Consumption of Lean Fish Reduces the Risk of Type 2 Diabetes Mellitus: A Prospective Population Based Cohort Study of Norwegian Women

Abstract

BackgroundThe effects of fish consumption and n-3 fatty acids on type 2 diabetes mellitus (T2DM) have recently been debated.ObjectiveWe explored the risk of T2DM in relation to consumption of lean fish, fatty fish, fish products and total fish as well as cod liver oil supplements in a representative sample of Norwegian women.DesignThis was a prospective population based cohort study in 33740 women free of T2DM, stroke, angina or heart attack and with detailed information on important co-variates and dietary intake at baseline. Risk ratios and corresponding 95% CI were estimated using Poisson regression with log-person time as offset.ResultsLean fish consumption was inversely associated with T2DM compared to zero intake. Risk ratios and 95% CI for intake of 75 and 100 g lean fish per day were 0.71 (0.51, 0.98) and 0.67 (0.46, 0.98), respectively. There was no effect of intake of fatty fish, fish products, total fish or use of cod liver oil supplements on the risk of T2DM.ConclusionLean fish consumption of 75–100 g/d had a beneficial effect on T2DM. It remains unclear whether lean fish in itself has a protective effect on T2DM or that lean fish consumers have a protective life-style that we were not able to take into account in this study. Unfavorable effects of fatty fish consumption or use of cod liver oil supplements on T2DM were not observed.

Lean Fish Consumption Is Associated with Beneficial Changes in the Metabolic Syndrome Components: A 13-Year Follow-Up Study from the Norwegian Tromsø Study

“…The beneficial effects of fish consumption on both CVD [6,7,8,9,10,11,12] and DM2 have been described previously [13,14,15]. Since MetS consists of several of the same risk factors as CVD and DM2, one would expect fish consumption to reduce the risk of MetS as well.…”

Plasma fatty acids as predictors of glycaemia and type 2 diabetes

“…In infants, this index was suggested to be a more important marker of the fatty acid status than the absolute amounts of fatty acids [23,38]. In some [39][40][41], but not all [42,43] observational studies, fish consumption has been associated with a lower risk of diabetes. Whether the possible beneficial effects of fish consumption are attributable to long-chain n-3 fatty acids or to other components of fish remains unclear.…”

“…Whether the possible beneficial effects of fish consumption are attributable to long-chain n-3 fatty acids or to other components of fish remains unclear. In the prevention of type 2 diabetes, the consumption of lean fish may be even more beneficial than the consumption of fatty fish [41]. Instead, fish oil supplementation might have adverse effects on glucose metabolism, including increased gluconeogenesis and impaired insulin secretion and insulin sensitivity [44][45][46][47].…”

Fish consumption and frying of fish in relation to type 2 diabetes incidence: a prospective cohort study of Swedish men

“…Shellfish consumption has been specifically addressed in six studies, also providing heterogeneous results suggesting inverse [13], direct [6] or no association [5, 7, 12, 41] with type 2 diabetes risk. Five cohort studies distinguished between lean and fatty fish: one showed a weak inverse association with fatty fish but not with lean fish [41], one observed higher risk associated with lean fish but not with fatty fish [7], one observed an inverse association with lean fish but not with fatty fish [14], and two did not observe statistically significant associations [6, 12]. …”