Over the past several months the CDC has created a list of health conditions that increase the risk of severe illness from COVID-19.1 These include Type 2 diabetes, cancer, obesity, serious heart conditions and chronic kidney disease.

To reduce your risk, it would make sense to address the health issues that raise it. But some are not easily or quickly changed. However, you can make a significant difference by making one change to your daily routine: optimizing your vitamin D level.

Getting the right amount of Vitamin D is likely a beneficial strategy that is the easiest and least expensive of most options in minimizing the risk of any infectious disease in the coming months, including COVID-19 and the flu.

Vitamin D deficiency affects men and women of all age groups and races,2,3,4 including areas of the world where there is abundant sunshine, such as in the Mediterranean.5 This is vital since vitamin D deficiency has been identified in numerous studies as a risk factor for COVID-19 and related complications,6 including severe disease7 and death.8

Vitamin D Level Predictive of Disease Severity

Dr. Grigorios Panagiotou, from Newcastle Upon Tyne Hospitals in the U.K., has released data from yet another study demonstrating people who required intensive care were more often deficient in vitamin D than those who were not admitted to the ITU (intensive therapy unit).9

The data were collected from a single center, and Panagiotou and his team analyzed the inpatient information from 134 patients who had a positive COVID-19 test; he also looked at each person’s serum 25-hydroxyvitamin D level taken on admission to the hospital. The researchers were interested in the prevalence of vitamin D deficiency in relationship to COVID-19 severity and mortality.10

While the mean vitamin D levels were comparable between those in the intensive care unit and those in the medical unit, only 19% of the patients in the intensive care had levels over 50 nmol/L (20 ng/mL), compared to 39.1% of those in the medical unit. Essentially, they discovered that patients in the ITU were more likely to have a Vitamin D deficiency than those in the medical unit, even though they were younger.

Once patients were identified as having insufficient levels of vitamin D, they were immediately treated with Colecalciferol, a vitamin D supplement.11 The researchers theorize the lower mortality rates in their study may have been related to the rapid treatment for deficiency.12 Endocrine Today reports that the researchers wrote:13

“Vitamin D receptors are highly expressed in B- and T-lymphocytes, suggesting a role in modulating innate and adaptive immune responses. [Vitamin D] levels reach their nadir at the end of winter, and low levels are associated with increased risk of acute respiratory tract infections during winter [and are] mitigated by vitamin D supplementation.

Clinical trials involving vitamin D supplementation in COVID-19 are ongoing but may not report within the time frame of this pandemic.”

There are numerous other multinational studies with results that have demonstrated a strong association between vitamin D levels and disease severity. On the strength of that evidence, France, Scotland and the U.K. are taking supplementation and optimization of vitamin D seriously.14,15,16

Many of the past studies were observational and could not be used to make links to causation based on the design of the study. However, studies that can demonstrate causation are currently underway. For a discussion of the past, current and some of the planned studies, see “Vitamin D in the Prevention of COVID-19.”

New Study Focused on Question of Genetic Link

Data are being gathered from 628 health care workers from Nottingham University hospitals as scientists look for a genetic link that may explain why “blacks, Asians and minority ethnic people (referred to as BAME populations in Britain)”17 have a higher risk of serious illness from COVID-19. U.S. News reports this population makes up approximately one-third of those in critical care units, but only 13% of the general U.K. population.

The authors of other studies have realized various outcomes. In one, data were gathered from February 1, 2020, to April 25, 2020. Scientists used the data to analyze deaths in hospitals from confirmed cases of COVID-19.18 The researchers concluded:

“We have quantified a range of clinical risk factors for death from COVID-19, some of which were not previously well characterised, in the largest cohort study conducted by any country to date. People from Asian and black groups are at markedly increased risk of in-hospital death from COVID-19, and contrary to some prior speculation this is only partially attributable to pre-existing clinical risk factors or deprivation …”

In the past, some experts have identified differing socioeconomic and cultural reasons for the increased rates of disease and death. However, Ana Valdes, Ph.D., who is leading the Nottingham study, believes these reasons cannot completely explain the different infection rates. She is quoted in US News as saying:19

“… some of the people we had in our (Nottingham) hospitals who had the worst cases, really serious issues, were consultants and surgeons … exposure in the hospitals is really the same for Asians, blacks and whites. They are in the same wards. And at the same level of exposure, we see our Asian colleagues had a much higher prevalence of the symptomatic disease.”

Vitamin D Levels Also Being Assessed

Some experts are skeptical that a genetic link might be found. Winston Morgan, Ph.D. from the University of East London, makes the argument that:20

“There are certain genetic mutations that can be found among specific ethnic groups that can play a role in the body’s immune response. But because of the loose definition of race (primarily based on genes for skin colour) and recent population movements, these should be seen as unreliable indicators when it comes to susceptibility to viral infections. Indeed, race is a social construct with no scientific basis.”

Valdes admits that the critics of the hypothesis may be correct, but the way to find that out is through testing. She anticipates that if a link is established, it could lead to health recommendations involving dietary changes to help support a person’s immune response. A link between people of color and low vitamin D levels may lead to a recommendation for vitamin D supplementation.

Despite current evidence to the contrary,21,22 Morgan is also skeptical that vitamin D deficiencies increase the risk for darker-skinned people to experience serious COVID-19. In his article in The Guardian, he wrote:23

“Another target that has come in for speculation is vitamin D deficiency … In terms of a link to susceptibility to Covid-19, this has not been proven. But very little work on this has been done and the pandemic should prompt more research on the medical consequences of vitamin D deficiency generally.”

Vitamin D Works Beyond the Immune System

Although raising your vitamin D levels is an important step in protecting yourself from infectious disease, it also plays an important role in other areas of health. This means that while the threat of COVID-19 may have prompted you to take action to raise your vitamin D levels, you’ll also likely experience additional health benefits from doing so.

For example, vitamin D has a positive effect on Crohn’s disease, an inflammatory bowel disease characterized by dysbiosis. The results from one study with vitamin D supplements showed that vitamin D influenced the gut bacteria in those with Crohn’s disease but not in the healthy control group.24 The study team said they believed vitamin D may be able to modulate the composition of the bacteria and increase beneficial strains.

Vitamin D insufficiency has been associated with an increased inflammatory response in the body, leading to depression, pain and cancer. In one paper the writers addressed the need for effective treatment of depression and concluded:25

“Effective detection and treatment of inadequate vitamin D levels in persons with depression and other mental disorders may be an easy and cost-effective therapy which could improve patients’ long-term health outcomes as well as their quality of life.”

Researchers have also made an association between vitamin D levels and cancer. Based on a PubMed database search in 2006, researchers believe they found evidence that “The majority of studies found a protective relationship between sufficient vitamin D status and lower risk of cancer.”26

In 2018, a prospective study of several thousand participants in Japan produced results indicating that those with higher vitamin D levels had lower risks of all types of cancer.27 Other scientists have associated it with breast cancer tumor aggressiveness.28

In 2020, one team reported that based on a review of the research, there was evidence for the assertion that adequate vitamin D levels could prevent and improve the prognosis in some cancers, including colon cancer and blood cancers.29 Vitamin D is essential for maintaining a healthy skeleton because it regulates the metabolism of both calcium and phosphate.30 This helps reduce the risk of osteoporosis, frailty, falls and subsequent loss of independence.

Test First, Calculate and Then Supplement

I believe vitamin D is vital to improving immune function so that your body can resist viral infections. In “Vitamin D Combats Viral Infections and Boosts Immune System,” you’ll find an interview with three vitamin D experts and more information about how this simple step can reduce mortality risk from infectious disease, including COVID-19.

During the last part of winter, most people’s serum vitamin D levels drop to their lowest point. As I’ve written before, experts believe there will be a potential rise in the number of people exposed to SARS-CoV-2 this fall, which they are calling a “second wave.” It’s important to raise your vitamin D level to between 60 ng/mL and 80 ng/mL before that happens.

The only way to know your level is to do a simple blood test, which you can take at home. One of the easiest ways to do this is to participate in the GrassrootsHealth nutrition project, which includes a vitamin D test kit. Once you have your current level, you can calculate the supplemental dose you might need to raise your level.

You’ll find an explanation of how to interpret your vitamin D results and calculate the dose of vitamin D3 needed to raise the measurement to your desired level in “Your Vitamin D Level Must Reach 60 ng/mL Before the Second Wave.” You’ll find more help on how to time your supplements at GrassrootsHealth.

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