The incidence of diabetes in the United States has been rising for years, making it the seventh leading cause of death in the country, according to the National Institutes of Health, but promising new research indicates that fish oil can help prevent its occurrence.

The study, published recently in the Journal of Clinical Endocrinology & Metabolism, indicates that regular consumption of fish oil supplements works to reduce type 2 diabetes risk because it raises the level of adiponectin, a hormone in the human bloodstream.

The increase in the level of adiponectin also works to reduce the risk of heart disease in people who consume fish-oil or omega-3 fatty acid supplements. The hormone has also been linked to the metabolism of glucose and can help control inflammation - a major factor in obesity (which, in turn, is linked to increased risk of diabetes).

Mimicking earlier findingsJason Wu, PhD, of Harvard University's School of Public Health and the primary author of the study, said that in previous studies involving animals researchers discovered that fish oil helped boost circulation of adiponectin, adding that it was not known whether fish oil had a similar hormone-boosting effect in humans until now. Wu also said 14 recent clinical trials provided the evidence that fish oil supplementation worked to increase adiponectin levels, thereby decreasing the incident of type 2 diabetes.

The study involved 682 people who were provided fish oil supplements and another 642 who were given placebos. The results showed that those receiving the supplementation had an increase in the level of adiponectin by 0.37ug/mL over those who had been given a placebo.

Despite the results, it remains unclear as to whether fish oil can influence the metabolism of glucose as it pertains to the development of type 2 diabetes. But the results nonetheless support earlier studies indicating that fish oil supplementation helps control glucose levels and aids in the metabolism of fat cells that may occur due to fish oil consumption.

Wu's results mirror those of two earlier studies, whose results were published in 2011. Per Reuters:

In one study, of more than 3,000 older U.S. adults, researchers found that those with the highest blood levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) - two omega-3s found in fatty fish - were about one-third less likely to develop diabetes over the next decade than their counterparts with the lowest levels.

In the other, researchers found that among 43,000 Singapore adults, those who got the most alpha-linolenic acid (ALA) in their diets had a decreased diabetes risk. ALA is an omega-3 fat found in certain plant foods, including flaxseed, canola oil and soy.

In those studies it also was not clear that fish-oil or omega-3 supplements actually worked to reduce type-2 diabetes, but in those and subsequent studies, there is at least anecdotal evidence to support such a theory.

'Stronger evidence'Andrew Odegaard of the University of Minnesota in Minneapolis, one of the researchers on the Singapore study, said there is no "magic bullet" in the fight against diabetes or other diseases, but there are certainly scientifically proven ways in which to reduce your risk. Consumption of healthy "whole foods" like fruits, vegetables, veggie oils and fish all work to mitigate disease, and that includes diabetes.

"Approaching your dietary intake with this 'big picture' approach should take care of the small things, like essential nutrients such as omega-3 fatty acids," Odegaard told Reuters Health.

The 2011 U.S. study examined an aspect of the fish oil-type 2 diabetes link that had not previously been looked at: Examining people's actual omega-3 fatty acid blood levels and their later risk of contracting diabetes.

"That type of study generally offers stronger evidence than those which ask people about their eating habits," Reuters reporte