DOI: 10.1016/j.ajcnut.2025.09.011Researchers from Vanderbilt University Medical Center have demonstrated in a precision-based clinical trial that a magnesium supplement increases gut bacteria in humans that have been shown to synthesize vitamin D and inhibit colorectal cancer carcinogenesis. These results from the Personalized Prevention of Colorectal Cancer Trial were published in The American Journal of Clinical Nutrition. "Our previous study showed magnesium supplementation increased blood levels of vitamin D when vitamin D levels were low," said Qi Dai, MD, Ph.D., professor of Medicine. "The current study reveals that magnesium supplementation also increases the gut microbes which have been shown to synthesize vitamin D in the gut without sunlight and locally inhibit colorectal cancer development." The findings suggest that magnesium supplementation treatment may decrease colorectal cancer risk in individuals with inadequate TRPM7 function.