Quercetin is a natural plant pigment that gives color to many fruits and vegetables, such as apples, onions, berries, and broccoli. It is also found in some beverages, such as red wine and green tea. Quercetin is one of the most abundant and widely studied flavonoids, a group of compounds that have antioxidant and anti-inflammatory effects in the body.
Antioxidants are substances that can protect your cells from damage caused by free radicals, which are unstable molecules that can harm your DNA and other cellular components. Free radicals are produced by normal metabolic processes, but also by exposure to environmental factors, such as pollution, smoking, and radiation. Too many free radicals can lead to oxidative stress, which is linked to various chronic conditions, such as heart disease, high blood pressure, and Alzheimer’s disease.
Anti-inflammatories are substances that can reduce inflammation, which is a natural response of your immune system to fight infections and injuries. However, chronic or excessive inflammation can also contribute to many diseases, such as arthritis, asthma, and diabetes.
Quercetin has been shown to have both antioxidant and anti-inflammatory effects in various animal and human studies. Some of the potential benefits of quercetin supplements are:
- Lowering blood pressure: High blood pressure, or hypertension, is a major risk factor for cardiovascular diseases, such as heart attack and stroke. Quercetin may help lower blood pressure by relaxing the blood vessels and reducing the production of a hormone called angiotensin II, which constricts the blood vessels. A meta-analysis of 17 randomized controlled trials found that quercetin supplements significantly reduced systolic and diastolic blood pressure compared to placebo.
- Improving brain health: Quercetin may protect the brain from oxidative stress and inflammation, which can impair the function and survival of neurons. Quercetin may also modulate the activity of certain neurotransmitters, such as dopamine and serotonin, which are involved in mood, memory, and learning. A review of 21 animal studies concluded that quercetin improved cognitive performance and prevented neurodegeneration in various models of brain disorders.
- Supporting immune function: Quercetin may enhance the immune system by stimulating the production and activity of immune cells, such as macrophages, natural killer cells, and T cells. Quercetin may also inhibit the release of histamine, a chemical that causes allergic reactions, such as sneezing, itching, and swelling. A study of 1,002 healthy adults found that quercetin supplements reduced the incidence and severity of upper respiratory tract infections, such as the common cold and flu.
- Aiding weight management: Quercetin may help regulate body weight by influencing the metabolism of fat and glucose. Quercetin may increase the breakdown of fat and decrease the formation of new fat cells. Quercetin may also improve insulin sensitivity and glucose uptake, which can lower blood sugar levels and prevent diabetes. A randomized controlled trial of 80 overweight or obese women found that quercetin supplements for 12 weeks reduced body mass index, body fat percentage, and waist circumference compared to placebo.
- Preventing cellular damage: Quercetin may prevent or slow down the growth and spread of abnormal cells, such as cancer cells, by inducing apoptosis, or programmed cell death, and inhibiting angiogenesis, or the formation of new blood vessels. Quercetin may also modulate the expression of genes and enzymes that are involved in the development and progression of cancer. A review of 37 human studies suggested that quercetin intake from dietary sources or supplements was associated with a lower risk of various types of cancer.
- Fighting free radicals: Quercetin is a potent antioxidant that can scavenge free radicals and protect your cells from oxidative stress, which is linked to chronic diseases such as cancer, heart disease, and diabetes. Quercetin may also help prevent or slow down the aging process by reducing the accumulation of oxidative damage in your DNA and proteins. Additionally, quercetin may modulate the expression of genes and enzymes that are involved in the antioxidant defense system, such as glutathione and superoxide dismutase.
- Relieving allergies: Quercetin may help reduce allergic reactions by inhibiting the release of histamine, a chemical that causes symptoms such as sneezing, itching, and swelling. Quercetin may also modulate the immune response and prevent the activation of mast cells, which are involved in allergic inflammation. Furthermore, quercetin may reduce the production of cytokines and leukotrienes, which are inflammatory mediators that worsen allergy symptoms.
- Reducing the risk of heart problems: Quercetin may help lower the risk of heart disease by improving the function and health of your blood vessels. Quercetin may relax the blood vessels and reduce the production of a hormone called angiotensin II, which constricts the blood vessels and increases blood pressure. Quercetin may also prevent the oxidation of LDL (bad) cholesterol, which can lead to plaque formation and atherosclerosis. Additionally, quercetin may inhibit platelet aggregation and thrombosis, which are processes that can cause blood clots and stroke.
Quercetin supplements are generally safe and well-tolerated, but they may interact with some medications, such as blood thinners, antibiotics, and cyclosporine. Therefore, it is advisable to consult your doctor before taking quercetin supplements, especially if you have any medical conditions or are taking any medications.
Quercetin supplements are available in various forms, such as capsules, tablets, powders, and liquids. The typical dosage ranges from 500 to 1,000 mg per day, but it may vary depending on the purpose and individual factors. Quercetin supplements may have a low bioavailability, which means that they are poorly absorbed and utilized by the body. To enhance the bioavailability of quercetin, some supplements may combine it with other substances, such as bromelain, vitamin C, or phospholipids.
Quercetin is a natural and powerful plant pigment that has multiple benefits for your health. By taking quercetin supplements, you may be able to lower your blood pressure, improve your brain health, support your immune function, aid your weight management, and prevent cellular damage. However, remember to consult your doctor before taking quercetin supplements and follow the recommended dosage and instructions.
