Vitamin D shows potential to prevent long COVID symptoms postinfection

A study has found that taking vitamin D supplements reduces the risk of developing long COVID symptoms weeks after infection. Although the supplement did not decrease the severity of COVID-19 infections or reduced the number of hospital visits, it may have a connection to long COVID outcomes. 

Vitamin D is often linked to immune health, and its role in COVID-19 has shown mixed results in previous studies. This study investigated whether a high dose of vitamin D3 supplementation (a more potent form than vitamin D2) could influence the outcomes for people previously diagnosed with COVID-19.

“There’s been tremendous interest in whether vitamin D supplements can be of benefit in COVID, and this is one of the largest and most rigorous randomized trials on the subject,” says senior author of the study, JoAnn Manson, MD, DrPH, of the Mass General Brigham Department of Medicine, Boston, US.

“While we didn’t find that high-dose vitamin D reduced COVID severity or hospitalizations, we observed a promising signal for long COVID that merits additional research.”

Potential for long COVID

The study, published in the Journal of Nutrition, was conducted on 1,747 adults in the US and Mongolia, who were assigned 9,300 IU per day for two days, and then 3,200 IU per day for four weeks, or a placebo. It also included 277 household contacts, who were also given the vitamin D3 supplement or the placebo.

Participants started supplementation on average three days after a positive COVID-19 test.

Vitamin D3 supplementation did not reduce the risk of infection, the severity of infection, or hospitalization rates.Vitamin D3 supplementation did not reduce the risk of infection, the severity of infection, or hospitalization rates. This also did not decrease for the household contacts that were supplementing with the high doses of vitamin D3.

However, they found that participants who continuously supplemented with vitamin D3 appeared somewhat less likely to report persistent symptoms eight weeks after COVID-19 infection than the placebo group.

“Long COVID, which can include symptoms of fatigue, shortness of breath, brain fog, other cognitive challenges, and more, continues to significantly impact people’s lives,” says Manson.

The new findings suggest a potential signal between vitamin D and long COVID. Among the participants who took the supplement, 21% reported at least one lingering symptom compared to 25% in the placebo group.

“We hope to conduct further research in larger populations on whether long-term vitamin D supplementation reduces the risks and severity of long COVID,” notes Manson.

Other supplements have also been highlighted for their potential for long COVID symptoms. dsm-firmenich previously proposed that omega-3 fatty acids may be a possible solution to the cognitive effects reported by some who have been infected with COVID-19.

A prior clinical trial revealed that a daily dose of vitamin D3 and vitamin K2 MK-7 can help improve symptoms of post-COVID-19. The single-site randomized controlled study used a vitamin K2 MK-7 ingredient supplied by Balchem (K2Vital MCT). The study confirmed the anti-inflammatory properties of the combination, highlighting the potential to fill a critical gap that could have global applications.