SMOOTHIES, WITH THEIR incredible versatility and convenience, have emerged as a popular choice for a quick and nutritious meal or snack. They offer a flexible platform to incorporate various fruits, vegetables, and other nutritious ingredients. However, recent research suggests that one common smoothie ingredient, bananas, may negatively impact the bioavailability of certain beneficial compounds, particularly flavanols, in foods like berries.
Bananas are a versatile fruit often used in smoothies for their creamy texture and natural sweetness. They are also rich in essential nutrients like potassium, vitamin C, and vitamin B6. However, bananas contain polyphenol oxidase (PPO), which initiates enzymatic browning when the fruit is exposed to air. This enzymatic reaction is responsible for the brown discolouration that occurs when bananas are left out for too long.
The presence of PPO in bananas can also impact other smoothie ingredients, particularly those rich in flavanols. Flavanols, a type of flavonoid, are plant compounds that boast powerful antioxidant properties and potential health benefits. Foods like apples and berries, which are sources of flavanols, are often included in smoothies for their nutritional value and potential positive impact on health.
A significant study was conducted on a group of healthy men aged 25-60, specifically examining the influence of PPO-containing fruits like bananas on the bioavailability of flavanols in smoothies. The participants were divided into two groups, one consuming a banana smoothie with high PPO activity and the other consuming a mixed berry smoothie with low PPO activity. The results were significant and eye-opening, demonstrating that the consumption of flavanols in the high PPO banana smoothie notably decreased the levels of flavonols in circulation after consumption.
These findings suggest that foods made with PPO-containing fruits and vegetables can affect the bioavailability of flavanols. Similar research has shown that other foods, such as acai bowls, soups, sauces, and guacamole, also experience a decrease in flavanol levels after being pureed and exposed to oxygen at an elevated rate.
Despite these findings, bananas remain popular for smoothie preparation due to their taste and texture. However, individuals looking to maximise the flavanol content of their smoothies may consider alternatives to bananas, such as pineapple, oranges, mango, or yoghurt, which have lower PPO activity.
To create a nourishing smoothie, it’s highly recommended to start with a base of leafy greens like spinach or kale, add fresh or frozen fruits for flavour and nutrition, incorporate a protein source such as Greek yoghurt, nut butter, or protein powder, and include a liquid such as almond milk or coconut water. It’s also crucial to avoid adding excessive sugar or sweeteners and to actively experiment with different flavour combinations to find what works best for you and your health goals.
While bananas and other fruits like avocados can contribute to smoothies’ creaminess and nutritional content, it’s essential to be mindful of their potential impact on flavanol levels. Drinking smoothies soon after preparation and preventing them from turning brown can help maintain the integrity of flavanols.
In conclusion, while bananas may negatively impact the bioavailability of flavanols in smoothies, it’s crucial to consider the overall nutritional content of your diet. A well-rounded diet that includes a variety of proteins, grains, healthy fats, and fruits and vegetables will help ensure that you receive essential nutrients and health benefits, regardless of specific smoothie ingredients. Smoothies can still be a convenient and delicious way to boost your intake of nutrients, provided that you take the initiative to make informed choices about ingredient selection and preparation methods.
