Reducing the intake of dietary saturated fatty acids (SFA) to ⩽10 % of total energy intake is a key public health strategy aimed at lowering current cardiovascular disease (CVD) incidence. Consumption of dairy products (including butter) represents approximately 35 % of total dietary SFA intake(1). Supplementation of the bovine diet with oleic acid-rich plant oil has been reported to depress SFA and increase cis-monounsaturated fatty acids levels in milk, providing a strategy to lower total dietary SFA intake (Reference Kliem2). This human intervention study aimed to investigate whether consumption of SFA-reduced, compared with conventional dairy products, would impact on the fasting lipid profile, glucose and insulin concentrations of adults at moderate CVD risk.
Fifty-four adults (mean age 53 (SD 13) years, BMI 26 (SD 3) kg/m2), completed a double blind, randomised, controlled 12-week cross-over study with an 8-week washout period between treatment arms. Participants replaced habitual dairy foods/snacks with SFA-reduced or conventional UHT milk, Cheddar cheese and butter (fatty acid (FA) composition of SFA-reduced vs. conventional dairy products: total SFA: -7·0 g/d, C18:1cis: 3·0 g/d, C18:1trans: 2·4 g/d), achieving an isoenergetic daily dietary exchange (41 g/d total fat). At the beginning and end of each treatment period, fasting blood samples were collected for biochemical analysis. LDL-C was estimated using the Friedewald formula. The homeostatic model assessment of insulin resistance (HOMA-IR) was calculated using the glucose and insulin data.
Values are mean ± SE. Due to ongoing blinding, treatments are referred to as Diet A and B. HDL-C, high density lipoprotein cholesterol; LDL-C, low density lipoprotein cholesterol; Δ, change from baseline (wk12-wk0).
Preliminary results using mixed model analyses indicate that from baseline, only LDL-C concentrations were influenced by the FA composition of the dairy products, with the observed increase in LDL-C concentrations with Diet B shown to be significantly attenuated following Diet A. These preliminary findings are part of the RESET intervention trial (NCT02089035), which will also investigate the impact of consumption of SFA-reduced dairy products on inflammatory markers and vascular function.
This research was supported by the MRC (MR/K020218/1), ARLA Foods and AarhusKarlshamn (AAK) UK.