Quercetin, Zinc, Vitamin C and Vitamin D3: Can They help Against Coronavirus? (2022)
The claim: Vitamin D, Vitamin C, Zinc and Quercetin can prevent or treat COVID-19?Since the early stages of the pandemic, people have claimed supplements like quercetin, zinc, vitamin D and vitamin C can help treat and prevent COVID-19. But public health organizations and experts say there is little evidence these products are effective at treating or preventing COVID-19?
|McCullough et al. Reviews in Cardiovascular Medicine, 2020|
COVID-19 kills some people and spares others. How do you ensure that you are on the right side of the statistics? There are just too many self-proclaimed medical experts recommending all kinds of supplements for COVID-19 out there. On one side are experts telling you that supplements don't work and you should avoid them and just rely on wholesome foods. On the other, are experts telling you to take all kinds of supplements that will help protect you against COVID-19. Do they actually work? Some supplements do have evidence and some don't.
This guide is based on various references to scientific literature and hopefully, can help you make sense of the options and to separate the facts from fiction.
|Image credit: ClevelandClinic|
How do you deal with different expert groups dishing out conflicting guides? A common issue is that certain groups have pre-defined narrative that they would like to support. Therefore, only studies that support that pre-defined narrative are picked and cited as references. This is what we call as 'cherry-picking'. Cherry picking will naturally lead to a 'biased' decision. In order to avoid that, scientific information needs to be analyzed in a comprehensive, updated and non-biased manner in order to come up with the best 'evidence-based' decision.
1. Vitamin D and COVID-19Based on several publications and studies, vitamin D seems to be the “most promising” supplement for COVID-19 protection. Many studies have showed the link between vitamin D deficiency and COVID-19.
2. Quercetin and COVID-19
There is evidence that vitamin C and quercetin co-administration exerts a synergistic antiviral action due to overlapping antiviral and immunomodulatory properties and the capacity of ascorbate to recycle quercetin, increasing its efficacy.
- Quercetin oral 500 mg twice a day.
- Vitamin C 3000 mg
- Vitamin D3 5000 IU
- Zinc sulphate 220 mg
3. Vitamin C and COVID-19
Word of Caution - The U.S. Recommended Dietary Allowance (RDA) for vitamin C is 75 to 120 milligrams per day. Taking large doses of vitamin C (ascorbic acid) on a regular basis lowers your level of copper, so if you are already deficient in copper and take high doses of vitamin C, you can compromise your immune system.
Temporarily taking megadoses of vitamin C supplements to combat a case of the cold or flu is likely not going to cause a problem.
Many vitamin C supplements that are above the US RDA are sold in the market. It’s important to seek a physician’s advice if you intend to take high dose vitamin C on a long term basis. High doses of vitamin C (over 500 mg per day) over the long-term may increase the risk of cataracts. High-dose vitamin C can also reduce the effectiveness of certain medications and interfere with certain blood tests.
4. Zinc and COVID-19Foods that are high in zinc include oysters, crab, lobster, mussels, red meat, and poultry. Cereals are often fortified with zinc. Most multivitamin and nutritional supplements contain zinc.
Taking zinc long term is typically safe for healthy adults, as long as the daily dose is under the set upper limit of 40 mg of elemental zinc (PubMed).
Excessive doses may interfere with copper absorption, which could negatively affect your immune system as it can cause copper deficiencies, blood disorders, impair the absorption of antibiotics and potentially permanent nerve damage or loss of smell.
Zinc Sulphate is also part of Dr. Vladimir Zelenko anti-coronavirus experimental protocol. Please take note that the protocol is experimental and has not been 100% proven. Do discuss with your doctor before taking the medication as per the protocol. You can check out his publication in the International Journal of Antimicrobial Agents.
Based on the statement released on 2 October (2020) by the previous U.S. president’s (Donald Trump) physician, zinc is also part of the treatment given to the US President. According to the president's physician, "Trump has been taking zinc, vitamin D, famotidine, melatonin and a daily aspirin.”
5. Melatonin and COVID-19
"Patients who used melatonin as a supplement had, on average, a 28% lower risk of testing positive for SARS-CoV-2. Blacks who used melatonin were 52% less likely to test positive for the virus."
- Melatonin: 6 mg before bedtime (causes drowsiness).
ConclusionDo take note that the dosages for micronutrients or vitamins are higher for treatment as opposed to maintenance or preventive. This is probably due to higher demand of the body or the deficiency of the micronutrients are worse during a complicated viral infection. However, for prevention or maintenance, the dosages for most of the micronutrients are much lower.
- Wear protective face mask. This is to protect not only yourself but others.
- Abundant evidence suggests that eating whole in fruits, vegetables and whole grains—all rich in networks of naturally occurring antioxidants and their helper molecules—provides protection against free radicals.
- Getting Enough Sleep
- Avoid sugar, red meat and processed foods.
- Don't smoke.
- Take steps to avoid infection, such as washing your hands frequently, using hand sanitizer and cooking meats thoroughly.
- Try to minimize stress.
- Drink enough water to keep your body hydrated.
- Avoid excess alcohol.
- Avoid crowded areas.
- Regular physical activity (outdoor activities may not be allowed in countries with 'lock-down'). Those with active lifestyle has lower risk if hospitalised as compared to those with sedentary lifestyle (Infectious Diseases and Therapy, 2021)
- Consult your nearest local healthcare provider if you have any doubt.