Health Benefits of Flavonoids
- Apr 6, 2015
- 4 min read
Everyone and their dog knows that fruits and vegetables are healthy and are an essential part of a balanced, and nutritious diet. Registered Dietitienas (RDs) and Registered Dietitian Nutritionists (RDNs) are constantly reminding us to "make half of your plate fruits and vegetables!" But there's more to fruits and vegetables than meets the eyes.
What are Flavonoids?
Flavonoids. Those sound...flavorful? Originally discovered in the early 1930's, scientists thought they had discovered another vitamin. They named their discovery, "Vitamin P." As they researched further, it became clear that this compound was not a vitamin at all, but was, in fact, a phytochemical. Phytochemicals are compounds produced by plants that may affect health. Flavonoids are one of the largest groups of phytochemicals with more than 4,000 varieties identified, all sharing a common chemical structure. They are divided into 6 sub-groups: anthocyanidins, isoflavones, flavanols, flavones, flavonols, and flavanones. The USDA has put together comprehensive databases that provide a detailed summary of some of the most common flavonoid-containing foods in our diet.
Health Benefits of Flavonoid-Rich Diets
There is evidence from studies to support the consumption of flavonoid-rich foods may decrease the risk for cardiovascular disease by reducing inflammation, improving vascular function, and reducing blood pressure. Two clinical studies found that drinking 4-5 cups of black tea for 4 weeks improved vascular function in patients with coronary artery disease and in patients with mildly high cholesterol. A high-flavonoid diet may also decrease the risk for stroke related to these same properties. Studies have found mixed results with high-flavonoid diets and reducing cancer risk. Some studies have found that flavonoids from certain food sources decrease risk of certain cancers but not all. More clinical human trials are needed to further test this.
There is more emerging evidence to support that consumption of flavonoid-rich foods is good for the brain. Inflammation, oxidative stress, and accumulation of transition metals due to body metabolism appear to be factors in the development of diseases such as Parkinson's and Alzheimer's. Flavonoids have antioxidant, anti-inflammatory, and metal scavenging properties and may help slow the decline or reduce the risk of these diseases. Many studies have found no significant effect of flavonoids on these diseases. However, one major study shows evidence that flavonoids, especially those in berries, may be associated with reduced cognitive decline in older adults. A 2012 study found that women who had the highest intake of flavonoid-rich berries had the slowest rate of cognitive decline. In addition to berries, the women typically consumed tea, apples, oranges, and onions.
Getting Flavonoids in Your Diet
How do we fit flavonoids into our diet? There is no dietary recommendation for the amount of flavonoids we should be getting. They are usually not listed on Nutrition Facts Panels as they are not required to be. Some foods, like teas, will list them on the label. So, we simply have to be aware of rich sources and incorporate those into our diet wherever we can! Here are some simple tips for getting more flavonoids into your diet:
Make half of your plate fruits and vegetables - emphasize dark green, red, and orange vegetables, citrus fruits, berries, and apples. Most Americans consume less than 50% of the recommeded intake for fruit and less than 60% of the recommended intake for vegetables. Make your plate colorful!
Don't forget about herbs! Herbs and spices are also rich sources of flavonoids. Adding parsley, oregano, and cinnamon can spice up your dishes and give you the beneficial flavonoids.
Drink tea. Black and green teas are rich in flavanols. Skip the coffee and get your caffeine from tea!
Choose a darker chocolate. Not everyone likes dark chocolate, but dark chocolate has more flavonoids than milk chocolate which has more than white chocolate due to the higher cocoa content. Go darker to get more flavonoids.
Eat the whole fruit with the skin. Flavonoids in fruit tend to be most concentrated near the skins, so eating the whole fruit will provide more benefit than peeled, mashed, or juiced.
Replacing one food with another is an easy way to get more flavonoids. Red and purple grapes have more than white grapes. Green and white teas have more flavonoids than black tea. Whole grains have more than refined grains.
Organic is not necessarily better in this case. Organic practices do not necessarily mean higher flavonoid content than conventional methods. Higher flavonoid content is not a key reason to purchase organic.
There are ways that flavonoid content in foods can be affected. Types of food processing such as fermentation, drying and heating as well as food preparation methods such as peeling, boiling, and baking can reduce flavonoid content. Some give the advice to buy products on the top layer of the store because light activates the production of flavonoids in foods. This is true, however, the increase that occurs in the grocery store is likely minimal at best.
A note of caution: flavonoid supplements are not all they're cracked up to be. Supplements are not regulated by the FDA and are therefore not required to guarantee their content. Few flavonoid products have been proven to deliver benefits of whole foods. Besides, imagine trying to distill a small compound found in plants to just that compound - pretty tough! It's easy to get more flavonoids in by eating a balanced diet, and that includes chocolate! Yes, chocolate is part of a balanced diet. Making simple substitutions can make this easier and more achievable. Happy eating!
Sources:
Kumar S, Pandey AK. Chemistry and biological activities of flavonoids: an overview. Sci World J. 2013; 2013:1-16.
Devore EE, Kang JH, Breteler MM, Grodstein F. Dietary intakes of berries and flavonoids in relation to cognitive decline. Ann Neurol. 2012; 72:135-143.
Rosenbloom C, Romotsky S. Flavonoids for Health. Dietetics In Health Care Communities: Connections. 2015; 40(3):1-2, 4-6.
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