
Dr Karan Rajan says the claim that bananas destroy berry nutrition is an example of bad science communication
A claim circulating widely on social media suggests that adding bananas to berry smoothies destroys the nutritional value of the berries.
However, according to Dr Karan Rajan, a UK-based surgeon and health content creator, this is simply an example of poor science communication.
Where did the claim come from?
Taking to Instagram on Friday, Dr Rajan explained the origins of the claim and why it remains safe to continue blending bananas and berries together.
"The claim that bananas can destroy the nutritional value of a berry smoothie comes from a real study," he stated. "Unfortunately, the study did not test what happens when you mix bananas and berries together."
The 2023 study, titled Impact of polyphenol oxidase on the bioavailability of flavan-3-ols in fruit smoothies: a controlled, single-blinded, cross-over study, actually tested what happens when powdered flavonol from cocoa powder is added to two separate smoothies — one containing banana and one containing mixed berries.
Whether the enzyme polyphenol oxidase from a banana behaves the same way towards dissolved cocoa powder extract as it does towards the flavonol contained within the food matrix of a berry remains entirely unknown.
Why bananas in berry smoothies remain safe
Berries contain a wide variety of polyphenols and other essential nutrients that provide numerous health benefits.
As Dr Rajan put it: "Even if the polyphenol oxidase enzyme from the bananas eliminated every single polyphenol in berries, which it does not, berries would still be amazing: fibre, folate, B vitamins, manganese, vitamin C."
He also drew attention to the limitations of the original study, which was conducted on just 19 participants. Whilst this does not in itself disprove the findings, it raises legitimate questions about whether the results can be reliably applied to a broader population.
"And the study just looked at one class of polyphenols, epicatechin. Berries contain dozens of structurally distinct polyphenol classes: anthocyanidins, procyanidins, quercetin, and ellagitannins. We have no data on what banana does to any of them," Dr Rajan explained.
His conclusion was straightforward: "Please keep enjoying bananas with your berry smoothies. Bad science communication is far more dangerous than any banana ever is. Keep blending away."
Note to readers: This article is for informational purposes only and not a substitute for professional medical advice. Always seek the advice of your doctor with any questions about a medical condition.
