Why You Likely Need More Vitamin D

How much sun did you get this summer? If your homebody tendencies extended into August, you may want to consider taking a few more strolls outside when the sky is clear and sunny—or taking a supplement if you’re Vitamin D-deficient, which a doctor can diagnose with a blood test.

The sunshine vitamin’s role in COVID-19 outcomes has become a topic of intense study as medical researchers rush to understand more about the novel disease. While claims that vitamin D can prevent you from catching COVID in the first place are mostly bunk, “there are a few studies showing that [COVID-] patients who have a vitamin D deficiency have worse clinical outcomes,” says Dr. Aldo J. Montano-Loza, Professor of Medicine, in the Division of Gastroenterology and Liver Unit at the University of Alberta. “[People] need admission to the hospital more frequently, [need] more admissions to ICUs, and some studies show an association with higher mortality.” The hypothesis, he explains, is not just in the vitamin’s well-established role in immune function, but its ability to regulate immune response. “Some patients develop cytokine storm syndrome, a severe state of inflammation triggered by the infection,” he says. The thinking is vitamin D treatment may help mitigate those storms.

Along with a team of researchers, Dr. Montano-Loza is preparing to launch a team study on whether administering controlled doses to COVID-19 patients severely deficient in the vitamin could play a role in treating the disease. In the meantime, “it’s good advice for all of us to have the recommended supplementation of vitamin D, maybe 1,000 IUs [international], but no more than 2,000 IUs per day,” though you should talk to your doctor first about supplements if you have bone or kidney conditions. Fortified dairy products and fatty fish, such as mackerel or salmon, are good sources of vitamin D–and if you’re going the supplement route, it’s best to take them with a meal.