Having a morning smoothie is a classic healthy option, but one common ingredient might be undermining its nutritional benefits. Recent research reveals that bananas, a favorite for adding creaminess and natural sweetness, can inhibit the absorption of vital nutrients present in berries and other fruits.
A study published in Food & Function by researchers at the University of Reading demonstrated that adding a banana to a berry smoothie can decrease flavanol absorption by up to 84%. Let’s explore the findings in more detail.
Bananas interfere with nutrient absorption in smoothies
Flavanols are natural compounds and antioxidants acclaimed for supporting cardiovascular well-being, enhancing cognitive function, and promoting healthy blood flow. They are abundant in berries, apples, and cocoa. However, when blended with bananas, the beneficial properties of these compounds diminish.
The problem stems from polyphenol oxidase (PPO), an enzyme naturally present in bananas that not only triggers the browning process when fruits are cut or bruised but also actively breaks down valuable flavanols during digestion, significantly reducing their bioavailability. This enzymatic reaction has a profound impact on nutrient absorption.
In the study, participants consumed one of three types of interventions: smoothies made with a blend of bananas and berries, solely berry-based smoothies, or flavanol capsules. Blood and urine analyses provided clear evidence that flavanol levels in subjects who consumed the banana-berry blend were nearly 85% lower than those in the berry-only or capsule groups.
While bananas provide important nutrients such as potassium, vitamin B6, and dietary fiber, their high PPO activity compromises the benefits of flavanol-rich ingredients. If you are blending a smoothie specifically to boost your flavanol intake, bananas may be counterproductive.
Better fruit choices for your smoothies
The bright side is that many fruits offer flavanols without impeding their absorption. If you want a nutrient-packed smoothie, pair these flavanol sources with ingredients that have low PPO activity:
- Berries: Blueberries, blackberries, and strawberries are excellent sources of flavanols. Blend them with liquids like almond milk or yogurt to help preserve their nutrients.
- Apples and pears: Although these fruits contain flavanols, their PPO levels can increase upon cutting. Use them fresh and consume them quickly to maximize their benefits.
- Grapes: Red and purple grapes are rich in flavanols. Freezing them not only retains their nutrient profile but also creates a thicker smoothie texture.
- Cocoa powder: Unsweetened cocoa is among the most concentrated sources of flavanols. Add a spoonful to berry blends for a significant antioxidant boost.
For smooth creaminess without the drawbacks of bananas, consider alternatives such as mango, pineapple, or oranges, all of which exhibit minimal PPO activity. Also, ingredients like Greek yogurt or avocado can enhance thickness while keeping flavanols intact.
Smoothies can indeed be a nutrient powerhouse, but the compatibility of ingredients is key to unlocking their full benefits. The PPO enzyme in bananas significantly reduces flavanol absorption, diminishing the health advantages offered by berries and other fruits. For optimal results, blend berries with low-PPO alternatives like mango, citrus, or yogurt, and turn your smoothie into a smarter choice for your health.