A recent study conducted by researchers at Vanderbilt University Medical Center has highlighted a crucial relationship between magnesium and vitamin D levels in the body. Published in the December issue of The American Journal of Clinical Nutrition, the randomized trial found that magnesium not only increases vitamin D levels in those who are deficient but also lowers them in individuals with excess amounts, indicating its regulatory role.
This discovery could clarify why vitamin D supplements do not yield consistent results across different populations. The findings may also shed light on the mixed results from previous studies linking vitamin D to serious health issues such as colorectal cancer and cardiovascular disease.
Magnesium’s Role in Vitamin D Regulation
The study involved 250 adults at higher risk for colorectal cancer, either due to known risk factors or a history of precancerous polyps. Participants received either magnesium supplements or a placebo, with dosages adjusted to their usual dietary intake. The results showed that magnesium enhanced vitamin D levels in those who were deficient while decreasing levels in individuals with high vitamin D.
Qi Dai, MD, PhD, Ingram Professor of Cancer Research and lead author, explained that the optimal vitamin D range seems to be in the middle of a U-shaped curve. This middle range is associated with the lowest risk of cardiovascular disease, suggesting that maintaining balanced vitamin D levels is crucial for health.
Understanding Mixed Results in Vitamin D Research
Despite previous research suggesting a connection between vitamin D and cardiovascular health, the recent VITAL trial failed to establish a clear link. Dai and co-author Martha Shrubsole, PhD, a research professor of Medicine in the Division of Epidemiology, are exploring whether magnesium could help explain these inconsistencies.
“There’s a lot of information being debated about the relationship between vitamin D and colorectal cancer risk that is based upon observational studies versus clinical trials,” said Shrubsole. “The information is mixed thus far.”
The researchers turned their attention to magnesium after observing that vitamin D supplements do not work uniformly for all individuals. Dai noted that magnesium deficiency can inhibit vitamin D synthesis and metabolism, which may explain why some people do not experience an increase in their vitamin D levels, even with high doses of supplements.
Magnesium deficiency is a widespread issue in the United States, with estimates suggesting that up to 80 percent of the population does not meet the recommended dietary allowance (RDA) for magnesium. Shrubsole emphasized the importance of addressing magnesium deficiency alongside vitamin D insufficiency, which is already recognized as a significant public health concern.
To raise magnesium levels effectively, researchers recommend dietary sources. Foods rich in magnesium include dark leafy greens, beans, whole grains, dark chocolate, fatty fish like salmon, nuts, and avocados.
The study’s findings add to the growing body of evidence indicating that maintaining proper magnesium levels may be essential for optimizing vitamin D’s health benefits. As research continues, understanding the interplay between these two nutrients could provide new insights into preventing diseases linked to vitamin D imbalance.
Additional co-authors from Vanderbilt include Xiangzhu Zhu, MD, Hui Nian, PhD, Harvey Murff, MD, MPH, Reid Ness, MD, MPH, Douglas Seidner, MD, and Chang Yu, PhD.
