Background: The 2 major dietary sources of trans fatty acids (TFAs) are partially hydrogenated oils and ruminant-derived products. Epidemiologic data suggest that chronic consumption of industrial sources of TFAs could be damaging to insulin sensitivity, but intervention studies on this issue have remained inconclusive.
Objective: The trial was designed to compare the effects of dairy compared with industrial sources of TFAs on insulin sensitivity in overweight women.
Design: Sixty-three healthy women with abdominal obesity [waist circumference >88 cm and a body mass index (in kg/m(2)) >28] were recruited. After a run-in period, the volunteers were randomly assigned to consume 1 of 3 four-week diets: 60 g low-TFA lipids/d (0.54 g/d; n = 21), ruminant TFA-rich lipids (4.86 g/d; n = 21), or industrial TFA-rich lipids (5.58 g/d; n = 21). Changes in peripheral insulin sensitivity were assessed by using hyperinsulinemic-euglycemic clamps.
Results: After the intervention period, fasting glycemia and insulinemia and insulin sensitivity were not significantly modified in either group (P > 0.05).
Conclusions: These data indicate that consumption of dairy- and industrial-source TFAs for 4 wk at nutritional levels do not impair peripheral insulin sensitivity in insulin-resistant women. Our study may not preassess the effects of TFAs in normal insulin-sensitive individuals. This trial was registered at ClinicalTrials.gov as NCT00617435.