Studies are taking place, but so far there’s not enough data to make definitive conclusions. An American Journal of Clinical Nutrition study in 2002 looked at regular tea drinkers in the Netherlands and discovered lower rates of heart disease in this population.
The National Institutes of Health has studied the benefits of quercetin as an antioxidant for cancer treatment and decreasing resistance to drugs.
A Mayo Clinic study points to the possibility that quercetin can help block the male hormones that cause prostate cancer. Some other potential positive effects of quercetin supplements are:
- Acts as a powerful antioxidant
- Helps lower bad cholesterol
- Lowers rates of heart disease with high consumption of quercetin-containing foods
- Improves lung function and lower rate of respiratory problems
- Helps allergies, such as hay fever, by working as an antihistamine
- May help prevent heart disease and cancer
More studies need to be completed on quercetin supplements before more doctors will recommend its use, however.
The source, form, and amount of quercetin have a huge impact on whether the supplement you take is any good. You can find it in powder form and coated tablets. Like many other products in a largely unregulated supplement industry, quercetin products vary greatly in their concentration and quality.
There are other reasons to wait for more information on quercetin. People are not sure what doses are effective and safe, and we don’t have information on the long-term effects of taking this supplement.
University of California, Berkeley has looked at quercetin and suggests that with further study, its benefits will be more definite.
The UC Berkeley Wellness Newsletter does recommend a diet heavy on foods with quercetin, including apples, raspberries, black and green tea, buckwheat, onions, red wine, red grapes, citrus fruit, cherries, broccoli, and leafy greens. These foods offer other obvious benefits as well, and the quercetin you’ll consume is in a safe form.