Fish is commonly referred to as “brain food,” and now research is also showing that it may help prevent some chronic diseases like diabetes.
A recent study found that men who got more than 5 grams of omega-3 polyunsaturated fatty acids — fats that are primarily found in fish and other seafood — per day had a lower risk of developing type 2 diabetes than men who consumed lower amounts.
The authors of this study noted that a more diverse study sample is needed to confirm these findings.
This study was led by Jyrki K. Virtanen, PhD, from the Institute of Public Health and Clinical Nutrition at the University of Eastern Finland in Kuopio, Finland. This research team examined the relationship between omega-3 polyunsaturated fatty acids (PUFA) from fish and type 2 diabetes.
Omega-3 polyunsaturated fatty acids are essential fats that play a role in brain function and growth and development, but the body does not produce these fats. They must be consumed in the diet.
Dr. Virtanen and colleagues analyzed data from 2,212 men in the Kuopio Ischaemic Heart Disease Risk Factor study. These men, who were between the ages of 42 and 60 years old, did not have type 2 diabetes at the beginning of the study between 1984 and 1989.
The researchers looked at intake of four types of omega-3 polyunsaturated fatty acids. Serum polyunsaturated fatty acid levels were measured from blood samples to determine levels of exposure to polyunsaturated fatty acid levels.
The participants were instructed to record what they ate for four days, and their records were run through a nutrition software program to determine the nutrients present in the foods they ate. They were separated into four groups depending on the amount of omega-3 polyunsaturated fatty acids they consumed ranging from lowest (less than 3.62 grams per day) to highest (more than 5.33 grams per day).
Type 2 diabetes status was determined through a combination of self-report, a fasting plasma glucose test (measures blood sugar levels) and an oral glucose tolerance test (measures how well the body breaks down glucose) at 4, 11 and 20 years after the study began.
The researchers accounted for several factors that could have influenced the development of type 2 diabetes, including medical history, medication use, family history of diabetes, smoking status, alcohol consumption, blood pressure, body mass index (a measure of height and weight), education and annual income.
The researchers found that during the follow-up period, about 19 percent of men developed type 2 diabetes.
Study participants who consumed more than 5.3 grams per day of three of the types of omega-3 polyunsaturated fatty acids — eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA) — had a 33 percent lower risk of type 2 diabetes than men who consumed less than 3.62 grams per day.
The fourth type of omega-3 polyunsaturated fatty acid — alpha-linolenic acid (ALA) — was not found to be related to diabetes risk.
Since fish can contain high levels of mercury, which has been linked to a higher risk for cardiovascular diseases, the researchers also measured hair mercury levels to determine the relationship between mercury levels and risk of type 2 diabetes. The researchers did not find a relationship between hair mercury levels and risk of type 2 diabetes.
The study's authors concluded that omega-3 polyunsaturated fatty acids appeared to be connected to a lower risk of type 2 diabetes, but research is needed in more diverse populations to confirm this finding.
This study was published in the January issue of Diabetes Care.
The authors reported no competing interests.