A recent clinical trial led by researchers at Vanderbilt University Medical Center has found that magnesium supplements may enhance gut bacteria that help protect against the development of colorectal cancer. The study highlights that the effectiveness of magnesium supplementation varies based on genetic factors and sex, indicating a more personalized approach to cancer prevention.
Colorectal cancer remains a significant health concern, ranking as the third most common cancer globally and the second leading cause of cancer-related deaths. Despite increased use of colonoscopies for cancer surveillance, the incidence of this disease continues to be alarming. The latest findings, published in The American Journal of Clinical Nutrition, could offer new insights into prevention strategies.
Qi Dai, MD, PhD, a professor of medicine at VUMC and the study’s corresponding author, noted the link between magnesium and vitamin D metabolism. “Our previous study showed magnesium supplementation increased blood levels of vitamin D when vitamin D levels were low,” he stated. The current study suggests that magnesium not only increases blood levels of vitamin D but also fosters beneficial gut bacteria that can inhibit the development of colorectal cancer.
The clinical trial involved 240 participants with a history of colorectal polyps, a known risk factor for cancer. Participants were randomly assigned to receive either personalized magnesium supplements or a placebo over a span of 12 weeks. The dosage of magnesium glycinate was tailored based on each individual’s calcium-to-magnesium intake ratio, typically around 2:1.
Researchers assessed changes in gut microbiota by analyzing stool samples, rectal swabs, rectal tissue, and blood samples before and after the supplementation period. They focused on two specific gut bacteria: Carnobacterium maltaromaticum and Faecalibacterium prausnitzii, both of which have shown promise in enhancing vitamin D synthesis in prior studies involving mice.
The study examined how variations in the TRPM7 gene, which regulates magnesium levels in the body, influenced the effects of supplementation. This gene acts like a “magnesium gate” in cells, and its functionality can impact magnesium regulation.
In participants without the TRPM7 missense variant, magnesium supplementation significantly increased levels of C. maltaromaticum and, to a lesser extent, F. prausnitzii. Notably, the response was strongest in women, suggesting a potential influence of hormones such as estrogen. Conversely, those with the TRPM7 missense variant experienced a reduction in these beneficial bacteria.
Exploratory follow-up colonoscopies revealed critical insights. Individuals with the highest levels of F. prausnitzii had nearly 2.8 times the risk of developing new polyps compared to those with lower levels. In contrast, higher levels of C. maltaromaticum were associated with an approximately 85% lower risk of serrated polyps, which are linked to increased colorectal cancer risk.
Despite these promising findings, the study has limitations. The increase in F. prausnitzii was not statistically significant after corrections for multiple comparisons, indicating caution in interpretation. The trial’s participants were primarily older, White individuals from Tennessee, which may limit the generalizability of the results. Additionally, the relatively short duration of the trial means the long-term effects of magnesium supplementation remain unclear.
The research suggests that magnesium supplementation could play a role in colorectal cancer prevention, particularly for women and individuals without certain TRPM7 genetic variants. This raises the possibility of a “precision nutrition” approach, where genetic testing could determine optimal candidates for magnesium supplementation. However, further research is essential before these findings can be widely applied in clinical settings.
As the fight against colorectal cancer continues, this study opens new avenues for understanding how dietary supplements can be tailored to individual genetic profiles, potentially leading to more effective prevention strategies in the future.