Getting enough magnesium in your diet could help prevent type 2 diabetes. Dr. Ka He of the University of North Carolina at Chapel Hill and colleagues have found that people who consumed the most magnesium from foods and vitamin supplements were about half as likely to develop diabetes over the next 20 years as people who took in the least magnesium.
In their study, the researchers looked at magnesium intake and diabetes risk in 4,497 men and women aged 18 to 30 years old, none of whom were diabetic at the study’s outset. During a 20-year follow-up period, 330 of the subjects developed diabetes.
The people with the highest magnesium intake, who averaged about 200 milligrams of magnesium for every 1,000 calories consumed, were 47 percent less likely to develop diabetes than those with the lowest intakes, who consumed about 100 milligrams of magnesium per 1,000 calories. The researchers noted in Diabetes Care, however, that large clinical trials testing the effects of magnesium on diabetes risk are needed to determine whether a causal relationship truly exists.
The results of this study could explain why consumption of whole grains, which are high in magnesium, is associated with lower diabetes risk. And while whole grains are a common source of magnesium, there are several other sources of magnesium to consider. Green vegetables such as spinach are good sources because the center of the chlorophyll molecule (which gives green vegetables their color) contains magnesium. Some legumes (beans and peas), nuts and seeds, and whole, unrefined grains are also good sources. Tap water can also be a source of magnesium, but the amount varies according to the water supply. Water that naturally contains more minerals is described as “hard.” “Hard” water contains more magnesium than “soft” water.
Several other studies have reached similar conclusions, such as the Nurses’ Health Study (NHS) and the Health Professionals’ Follow-up Study (HFS). The proposed reasons why an increased intake of magnesium could lower the risk for developing diabetes vary, but according to the National Institutes of Health, “Magnesium plays an important role in carbohydrate metabolism. It may influence the release and activity of insulin, the hormone that helps control blood glucose (sugar) levels. Low blood levels of magnesium (hypomagnesemia) are frequently seen in individuals with type 2 diabetes. Hypomagnesemia may worsen insulin resistance, a condition that often precedes diabetes, or may be a consequence of insulin resistance. Individuals with insulin resistance do not use insulin efficiently and require greater amounts of insulin to maintain blood sugar within normal levels. The kidneys possibly lose their ability to retain magnesium during periods of severe hyperglycemia (significantly elevated blood glucose). The increased loss of magnesium in urine may then result in lower blood levels of magnesium. In older adults, correcting magnesium depletion may improve insulin response and action.”
The lesson? “Increasing magnesium intake may be important for improving insulin sensitivity, reducing systemic inflammation, and decreasing diabetes risk,” Dr. He and colleagues wrote. “Further large-scale clinical trials are needed to establish causal inference and elucidate the mechanisms behind this potential benefit.”
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