Phytosterols in low- and nonfat beverages as part of a controlled diet fail to lower plasma lipid levels

Abstract

Dietary phytosterols have been shown to reduce plasma cholesterol concentrations when consumed in different food matrices, but their effectiveness in nonfat or low-fat beverages has not been established. The objective of this study was to examine whether phytosterols alter plasma lipid levels when incorporated into nonfat or low-fat beverages. Fifteen moderately hypercholesterolemic men and women consumed three precisely controlled diets for periods of 21 days each in random order. Diets contained either a nonfat placebo beverage (NF), a beverage that is nonfat with added phytosterols (NFPS), or a beverage that is low in fat with added phytosterols (LFPS). Total cholesterol concentrations were not different between groups at endpoint, decreasing ( P Ͻ 0.05) equally by 8.5%, 11.6%, and 10.1% with NF, NFPS, and LFPS consumption, respectively. There was no effect of dietary treatment on LDL cholesterol concentrations, which decreased over time ( P Ͻ 0.05) by 5%, 10.4%, and 8.5% with NF, NFPS, and LFPS, respectively. HDL cholesterol and triacylglycerol concentrations were unaffected by the diets. Provision of phytosterols as part of nonfat and low-fat beverages did not exert any greater hypocholesterolemic effect than a nonfat placebo beverage. These results show that intake of phytosterols in a low-fat beverage format is not efficacious for lipid level modification. Low-fat diets containing less than 30% of energy as fat and less than 10% as saturated fat have long been promoted for lowering plasma cholesterol concentrations in hypercholesterolemic patients. Recently, the National Cholesterol Education Program Adult Treatment Panel III guidelines have added the inclusion of phytosterols as part of their therapeutic lifestyle changes dietary guidelines (1) in addition to the traditional recommendations to lower total fat, saturated fat, and cholesterol intakes.Furthermore, in 2000, the US Food and Drug Administration issued a health claim stating that foods containing plant sterol and stanol esters, when consumed in foods low in saturated fat and cholesterol, reduced the risk of coronary heart disease (2). Phytosterols have traditionally been incorporated into margarines, spreads, and other high-fat foods and have been shown to be efficacious in lowering total cholesterol (TC) and LDL cholesterol (3)(4)(5)(6)(7)(8)(9)(10)(11). In a recent meta-analysis, it was reported that consumption of more than 2 g of phytosterols/day reduced LDL cholesterol concentrations by 0.33 to 0.54 mmol/l, depending on the age of the subjects studied, and that intakes of less than 2 g/day led to reductions in LDL cholesterol of at least 0.4 to 0.5 mmol/l (3). It is thus generally agreed that phytosterol consumption leads to, on average, a 10% reduction in TC and a 13% reduction in LDL cholesterol concentrations.Phytosterols exert their cholesterol-lowering action by suppressing intestinal cholesterol absorption while partially suppressing cholesterol biosynthesis (9, 12, 13). While they are only partially absorbed into the circul...

Phytosterols in nonfat and low-fat beverages have no impact on the LDL size phenotype

“…Analyses were conducted as part of a study from which data on plasma lipid levels have already been reported (Jones et al, 2003). Briefly, 15 healthy volunteers (nine men, six women), aged between 22 and 68 y, with LDL-cholesterol between 3.25 and 6.0 mmol/l, high-density lipoprotein (HDL) cholesterol above 0.8 mmol/l, triglycerides (TG) concentrations below 4.0 mmol/l and body mass index (BMI) between 22 and 32 kg/m 2 were recruited as described previously (Jones et al, 2003).…”

“…Briefly, 15 healthy volunteers (nine men, six women), aged between 22 and 68 y, with LDL-cholesterol between 3.25 and 6.0 mmol/l, high-density lipoprotein (HDL) cholesterol above 0.8 mmol/l, triglycerides (TG) concentrations below 4.0 mmol/l and body mass index (BMI) between 22 and 32 kg/m 2 were recruited as described previously (Jones et al, 2003). Individuals reporting a personal endocrine disorder, dyslipidemia, hypertension, familial sitosterolemia, gastrointestinal disorders, iliac bypass surgery, heart disease or unstable angina in the last 3 months prior to screening were excluded.…”

“…The study was performed as a double-blind randomized, crossover placebo-controlled trial with three experimental phases (Jones et al, 2003). Experimental phases consisted of 21 feeding day periods, each separated by a 4-week washout period where participants returned to their habitual ad libitum diets (Jones et al, 2003).…”

“…Experimental phases consisted of 21 feeding day periods, each separated by a 4-week washout period where participants returned to their habitual ad libitum diets (Jones et al, 2003).…”

“…Three types of beverage, either nonfat placebo (NF control), nonfat with phytosterols (NFPS) or low-fat (1% fat by weight) with phytosterols (LFPS) were supplied (Jones et al, 2003). Participants consumed daily three beverages of 100 ml at meal time.…”