Does Varying The Fatty Acid Composition Of A High-fat Meal Modify Postprandial Lipemia?

Abstract

PURPOSE: The western diet is typically high in saturated fats (SF) or omega-6 polyunsaturated fatty acids (O6) with insufficient amounts of omega-3 polyunsaturated fatty acids (O3). When chronic, this diet has been associated with an increased risk of cardiovascular, metabolic, and respiratory diseases. The purpose of this study was to examine the effect of varying the fatty acid composition of an acute High-Fat Meal (HFM) on postprandial lipemia. METHODS: Fifteen individuals [6 M, 9 F; body mass index (BMI) = 25.3 ± 6.6 kg/m2] consumed three HFM smoothies separated by a minimum of 48 hours. The three smoothies were high in SF [63% total fat, <0.02% from O3 and O6], O6 [15:1 O6 to O3], and O3 [15:1 O3 to O6]. All were standardized to 12 kcal/kg body weight, 63% total fat, and 0.72 g/kg sugar. Blood triglycerides (TG) were collected at baseline, 2 hr and 4 hr postprandially. RESULTS: There was a significant main effect of time for SF HFM and O3 HFM in TG from baseline to 4 hr (P=0.001 and 0.006), and a quadratic effect in TG from baseline to 4 hours in O6 HFM, where TG increased from baseline to 2 hr and returned near baseline values at 4 hr (P<0.001). There was an interaction effect between condition and time effect for TG (P<0.05) and no difference between O3 and O6 TG concentrations at any time point (P>0.05). The TG concentrations were significantly lower from 2 hr to 4 hr postprandially in the high O6 (P=0.005) and high O3 HFMs (P=0.033) compared to the SF HFM, which was increased from 2 to 4h. CONCLUSIONS: O6 and O3 HFMs led to a more accelerated peak in postprandial TG and trended towards baseline by 4 hr. The SF HFM resulted in a sustained elevation in TG with significantly higher concentrations at 4 hr than at baseline. These findings suggest that varying types of fatty acids can lead to markedly different metabolic responses and that diets high in SF could have prolonged exposure to high blood triglycerides, increasing the risk of atherosclerosis and other chronic diseases.