Researchers in the United Kingdom completed a prospective analysis of the EPIC-Norfolk study to assess if consumption of different types of fish and seafood was associated with future risk for developing Type 2 diabetes. They analyzed 21,984 participants (12,183 women) aged 40 to 79 years. Researchers obtained health and lifestyle information via questionnaire, and height, weight and waist circumference via health examination at baseline.
Median follow-up of 10.2 years yielded 725 incident cases of diabetes. Higher total fish intake was associated with a significantly lower risk for diabetes (OR=0.75; 95% CI, 0.58-0.96), after adjustment for age, sex, family history, education, smoking, physical activity, dietary factors and obesity.
Researchers reported a similar inverse association with diabetes risk and white fish and oily fish intakes; however, the associations were not significant after adjustment for obesity or dietary factors.
People who consumed one or more portions of shellfish per week had an increased risk for diabetes (OR=1.36), according to results of adjusted analyses.
The associations between total fish and shellfish intake and risk of diabetes observed in our study were independent of a comprehensive range of potential confounders. These included an attempt to adjust for possible clustering of healthier lifestyles and factors that may accompany greater fish intake (physical activity, alcohol intake, smoking, plasma vitamin C levels or fruit/vegetable intake, and education level). The associations between white fish and oily fish intake and diabetes risk were not significant after adjustment for general and central obesity (BMI and waist circumference), indicating that, although the association was independent of other dietary exposures, obesity could act as a mediator between white or oily fish intake and diabetes risk. In support of this theory, it has been shown that individuals consuming white or oily fish, as part of a calorie-restricted diet for 8 weeks, on average lost 1 kg of body weight more than control subject
In summary, we report that specific types of fish intake are differentially associated with the risk of diabetes. Total intake of both white fish and oily fish was associated with a lower risk of diabetes, reinforcing the public health message to consume fish regularly. Shellfish intake was associated with an increased risk of diabetes, which highlights the potential importance of seafood preparation and cooking methods. The increased risk of diabetes with shellfish intake requires further study.
Patel PS. Diabetes Care. 2009; 32:1857-1863.