Supplements containing a compound found in curry spice may help prevent diabetes in people at high risk, according to a Thai study.

Researchers, whose results were published in the journal Diabetes Care, found that over nine months, a daily dose of curcumin seemed to prevent new cases of diabetes among people with so-called prediabetes - abnormally high blood sugar levels that may progress to full-blown type 2 diabetes.

Curcumin is a compound in turmeric spice. Previous lab research has suggested it can fight inflammation and so-called oxidative damage to body cells. Those two processes are thought to feed a range of diseases, including type 2 diabetes.

"Because of its benefits and safety, we propose that curcumin extract may be used for an intervention therapy for the prediabetes population," wrote study leader Somlak Chuengsamarn of Srinakharinwirot University in Nakomnayok, Thailand.

The study included 240 Thai adults with prediabetes who were randomly assigned to take either curcumin capsules or a placebo. The ones taking curcumin took six supplement capsules a day, each of which contained 250 milligrams of "curcuminoids".

After nine months, 19 of the 116 placebo patients had developed type 2 diabetes. That compared with none of the 119 patients taking curcumin.

The researchers found that the supplement seemed to improve the function of beta-cells, which are cells in the pancreas that release the blood sugar-regulating hormone insulin. They speculate that the anti-inflammatory effects of curcumin help protect beta-cells from damage.

But a diabetes expert not involved in the study said it's still too early for people to head to the health food store for curcumin supplements.

"This looks promising, but there are still a lot of questions," said Constance Brown-Riggs, a certified diabetes educator and spokesperson for the Academy of Nutrition and Dietetics.

The trial lasted only nine months, and it's already known from longer-lasting, larger trials that lifestyle changes - including calorie-cutting and exercise - can prevent or delay type 2 diabetes in people with prediabetes.

Brown-Riggs added that consumers can't be sure that a product actually contains the ingredients, or the amount of ingredient, listed on the label.

"If I was talking to a patient about this, I'd say concentrate on eating healthy and overall lifestyle," she said.