Do vitamin D, zinc, and other supplements help prevent COVID-19 or hasten healing? – . Health Blog

The appeal of safe, natural treatments is undeniable. This applies to age-old illnesses like colds and to new illnesses, especially when there is no known cure. So it makes sense that there is a lot of interest in supplements for COVID-19, be it for prevention or treatment.

In fact, zinc, melatonin, vitamin C, vitamin D, and other nutritional supplements have been prescribed since the earliest days of the pandemic.

But do they work?

Why Diet Supplements Could Help Prevent or Treat COVID-19

While science can show whether a drug is effective, we may not always know why. When antibiotics were first discovered in the 1920s, understanding of biology was limited. However, the lack of an explanation for their benefits hasn't stopped doctors from recommending these highly effective treatments.

When it is less clear whether a drug is working, biological plausibility – that is, a logical and well-understood reason why the drug should work – increases the expectation that it might.

What indicates that vitamin C, vitamin D, zinc, and melatonin could work against any virus?

• Vitamin C is an antioxidant that has long been considered a key player in healthy immune function.
• Zinc can have antiviral activity, whether by improving immune cell function, which counteracts viral infections, or by reducing the ability of viruses to multiply.
• Some evidence (see this study and this study) suggests that the combination of vitamin C and zinc can limit the duration and severity of cold symptoms.

The cases for vitamin D and melatonin are different. While there is also evidence that vitamin D and melatonin can have positive effects on immune function, a specific antiviral effect remains unproven.

What is the evidence that dietary supplements are helpful for COVID-19?

Although COVID-19 is a new disease, some clinical studies have explored the possibility that dietary supplements may be effective. And unfortunately, most of the evidence is inconclusive.

For example, some observational studies link lower blood vitamin levels with a higher risk of testing positive for the virus that causes COVID-19 (see this and this study). However, studies like this cannot prove that vitamin D protects people from infection. Also, a randomized controlled trial in people with moderate to severe COVID-19 who received high doses of vitamin D showed no benefit.

Similarly, a 2021 study of zinc and vitamin C showed no benefit for people with mild COVID-19. In this study, people whose symptoms did not require hospitalization were randomly selected

• Vitamin C only, 8,000 mg / day (the recommended daily amount is 75 mg / day for women and 90 mg / day for men)
• zinc only, 50 mg / day (the recommended daily amount is 8 mg / day for women, 11 mg / day for men)
• both supplements in the doses above
• no addition.

The researchers found that people who received the supplements individually or in combination showed no improvement in symptoms or a faster recovery compared to otherwise similar patients who did not receive the supplements.

Proponents of melatonin for COVID-19 have encouraged researchers to conduct studies with this supplement, but so far no convincing evidence of any benefit is available.

Why not take it without convincing evidence, why not take it anyway?

Despite questions about the general benefits of these supplements, many doctors began routinely prescribing them in the early days of the COVID-19 pandemic. The logic could have been that with so little knowledge of how best to treat this new infection, and a long history of safety for these supplements, why not?

However, there are significant dangers to consider. These include side effects, allergic reactions, drug interactions, the cost of unnecessary supplements, and the dangers of ingesting too much. For example:

• High doses of vitamin C can cause diarrhea or an upset stomach. There were also concerns that high-dose vitamin C supplementation might interfere with blood thinners or cholesterol-lowering drugs.
• High doses of vitamin D can cause severe symptoms such as stomach upset, kidney injury, and pancreatitis, and can even be life-threatening.

That said, people with nutritional deficiencies should be given supplements. Zinc or vitamin D deficiencies are not uncommon and can lead to poor immune function. Therefore, even without specific evidence linking supplement use with improvement in people with COVID-19, these supplements may be suitable for people suspected or confirmed to have a deficiency. For example, a person with low sun exposure and a diet low in dairy products may likely be vitamin D deficient. A simple blood test can confirm or rule out a vitamin D or zinc deficiency.

When taking supplements, it is safest to follow the recommended daily amounts your body needs, unless your doctor recommends otherwise (see this information for those ages 51 and older and this information for a full range of dietary supplements).

The final result

Based on science, there is reason to hope that dietary supplements like vitamin C or D, zinc or melatonin could help in the fight against COVID-19. While there is still no evidence of this, additional research may show a benefit in certain situations or with a different dose or formulation of the dietary supplement. So it's worth staying open.

In the meantime, we shouldn't reject the results of negative studies just because the results didn't meet our expectations. When it comes to preventing or treating COVID-19, I rely on the CDC's recommendations more than unproven supplements.

Check with your doctor before starting any supplementation. Ask about the dosage, other medications you are taking, and other health problems you have. The last thing you want to do is take a supplement that does more harm than good.

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