Oct. 18, 1999 (Washington) -- White people with low levels of magnesium in their blood are more likely to develop type 2 diabetes than those with normal levels of the mineral, according to a study published in the current issue of the Archives of Internal Medicine. The finding might help pinpoint who is at risk of developing the condition. But more studies are needed to determine if magnesium supplements would prevent type 2 diabetes or help to treat it, the study's lead tells WebMD.
This is only an initial study, and further studies are needed following people on a low magnesium diet and people with a high magnesium diet to see who develops diabetes and who does not, according to lead author W.H. Linda Kao, MHS. "We are definitely not recommending [blood magnesium] screening yet" or changes in dietary recommendations, which already stress eating foods high in magnesium. Kao is a postdoctoral fellow in the department of epidemiology at Johns Hopkins University School of Hygiene and Public Health in Baltimore.
Kao and other researchers from Johns Hopkins, the University of Minnesota, and the University of North Carolina studied more than 10,000 nondiabetic individuals for a total of six years.
This study is believed to be the first of its type in humans to examine the suspected relationship between blood magnesium level, dietary intake of magnesium, and type 2 diabetes. Type 2 diabetes usually develops in adults and generally does not require injections of insulin.
"From the highest to the lowest [blood] magnesium levels, there was an approximate two-fold increase in the incidence rate" of type 2 diabetes, the researchers write. But this correlation did not show up among black study participants, a finding Kao says is "really puzzling."
Researchers suspect that because the incidence of diabetes is already higher in blacks than in whites, the effect of magnesium is lost among other risk factors, such as obesity, high cholesterol, and high blood pressure.
In a previous study that involved more than 14,000 individuals filling out food frequency questionnaires, "low dietary magnesium was associated with a risk of diabetes, which we didn't find," Kao says. "That is no surprise because the food frequency questionnaires are hard to complete." She tells WebMD that she believes a link does exist.
However, Trevor J. Orchard, MD, of the Rangos Research Center in Pittsburgh, writes in an editorial accompanying the study that "the likely interpretation" of the study is that diabetes itself is the cause of a low magnesium level. But the correlation the authors report is "barely significant," he writes.