There is no clinical evidence to prove low levels of Vitamin D lead to severe COVID-19 symptoms but there is a definite connect between the “sunshine vitamin” and immune responses to the disease, say experts as the pandemic spreads across the world and concerns mount over a new mutant strain.
Stressing that Vitamin D is inexpensive and has negligible risk when compared to the considerable risk of COVID-19, global researchers on the disease have asked governments to make it part of their strategy against the novel coronavirus.
Many factors such as age, being male and comorbidities are known to predispose individuals to higher risk from exposure to SARS-CoV-2, but inadequate Vitamin D is by far the most easily and quickly modifiable risk factor with abundant evidence to support a large beneficial effect, said Prof Afrozul Haq, former dean of the School of Interdisciplinary Sciences and Technology (SIST) at New Delhi’s Jamia Hamdard University.
He is one of the 170 experts who earlier this month wrote an open letter on the matter.
Calling for immediate widespread increased Vitamin D intake, the letter posted on the website vitamindforall.org states that “research shows low vitamin D levels almost certainly promote COVID-19 infections, hospitalisations, and deaths”.
“This campaign group of Vitamin D and COVID-19 researchers, including myself, started the process to write this letter for the purpose to make all aware about the benefits of Vitamin D supplementation in COVID-19 infected patients and sending this letter to all health ministries, healthcare workers, governmental bodies and NGOs,” Haq told PTI.
According to the letter, which had 171 signatories by Wednesday, evidence suggests the possibility that the COVID-19 pandemic sustains itself in large part through infection of those with low Vitamin D and deaths are concentrated largely in those with deficiency.
“The mere possibility that this is so should compel urgent gathering of more vitamin D data. Even without more data, the preponderance of evidence indicates that increased vitamin D would help reduce infections, hospitalizations, ICU admissions, & deaths,” it said.
As debate on the matter escalated, immunologist Vineeta Bal added a note of scepticism, noting that most of the experts are based in developed countries where Vitamin D daily supplementation may be feasible, practical and affordable.
“But that is not the case with India. Vitamin D deficiency is extremely common in India. Regular supplementation is not part of standard recommendations, not even for pregnant women,” Bal, visiting professor at Pune’s Indian Institute of Science Education and Research, told PTI.
“If individuals are heavily deficient, supplementation as recommended in the letter is likely to take weeks or months to achieve desirable levels of Vitamin D in the serum,” she said.
The scientist added that this cannot be considered an emergency measure, when the country lacks manpower and facilities even for the vaccine programme.
In her view, Vitamin D supplementation should be a long-term, non-emergency measure and something that could be useful in the COVID-19 scenario as well.
“Not just Vitamin D, other vitamins and micronutrients such as zinc have also shown beneficial effects,” she explained.
According to Prof Srijit Mishra, another signatory to the letter, the recommendation is Vitamin D intake for adults of up to 4,000 international Units (IU) or 100 microgrammes (mcg) daily. Those at an increased risk of deficiency due to excess weight, dark skin, or living in care homes may need higher intakes.
“The current evidence suggests that 25-hydroxyvitamin D serum levels over 30 nanograms per millilitre (ng/ml), a test to measure Vitamin D level is a widely endorsed minimum to reduce COVID-19 risk,” Mishra, from Mumbai’s Indira Gandhi Institute of Development Research (IGIDR), told PTI.
Bal said Vitamin D is generally known to have many beneficial contributions in immune responses, and added, “There are no reports, to the best of my knowledge, where there are radical improvements brought about by supplementation of Vitamin D in normal individuals.”
In her judgment, Vitamin D can have an additional role to play along with other medications but not a primary role. The linkage between Vitamin D and better immune competence does exist based on experimental data, and data on patients is almost invariably associative and does not prove a cause-and-effect relationship, she said.
While no clinical trials have tested Vitamin D’s efficacy as a treatment or a preventive measure, several studies have found an association between low levels of Vitamin D and COVID-19.
However, a review of five of these studies by the National Institute for Health and Care Excellence (NICE) in the UK concludes that the studies provide no evidence that Vitamin D levels influence the risk of getting COVID-19 or dying as a result.
“There is no evidence to support taking Vitamin D supplements to specifically prevent or treat COVID-19,” authors of the study wrote.
Mishra also noted that the evidence so far on risk-factors of COVID-19 with low Vitamin D level is associational, with some studies pointing out that low levels of the vitamin had a higher risk in infection and positivity rates.
He said a communication from UK-based NNEdPro Global Centre for Nutrition and Health has brought out a 10-point summary on diet, nutrition and the role of micronutrients for combating COVID-19.
“The note identifies the relevance of various micronutrients, including Vitamin D. However, as the NNEdPro write-up clearly points out, this advice on nutritional adequacy should not be constituted as a substitute for key public health and medical advice on prevention,” Mishra said.