Herbal Extract Shows Promise for Diabetes

Wed Feb 16,12:34 PM ET Health - Reuters

By Amy Norton

NEW YORK (Reuters Health) - An herb long used in traditional Indian medicine appears to control the rise in blood sugar that follows a meal -- suggesting, researchers say, that it could help treat or even prevent type 2 diabetes.

Their study of 39 adults without diabetes found that a beverage made from the herb, known as Salacia oblonga, stemmed participants' normal post-meal rise in blood sugar. There was a similar reduction in blood levels of insulin, which helps shuttle sugar from the blood and into cells to be used for energy.

The herb, according to the study authors, seems to work similarly to oral diabetes drugs known as alpha-glucosidase inhibitors, which impede the body's absorption of carbohydrates.

The study, which was funded by Columbus-based Abbott Laboratories, is published in the Journal of the American Dietetic Association.

The next step is to test S. oblonga's ability to slow post-meal sugar absorption in people with diabetes, study co-author Dr. Steven R. Hertzler told Reuters Health.

"We still want to see what this does in people with type 2 diabetes," said Hertzler, an assistant professor of nutrition at Ohio State University in Columbus.

Though S. oblonga has a long tradition of use in Indian ayurvedic medicine, few studies have looked at the herb's effects in humans, Hertzler noted.

What research has been done has been conducted largely in Japan, where S. oblonga has been sold as a food supplement for several years. The plant grows in limited regions of India and Sri Lanka, and it is not yet well known in the U.S., according to Hertzler and his colleagues.

For their study, the researchers had 39 healthy adults drink four different liquid meals on four separate days. Three of the beverages had varying doses of S. oblonga, along with generous portions of protein, carbohydrates, fat and fiber; the fourth beverage did not contain the herb.

The researchers found that the drink with the largest S. oblonga dose -- 1,000 milligrams -- cut the participants' post-meal blood sugar rise by about one-quarter compared with sugar levels after the herb-free drink. An even larger decline was seen in insulin levels.

Good blood sugar control is vital in diabetes because it reduces the risk of long-term complications such as kidney dysfunction, heart disease, vision loss and nerve damage.

The hope, according to Hertzler, is that S. oblonga can help diabetics maintain healthy blood sugar levels over time, and thereby help prevent complications.

He and his colleagues are about to begin a clinical trial that will look at how the herb affects post-meal blood sugar and insulin levels in people with type 2 diabetes. Future studies will have to investigate whether there's a long-range benefit, Hertzler said.

It's also possible, he noted, that S. oblonga could prove useful in preventing type 2 diabetes.

The disease arises when the body becomes resistant to the activity of insulin, allowing blood sugar levels to soar. Maintaining normal blood sugar and insulin levels through diet, exercise and weight control cuts the risk of developing the disease. So there's the potential, Hertzler said, for S. oblonga to help prevent diabetes in people at high risk, due to factors like family history or obesity.

What's attractive about the herbal extract, he said, is that it can be incorporated into a food or beverage, such as tea, which could help people stick with it.

What's not so attractive is the gas and cramping the herb can cause, owing to its effects on carbohydrate absorption. In this study, the highest S. oblonga dose caused more bouts of gas and stomach distension.

However, the same types of problems occur with standard alpha-glucosidase inhibitors, Hertzler said, adding that it's possible that any such side effects would dissipate in a person who used the herb regularly.

SOURCE: Journal of the American Dietetic Association, January 2005.