Abstract

OBJECTIVE: To compare the effects of cod protein to those of other animal proteins on insulin sensitivity in insulin-resistant human subjects.

RESEARCH DESIGN AND METHODS: Insulin sensitivity (M/I) was assessed using a hyperinsulinemic-euglycemic clamp in 19 insulin-resistant subjects fed a cod protein (CP) diet and a similar diet containing lean beef, pork, veal, eggs, milk and milk products (BPVEM) for four weeks in a crossover design study. Both diets were formulated to differ only in protein source thus providing equivalent amounts of dietary fibres, monounsaturated, polyunsaturated (including omega-3) and saturated fatty acids (1.1:1.8:1.0). β-cell function, estimated by oral glucose tolerance test (OGTT)-derived parameters, was also assessed.

RESULTS: There was a significant improvement in insulin sensitivity (P = 0.027) and a strong tendency for a better disposition index (β-cell function x M/I) (P = 0.055) in subjects consuming CP compared with BPVEM. When taking into account median baseline M/I (4.8x10^-3 mg·kg^-1·min^-1·pmol^-1), an interaction on 30-min C-peptide/30-min glucose ratio, used as an index of β-cell function, was observed between diet and M/I status (P = 0.022). Indeed, this ratio strongly tended to increase in subjects with low M/I consuming CP compared to BPVEM (P = 0.065).

CONCLUSIONS: Dietary cod protein improves insulin sensitivity in insulin-resistant individuals, and thus could contribute to prevent type 2 diabetes by reducing the metabolic complications related to insulin resistance.

CONCLUSIONS: Clinicaltrials.gov identification #NCT00400036.