A recent clinical trial led by researchers at Vanderbilt University Medical Center indicates that magnesium supplements may enhance gut bacteria that help prevent the development of colorectal cancer. This finding is particularly significant given that colorectal cancer is the third most prevalent cancer worldwide and the second leading cause of cancer-related deaths.
The study involved a double-blind randomized controlled trial with 240 participants who had a history of colorectal polyps, a known risk factor for colorectal cancer. Participants were assigned to either receive personalized magnesium supplements or a placebo over a period of 12 weeks. The magnesium dose was tailored based on the individuals’ calcium-to-magnesium intake ratios, typically set at approximately 2:1.
Previous research suggested that magnesium could boost blood levels of vitamin D, which is critical for bone health and linked to cancer prevention. According to Qi Dai, MD, PhD, a professor of medicine at VUMC and the study’s corresponding author, the current study expands on earlier findings by demonstrating that magnesium also promotes the growth of gut microbes, specifically Carnobacterium maltaromaticum and Faecalibacterium prausnitzii, which have been shown to inhibit colorectal cancer development.
Genetic Variability and Its Impact on Magnesium Supplementation
The research also examined how genetic variations, specifically in the TRPM7 gene, influenced the efficacy of magnesium supplementation. This gene is essential for magnesium regulation in the body, acting like a “magnesium gate” in cells. Variants in the TRPM7 gene can affect how well magnesium levels are managed.
Participants without the TRPM7 missense variant showed a significant increase in the abundance of C. maltaromaticum and, to a lesser extent, F. prausnitzii, with the most pronounced effects observed in women. This raises the possibility that hormonal factors, such as estrogen, may enhance the benefits of magnesium supplementation. Conversely, those with the TRPM7 missense variant experienced a reduction in these beneficial gut bacteria, indicating that genetic factors can alter individual responses to magnesium.
Findings and Implications for Colorectal Cancer Prevention
Follow-up colonoscopies revealed that participants with the highest levels of F. prausnitzii had a nearly 2.8-fold increased risk of developing new polyps compared to those with lower levels. In contrast, higher levels of C. maltaromaticum were associated with approximately an 85% lower risk of developing serrated polyps, which are associated with a heightened risk of colorectal cancer. However, this latter finding was only marginally significant, suggesting that further investigation is necessary.
Despite these promising results, the study has limitations. The increase in F. prausnitzii did not retain statistical significance after adjusting for multiple comparisons, necessitating cautious interpretation of the findings. Additionally, the trial’s demographic was fairly homogenous, with most participants being older, White, and from a single geographic area in Tennessee, US. This raises questions about the generalizability of the results.
The relatively short duration of the trial also means that long-term effects of magnesium supplementation on colorectal cancer risk remain uncertain. Nonetheless, the research opens the door for a possible “precision nutrition” approach, where genetic testing could inform which individuals might benefit most from magnesium supplementation.
The study is set for publication in The American Journal of Clinical Nutrition, emphasizing the need for further research to solidify these findings and potentially guide clinical advice in the future.
