Vitamin D Supplements and Long COVID: New Insights from Research

Recent research might provide a clue about why some people experience lingering COVID symptoms after recovering from the virus, particularly concerning vitamin D supplements.

A study conducted by researchers at Mass General Brigham explored whether high doses of vitamin D could impact outcomes related to COVID-19, specifically focusing on long COVID—a condition characterized by prolonged symptoms such as fatigue, breathlessness, and cognitive difficulties.

The findings were published in The Journal of Nutrition.

The clinical trial involved 1,747 adults who tested positive for COVID-19, along with 277 household members. Participants were divided into two groups: one received vitamin D3 supplements and the other a placebo for four weeks.

Dr. JoAnn Manson, the lead author of the study, expressed to a news outlet that the results might indicate a potential benefit regarding long-term symptoms.

“One of the main takeaways is that vitamin D supplementation shows promise in reducing the likelihood of developing long COVID, although it does not seem to influence the severity of the acute infection,” Manson noted.

Interestingly, while vitamin D did not appear to significantly alter short-term health markers like symptom severity or hospital visits, a closer look at participants who adhered strictly to the supplementation regimen did yield some noteworthy observations.

In that subgroup, about 21% of those taking vitamin D reported at least one lingering symptom eight weeks post-infection, contrasting with 25% among the placebo group.

“This study is one of the largest and most comprehensive randomized trials looking into the benefits of vitamin D during COVID,” Manson added. “Although we didn’t observe a reduction in COVID severity or hospitalizations, the initial signal we found regarding long COVID merits further investigation.”

Manson highlighted that the role of vitamin D in regulating inflammation could potentially explain its effects on longer-term complications following infection.

The researchers acknowledged certain limitations in their trial, such as conducting it remotely due to the pandemic and starting vitamin D supplementation a few days after participants’ COVID diagnoses. Manson pointed out that ideally, supplementation should begin before or right after infection.

She emphasized the need for larger studies to better understand whether vitamin D could indeed lower the risk or severity of long COVID symptoms.

Researchers are also planning more trials to evaluate whether vitamin D supplementation may assist those already experiencing long COVID symptoms.