From the early days of the COVID-19 pandemic, researchers examining the question of why some people were better protected from the infection than others began to look at a possible role for vitamin D. The nutrient, which is obtained from food and exposure to sunlight, is known to contribute to a well-functioning immune system in a variety of ways, including defending the body from invading viruses and other pathogens.
“Vitamin D is cheap, easily available and relatively safe,” says genetic epidemiologist Fotios Drenos of Brunel University London. Investigating whether the vitamin could make a difference in COVID patients “was an important question to ask,” he says.
Researchers already knew that vitamin D can be helpful in staving off respiratory infections. A 2017 meta-analysis of 25 randomized controlled trials involving about 11,000 people concluded that giving daily or weekly vitamin D supplements reduced the risk of acute respiratory infections—with the strongest impact predictably falling on those who started off with a serious deficiency of the vitamin. That meta-analysis, led by Adrian Martineau of Queen Mary University of London, was updated this year with data from a total of 46 trials and 75,500 participants. Martineau’s team confirmed its earlier finding but determined that the impact of the supplements appears to be quite small.
Epidemiological data emerging early in the pandemic also suggested that the vitamin might be useful. People older than age 65 and people of color are more likely to have lower levels of vitamin D. Both groups face a higher risk of poor outcomes from COVID-19, although the reasons for their vulnerability are multifaceted. In addition, studies have shown that countries farther away from the equator—where levels of the vitamin tend to be lower because of less sunlight—have higher COVID death rates than those closer to the equator.
Taken together, such data points are far from conclusive, but they served as a spur to investigate further. Fortunately, several large, potentially relevant studies of vitamin D were already underway when the pandemic struck, and others were swiftly begun.
Scientific evidence on vitamin D
In Brisbane, Australia, cancer researcher Rachel Neale of the QIMR Berghofer Medical Research Institute has been leading the massive D-Health Trial, a randomized controlled trial of five years of vitamin D supplementation in 21,315 older adults. It has compared monthly high doses of the vitamin (60,000 international units) with a placebo and has looked at a wide range of outcomes, including heart disease, cancer, bone fractures and overall mortality. Acute respiratory tract infection has also been among the outcomes measured in the study, and with the COVID pandemic raging, Neale and her colleagues decided to examine those data early. Their analysis, published in the Lancet Diabetes & Endocrinology in January, showed that vitamin D did not reduce the risk of acute respiratory tract infection but may have slightly reduced the duration of symptoms. Neale points out, however, that vitamin D levels tend to be high in Australia because of the long hours of sunshine, so supplementation may have a lower impact there than in less sunny places.
Another researcher who started looking at the vitamin early in the pandemic—but in a more northerly latitude—is David Meltzer, a health economist and a professor of medicine at the University of Chicago.
- “I got an e-mail in the first week of March [2020] talking about the [2017] Martineau paper, and I was struck by the results, particularly in people who are deficient in vitamin D,” he recalls. “We had a lot of people being tested for COVID-19 in our hospital, and we had historical data from these individuals, so we cross-referenced the positive tests and the vitamin D data on record.”
- The results in a diverse population of 4,638 people were published in JAMA Network Open this past March. Meltzer and his colleagues found that the risk of a positive COVID test was 2.64 times greater for Black individuals with low levels of vitamin D than for those with higher levels. There was no significant correlation in white participants. “Chicago has long winters, and people with darker skin produce less vitamin D. Our northern location and the predominance of Black people attending the hospital allowed us to spot the link,” Meltzer observes.
The lack of a clear response from existing studies may reflect the limitations of the test design, including populations already rich in vitamin D, small sample sizes, or inconsistencies in dosage or measurement methods. Nevertheless, research activities with vitamin D are currently underway even more, among different study groups according to: racial diversity, geographical position, age criteria, number of covid virus antibodies.
COVID-19: How to boost the immune system with vitamins
A functioning immune system is crucial in the fight against COVID-19. To maintain it, the body needs sufficient vitamins and other nutrients. But that is exactly what many people lack
Wearing masks, keeping your distance, washing your hands — those rules currently apply around the globe. There is not much more we can do, except wait for an effective drug against COVID-19 to be developed. Right? No, not quite!
There is something else that is now more important than ever and that should be no less stressed than good hand hygiene. Something that has not gained a prominent place in either the public debate or in the catalogue of government recommendations: a functioning immune system.
Biochemist Adrian Gombart, who is doing research on the relevance of nutrients for the immune system at the Linus Pauling Institute of Oregon State University, wanted to change this situation. Together with his colleagues, he set about producing a review paper summarizing the results of studies on different nutrients and their influence on the human immune system. These are findings that could be an additional weapon in the fight against the novel coronavirus.
Nothing works without vitamins
"The measures being taken are all important. But it is also important that we pay attention to our nutrient status so that our immune system can function at all," said Gombart. This is especially important in stressful times like these, when we tend to comfort ourselves with junk food, he says. After all, getting enough nutrients is not really a focus of our interest at the moment.
Yet vitamins C and D and other micronutrients such as zinc, iron and selenium are much more than just "nice to have." In the worst case, a nutrient deficiency can open the door to the viruses because the body is unable to defend itself against the invaders. For people who belong to a risk group, the danger of a severe course of disease is then particularly high.
This comes down to simple biochemistry: "Every cell in our body uses different micronutrients to function," says Gombart. Micronutrients include vitamins, minerals and omega fatty acids.
Unlike macronutrients such as fat, carbohydrates and protein, the micronutrients do not provide the body with energy, but they are nevertheless essential for the basic functions of an organism — not only for cell metabolism, but also for the defense system.
Holding the lines of defense
Adrian Gombart's research focuses mainly on vitamin D. "A few years ago, our research group discovered that vitamin D regulates the expression of a gene encoding an antimicrobial peptide," he says. Such peptides are involved in the body's non-specific defense mechanisms. "Vitamin D is also involved in the regulation of other immune-related genes," Gombart says.
On the other hand, a vitamin D deficiency can leave a gap in our body's defenses. Intruders then have an easier time of it.
But in the best-case scenario, the human body can do a lot to defend itself. Intruding germs must first pass through the skin and mucous membranes. If they manage to overcome this first line of defense, the body reacts to the invaders with phagocytes, antimicrobial proteins and inflammation. These processes are among the body's non-specific defense mechanisms. But if this generalized defense does not help, things have to become more precise.
SARS-CoV-2 can be fought only by a very specific immune response. Lymphocytes detect foreign microorganisms and molecules alien to the body — such as viruses. The lymphocytes can then produce antibodies and go into battle like sharpshooters.
Vitamin C against pathogens
These processes can function as they are meant to only if the body is well-equipped — for example, with vitamin C. "Vitamin C is needed, among other things, to form reactive oxygen species, also known as oxygen radicals. These radicals are another of the body's weapons in the fight against pathogens," says Gombart. Vitamin C is also involved in the production of antibodies, without which the body cannot keep COVID-19 in check.
High doses of vitamin C are thus used to treat patients suffering from COVID-19 and undergoing intensive medical treatment, says Isabelle Schiffer.
Schiffer is a geneticist and gerontologist and the scientific spokesperson of the Forever Healthy Foundation.
Food or dietary supplement?
The positive effect of elderberry is that it contains numerous vitamins and trace elements. Both Isabelle Schiffer and Adrian Gombart believe that it is currently advisable to increase the dose of vitamins and other micronutrients with the help of supplements. Most people lack enough vitamin D in particular.
The German Federal Institute for Risk Assessment (BfR) does not share their view of the efficacy of supplements: "In principle, a balanced and varied diet provides the healthy body with all substances essential to life," it says in a statement.
However, the institute admits that there are exceptions to this rule: During pregnancy and breastfeeding, the need for nutrients is increased. Elderly people, who are the top risk group in the current situation, also often tend to not have enough of them.
There is much to suggest that the question of a functioning immune system deserves a higher priority in the political debate on public health. Healthy eating should not be a question of lifestyle but a measure for the prevention of disease. Just like thorough hand washing.
Is It Possible to Have a Vitamin C Overdose?
Supplement marketers go into overdrive during cold and flu season, advertising products that promise to decrease your odds of getting sick. Vitamin C is among the best-known, most accessible antioxidants that have been touted to help prevent you from getting sick.
Also called ascorbic acid, vitamin C is one of the many water-soluble nutrients found naturally in fruits and vegetables. Many people also take supplements to ensure they’re getting enough of it. This has raised concerns over the likelihood of an accidental overdose.
Too much vitamin C can cause undesirable effects. However, a severe overdose is rare and unlikely. The key is to learn how much vitamin C you really need.
How Much Is Too Much?
According to the National Institutes of HealthTrusted Source, the average adult woman requires 70mg of vitamin C a day. The average man requires 90mg. Recommended amounts are higher for pregnant and nursing women.
It’s important to discuss your individual nutritional needs with your doctor. The maximum recommended amount, or upper limit, is 2,000mg per day for all adults.
Taking more than the upper limit for vitamin C isn’t life-threatening, but you may experience side effects like:
- abdominal pain
- cramps
- diarrhea
- headaches
- nausea (and possible vomiting)
- sleeping problems
People with hemochromatosis are in danger of a vitamin C overdose. This condition causes your body to store excessive amounts of iron, which is exacerbated by taking too much vitamin C. This condition can lead to body tissue damage.
Vitamin C supplements may also interact with certain medications. This is especially true of medications for heart disease and cancer. Be sure to check with your doctor before taking a supplement.
Sources:
https://www.scientificamerican.com/article/can-vitamin-d-help-protect-against-covid/
https://www.dw.com/en/coronavirus-and-how-to-boost-the-immune-system-with-vitamins/a-53360766
