Quercetin is a member of the water-soluble plant pigments called flavonoids, which offer antioxidant protection against disease and inflammation in all cell environments. Quercetin is the most abundant flavonoid in the average diet, and it is a natural pigment found in plants and foods including onions, green and black tea, coffee, apples, berries, citrus, broccoli, some leafy green vegetables, beans, and wine.
- Provides antioxidant protection
- Offers allergy relief by inhibiting the release of histamine
- Supports cardiovascular health
- Supports healthy blood pressure
- Inhibits intestinal glucose absorption
- Supports healthy glucose levels
- Protects against insulin resistance
- Supports healthy blood lipid levels
- Reduces blood platelet aggregation
- Boosts immunity
- Provides neuroprotective effects
- May improve exercise performance
History of Usage
The name quercetin has been used since 1857 and is taken from quercetum, after the oak genus Quercus. Initially, quercetin was considered to be a vitamin and given the name “vitamin P.” It was identified after the Hungarian biochemist Albert Szent-Gyorgyi discovered bioflavonoids in 1937, for which he won a Nobel Prize. Quercetin was initially overlooked due to the fact that it did not appear to be a necessary micronutrient. As epidemiological studies demonstrated the beneficial effects of flavonoids on cardiovascular health in the 1990s, more researchers began doing in-depth investigations on quercetin.
Quercetin is one of the most abundant flavonoids in the diet, with an average daily consumption of 25-50 mg. Supplements containing quercetin are available in the form of tablets, capsules, powders, and tinctures.
Quercetin is not absorbed well on its own. It is more easily absorbed when combined with other compounds, such as vitamin C or digestive enzymes like bromelain. According to several studies, quercetin works synergistically with other flavonoid supplements such as resveratrol, genistein, and catechins. Quercetin exhibits antibacterial effects against almost all strains of bacteria, particularly those affecting gastrointestinal, respiratory, urinary, and dermal systems. Quercetin exerts anti-allergy effects by inhibiting the release of histamine from mast cells, acting as a natural antihistamine.
Quercetin has been demonstrated to reduce stomach acid output and lipid peroxidation in gastric cells, acting as a gastroprotective agent. It also inhibits Helicobacter pylori infection. Epidemiological surveys show that diets with more vegetables and fruits have protective effects against cancer. Quercetin has potential anticancer properties that include antiproliferative, growth factor suppression, and antioxidant protection.
Quercetin ,along with ascorbic acid, reduces the incidence of oxidative damage to human lymphocytes and neurovascular structures in the skin and inhibits damage to neurons. It has been shown to protect brain cells against oxidative stress.
Quercetin is now included in energy and nutraceutical drinks because of its vast benefits, including energy boost, antioxidant properties, anti-inflammatory, and enhancement of lung functioning. It is also gaining in popularity because of its pharmacological properties, including anti-inflammatory, antiviral, antimicrobial, cardiovascular, anticancer, antiobesity, neuroprotective, and a reproductive system protectant. The US market is expected to grow by $110 million by 2024 at a CAGR of 6.53%.
- Pregnant and nursing mothers should consult their health care provider before taking quercetin.
- Quercetin appears safe without side effects.
- If more than 1,000 mg is ingested, it may cause headache, stomach ache, or physical tingling sensations.
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