Too Much Iron Linked to Diabetes Risk

Updated 12:08 PM EST, Fri, Jan 2, 2009

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Most realize that diet plays a large role in one's risk of getting type 2 diabetes, but beyond sugar intake and obesity, it turns out that eating too much iron may put some at a higher risk for this disease.

In a study, published in Diabetes Care, researchers have found that women who eat too much of one particular type of iron, heme iron, had as high as a 28 percent increased risk of developing type 2 diabetes.

"Heme iron intake was positively associated with the risk of diabetes independent of other risk factors for diabetes," writes Dr. Swapnil Rajpathak, lead study author from the department of nutrition at the Harvard School of Public Health.

For the study, Dr. Rajpathak and colleagues followed over 85,000 middle-aged women over the course of 20 years. During that time, over 4,500 of the women developed type 2 diabetes. After ruling out other dietary factors that could have impacted diabetes risk, the researchers determined that heme iron, the type of iron found in animal products, was most closely linked to increased diabetes risk.

Since animal products have already been linked to heart disease, Rajpathak, suggests that his findings offer yet another reason to steer clear of a double serving of steak.

However, while red meat contains a relatively large amount of heme iron, fish chicken and pork also contains some amount of this mineral. Therefore, eating too much of any type of meat may increase the risk of diabetes.

While the exact mechanism is not understood, Rajpathak suggests that iron's role in the body is the cause of this link. Iron is involved in many of the body's processes that create excess reactive oxygen. Too much oxygen slowly damages the body, including the body's ability to respond to insulin, one of the causes of type 2 diabetes.

Other forms of iron, such as that derived from plant products, are less readily absorbed by the body, he explains, therefore they do not seem to impact diabetes risk.