Cardiovascular disease (CVD) risk can be lowered by introduction of plant sterols (PSs) to the diet, since PSs have been shown to reduce low-density lipoprotein cholesterol (LDL-C). Given that the efficacy of PSs as cholesterol-lowering agents depends on their appropriate solubilization, the cholesterol-lowering efficacy of PSs in non-traditional matrices needs to be determined. The primary aim of this thesis was to examine the consumption of PSs (i) in an oil that is rich in medium-chain triglycerides (MCTs) or (ii) low-fat yogurt with or without a meal, on changes in lipid parameters. Additional objectives were to assess the effects of MCTs with PSs on body composition and energetics, to compare the effects of PSs in a low-fat matrix consumed with or without a meal on cholesterol synthesis, to evaluate the risks of PSs in a low-fat matrix on blood levels of carotenoids and fat-soluble vitamins, and to investigate the relationship between the response to PSs, cholesterol kinetics, and genotyping. For this purpose, two randomized, controlled, crossover feeding trials were conducted. First, 23 overweight, hyperlipidemic men consumed PSs in MCTs or an olive oil control for 6 weeks each. In the second trial, 26 hyperlipidemic subjects consumed a placebo yogurt, a PS-enriched yogurt consumed with a meal, or afternoon PS-enriched yogurt as a snack for 4 weeks each. PSs, mixed within an MCT matrix, lowers plasma total cholesterol (TC) and LDL-C without changing the high-density lipoprotein cholesterol concentrations. However, no changes in body composition or energetics were observed. Second, a PS-enriched low-fat yogurt as a snack lowered TC, along with a lowering trend in LDL-C, to a greater extent than when consumed with a meal without any risk of deficiency in fat-soluble antioxidants. An increase in cholesterol biosynthesis was also observed in both PS phases compared with the control phase. In addition, 3 subjects who were non-responsive to PS intervention and had higher cholesterol absorption rates were observed; however, no recognizable pattern of genetic polymorphism was detected. Overall, these novel matrices for PS incorporation consumed with or between meals may be an effective way of decreasing the risk of CVD; however, some individuals respond better to PS intervention.
Safety aspects and cholesterol-lowering efficacy of low fat dairy products containing plant sterols