Is A Lack of Magnesium Related to Type 2 Diabetes in Obese Children?

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Magnesium deficiency is associated with insulin resistance in obese children, by M. Huerta and colleagues. Diabetes Care 28:1175-1181, 2005.

What is the problem and what is known about it so far?

Insulin resistance occurs when the body does not use insulin, a protein made by the pancreas, to turn glucose into energy. Children who are obese (seriously overweight) are more likely to have insulin resistance. This might be because they have low magnesium levels in their blood.

Magnesium is a mineral that helps the body break down carbohydrates and control insulin. It is found in many foods, including fish, milk, green leafy vegetables, nuts, whole-grain breads, and yogurt. Because obese children are more likely to eat an unhealthy diet, they might not get the magnesium they need. This could cause them to have insulin resistance and get type 2 diabetes later in life.

Why did the researchers do this particular study?

This study was done to see if obese children get enough magnesium in their diets and if a lack of magnesium can cause insulin resistance and eventually type 2 diabetes.

Who was studied?

Researchers studied 24 obese and 24 lean children who were between 8 and 17 years old.

How was the study done?

After not eating for 10 hours, each child was given a complete physical exam and had their weight and height measured. Researchers also took blood samples from each child to get their magnesium, blood glucose, and cholesterol levels. Then, the children took a survey about what kinds of foods they ate. Using the answers to the survey, researchers could see whether each child was eating enough foods that contain magnesium. Finally, researchers compared the children's magnesium levels with their insulin levels.

What did the researchers find?

This is the first study linking low magnesium levels to insulin resistance in obese children. Researchers found that 55% of obese children did not get enough magnesium from the foods they ate, compared with only 27% of lean children. Obese children had much lower magnesium levels in their blood than lean children. Children with lower magnesium levels had a higher insulin resistance.

The results of the diet survey showed that obese children got 14.4% less magnesium from the foods they ate than lean children. An important finding was that even though obese and lean children ate about the same number of calories per day, obese children ate more calories from fatty foods than lean children. Researchers found that lean children were more likely to have higher magnesium levels because they were more likely to eat low-fat foods that contain magnesium, such as fruits, vegetables, and high-fiber grains.

In addition to not eating enough foods that have a lot of magnesium, obese children might also have problems using magnesium from the foods they eat. Extra body fat can prevent the body's cells from using magnesium to break down carbohydrates.

What are the limitations of the study?

There were racial differences between the obese and lean groups that may have affected the study. African Americans, Asians, and Hispanics are more likely to get type 2 diabetes in general, and their higher risk for other factors that lead to insulin resistance may have affected the results.

This study also relied on the childrens' responses to a survey. This isn't the most reliable way to record what kinds of food the children ate.

What are the implications for the study?

Type 2 diabetes can be controlled or prevented through weight loss and by eating a healthier diet. Eating a variety of fruits, vegetables, lean meats, whole grains, and low-fat dairy products will not only prevent children from becoming obese, but it will also help them to get the vitamins and minerals their bodies need to produce and use insulin properly.

FOR MORE INFORMATION

101 Weight Loss Tips for Preventing and Controlling Diabetes, by Anne Daly, Linda M. Delahanty, and Judith Wylie-Rosett (Alexandria, Va., ADA, 2002)

Magnesiumintake and risk of type 2 diabetes in men and women, by R. Lopez-Ridaura and colleagues. Diabetes Care 27:134-140, 2004.

Magnesium,” Office of Dietary Supplements, National Institutes of Health