Magnesium linked to fewer gallstones

Increased intake of magnesium from dietary supplemental forms may decrease a man's risk of developing gallstones, suggests a new study published in The American Journal of Gastroenterology.

The highest intake of magnesium was associated with a 28 per cent reduction in the risk of gallstones, based upon data taken from 42,705 male Americans .

Gallstone disease is a major source of morbidity in developed countries and an important risk factor for gallbladder cancer. About 10-15 per cent of the US population (20 million people) have gallstones, and 1 million new cases are diagnosed yearly, according to the US National Institutes of Health.

Researchers from University of Kentucky Medical Center, Brigham and Women's Hospital and Harvard Medical School, Harvard School of Public Health, and the National Cancer Institute, assessed the consumption of magnesium among the study population using a validated semi-quantitative food frequency questionnaire (FFQ).

Over the course of an average of 13 years of follow-up, the researchers documented 2,195 cases of gallstones. The average intake of magnesium was calculated to 352.8 milligrams per day for the study population.

Men with the highest levels of magnesium intake (454 mg/d) were 28 per cent less likely to develop gallstones, compared to men with the lowest average intake (262 mg/d).

"Low magnesium consumption has been associated with high fasting insulin concentrations. Chronic hypersecretion of insulin, a feature of insulin resistance, may increase the cholesterol saturation index in the bile, and thus may facilitate gallstone formation," they added.

"In animal and clinical studies, a magnesium-deficient diet can elevate plasma triglycerides and decrease plasma HDL-cholesterol levels, and thus may increase the risk for gallstones."

In an accompanying editorial, Cynthia Ko from the University of Washington in Seattle made important points concerning the study results.

"The primary outcome of this study was symptomatic gallstone disease and cholecystectomy - the most advanced stages of gallstone-related diseases. These results suggest that low magnesium intake predisposes to symptomatic gallstones. However, these results cannot necessarily be generalized to asymptomatic gallstones, which comprise the majority of all gallstones," she said.

"Therefore, we cannot determine where in the pathophysiological process leading to symptomatic gallstones is magnesium intake important.

"For example, does higher magnesium intake protect against initial formation of gallbladder sludge and stones? Or, does higher magnesium intake decrease the likelihood of the already existing gallstones becoming symptomatic? Or both?" asked Ko.

Earlier dietary surveys show that a large portion of adults does not meet the RDA for magnesium (320 mg per day for women and 420 mg per day for men).

Bonnie - a great study that is a microcosm for why magnesium is critical for every organ. Ms. Ko's editorial questions whether the magnesium acts as a preventative, decreases the likelihood of existing gallstones, or both. In my experience, I would say both. What cannot be questioned is that supplemental magnesium is extremely important for broad-based health benefits.