What Is Quercetin?
Quercetin's impact on immune system health has become a subject of scientific research and has attracted much attention in recent years. Particular attention has been paid to its role in strengthening the body's resistance to the respiratory tract and enhancing the antiviral effects of zinc.
Quercetin is a flavonoid, a class of plant pigments that helps create the color of many fruits and flowers. Contains flavonoids, one of the reasons many foods, herbs and spices provide health benefits. For example, the benefits of berries, dark chocolate, and most herbal extracts (such as ginkgo, grape seed, pine bark, milk thistle, etc.) are thought to be directly related to the flavonoids they contain.
Health Benefits of Quercetin
Flavonoids may help enhance the body's response to environmental and other biological challenges. Experimental studies show that quercetin is an active flavonoid, making it ideal for helping the body cope with increasing challenges.
1. Quercetin may help protect cells
Quercetin can act like an "on button" to promote some beneficial effects in cells, such as cell repair. It also acts as an "off button" to help cells protect themselves from damage or infection.
2. Quercetin may help protect against oxidation
Quercetin may have antioxidant effects or may strengthen the body's enzymatic antioxidant system, which aids the body during periods of biological stress (immune priming, inflammation, and allergies).
3. Quercetin may help reduce inflammation
Quercetin controls the production and release of inflammatory mediators, substances that make the body's efforts to balance inflammation more difficult.
4. Quercetin may help improve body performance
Quercetin is thought to have a special effect on immune system health and may help improve the body's resistance to respiratory diseases. In fact, quercetin has been receiving particular attention recently due to its effects on immune function and its ability to increase intracellular zinc ion levels. Free zinc ions control an enzyme called replicase; viruses use replicase to replicate within human cells. Quercetin acts as an ionophore, helping to transport zinc ions into cells.
Clinical Study of Quercetin, Athletic Performance, and Immunity
One of the most scientifically studied applications of quercetin is to enhance athletic performance.
More than a dozen clinical trials have shown that quercetin may slightly help improve athletic performance. For example, in a study of 11 elite cyclists (male), supplementation with quercetin (1,000 mg per day) for 6 weeks improved 30 km time trial performance by 3.1%. 1 For elite athletes, this small improvement can be quite significant.
Another study, conducted on cyclists, came up with surprising findings. In this study, 40 trained male cyclists cycled for 3 hours a day over a 3-day period at approximately 57% of maximal load before, during, and 2 weeks after. , taking quercetin (1,000 mg daily) or placebo. The results show that quercetin not only optimizes physical performance, but also much more.
After three days of intensive exercise, only one of 20 cyclists developed upper respiratory congestion and other symptoms within 14 days, compared with nine of 20 in the placebo group. 2
The results are actually not that surprising. Quercetin has some benefits on white blood cell function and may provide some protection against respiratory viruses. It helps white blood cells move to areas of need and enhances their ability to destroy foreign molecules. Studies have shown that quercetin in cell cultures reduces the infectivity of a variety of different viruses to human cells and reduces the rate of viral replication through several pathways. 3
The unexpected finding sparked a follow-up trial of 1,002 adults aged 18 to 85. 4 The aim was to measure the effect of two different doses of quercetin (500 and 1000 mg/day) on symptoms of colds or upper respiratory tract infections (URTI) (controlled with placebo).
Subjects took the supplement for 12 weeks and recorded URTI symptoms daily. No significant effects were found overall, but when they looked at differences between groups, they found that a group of subjects aged 40 and older who reported themselves to be in good health and who took 1,000 mg of quercetin daily had fewer respiratory symptoms compared to the control group. 36%, and the total number of sick days decreased by 31%.
These results suggest that 1,000 mg of quercetin per day may have some effect in optimizing immune function. Achieving benefit in other groups may require higher doses or the use of more bioavailable quercetin formulations.
The synergistic effect of quercetin, zinc and vitamin C
While quercetin may have some direct effects in protecting against viral infections, its primary role is as an ionophore, helping to transport unbound free zinc into cells.
Free zinc ions can control the replication of many viruses. When many viruses infect cells, they insert a piece of genetic code and an enzyme called replicase to replicate the virus. Zinc blocks replication enzymes, thereby preventing viral replication or spread. This is one reason zinc is often recommended for cold relief.
However, for zinc to have this effect on viral replication enzymes, it requires open "ionophores" (special membrane channels that allow ions to enter the cell). Quercetin can act as a zinc ionophore, increasing intracellular zinc ion levels to prevent viral replication. This effect of quercetin may be responsible for the reduction in respiratory infections found in the above study. 5
Another nutrient partner of quercetin is vitamin C. When vitamin C and quercetin were combined in test-tube studies, the synergistic effect resulted in greater immune-boosting and anti-viral effects than when used alone.
Vitamin C can also regenerate active quercetin in the body. Antioxidants become inactive when they neutralize free radicals. When this happens to quercetin, vitamin C can make it reparatively active. Therefore, it is very important to get enough vitamin C (through diet and supplements).
In addition to regular consumption of foods rich in vitamin C (fruits such as berries, citrus and mango; green leafy vegetables; broccoli; bell peppers, etc.), it is also recommended to supplement with additional vitamin C (at least 60 mg per day, but at least 60 mg per day to obtain the most benefits) 250 mg).
