Magnesium, Inflammation, and the Risk of Type 2 Diabetes and Cardiovascular Disease

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Magnesium intake, C-reactive protein, and the prevalence of metabolic syndrome in middle-aged and older U.S. women, by Y. Song and colleagues. Diabetes Care 28:1438–1444, 2005.

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

Magnesium is an important mineral that helps the body to complete hundreds of functions, including making and controlling insulin. It also plays a role in lowering inflammation in the body. Headaches and muscle pain, for example, can occur when magnesium levels in the body are low.

Researchers believe that magnesium's role in lowering inflammation might also help to prevent the metabolic syndrome, a group of conditions including obesity (being seriously overweight), high blood pressure, high cholesterol (a fatty substance that builds up in the blood vessels), and high triglycerides (fats in the blood). People with the metabolic syndrome are more likely to get type 2 diabetes. They are also more likely to have high C-reactive protein levels.

C-reactive proteins are a sign of inflammation. Your liver produces C-reactive proteins when you are sick or injured. High levels of C-reactive proteins in your blood are an early sign of heart and blood vessel disease. When C-reactive protein is high, it means there is ongoing inflammation somewhere in your body, such as in your blood vessels, your gums, or your joints.

Why did the researchers do this particular study?

Only a few studies have been done to see whether magnesium intake is related to inflammation in the body. The researchers wanted to know if women who have more magnesium in their diet or take magnesium supplements had a lower risk of inflammation and the metabolic syndrome.

Who was studied?

A total of 11,686 female health professionals who were younger than 45 years old and had not had heart and blood vessel disease, a stroke, or cancer.

How was the study done?

The women answered questions about what kinds of food they ate, how big the portions were, and whether they took vitamin supplements. This information was used to figure out how much magnesium each woman took each day. Then, they measured the women's blood glucose, blood pressure, and height and weight to see if they had the metabolic syndrome.

What did the researchers find?

Women who got more magnesium in their diet were less likely to have the metabolic syndrome, inflammation in the body, and heart and blood vessel disease. Most women got magnesium from the foods they ate rather than from supplements. Overweight women and smokers benefited the most from magnesium. Women who ate more foods with magnesium were older, had a healthier weight, were more likely to exercise, and were less likely to have high blood pressure or smoke cigarettes. Their diets were lower in fat and cholesterol, and they ate more fiber.

Inflammation in the body was less common in women who got more magnesium. Women who had the highest magnesium intake had 12% lower C-reactive protein levels than women with the lowest magnesium intake. Again, the benefits of magnesium were more obvious in overweight women and smokers.

What are the limitations of the study?

By only looking at the women's diets, it is difficult to know if something other than magnesium is helping to lower inflammation. Also, only white female health professionals took part in the study, so the results might not apply to everyone.

What are the implications for the study?

This study shows that the magnesium found in a healthy, well-balanced diet can protect the body against inflammation and high blood glucose, conditions that can lead to type 2 diabetes and heart and blood vessel disease. For most people, the best way to make sure that they get enough magnesium is to eat a wide variety of whole grains, green leafy vegetables (such as spinach), low-fat dairy products (such as yogurt), and nuts. In general, eating a balanced diet that includes lots of fruits and vegetables also helps to prevent obesity and helps the body to get all of the essential vitamins and minerals it needs to stay healthy.

FOR MORE INFORMATION

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

“C-Reactive Protein: A Red Light For Your Health,” by Terri Kordella. Diabetes Forecast, June 2003.

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