An omega-3 fatty acid found in fish oil has been shown to improve insulin function in overweight individuals who are vulnerable to type 2 diabetes, according to a report from Reuters Health.
Researchers found that daily supplements of docosahexaenoic acid (DHA) taken over a period of three months produced a "clinically significant" improvement in insulin sensitivity in overweight subjects of the study. Dr. Yvonne Denkins, a nutrition researcher at the Pennington Biomedical Research Institute, Louisiana State University in Baton Rouge presented the findings at the annual Experimental Biology 2002 conference in New Orleans this week.
The report notes that more than nine out of ten diabetics have type 2 diabetes, where the body's gradual failure to respond to insulin can cause blood sugar levels to rise to dangerous levels.
Previous studies have produced positive links between fish oil and protection against the Type 2 diabetes. Denkins highlighted the epidemiological studies on the Greenland Eskimos, a population that eats mainly whale blubber.
"These are people that are overweight, that should be diabetic and have heart disease, but they do not. The scientists that studied them thought it was probably because of what they eat, and they found that it was the omega-3s," she said.
In their study, Denkins and colleagues asked 12 overweight men and women, aged 40 to 70, to consume 1.8 grams of DHA at breakfast for 12 weeks. While none of the study participants had full-blown diabetes, they all suffered from insulin resistance - a pre-diabetic condition in which the body fails to efficiently respond to insulin.
Blood tests taken at the beginning and end of the study were used to determine the changes in insulin resistance.
"We did see a change in insulin sensitivity after 12 weeks of DHA supplementation," Denkins told Reuters Health. She said that 70 per cent of the participants showed an improvement in insulin-related function and 50 per cent experienced "a clinically significant change."
However she also stressed that the small size of the study sample means that the results are preliminary, and diabetics should not replace their medication with any dietary supplement, including fish oil. A doctor should be consulted if people wished to increase their intake of fish oil, especially if they are being treated for any cardiovascular condition, Denkins said, as DHA has a slight blood thinning effect.
Nutrition experts currently recommend a daily intake of 0.6 grams of omega-3 fatty acids, preferably from fish. According to Denkins, this is about two servings of cold-water fish weekly, such as halibut, herring, mackerel or salmon.