Magnesium and the Metabolic Syndrome

Summarized by Robert W. Griffith, MD
June 19, 2006

Summary

Eating more magnesium is associated with a lessened chance of developing the metabolic syndrome, which often goes on to cause cardiovascular disease and diabetes.

Introduction

The metabolic syndrome, only 'discovered' in the last decade, is associated with increased risk of coronary heart disease and type 2 diabetes, and is estimated to occur in about a quarter of all American adults¹. The medical journal Circulation has now reported that a low intake of magnesium in the diet is linked to a greater frequency of the metabolic syndrome.

The mineral magnesium hasn't received as much attention as calcium or iron. Deficiency is only rarely reported, although it's regarded as an essential food component, and is important for the contraction and relaxation of muscles. Magnesium is also involved in the synthesis of protein, and helps certain enzyme function. Until now, available information on the mineral's influence on the risk of cardiovascular diseases or diabetes comes from studies in middle-aged and older adults or diabetic patients.

What was done

The investigators, who were from Northwestern Univesity, Chicago, obtained data from over 4,500 adults aged 18 to 30. They selected this age group in order to estimate possible early clinical changes that could lead to the cardiovasular and diabetic disease observed in older adults with low magnesium intake. Enrolment in the study, called the Coronary Artery Risk Development in Young Adults (CARDIA) Study, was in 1985 and 1986; since then, 5 follow-up exams have been completed. The average 15-year follow-up rate is greater than 90%. Presence of the metabolic syndrome was diagnosed using the accepted criteria¹. People with the syndrome at baseline were excluded from further analysis. Dietary information was collected at baseline and in year 7 of the study. The participants were classified at the end of the study period into one of four groups,or quartiles, depending on their magnesium intake.

What was found

Just over half the participants were female, and half were black. Over 600 or them were first diagnosed as having the metabolic syndrome during the 15-year follow-up period.

For every 10 of those in the lowest quartile of magnesium intake who had the metabolic syndrome, there were only 7 people in the highest quartile. In other words, there was a 30% lower risk for participants with the highest magnesium intake compared to those with the lowest.

Apart from this relationship between magnesium intake and the metabolic syndrome, there were similar relationships between magnesium and the components of the syndrome (blood pressure, waist size, etc). The relationships were similar after multiple adjustments were made for lifestyle and dietary factors; they were unaffected by gender or race.

What this means

This study shows that low magnesium intake in youing adults is associated with the development of the metabolic syndrome and its components, independent of the baseline body mass index or other physical, lifestyle, or dietary factors. The question remains whether increasing dietary magnesium will protect against the metabolic syndrome, and subsequently diabetes and coronary heart disease. The average magnesium intake in the lowest quartile of the study was about 200 mg daily, and in the highest about 400 mg daily (calculated based on a 2,000 calorie-a-day diet). The Recommended Dietary Allowance (RDA) for magnesium for 19- to 30-year-olds is 400 mg for males and 310 mg for females.

The obvious question is: "Should I take a magnesium supplement?" Probably not, unless your physician suggests it, based on symptoms and lab tests. But you should, of course eat plenty of the magnesium-containg foods, because they provide not only plenty of magnesium, but a whole range of good things that you need for a healthy lifestyle.

The best dietary sources of magnesium are vegetables, particularly dark green, leafy vegetables. Other good sources include soy products, legumes, nuts (such as almonds and cashews), whole grains (such as brown rice and millet), as well as fruits and vegetables such as bananas, dried apricots, and avocados.

Source

• Magnesium intake and incidence of metabolic syndrome among young adults. K. He, K. Liu , M. Daviglus,  et al., Circulation, 2006, vol. 113, pp. 1675--1682

Footnotes
1. (1) The metabolic syndrome requires 3 of the following risk factors to be present: (a) Waist size over 40 inches (102 cm) in men, or 35 inches (88 cm) in women. (b) Serum triglyceride level over 150 mg/dL (1.7 mmol/L). (c) Serum HDL ('good') cholesterol below 40 mg/dL (1.0 mmol/L) in men, or 50 mg/dL (1.29 mmol/L) in women. (d) Blood pressure over 130/85 mm Hg (either number), or being on blood pressure medication. (e) Fasting blood sugar over 110 mg/dL (6.1 mmol/L). Take the self-test, at the link below.

Related Links
Another Benefit of Magnesium?
Serum Iron Levels are Linked to the Metabolic Syndrome
Do You Have the Metabolic Syndrome?

Please take a moment to give us your comments. For questions about Health matters you may check our "Questions & Answers" Portal and Service.