Newsfeed display by CaRP A magnesium rich-diet may help reduce the risk of metabolic syndrome and, perhaps, a heart attack or diabetes, researchers reported in Circulation: Journal of the American Heart Association.

Metabolic syndrome is a cluster of cardiovascular disease and diabetes risk factors including excess waist circumference, high blood pressure, elevated triglycerides, low levels of high-density lipoprotein (HDL) and high fasting glucose levels. The presence of three or more of the factors increases a person’s risk of developing diabetes and cardiovascular disease.

Magnesium can come from foods or supplements. Foods rich in magnesium include halibut, dry roasted almonds and cashews, spinach, whole-grain cereals, black-eyed peas, long-grain brown rice, kidney and pinto beans, avocadoes, bananas and raisins.

Previous studies indicate that magnesium can reduce the risk of the individual components of metabolic syndrome, but scientists lacked evidence of its efficacy against the syndrome.

"As far as we can determine, this is the first prospective evidence that shows magnesium intake provides a beneficial effect in the syndrome," said Ka He, M.D., Sc.D., lead author of the study and assistant professor of preventive medicine at Northwestern University in Chicago.

"We also saw that a higher magnesium intake was associated with a reduced risk of each individual component of the metabolic syndrome."

The observational study initially included 5,115 blacks and whites ages 18 to 30 enrolled in 1985 and 1986 in the Coronary Artery Risk Development in Young Adults Study (CARDIA). After excluding those with metabolic syndrome and diabetes at the beginning, and pregnancy in the study period, 4,637 participants (53.8 percent female) remained in the study.

The age of the participants at enrollment was important because "most of the evidence that magnesium lowers the risk of cardiovascular disease or diabetes comes from studies of older adults," He said. "People middle-aged or older are more likely to already have the onset of disease. Their lifestyle choices and health conditions may be affected by perceived ill health or treatment for existing disease that relates to individual components of the metabolic syndrome."

Fifteen years after enrollment, 608 of the participants had developed metabolic syndrome. For analysis, the researchers divided the volunteers into four equal-sized groups based on their magnesium intake. Only 16 percent took dietary supplements that contained magnesium.
The researchers found an inverse relationship between magnesium intake and the development of metabolic syndrome. The more of the nutrient consumed, the less a person’s risk.

Of the four groups, quartile 1 had the lowest magnesium intake, an average of 96 milligrams (mg) per 1,000 calories consumed. Quartiles 2, 3, and 4 had average ingestions, respectively, of 120.5 mg, 146.7 mg and 190.4 mg per 1,000 calories.

By year 15 of the study, 188 participants in quartile 1 had developed metabolic syndrome compared to 172, 131 and 117 in quartiles 2, 3, and 4, respectively. This translated into a 31 percent lower risk for volunteers with the highest magnesium intake compared to those with the lowest.

"We saw a risk reduction for the upper three quartiles but it was only statistically significant in the two highest-intake groups," He said. The Institute of Medicine recommends various dietary allowances (RDAs) for magnesium by gender and age group. RDAs:

For ages 14-18 are 410 mg daily for males and 360 mg for females.
For ages 19-30 are 400 mg for males and 310 mg for females.
After age 30 increases to 420 mg for males and 320 mg for females.
Are higher for females during pregnancy (40 mg for each age group).

He, however, warned against solely relying on magnesium to lower the risk of metabolic syndrome.

"This is an observational study," he said. "Without data from randomized clinical trials, we are not comfortable making any recommendation on a daily dose of magnesium intake in terms of metabolic syndrome prevention."

"Magnesium is just one component of a healthy diet, and a healthy diet is just one component of a healthy lifestyle," he said. "In general, people should eat more fruits and vegetables and reduce their intake of saturated fats and trans fats, get more physical activity, and stop smoking because a healthy lifestyle is important in disease prevention."

This study was funded by the National Heart, Lung, and Blood Institute.