Risk of MS among women drops by over 40% with greater vitamin D intake

New Norway study finds lower risk independent of sun exposure

Written by Michela Luciano, PhD | January 14, 2026

• Higher vitamin D intake significantly lowers multiple sclerosis risk among women, a study from Norway found.
• This protective effect is independent of sun exposure, which suggests vitamin D itself is key.
• Increasing vitamin D through diet and supplements is a safe, cost-effective prevention, the researchers noted.

A greater intake of vitamin D, from both food and supplements, was linked to a 42% lower risk of developing multiple sclerosis (MS) among women living in Norway, according to a large prospective study.

“Our findings suggest that a higher dietary intake of vitamin D decreases the risk of developing MS,” the researchers wrote, noting that the study was conducted in a Nordic country where people produce insufficient vitamin D from sun exposure most of the year.

“The risk estimates were similar whether vitamin D came from food or supplements,” the team noted.

The results also supported the researchers’ hypothesis that vitamin D itself, rather than sunlight alone, modifies MS risk, according to the team.

The study, “Vitamin D intake and multiple sclerosis risk in the Norwegian Mother, Father and Child cohort,” was published in the Journal of Neurology, Neurosurgery and Psychiatry. 

Vitamin D, best known for its role in maintaining bone health, also plays a crucial role in regulating the immune system and supporting brain and muscle health.

The body usually produces vitamin D when the skin is exposed to sunlight. But people living at northern latitudes have limited sun exposure, so they often rely more heavily on diet and supplements to maintain adequate levels.

Foods high in vitamin D include fatty fish such as salmon and tuna, as well as beef liver and egg yolks. Many foods, such as milk, yogurt, orange juice, and cereals, are also fortified with vitamin D to give them an extra boost.

Investigating vitamin D intake vs. sun exposure

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