Raised blood cholesterol (also referred to as blood LDL-cholesterol) is a major risk factor for developing heart disease. Dietary saturated fat is recognised as the main dietary component responsible for raising blood LDL-cholesterol, and reducing its intake has been the mainstay of dietary guidelines for the prevention of heart disease for over 30 years. However, there is very little evidence for a direct link between the intake of saturated fat and risk of dying from heart disease. One explanation for this, is that the link between saturated fat intake and heart disease is not a direct one, but relies heavily on the ability of saturated fat to raise blood LDL-cholesterol levels. This LDL cholesterol-raising effect of saturated fat is complex, and highly variable between individuals because of differences in the metabolism of dietary fat and cholesterol between people. The main aim of this study is to measure the amount of variation in blood LDL-cholesterol in 150 healthy volunteers (75 at the University of Surrey and 75 at the University of Reading) in response to lowering the amount of saturated fat in the diet to the level recommended by the government for the prevention of heart disease. This collaborative project between the Universities of Reading, Surrey and Imperial ('RISSCI-1 Blood Cholesterol Response Study') will permit identification of two subgroups of men who show either a high or low LDL-cholesterol response to a reduction in dietary saturated intake. These participants (n=36) will be provided with an opportunity to participate in a similar follow-up study ('RISSCI-2') that will also take place at the University of Surrey and Reading. In this follow-up study, the participants will be asked to repeat a similar study protocol as for RISSCI-1, but undergo more detailed measurements to determine how saturated fat is metabolised in the body.
Name: High SFA diet (Diet 1)
Name: Low SFA diet (Diet 2)
Description: Polymorphic genes with potential influence on the serum LDL response to dietary saturated fat, e.g.: ATP-binding cassette proteins (cholesterol efflux proteins) ABCG5 (e.g. C1950G) ABCG8 (e.g. D19H, C1895T), functional polymorphisms in the farnesoid X receptor (FXR) and bile acid transporters (e.g. solute carrier organics anion 1B1). Fatty acid desaturases (FADS1 and FADS2). The patatin-like phospholipase domain-containing protein (PNPLA3) (e.g. rs738409 C/G), eNOS. Lipid/cholesterol homeostasis: serum apolipoprotein genes: APOE (ε2,ε3,ε4 e.g. rs429358 and rs7412), APOA-I (e.g. -75G/A), APOA4 (e.g. 360-2), APOA5 (e.g. -113/T>:c), APOCIII, APOB (e.g. -516C/T). Lipase genes: (e.g. LPL, HL, MGLL). Lipoprotein receptor genes (e.g. pvu11 in the LDL receptor), lipid transfer proteins (e.g. CETP e.g Taq1B, MTP), and other polymorphic genes related to the absorption and metabolism of dietary fat and regulation of lipid/cholesterol homeostasis.Measure: Other relevant genes involved in the absorption and metabolism of dietary fat Time: Baseline
Description: Analyses conducted by Imperial College LondonMeasure: Metabolomic analysis for the determination of the low molecular weight metabolite profiles in the biological fluids Time: Baseline, 4 weeks (after diet 1), 8 weeks (after diet 2)
Description: BMI will also be calculated (kg/ height in m^2)Measure: Weight Time: Baseline, 4 weeks (after diet 1), 8 weeks (after diet 2)
Description: Measured via pulse wave assessment using the Mobil-O-graph device.Measure: Fasting vascular stiffness Time: baseline, 4 weeks (after diet 1), 8 weeks (after diet 2)
There are 3 SNPs
rs429358 and rs7412), APOA-I (e.g.
rs738409 C/G), eNOS.
rs429358 and rs7412), APOA-I (e.g.