Understanding the Nutritional Interaction: PPO and Flavanols
It has long been common practice to blend blueberries and bananas into smoothies for taste and texture. However, recent scientific findings suggest that while there's no harm in eating them together, this popular pairing may significantly reduce the nutritional payoff, especially when blended. The issue centers around an enzyme in bananas called polyphenol oxidase (PPO).
PPO is responsible for the browning reaction in bananas and other fruits when exposed to air. When blended with blueberries, the PPO from the banana breaks down the flavanols, a specific type of beneficial antioxidant abundant in blueberries. A 2023 study revealed that participants who consumed a smoothie containing both bananas and mixed berries had 84% lower levels of circulating flavanols compared to a control group. This means the body absorbs far fewer of the brain- and heart-health-promoting compounds.
Blending versus Eating Whole
One of the most critical nuances is the difference between blending the fruits and eating them whole. The blending process exposes the PPO enzyme to the flavanols more thoroughly and rapidly, accelerating the enzymatic reaction. When consumed whole, the enzyme and flavanols are not as intensely mixed, which may lessen the degradation effect. While more research is needed to confirm the exact impact of eating whole, the primary concern lies with blended preparations like smoothies.
Optimizing Your Fruit Consumption
For those who wish to maximize the antioxidant intake from their berries, there are several simple strategies to consider. Avoiding high-PPO fruits in your smoothie is the most direct solution. You can achieve a creamy texture with other low-PPO fruits and ingredients.
- Pair blueberries with low-PPO fruits: Consider blending blueberries with pineapple, oranges, or mango. These fruits are low in the polyphenol oxidase enzyme and will not interfere with flavanol absorption.
- Use alternative thickening agents: For creaminess, try adding ingredients like avocado, plain Greek yogurt, or plant-based milks instead of banana. Greek yogurt also adds probiotics, creating a powerful intestinal combination.
- Strategically time your intake: If you enjoy both fruits, simply eat them at different times. You could have a banana in the morning and a handful of blueberries with your lunch or as a separate snack later in the day. The body can still process and absorb the nutrients effectively when consumed separately.
- Add PPO inhibitors: To counteract the PPO enzyme, you can add PPO-inhibiting ingredients to your smoothie. Ascorbic acid (vitamin C), commonly found in lemon juice, can suppress PPO activity, helping to preserve the flavanols.
A Comparative Look: Blueberries vs. Bananas
Despite the PPO conflict, both fruits offer a wealth of health benefits on their own.
| Nutrient | Blueberries (per 100g) | Bananas (per 100g) | Key Benefit |
|---|---|---|---|
| Antioxidants | Very high (Flavanols) | Moderate | Cellular health, brain function |
| Potassium | Low (77mg) | Very High (358mg) | Heart health, blood pressure regulation |
| Vitamin K | Very High (19.3mcg) | Low (0.5mcg) | Bone health, blood clotting |
| Vitamin B6 | Low | Very High | Brain development, metabolism |
| Fiber | Good Source (2.4g) | Good Source (2.6g) | Digestive health, satiety |
| Sugar | Low (9.7g) | Higher (12.2g) | Energy source (caution for diabetics) |
Versatile Ways to Enjoy Blueberries and Bananas (Separately or with Care)
If you're still determined to enjoy both flavors, here are some recipe ideas that mitigate the PPO issue or separate the consumption.
- Blueberry & Banana Oatmeal: Stir blueberries into hot oatmeal after cooking. Top with sliced banana just before serving. The heat from the oatmeal helps denature the PPO, and the fruits aren't intensely blended.
- Separate Smoothie Approach: Make a blueberry smoothie with low-PPO fruits like pineapple and a separate banana smoothie. You can still enjoy both flavors in one meal without the nutrient conflict.
- Blueberry Pancakes with Banana Topping: Make fluffy blueberry pancakes and top them with slices of fresh banana and a drizzle of maple syrup. The cooked blueberries retain some benefits, and the banana is not blended in.
- Blueberry Banana Yogurt Parfait: Layer plain Greek yogurt with fresh blueberries and sliced bananas. The natural acidity of yogurt may help inhibit the PPO, but for best results, stir the blueberries in separately and top with banana slices.
- Baked Goods: Use the fruits in baked goods like muffins or bread. The high heat from baking will deactivate the PPO enzyme, allowing you to incorporate both flavors without worry.
Conclusion
Yes, you can eat blueberries and bananas together without any adverse health effects. The combination is a common and safe practice. However, recent research highlights that if your goal is to maximize the absorption of the flavanol antioxidants from blueberries, especially in a blended format like a smoothie, you should avoid combining them with high-PPO fruits like bananas. By understanding the nutritional nuances and using strategic food pairings, you can enjoy both delicious fruits while getting the maximum health benefits from each one.
Resources
- UC Davis News: Right Combo: Getting the Most Health Benefits From Fruit Smoothies
- Vitafoods Insights: Mixing berries with bananas limits bioavailability of flavan-3-ols
