Are vitamins C and D effective in the fight against COVID-19?

Dec. 9, 2020

By: Rick Ansorge, UCHealth

As the world watches as the United Kingdom rolls out a mass vaccination program for COVID-19, experts caution that everyone must continue to religiously practice personal protective measures through at least the end of 2021.

The best evidence continues to support these three basic personal practices: mask-wearing, maintaining a physical distance of at least six feet from other people, and frequent hand washing.

A healthy lifestyle is also key to reducing your risk of contracting COVID-19 or developing serious complications if you do.

man walking his dog in the winter, getting exercise and sunlight, both help the body deal with COVID-19.
Staying healthy will help the body fight any virus. Source: Getty Images.

“People need to be doing things like regular and healthy eating, regular and healthy exercise, and regular and healthy stress management,” said Dr. Ian Tullberg, medical director of UCHealth Urgent Care locations throughout Colorado. “If we’re healthy, our bodies are better adapted to handle microbial insults than if we’re overweight and overly stressed.”

Beyond these common-sense measures, what else can people do to decrease their risk of falling prey to a pandemic that shows no signs of abating? Some preliminary evidence suggests that certain common dietary supplements may help.

A photo of Dr. Ian tullberg
Dr. Ian Tullberg

One of the most promising of these is the mineral zinc. “There’s some evidence in the medical literature that zinc has been helpful in terms of not curing a viral infection, obviously, but in helping with some of the symptoms of common cold viruses,” Tullberg said. “One of them is a coronavirus.”

COVID-19 is commonly referred to as a “novel” coronavirus, meaning new.

“So if you look at how zinc works in one coronavirus, it most likely is going to be somewhat beneficial,” Tullberg added. “So I would recommend taking it as a supplement of choice to help out with your (COVID-19) symptoms.”

Zinc lozenges and pills are the best choice. “You want to be careful how you take it,” Tullberg said. “You do not want to take it intra-nasally. You want to take lozenges.”

Cold-EEZE – for example – is a popular lozenge that has been shown to shorten the duration of the common cold. So far, it has not been specifically studied as a treatment for COVID-19 patients.

Each lozenge contains 13.3 mg of zinc. The manufacturer recommends dissolving (not chewing) a lozenge in the mouth every 2-4 hours until symptoms subside. For adults, the recommended daily dose is six lozenges. For children ages 12-17, the recommended daily dose is four lozenges.

Researchers don’t know if zinc lozenges and pills can help healthy people avoid a COVID-19 infection. “There isn’t anything showing there’s any kind of prophylaxis from taking it,” Tullberg said. “But is it going to hurt you? No, so if you want to take it, please do.’’

Zinc is an integral part of some very preliminary prophylactic regimens developed by some healthcare organizations. These include the Eastern Virginia Medical School (EVMS), which recommends a daily zinc dose of 75 mg-100mg.

EVMS also recommends daily doses of vitamin D3 (1,000-4,000 IU), vitamin C (500 mg), and melatonin (0.3mg-2 mg each night). The school also recommends twice-daily doses of quercetin (250 mg-500 mg) and says that a daily dose of famotidine (Pepcid) of 20-40 mg may be added to the mix.

Tullberg is dubious that such measures are necessary, especially in healthy people who already have normal levels of nutrients such as vitamin D3 and vitamin C.

“Taking extra amounts of those vitamins is not really going to be beneficial unless you’re already deficient in those things,” he said.

woman running into the sun, getting her vitamin D, which may help against COVID-19.
Vitamin D is known as the sunshine vitamin but it can also be found in some foods, such as in some fish and in egg yolks. Those deficient in Vitamin D may struggle more to fight COVID-19, according to some research. Source: iStock.

Vitamin D deficiency is common in the United States, especially among Hispanic and Black people. These two groups are significantly more likely than other groups to be infected with COVID-19 and to develop serious, even fatal complications.

Severe COVID symptoms are also more common among seniors and people who have obesity or high blood pressure.

Several recent studies have shown that people with low levels of vitamin D are more likely to test positive for the virus than those with normal levels.

For example, more than 80% of 200 COVID-19 patients in a Spanish hospital had vitamin D deficiency, according to one recent study. Men were more likely than women to have low levels, and people with low levels also had raised serum levels of inflammatory markers such a ferritin and D-Dimer.

Other research shows that hospitalized patients with an often-fatal COVID-19 complication – acute respiratory failure – had extremely high rates of vitamin D deficiency.

Many studies point to the beneficial effect of vitamin D on the immune system, especially regarding protection against infections.

In developing their prophylactic COVID-19 protocol, the EVMS researchers noted that U.S. patients with low levels of vitamin D were more likely to be hospitalized. They also observed that nations with low average levels of vitamin D were more likely to experience serious outbreaks and higher mortality rates.

EVMS included vitamin C in their protocol because it’s a potent antioxidant that’s critical to the immune-cell function. They cite a large-scale study of more than 11,000 patients showing that vitamin C reduces the risk of contracting colds. They also cite research showing that vitamin C reduced the symptoms of colds, about 25% of which are caused by other coronaviruses.

EVMS endorsed quercetin because it’s also a potent antioxidant. They cite preliminary research showing the supplement binds to the spike protein in the novel coronavirus, which may inhibit its ability to infect cells.

Although melatonin is best known as a sleep aid, it made the list because it can block inflammation, especially in the lungs. It also reduces the risk of fibrosis, which is one of the most serious COVID-19 complications.

older man drinks water after a workout
Dehydration puts you at higher risk for any type of viral or bacterial illness, urinary tract infections and pneumonia. Photo: Getty Images.

Although there’s no proof that any of these supplements can combat COVID-19, Tullberg said, there’s one intervention that will definitely make a difference: hydration.

“If you’re dehydrated, you’re at higher risk of any type of viral or bacterial illness, urinary tract infections, and pneumonia. If you have dry mucus members because you’re not drinking enough fluids, that decreases your immune response because it decreases your immune barrier.”