Magnesium’s effects on gut bacteria varied by gene variant
A placebo-controlled trial found changes in rectal-swab bacteria that depended on genotype. These results do not demonstrate cancer prevention in people.
Based on the published abstract. The full paper may contain additional methods, results and limitations.
The 30-second takeaway
Magnesium changed the abundance of certain bacteria in rectal swabs, with results differing by TRPM7 genotype. Among participants without the missense variant, both target bacteria increased relative to placebo. The clearest finding was for C. maltaromaticum after correction for multiple testing. This does not establish a benefit for colorectal cancer prevention.
The abstract reports bacterial changes, not human cancer outcomes, and does not state treatment duration.
What researchers found
C. maltaromaticum in rectal swabs
Magnesium versus placebo among participants without the TRPM7 missense variant. Assessment timing was not reported. This result survived correction for multiple comparisons.
Sampling location mattered
Researchers sampled stool, rectal swabs and rectal tissue. Evidence that treatment response varied with genotype appeared only in rectal swabs for the target bacteria, so the result should not be treated as a uniform change throughout the gut.
A less certain subgroup result
Among people carrying the variant, C. maltaromaticum decreased relative to placebo, but that result did not survive correction for multiple testing. The abstract also says the treatment effect on this bacterium appeared mainly in females.
The original publication
Magnesium treatment increases gut microbiome synthesizing vitamin D and inhibiting colorectal cancer: results from a double-blind precision-based randomized placebo-controlled trial.
Sun E, Zhu X, Ness RM et al.
Am J Clin Nutr · 2025
- PubMed ID
- 40946805
- Record checked
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