Quercetin, also called a polyphenolic flavonoid and 3,3′,4′,5,7-pentapentahydroxyflavone, is a natural element in many foods. It has been studied and found to help with many common ailments, such as hypertension, cancer and high blood pressure. It can also increase energy, improve endurance and reduce after workout inflammation.
Where Does Quercetin Come From
Quercetin is a flavonoid. Flavonoids are pigments that give many plants, vegetables and fruits their color. Research has found that quercetin is in many fruits and vegetables. In fact, it is the most commonly eaten flavonoid and the most active of the bioflavonoids in laboratory experiments, according to the Memorial Sloan Kettering Cancer Center. Bioflavonoids are flavonoids that have biological activity in mammals.
Foods with the most quercetin are apples, citrus fruits, parsley, sage, tea, onions and red wine. Olive oil, leafy green vegetables, beans, grapes and other dark colored berries are also good sources.
Though a healthy diet is always the best way to ingest quercetin, those wanting to supplement their intake can take it in pill form. It is also extracted from plants to make natural yellow dye 10 for coloring food products. The first known extraction was in 1962, according to the National Center for Biotechnology Information.
There has been little research to prove what the exact dosage of quercetin should be. Those taking supplements should avoid taking more than 1 gram per day to avoid possible liver damage, according to the University of Maryland Medical Center.
Safety of Quercetin
Quercetin is safe in foods. Those taking a supplement may experience side effects of headaches and an upset stomach. According to the University of Maryland Medical Center, those with kidney problems, breastfeeding women and pregnant women should avoid quercetin supplements. Pregnant women should be particularly cautious because quercetin has been found to bind to DNA in vitro, which can inhibit antibiotics, according to the National Center for Biotechnology Information.
Proven Health Benefits
Flavonoids have very powerful healing properties, including anti-viral, anti-microbial, anti-inflammatory and anti-allergic potential, according to the Department of Pathology and Diagnostics of the University of Verona.
As an anti-inflammatory, it may protect against heart disease and cancer. A study by the Department of Nutrition at the University of North Carolina found that quercetin is just as good as or more effective than resveratrol in treating cancerous tumors.
It could also help men with pelvic pain. A study by Institute for Male Urology in Encino, California found that, “Therapy with the bioflavonoid quercetin is well tolerated and provides significant symptomatic improvement in most men with chronic pelvic pain syndrome.”
Quercetin is also an antioxidant, like many other flavonoids. Like other antioxidants, it may help protect cells from damage, get rid or neutralize damaging particles called free radicals, may prevent LDL (“bad”) cholesterol from damaging the heart and may prevent high cholesterol.
A study by the Division of Nutrition at the University of Utah found that quercetin reduces blood pressure in hypertensive subjects. It has also been used to strengthen capillaries, according to the National Center for Biotechnology Information.
Quercetin acts as an antihistamine. It blocks things that may cause allergic reactions, according to the Department of Medicine, Section of Infectious Diseases at the Boston University School of Medicine. Those with allergies may find that taking quercetin or eating foods rich in quercetin may prevent symptoms of allergies such as a runny nose or itchy eyes.
Does Quercetin Increase Energy?
Some people take quercetin to increase energy. In fact, cyclist Lance Armstrong was a strong proponent for quercetin as an energy supplement. It seems that it may help. In a study published by the US National Library of Medicine, researchers found that taking quercetin increases energy expenditure and persistently decreases circulating markers of inflammation. A study, published online by the International Journal of Sports Nutrition and Exercise Metabolism, found that taking quercetin can increase endurance without any extra physical training.