Smoothies are a popular and convenient way to get more fruits and vegetables into your diet. But did you know that adding a banana to your smoothie can actually reduce the health benefits of some of the other ingredients? A new study from the University of California, Davis, reveals how a common enzyme in bananas can affect the absorption of flavanols, a group of bioactive compounds that are good for your heart and brain.
What are flavanols and why are they good for you?
Flavanols are a type of phytochemical, which are natural substances found in plants that have various health benefits. Flavanols are especially abundant in apples, pears, berries, grapes, and cocoa. Flavanols have been shown to improve blood flow, lower blood pressure, reduce inflammation, and enhance cognitive function. Flavanols can also act as antioxidants, which protect your cells from damage caused by free radicals.
How does a banana affect flavanol absorption?
The researchers wanted to test how different levels of polyphenol oxidase (PPO), an enzyme that causes browning in fruits and vegetables, influence the availability of flavanols in smoothies. PPO is naturally present in many fruits and vegetables, but its activity varies depending on the type and ripeness of the produce. For example, bananas have high PPO activity, while berries have low PPO activity.
The researchers had participants drink a smoothie made with banana, which has high PPO activity, and a smoothie made with mixed berries, which have low PPO activity. They also gave them a flavanol capsule as a control. They then measured the levels of flavanols in their blood and urine after consuming the smoothies and the capsule.
They found that the banana smoothie had 84% lower levels of flavanols in the body compared to the control. This means that adding a banana to your smoothie can significantly reduce the amount of flavanols that you absorb from other ingredients. The researchers suggest that this is because PPO oxidizes flavanols, making them less available for absorption.
How to get the most out of your smoothies
The researchers recommend that if you want to get the most health benefits from your smoothies, you should avoid adding ingredients that have high PPO activity, such as bananas. Instead, you should opt for ingredients that have low PPO activity, such as pineapple, oranges, mango, or yogurt. You should also choose fruits that are rich in flavanols, such as berries, apples, pears, grapes, or cocoa.
The Academy of Nutrition and Dietetics advises people to consume 400 to 600 milligrams of flavanols daily for cardiometabolic health. To achieve this goal, you can try some of these delicious smoothie recipes:
- Berry Blast: Blend 1 cup of mixed berries (such as blueberries, raspberries, strawberries, or blackberries), 1/2 cup of plain yogurt, 1/4 cup of milk or plant-based milk, and 1 teaspoon of honey.
- Apple Pie: Blend 1 apple (cored and chopped), 1/2 cup of plain yogurt, 1/4 cup of milk or plant-based milk, 1/4 teaspoon of cinnamon, and a pinch of nutmeg.
- Chocolate Dream: Blend 1 banana (peeled and sliced), 1/4 cup of unsweetened cocoa powder, 1/4 cup of milk or plant-based milk, and 1 tablespoon of peanut butter.
Smoothies are a great way to enjoy the flavors and benefits of fruits and vegetables. But remember to choose your ingredients wisely and avoid adding bananas if you want to maximize the flavanol content of your smoothies.