As Americans’ waistlines continue to expand, type 2 diabetes is becoming an increasingly important public health threat.

Formerly known as “adult-onset diabetes,” the condition was once considered an affliction of older adults. These days, type 2 diabetes is becoming more commonplace in children and adolescents.

According to David Katz, M.D., MPH, nutrition expert and director of the Prevention Research Center at Yale University School of Medicine, “Type 2 diabetes is an enormous problem in the U.S., and it’s getting worse. The disease is driven largely by obesity and insulin resistance.”

Insulin resistance is a condition in which the body cannot effectively use insulin, the hormone responsible for the regulation of glucose, or sugar, in cells and tissues. When food is broken down into glucose in the digestive tract, insulin’s job is to escort the sugar into cells, where it can be used for energy.

In folks with insulin resistance, the body doesn’t respond normally to insulin. Initially, this results in high insulin levels, although blood sugar levels remain normal.

Over time, insulin levels fall, and because glucose isn’t able to enter the cells properly, blood sugar levels rise. This series of events leads to a condition called pre-diabetes, and eventually, diabetes.

“At least 50 million adults in the United States have insulin resistance,” said Katz, author of “The Flavor Point Diet.” “When children are markedly overweight, up to one-fourth of them have insulin resistance, and some have undiagnosed diabetes.”

Currently, there is no commonly used test to diagnose insulin resistance, and initially, the condition may not produce any symptoms. In addition to obesity, risk factors for insulin resistance include elevated blood pressure, low levels of heart-healthy HDL (high density lipoprotein) cholesterol, and high triglyceride levels.

Adults over the age of 45, especially those who are sedentary, have a greater chance of developing the disorder. Women with a waist measurement of more than 35 inches, and men with a waist measuring more than 40 inches are also at increased risk of developing insulin resistance.

What can you do if you’re at risk? Eating a nutritious, well-balanced diet, losing excess weight and exercising regularly are smart strategies.

Beyond lifestyle changes, a supplement known as chromium picolinate may also reduce the risk of insulin resistance. “Chromium picolinate is a supplement that is showing a great deal of promise,” said Katz, who leads a National Institutes of Health-funded study on the effects of chromium picolinate on insulin resistance.

In the body, chromium picolinate plays an important function in the regulation of blood glucose and insulin levels. “Chromium picolinate is a co-factor that helps insulin do its job properly,” Katz said.

More than 40 scientific studies support the role of the mineral chromium, alone or in combination with the B-vitamin biotin, in improving insulin function and glucose metabolism in people with pre-diabetes, diabetes and insulin resistance. “Research also suggests that the supplement provides a weight control benefit, which is important, since insulin resistance may actually increase appetite, food intake, and weight,” Katz said.

A study presented at the 2005 American Diabetes Association annual meeting demonstrated that daily supplementation with chromium picolinate reduces weight gain associated with diabetic drugs, while significantly improving insulin sensitivity and blood sugar control.

Chromium is an essential mineral that is present in small amounts in foods such as yeast, whole grains and seafood. Still, many experts believe that the American diet doesn’t provide optimal amounts.

“There’s a difference between getting adequate amounts of chromium in the diet, versus taking a supplement to get the optimal amount,” noted Katz. “In the face of insulin resistance, optimal levels of chromium are necessary.”

In August 2005, the U.S. Food and Drug Administration issued the first-ever qualified health claim for chromium picolinate, stating that its use was safe, and may possibly reduce the risk of type 2 diabetes. “Chromium is a nutrient that we’re already ingesting,” Katz said, “and there is very little evidence to suggest toxicity.”

Numerous chromium supplements are available at health food stores and pharmacies. Chromium picolinate, however, is the specific formulation that received FDA approval, and the one most commonly used in scientific studies.

“Currently, the recommended dose is 400 micrograms, to be taken twice a day,” Katz said. Individuals who plan to take chromium picolinate, he added, should discuss it with their doctors first.

“When you’re taking any nutritional supplement,” Katz emphasized, “it’s important to remember that you’re supplementing, and not substituting. No mater how good a supplement might be, it’s never a substitute for a healthy diet or an active lifestyle.”