Magnesium supplementation may change Vitamin D levels, study shows

New research suggests that magnesium may play a surprising role in regulating vitamin D levels in the body, raising them for those who are low and lowering them for those who are already high.

A study published in The American Journal of Clinical Nutrition examined nearly 240 participants, splitting them into two groups. One group received a tailored magnesium supplement, averaging 200 milligrams per day, while the other took a placebo. Researchers found that magnesium helps optimize vitamin D levels, but its effects depend on an individual’s existing vitamin D status.

Magnesium is essential for more than 300 enzyme systems in the body, including those responsible for converting vitamin D into its active form. “Low magnesium can impair this process,” explains Scott Keatley, R.D., co-owner of Keatley Medical Nutrition Therapy. “Correcting a deficiency may help raise vitamin D levels in people who are low by improving activation and transport.”

The study also revealed that magnesium may influence gut bacteria associated with vitamin D production, particularly in people with a specific gene called TRPM7. “Magnesium helps your body utilize vitamin D efficiently, both in the gut and throughout the body,” says Keri Gans, R.D., author of The Small Change Diet.

Despite these findings, experts caution that magnesium supplementation is not a universal solution. Vitamin D deficiency should still be primarily addressed with vitamin D supplements, adequate sun exposure, and a balanced diet. 

“It’s important to consume magnesium-rich foods or supplements thoughtfully, ideally under the guidance of a healthcare provider,” says Jessica Cording, R.D., author of The Little Book of Game-Changers.

Foods naturally high in magnesium include pumpkin seeds, almonds, spinach, black beans, and salmon, which also provide additional nutrients. Magnesium supplements are widely available, with glycinate and citrate forms generally better absorbed and tolerated. 

However, magnesium can interact with certain medications, including some antibiotics, diuretics, and proton pump inhibitors, making medical guidance essential.

Ultimately, the research highlights the interconnected roles of nutrients in the body. As Dr. Qi Dai, lead study author and professor at Vanderbilt University Medical Center, notes, “Magnesium doesn’t just support vitamin D absorption—it helps regulate its levels in a nuanced way, depending on individual needs.”