As a runner, you’re probably already paying attention to the foods on your plate – after all, nutrition can be a key aspect of performance. But have you ever heard of flavonoids in your foods? These compounds may have benefits for overall health (and maybe even athletic performance), and can be easily included in your daily routine!
But what exactly are they, and how can we eat enough? Let’s dive in…
Disclaimer: This post was written and reviewed by Chrissy Carroll, MPH, RD, RRCA Running Coach. It is for informational purposes only and should not be construed as individual nutrition advice. Consult your dietitian or doctor for personal nutrition advice.
Credit for some of the information below goes to fellow RDs Kim Stote, Kristi Crowe-White, and Taylor Wallace, who presented on this topic at FNCE 2022.
What are Flavonoids?
Flavonoids are a type of compound found in plants we consume, like fruits, vegetables, tea, and cocoa. At FNCE, presenters described these as “dietary bioactive compounds” – components in food that are not directly needed to meet basic human needs, but that have impacts on human health.
Flavonoids can be broken down into subclasses; here are some of the major types of subclasses and the food sources per research:
- Flavonols – onions, scallions, wine, tea, broccoli, berries, kale, lettuce
- Flavan-3-ols – tea, apples, berries, peaches, pears, chocolate, red wine
- Flavanones – grapefruit, lemon, lime, orange
- Flavones – parsley, oregano, artichokes, pepper, celery
- Isoflavones – soy, beans, peas, lentils
- Anthocyanidins – elderberry, berries, chickpeas, red cabbage, pomegranate, red grapes
Don’t worry, this isn’t going to get too sciencey – but it’s helpful to understand that there are different types.
Flavonoids and Health
Each subclass of flavonoids may have unique benefits for your body. They may have antioxidant properties, anti-inflammatory properties, and affect different cellular or enzymatic functions.
For example, research has shown that higher intake of flavan-3-ols is connected to better cardiovascular health, as evidenced by…
- Reduced blood pressure
- Improved flow mediated dilation (a measure of cardiovascular health)
- Reduced total cholesterol and increased HDL cholesterol
- Reduced HbA1c (a measure of blood sugar control)
That’s pretty incredible!
Research on flavonoids in general have also linked them to lower risk of upper respiratory tract infections and possibly lower risk of type 2 diabetes.
Interestingly, research suggests physical activity may enhance the uptake of active compounds from the flavonoids in the gut – so those regular runs are doing your body a favor in many ways! Your exercise routine may enhance your ability to absorb and use these compounds.
In fact, one study found the plasma level of these active compounds were 40% higher in regular runners compared to walkers (but walking still has beneficial effects too!).
Flavonoids and Exercise
In addition to the potential overall health benefits, can flavonoids play a role in exercise performance? The research isn’t super clear right now.
A 2021 systematic review in Nutrients found that 37% of the studies included in the review found a positive association between flavonoid intake and exercise performance. That’s certainly not a majority or anything conclusive.
The fact that not all studies have found improved performance could be due to no true effect – or could be because only specific flavonoids may play a role.
For example, when that systematic review broke down studies by subclass, they found that 54% of studies looking at anthocyanins found an improvement in athletic performance. Another review on anthocyanins noted that these benefits may be due to enhanced blood flow during exercise, metabolic pathways, and/or effects on peripheral muscle fatigue.
The lack of consistency in research could also be because specific foods have flavonoids that work synergistically with other compounds in that food. For example:
- Blackcurrant extract was linked to better sprint running performance in this study and cycling time trial performance in this study. (While this was research on an extract, you can eat and cook with black currants when they’re ripe).
- Citrus flavonoid supplementation helped cycling power output in a 2018 study.
- Another study looked at Haskap berries (blue honeysuckle), which are rich in anthocyanins. Ingesting these berries led to improved 5K time trial performance, and changes in heart rate and VO2 at submaximal running intensities.
- In this review, consistent flavanol intake from cocoa may improve mitochondrial efficiency during exercise. Another study found that two weeks of daily dark chocolate intake led to better cycling time trial performance. (There have not been many studies that found performance benefits with acute supplementation.)
- Decaffeinated green tea extract was found to improve cycling time trial performance over a 4-week period in a 2015 study. (The decaffeinated part is essential here, since we already know caffeine can boost performance.)
Dietary Recommendations for Runners
At this point, it’s clear that flavonoids are beneficial to health. It’s possible – but definitely not conclusive – that certain flavonoid-rich foods may play a role in performance. But what does that translate to as far as your diet?
Currently, the only dietary bioactive guideline that exists is for the flavan-3-ol subclass: 400-600 mg per day. That’s a food-based recommendation, not a supplement recommendation.
Considering the total flavonoid intake in the US is only about 200 mg per day – which is a total from all the subclasses – it’s clear most of us are probably falling short!
But you don’t have to get caught up in counting exactly how many milligrams you’re eating each day. Instead, consider these simple tips that can help you boost your intake:
- Drink a cup of green or black tea each day. (If you’re not a fan of tea on it’s own, try using it as the basis for liquid in a smoothie.)
- Eat a serving of berries each day. Strawberries, blackberries, blueberries, raspberries, cranberries – mix ‘em up! Berries are a great source of several flavonoid subclasses. You can have these as a snack, enjoy them over yogurt, put them on top of a salad, blend them in a smoothie…get creative. [Recommended recipes: beet green and berry smoothie, cranberry walnut overnight oats, and PB&J oatmeal.]
- Try to include a serving of fruits and/or vegetables at every meal and snack. For example, having pizza for dinner? Toss some mushrooms and spinach on there. Enjoying some jerky for a snack? Pair it with some dried cranberries.
- Mix up your produce! Make it a challenge to see how many different types of fruits and veggies you can include in your diet each week. Try new options from the store or farmer’s market. Or consider using a CSA which forces you to step outside your comfort zone a bit with their pre-picked selection.
- Include chocolate in your day! Yes, that’s a dietitian telling you that! 😉 This might be a few squares of dark chocolate, a homemade hot chocolate with cocoa powder, or blending cocoa powder into a nice-cream recipe. [Recommended recipes: chocolate banana baked oatmeal, chocolate cherry energy bites, and butternut squash brownies.]
- Add herbs and spices to your foods. Not only do these add flavor, but certain options also add a powerful punch of flavonoids. Consider parsley, thyme, oregano, and others.
- Jazz up plain water or seltzer water with squeezes of citrus, like lemon, lime, or orange. You can also consider refueling after a run with a big ‘ol glass of OJ – one of my fav post-run beverages! (My other fav is chocolate milk after a run).
- Research suggests the diversity and activity of your gut microbiome may influence how impactful flavonoids are, so it’s important to also eat foods that support that microbiome. You can do this by eating adequate dietary fiber (certain types help feed the gut bacteria). You can also incorporate food source of probiotics, which contain live cultures of healthy bacteria, like yogurt, kefir, sauerkraut, kimchi, or traditionally fermented vegetables.
The Bottom Line
Flavonoid-rich foods are linked to several health benefits, including cardiovascular health. While the link to exercise performance is less clear, it’s still smart for runners to include these foods regularly. Consider adding flavonoid-rich options like berries and tea to your regular routine, and include a wide variety of produce in your diet.
Feel free to pin this post to share with others or save for later.
- Should You Start Running Backwards? What The Research Says! - October 30, 2024
- Overstriding While Running: What It Is and How to Fix It! - October 29, 2024
- How to Start Running When You’re Out of Shape (Tips from a Coach) - October 29, 2024
Leave a Reply