Impact of dietary fatty acid composition on insulin action at the nucleus

The potential role of olive oil-derived MUFA in insulin sensitivity

Dietary fatty acids play an important role in the development of insulin resistance, the prelude to type 2 diabetes mellitus. This review addresses the potential role of olive oil-derived MUFA in insulin sensitivity, particularly how dietary fat interacts with insulin resistance looking at whole body metabolic measures, as well as molecular effects. The review focuses on the role of non-esterified fatty acids, fatty acid composition in vivo and dietary fat modification on insulin resistance in the metabolic syndrome. Particular emphasis is placed on the role of olive oil within the context of dietary modification to improve insulin sensitivity and for the prevention of the metabolic syndrome.

Fish-seafood consumption, obesity, and risk of type 2 diabetes: an ecological study

OBJECTIVES

There is substantial evidence that type 2 diabetes increases with the degree and duration of obesity. This study was conducted to examine the association, at the international level, between fish and seafood consumption and the prevalence of type 2 diabetes, taking into account the prevalence of obesity.

METHODS

An ecological study of 41 countries in five continents with different socio-demographic characteristics and sanitary conditions was carried out. Data on the prevalence of diabetes and obesity as well as food balance sheets were collected from websites. Correlations between the variables studied were followed by an exploration of their interaction.

RESULTS

After adjustment for total energy intake, there was a significant correlation (rho=0.81, P<0.0001) between the prevalence of type 2 diabetes in the 20- to 44- and 45- to 64-year age groups. Type 2 diabetes in the 45- to 64-year age group was about 5 times higher than in the 20- to 44-year age group. Obesity was positively associated with type 2 diabetes in both age groups (rho=0.39; P=0.012 and rho=0.48; P=0.002 in the 20- to 44- and 45- to 64-year age groups, respectively). An interaction effect was found between diabetes, obesity and total fish and seafood consumption. In countries with low fish and seafood consumption, the prevalence of type 2 diabetes increased significantly with obesity (0.8 +/- 0.3% vs. 2.5 +/- 1.8%; P=0.002 and 3.3 +/- 2.6% vs. 11.0 +/- 3.9%; P<0.0001 for the 20- to 44- and 45- to 64-year age groups, respectively). In countries with a greater prevalence of obesity, there was evidence of significantly reduced type 2 diabetes with high fish and seafood consumption (2.5 +/- 1.8% vs. 0.9 +/- 0.7%; P=0.007 and 11.0 +/- 3.9% vs. 6.2 +/- 4.1%; P=0.041 for the 20- to 44- and 45- to 64-year age groups, respectively).

CONCLUSION

The results of this study suggest that high fish and seafood intake may reduce the risk of type 2 diabetes in populations with a high prevalence of obesity.

Metabolic effects of omega-3 fatty acids

Some metabolic effects of dietary marine oils, or of dietary eicosapentaenoic or docosahexaenoic acid are reviewed. It is pointed out that docosahexaenoic acid appears more effective as regards induction of peroxisomal beta-oxidation. Similarly, docosahexaenoic appears more powerful in terms of suppression of hepatic delta9-desaturase activity and mRNA-levels. The potential inhibitory effect of polyunsaturated fatty acids, particularly docosahexaenoic acid, on mitochondrial beta-oxidation is discussed. Experiments with rats suggesting that the hypolipidaemic response of eicosapentaenoic acid is more marked when the fatty acid was given to fed rats, as compared to fasted rats, are discussed.