Maybe it’s a happy coincidence, but foods high in magnesium also tend to be incredibly healthy. In that vein, two studies by Harvard researchers suggested that a diet of magnesium rich foods can help prevent the onset of Type II diabetes.
The 2007 National Diabetes Fact Sheet estimates that 23.6 million people in the USA suffer from diabetes, the vast majority of those being Type II. It was also the 7th leading cause of death in the USA in 2006.
Two separate teams of researchers at the Harvard School of Public Health and Harvard Medical School (HMS) published their findings on magnesium and the associated reduced type II diabetes risk in the January 2004 issue of Diabetes Care.
One study used data from the Women’s Health Study (WHS) to track 38,025 women from 1993 through 1999. The other study looked at 85,060 women identified by the Nurses Health Study (NHS), and who were tracked for 18 years, and 42,872 men chosen from the Health Professionals Follow-Up Study who were tracked for 12 years.
The participants in both studies were adults. None had any personal history of diabetes, cardiovascular disease or cancer.
Magnesium was shown to have played a positive role in reducing the risk of type II diabetes in both studies. The WHS team concluded that only overweight and obese women would have a reduced risk of type II diabetes onset with increased magnesium intake, while the NHS study found that men and women of all weight groups would have decreased type II diabetes risk.
HMS Assistant Professor of Medicine Simin Liu, the study’s author, said he believed the studies differed because of differing definitions of “overweight.” In the WHS study, a woman was considered overweight if her BMI (total body fat), was above 25, which is the lower limit of an overweight categorization as defined by the National Institute of Health.
The NHS study, though, used a BMI of 27 to define an overweight person. HMS Assistant Professor of Medicine Frank B. Hu, the study’s author, said this was because 27 is the median BMI for overweight people. He added that his findings on dietary magnesium intake were independent of BMI and would not have changed with a different BMI index. He defended his study as the more accurate study because of the larger pool of participants in the NHS group.
In spite of these disagreements, both studies agreed that the general population would benefit from increased dietary magnesium intake, and that Americans generally fall short of the recommended levels of magnesium rich foods in their diet. This has been one factor suggested as a cause of the increasing cases of type II diabetes in the population.
A previous Harvard study, published in the Journal of the American College of Nutrition, suggested that higher dietary magnesium intake may reduce the risk of developing type II diabetes, because women with higher magnesium consumption tend to have greater insulin sensitivity. Decreased insulin sensitivity, also called insulin fasting, is the immediate cause of type II diabetes.
“The primary concern here is not which group is affected the most,” Hu commented“Whether you are overweight or obese or not, you need enough magnesium.”
Magnesium Supplements Do Not Have This Same Effect
Even while magnesium rich foods have shown a positive effect in preventing diabetes, the studies further found that multivitamins and other magnesium supplements have not shown similar effects.
“The NHS study didn’t show any supplemental effect of magnesium, only of magnesium-rich foods,” said Dr. Liu.
“This suggests that there may be something else in those foods that works with magnesium to reduce diabetes risk. For now, I can only recommend foods that are rich in magnesium.”
Magnesium rich foods include whole grains, nuts, and green leafy vegetables, broccoli, tofu and other items.
Hu and Liu both agreed there should be continued research to better determine the effects of magnesium and magnesium supplements on type II diabetes.