Most cases of diabetes are the result of poor lifestyle choices over the years, says board-certified family practitioner Dr. David Brownstein, Newsmax Health reports.  

"Most people who are overweight are already prediabetic," he says. 

In healthy people, the pancreas secretes insulin which signals tissues in the body to absorb glucose, the sugar that fuels the body, from the blood. When a person has insulin resistance (or insulin insensitivity), much more insulin is need in order for the body to absorb glucose. When the body can no longer produce enough insulin to overcome the resistance, glucose builds up in the blood, causing prediabetes. If the resistance continues, most people will develop Type 2 diabetes within 10 years.

"By the time a person develops prediabetes, they are nutritionally depleted and need supplements," says Brownstein. "Supplements can help restore sensitivity to the insulin receptors that help the body utilize glucose better.

 The following supplements have been shown to help restore insulin sensitivity and lower blood sugar levels:

• Magnesium. According to natural health expert Dr. Carolyn Dean, almost 80 percent of Americans are deficient in magnesium, and it's a primary factor in diabetes, cardiovascular disease, and muscular problems. 

• Bitter melon. According to diabetes.co.uk, bitter melon, a vegetable and traditional Chinese medicine, contains at least three anti-diabetic substances — charantin, vicine, and polypeptide-p. Charantin lowers blood glucose levels, and polypeptide-p acts similar to insulin. 

• Cinnamon. One study showed that eating 1 to 6 grams of cinnamon for 40 days reduced blood sugar levels by 24 percent. 

• Gymnema. Researchers found that 400 mg a day of the leaves of this shrub that's native to India and Africa  helps decrease the absorption of sugar from the intestine. One study published in the Journal of Ethnopharmacol found that patients with Type 2 diabetes who took 400 mg daily of Gymnema showed a significant reduction in blood glucose levels. All were able to reduce their dosages of conventional diabetes medication and 22 percent were able to discontinue their medication completely. Researchers said the data suggested that the beta cells had been regenerated or repaired.

• Alpha lipoic acid. Numerous studies show that alpha lipoic acid lowers blood sugar levels as well as reduces the symptoms of diabetic peripheral neuropathy.

• Fenugreek. Many studies have found that fenugreek seeds used in Indian recipes reduce blood sugar and increase insulin sensitivity in both Type 1 and Type 2 diabetes.