Bananas in smoothies may slash heart-healthy flavanols by 84%, study finds

A new study from UC Davis reveals that adding a banana to a smoothie may cut the body's absorption of beneficial flavanols by as much as 84%. These compounds, found in many plant-based foods, support heart and brain health. The findings suggest rethinking common smoothie ingredients to maximise nutritional benefits. Flavanols, a type of flavonoid, are known for their antioxidant, anti-inflammatory, and cardioprotective effects. They appear in foods like cocoa, berries, apples, and green tea. Research increasingly links long-term flavanol intake to better cognitive function, lower dementia risk, and improved heart health, including better blood pressure and cholesterol levels.

Blending fruits often enhances a smoothie's nutritional value by combining different compounds. However, enzymes in bananas—such as polyphenol oxidase—can break down flavanols, reducing their bioavailability. The UC Davis study found that swapping bananas for ingredients like berries, dark chocolate, or green tea may help preserve these benefits. For those who enjoy banana smoothies occasionally, complete avoidance isn't necessary. Instead, pairing bananas with flavanol-rich fruits like mango, pineapple, or citrus could offset some of the losses. Other alternatives include cantaloupe, honeydew, peaches, or even yogurt and coconut milk as bases.

The study highlights how ingredient choices can impact the health benefits of smoothies. While bananas remain a popular option, replacing them with berries or other flavanol-friendly foods could better support heart and brain health. The findings offer a simple adjustment for those relying on smoothies as a key source of these protective compounds.