This Popular Supplement May Help Inhibit Colorectal Cancer Development
New clinical evidence indicates that a widely used supplement may alter gut microbes involved in vitamin D biology and colorectal cancer processes.
Researchers at Vanderbilt University Medical Center have shown in a precision-focused clinical trial that taking a magnesium supplement can increase certain gut bacteria in people. These bacteria are known to produce vitamin D and to play a role in limiting the development of colorectal cancer.
The effect was seen mainly in women. The researchers suggest this difference may be linked to estrogen, which can influence how magnesium moves from the bloodstream into cells.
Genetics determine who benefits most
To understand who benefits most, the team examined gut microbiome data and colonoscopy findings from participants grouped according to their TRPM7 genotype. This gene is important for controlling how the body absorbs magnesium and calcium.
In earlier work from the same randomized trial, the investigators found that magnesium boosts vitamin D production and raises vitamin D levels in the blood. The new results indicate that magnesium also promotes vitamin D production directly within the gut. This locally produced vitamin D does not enter the bloodstream and instead acts where it is made.
These results from the Personalized Prevention of Colorectal Cancer Trial were recently published in The American Journal of Clinical Nutrition.
Gut microbes link magnesium to cancer risk
“Our previous study showed magnesium supplementation increased blood levels of vitamin D when vitamin D levels were low,” said Qi Dai, MD, PhD, 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 participants were divided into two groups: one that received the magnesium supplement and another that received a placebo. Their gut microbiome was analyzed from stools, rectal swabs, and rectal tissues. Among participants with adequate TRPM7 function, the magnesium supplement increased Carnobacterium maltaromaticum and Faecalibacterium prausnitzii, which were previously found to work synergistically to increase vitamin D and decrease colorectal carcinogenesis. Among those with inadequate TRPM7 function, the magnesium supplement reduced the abundance of F. prausnitzii in rectal mucosa.
From microbiome shifts to prevention strategies
Among 236 participants who all had a history of colorectal polyps, 124 underwent colonoscopies after completing the trial with a 3.5-year median follow-up time. A higher abundance of F. prausnitzii in rectal mucosa was associated with an almost threefold increase in developing additional polyps.
The findings suggest that magnesium supplementation treatment may decrease colorectal cancer risk in individuals with inadequate TRPM7 function. All together, these findings provide new insights into the interplays between nutrition and gut microbiome contributing to colorectal carcinogenesis and establish the foundation for a precision-based strategy for prevention of colorectal cancer in high-risk populations.
