Plant sterols and endurance training combine to favorably alter plasma lipid profiles in previously sedentary hypercholesterolemic adults after 8 wk

Combining Plant Sterols With Walking Lowers Postprandial Triacylglycerol More Than Walking Only in Chinese Men With Elevated Body Mass Index

This study examined if plant sterols and walking reduce postprandial triacylglycerol (TAG) concentrations in Chinese men with elevated body mass index (≥ 23.5 kg/m2). Fifteen Chinese men (mean [SD]: age = 25 [3] years and body mass index = 26.2 [1.5] kg/m2] completed four 10-day trials in random order with a 7- to 10-day washout between trials: (a) daily consumption of a control margarine while sedentary (C-S), (b) daily consumption of margarine containing 2 g/day of plant sterols while sedentary (PS-S), (c) daily consumption of a control margarine with 30-min daily walking (C-W), and (d) daily consumption of margarine containing 2 g/day of plant sterols with 30-min daily walking (PS-W). On Day 11 of each trial, postprandial TAG was measured after a high-fat milkshake. The 5-hr total area under the TAG curve was 22%, 25%, and 12% lower on PS-W (mean [SD]: 8.9 [4.3] mmol·5 hr/L) than C-S (11.4 [4.5] mmol·5 hr/L; p = .005; d = 0.56), PS-S (11.9 [4.9] mmol·5 hr/L; p = .004; d = 0.67), and C-W (10.1 [4.4] mmol·5 hr/L; p = .044; d = 0.27) trials, respectively. Similarly, 5-hr incremental area for PS-W (4.5 [2.7] mmol·5 hr/L) was 31%, 32%, and 18% lower than C-S (6.6 [3.3] mmol·5 hr/L; p = .005; d = 0.62), PS-S (6.6 [3.4] mmol·5 hr/L; p = .004; d = 0.64), and C-W (5.5 [2.8] mmol·5 hr/L; p = .032; d = 0.29). Ten days of daily plant sterol intake combined with walking presents an intervention strategy to lower postprandial TAG in Chinese men with elevated body mass index.

Moderate-to-high intensity exercise with person-centered guidance influences fatigue in older adults with rheumatoid arthritis

Fatigue is described as a dominant and disturbing symptom of rheumatoid arthritis (RA) regardless of the advances in pharmacological treatment. Fatigue is also found to correlate with depression. The objective was to evaluate the impact of moderate-to-high intensity, aerobic and resistance exercise with person-centered guidance on fatigue, anxiety and depression, in older adults with RA. Comparisons were made between older adults (> 65 years) with RA taking part in a 20-week moderate-to-high intensity exercise at a gym (n = 36) or in home-based exercise of light intensity (n = 38). Assessments were performed at baseline, at 20 weeks, and at 52 weeks. Outcomes were differences in Multidimensional Fatigue Inventory (MFI-20), Visual Analog Scale Fatigue (VAS fatigue), and Hospital Anxiety and Depression Scale (HADS). Analysis of metabolomics was also performed. The subscales "physical fatigue" and "mental fatigue" in MFI-20 and symptoms of depression using HADS depression scale improved significantly at week 20 in the exercise group compared with the control group. Exercise did not influence global fatigue rated by VAS or subscales "reduced motivation", "reduced activity" and "general fatigue" in MFI-20. No significant change was found on the anxiety index of HADS. The improvements in physical fatigue were associated with changes in the metabolism of lipids, bile acids, the urea cycle and several sugars. Moderate-to-high intensity exercise with person-centered guidance decreased fatigue and improved symptoms of depression and were accompanied by metabolic changes in older adults with RA.

Preventing cardiovascular heart disease: Promising nutraceutical and non-nutraceutical treatments for cholesterol management

Hypercholesterolemia is one of the major risk factors for the development of cardiovascular disease. Atherosclerosis resulting from hypercholesterolemia causes many serious cardiovascular diseases. Statins are generally accepted as a treatment of choice for lowering low-density lipoprotein (LDL) cholesterol, which reduces coronary heart disease morbidity and mortality. Since statin use can be associated with muscle problems and other adverse symptoms, non-adherence and discontinuation of statin therapy often leads to inadequate control of plasma cholesterol levels and increased cardiovascular risk. Moreover, there is compelling evidence on the presence of still considerable residual cardiovascular risk in statin-treated patients. Ezetimibe improves cholesterol-lowering efficacy and provides mild additional cardiovascular protection when combined with statin treatment. Despite a favorable safety profile compared to statins, ezetimibe-induced cholesterol-lowering is modest when used alone. Hence, there is a critical need to identity additional effective hypolipidemic agents that can be used either in combination with statins, or alone, if statins are not tolerated. Thus, hypolipidemic agents such as proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, apolipoprotein B-100 antisense oligonucleotides, cholesteryl ester transfer protein (CETP) inhibitors, and microsomal triglyceride transfer protein (MTTP) inhibitors, as well as yeast polysaccharides (beta-glucans and mannans) and compounds derived from natural sources (nutraceuticals) such as glucomannans, plant sterols, berberine, and red yeast rice are being used. In this review, we will discuss hypercholesterolemia, its impact on the development of cardiovascular disease (CVD), and the use of yeast polysaccharides, various nutraceuticals, and several therapeutic agents not derived from 'natural' sources, to treat hypercholesterolemia.

The effects of continuous vs intermittent exercise on lipid profile in obese children

Methods:

A randomised pretest–posttest design was implemented to compare the effects of continuous and intermittent exercise, measuring lipid profiles in obese children before and after the intervention. Thirty obese children (11 male and 19 female; age range: 12–15 years; body mass index ≥25) were randomised into two exercise intervention groups to engage in an 8-week exercise programme consisting of either continuous exercise (Group A) or intermittent exercise (Group B).

Results:

Data showed that there was a significant decrease in total cholesterol, triglycerides and low-density lipoprotein (LDL) cholesterol and a significant increase in high-density lipoprotein (HDL) cholesterol in both groups following intervention. There was a significant improvement in the lipid profile results of Group B compared with Group A.

Conclusions:

Intermittent exercise programmes are more effective than continuous exercise programmes in improving lipid profiles in children with obesity. Findings from this research could lead to improved health outcomes in obese patients by increasing aerobic capacity, wellness and metabolic fitness.

Consumption of a dietary portfolio of cholesterol lowering foods improves blood lipids without affecting concentrations of fat soluble compounds

BACKGROUND

Consumption of a cholesterol lowering dietary portfolio including plant sterols (PS), viscous fibre, soy proteins and nuts for 6 months improves blood lipid profile. Plant sterols reduce blood cholesterol by inhibiting intestinal cholesterol absorption and concerns have been raised whether PS consumption reduces fat soluble vitamin absorption.

OBJECTIVE

The objective was to determine effects of consumption of a cholesterol lowering dietary portfolio on circulating concentrations of PS and fat soluble vitamins.

METHODS

Using a parallel design study, 351 hyperlipidemic participants from 4 centres across Canada were randomized to 1 of 3 groups. Participants followed dietary advice with control or portfolio diet. Participants on routine and intensive portfolio involved 2 and 7 clinic visits, respectively, over 6 months.

RESULTS

No changes in plasma concentrations of α and γ tocopherol, lutein, lycopene and retinol, but decreased β-carotene concentrations were observed with intensive (week 12: p = 0.045; week 24: p = 0.039) and routine (week 12: p = 0.031; week 24: p = 0.078) portfolio groups compared to control. However, cholesterol adjusted β-carotene and fat soluble compound concentrations were not different compared to control. Plasma PS concentrations were increased with intensive (campesterol:p = 0.012; β-sitosterol:p = 0.035) and routine (campesterol: p = 0.034; β-sitosterol: p = 0.080) portfolio groups compared to control. Plasma cholesterol-adjusted campesterol and β-sitosterol concentrations were negatively correlated (p < 0.001) with total and LDL-C levels.

CONCLUSION

Results demonstrate that consuming a portfolio diet reduces serum total and LDL-C levels while increasing PS values, without altering fat soluble compounds concentrations. The extent of increments of PS with the current study are not deleterious and also maintaining optimum levels of fat soluble vitamins are of paramount necessity to maintain overall metabolism and health. Results indicate portfolio diet as one of the best options for CVD risk reduction.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00438425.

Consumption of plant sterol-enriched foods and effects on plasma plant sterol concentrations--a meta-analysis of randomized controlled studies

OBJECTIVE

Intake of plant sterol (PS)-enriched foods effectively lowers plasma total- and LDL-cholesterol concentrations while increasing plasma PS concentrations. The magnitude of this increase has not been systematically assessed. This study aimed to investigate the effect of PS-enriched foods on plasma PS concentrations by performing a meta-analysis of randomized controlled studies.

METHODS

Published PS intervention studies reporting plasma PS concentrations were searched through June 2012. Studies were selected that fulfilled pre-defined in- and exclusion criteria. Data were extracted, particularly on campesterol, sitosterol, total- and LDL-cholesterol. Random-effects models were used to calculate net effects while weighing each study by the inverse of its variance. Potential sources of heterogeneity were investigated.

RESULTS

The meta-analysis included data from 41 studies (55 strata) with in total 2084 subjects. The average dose of PS from enriched foods was 1.6 g/d (range: 0.3-3.2 g/d). Plasma sitosterol and campesterol concentrations were increased by on average 2.24 μmol/L (31%) and 5.00 μmol/L (37%), respectively, compared to control. Total- and LDL-cholesterol were reduced by on average 0.36 mmol/L (5.9%) and 0.33 mmol/L (8.5%), respectively. The increase in sitosterol and campesterol was impacted by the dose of PS, the baseline PS concentration and the PS composition of the test products. In the highest PS dose category (2.0-3.2 g/d), increases in sitosterol and campesterol were on average 3.56 and 7.64 μmol/L, respectively.

CONCLUSION

Intake of PS-enriched foods increases plasma sitosterol and campesterol concentrations. However, total PS remain below 1% of total sterols circulating in the blood.

A comparison of the LDL-cholesterol lowering efficacy of plant stanols and plant sterols over a continuous dose range: results of a meta-analysis of randomized, placebo-controlled trials

PURPOSE

To determine if plant stanols and plant sterols differ with respect to their low-density lipoprotein cholesterol (LDL-CH) lowering efficacies across a continuous dose range.

METHODS

Dose-response relationships were evaluated separately for plant stanols and plant sterols and reductions in LDL-CH, using a first-order elimination function.

RESULTS

Altogether, 113 publications and 1 unpublished study report (representing 182 strata) complied with the pre-defined inclusion and exclusion criteria and were included in the assessment. The maximal LDL-CH reductions for plant stanols (16.4%) and plant stanol ester (17.1%) were significantly greater than the maximal LDL-CH reductions for plant sterols (8.3%) and plant sterol ester (8.4%). These findings persisted in several additional analyses.

DISCUSSION AND CONCLUSIONS

Intakes of plant stanols in excess of the recommended 2g/day dose are associated with additional and dose-dependent reductions in LDL-CH, possibly resulting in further reductions in the risk of coronary heart disease (CHD).

Exercise enhances whole-body cholesterol turnover in mice

PURPOSE

Regular exercise reduces cardiovascular risk in humans by reducing cholesterol levels, but the underlying mechanisms have not been fully explored. Exercise might provoke changes in cholesterol and bile acid metabolism and thereby reduce cardiovascular risk. We examined whether voluntary wheel running in mice modulates cholesterol and bile acid metabolism.

METHODS

Male mice (10 wk old) were randomly assigned to have access to a voluntary running wheel for 2 wk (RUN group) or remained sedentary (SED group). Running wheel activity was recorded daily. In a first experiment, fecal sterol outputs, fecal bile acid profiles, plasma parameters, and expression levels of genes involved in cholesterol and bile acid metabolism were determined. In a second experiment, bile flow, biliary bile acid profile, and biliary secretion rates of cholesterol, phospholipids, and bile acids were determined.

RESULTS

The RUN group ran an average of 10 km.d and displayed lower plasma cholesterol compared with SED (P = 0.030). Fecal bile acid loss was induced by approximately 30% in running mice compared with SED (P = 0.0012). A approximately 30% increase in fecal cholesterol output in RUN (P = 0.014) was consistent with changes in parameters of cholesterol absorption, such as reduced plasma plant sterol-cholesterol ratio (P = 0.044) and decreased jejunal expression of Npc1l1 (P = 0.013). Supportive of an increased cholesterol synthesis to compensate for fecal sterol loss were increased hepatic mRNA levels of HMGCoA reductase (P = 0.006) and an increased plasma lathosterol-cholesterol ratio (P = 0.0011) in RUN.

CONCLUSIONS

Voluntary wheel running increased cholesterol turnover in healthy mice owing to an increased fecal bile acid excretion and a decreased intestinal cholesterol absorption. Enhanced cholesterol turnover may contribute to the established reduction of cardiovascular risk induced by regular exercise.

Red algal cellular biomass lowers circulating cholesterol concentrations in Syrian golden hamsters consuming hypercholesterolaemic diets

Preliminary evidence suggests that consumption ofPorphyridium cruentum(PC) biomass results in hypocholesterolaemic effects; however, mechanisms responsible have not been elucidated. The aim of the present study was to determine whether PC biomass lowers circulating cholesterol concentrations, dose dependently, in hamsters fed hypercholesterolaemic diets for 28 d and determine whether cholesterol biosynthesis is affected. Biomass added to diets at 2·5, 5 and 10 % resulted in 14, 38 and 53 % reductions (P < 0·001) in total plasma cholesterol, respectively, compared with a control diet. Similarly, non-HDL-cholesterol concentrations in the 5 and 10 % PC groups were reduced (P < 0·001) 28 and 45 %, respectively,v.controls. These effects were unrelated to cholesterol fractional synthesis rate (FSR), as this did not differ between either treatment or control animals. PC consumption had no effect on food intake, plasma glucose concentrations or energy expenditure, but percentage of body fat was lower (P < 0·001) in the 5 and 10 % PC groups compared with controls. These data show that PC reduces total plasma cholesterol and non-HDL-cholesterol when incorporated into the diet at levels as low as 2·5 %. The mechanism of action for this reduction may be related to increased excretion since food intakes and cholesterol FSR were not reduced in the animals receiving the PC. In conclusion, the use of PC biomass reduces circulating cholesterol, dose dependently, in hypercholesterolaemic hamsters but not via reductions in cholesterol FSR. There is potential for the use of this biomass as a functional ingredient to aid in the management of blood cholesterol concentrations.

Continuous dose-response relationship of the LDL-cholesterol-lowering effect of phytosterol intake

Phytosterols (plant sterols and stanols) are well known for their LDL-cholesterol (LDL-C)-lowering effect. A meta-analysis of randomized controlled trials in adults was performed to establish a continuous dose-response relationship that would allow predicting the LDL-C-lowering efficacy of different phytosterol doses. Eighty-four trials including 141 trial arms were included. A nonlinear equation comprising 2 parameters (the maximal LDL-C lowering and an incremental dose step) was used to describe the dose-response curve. The overall pooled absolute (mmol/L) and relative (%) LDL-C-lowering effects of phytosterols were also assessed with a random effects model. The pooled LDL-C reduction was 0.34 mmol/L (95% CI: -0.36, -0.31) or 8.8% (95% CI: -9.4, -8.3) for a mean daily dose of 2.15 g phytosterols. The impacts of subject baseline characteristics, food formats, type of phytosterols, and study quality on the continuous dose-response curve were determined by regression or subgroup analyses. Higher baseline LDL-C concentrations resulted in greater absolute LDL-C reductions. No significant differences were found between dose-response curves established for plant sterols vs. stanols, fat-based vs. non fat-based food formats and dairy vs. nondairy foods. A larger effect was observed with solid foods than with liquid foods only at high phytosterol doses (>2 g/d). There was a strong tendency (P = 0.054) towards a slightly lower efficacy of single vs. multiple daily intakes of phytosterols. In conclusion, the dose-dependent LDL-C-lowering efficacy of phytosterols incorporated in various food formats was confirmed and equations of the continuous relationship were established to predict the effect of a given phytosterol dose. Further investigations are warranted to investigate the impact of solid vs. liquid food formats and frequency of intake on phytosterol efficacy.

Cholesterol-lowering effect of plant sterols

Plant sterols are plant components that have a chemical structure similar to cholesterol except for the addition of an extra methyl or ethyl group; however, plant sterol absorption in humans is considerably less than that of cholesterol. In fact, plant sterols reduce cholesterol absorption and thus reduce circulating levels of cholesterol. Earlier studies that have tested the efficacy of plant sterols as cholesterol-lowering agents incorporated plant sterols into fat spreads. Later on, plant sterols were added to other food matrices, including juices, nonfat beverages, milk and yogurt, cheese, meat, croissants and muffins, and cereal and chocolate bars. The beneficial physiologic effects of plant sterols could be further enhanced by combining them with other beneficial substances, such as olive and fish oils, fibers, and soy proteins, or with exercise. The addition of plant sterols to the diet is suggested by health experts as a safe and effective way to reduce the risk of coronary heart disease.

Efficacy of plant sterols is not influenced by dietary cholesterol intake in hypercholesterolemic individuals

Plant sterols (PSs) reduce plasma total and low-density lipoprotein cholesterol (LDL-C) levels by reducing cholesterol absorption; however, it is not known whether the level of dietary cholesterol intake has an impact on the efficacy of PSs on blood lipids. The purpose of this study was to determine the effect of high vs low dietary cholesterol levels on the lipid-lowering efficacy of free PSs. The study was a semirandomized, double-blind, crossover trial consisting of four 28-day feeding phases each separated by a 4-week washout period. Otherwise healthy hypercholesterolemic subjects (n = 22) consumed each of (a) low-cholesterol control (C(-)S(-)), (b) high-cholesterol control (C(+)S(-)), (c) 22 mg PSs per kilogram of body weight with a low-cholesterol diet (C(-)S(+)), and (d) 22 mg PSs per kilogram of body weight with a high-cholesterol diet (C(+)S(+)). Blood was drawn on the first and last 2 days of each phase to measure plasma total cholesterol, LDL-C, high-density lipoprotein cholesterol, and triacylglycerols as well as plasma campesterol and beta-sitosterol concentrations. Dietary cholesterol had no effect on PS efficacy as a cholesterol-lowering agent because no interaction was found between the 2 factors. However, dietary cholesterol and PS intake had significant independent effects on plasma total cholesterol, LDL-C, and high-density lipoprotein cholesterol levels. beta-Sitosterol levels in plasma increased (P < .0001) as a result of PS supplementation. Data from the present study indicate that, although PSs and dietary cholesterol exert independent effects on plasma cholesterol, PS efficacy is not affected by varying levels of cholesterol intake.

Modulation of apolipoprotein A1 and B, adiponectin, ghrelin, and growth hormone concentrations by plant sterols and exercise in previously sedentary humans

Plant sterols combined with exercise beneficially alter lipid levels in hypercholesterolemic adults. The effect of this combination therapy on other indicators of coronary heart disease risk, however, has yet to be determined. The objective of this trial was to investigate the effect of plant sterols and exercise, alone and in combination, on levels of apolipoprotein (apo) A1 and B, adiponectin, ghrelin, and growth hormone in previously sedentary hypercholesterolemic adults. In an 8 week, parallel-arm trial, 84 subjects were randomized to 1 of 4 groups: combination, exercise, plant sterols, or control. Body mass decreased by 1.1% (p < 0.01) and 0.9% (p < 0.05) in the combination and exercise group, respectively. Low-density lipoprotein cholesterol levels decreased (p < 0.01) by 0.30 mmol/L in the combination group and by 0.49 mmol/L in the plant sterol group. High-density lipoprotein cholesterol levels increased by 7.5% and 9.5% (p < 0.01) in the combination and exercise groups, respectively. Plant sterols increased (p < 0.05) adiponectin levels by 16%. No change in apoA1, apoB, ghrelin, or growth hormone levels were noted in any intervention group. ApoA1 was correlated with high-density lipoprotein cholesterol (r = 0.33, p = 0.01), whereas apoB was weakly related to low-density lipoprotein cholesterol levels (r = 0.13, p = 0.002). Adiponectin was associated with body mass index (r = -0.10, p = 0.006) and high-density lipoprotein cholesterol (r = 0.17, p = 0.0003). These findings suggest that plant sterols can increase adiponectin levels, thereby possibly reducing the risk of future coronary heart disease.

Effect of plant sterols and exercise training on cholesterol absorption and synthesis in previously sedentary hypercholesterolemic subjects

Plant sterols combined with exercise beneficially alter lipid profiles in hypercholesterolemic adults. Although the mechanism by which plant sterols favorably modulate lipid levels is well established, no trial to date has examined the effect of exercise, alone or combined with plant sterols, on cholesterol kinetics. Thus, the current objective was to examine the effects of exercise, plant sterols, and the combination of exercise and plant sterols on cholesterol absorption and synthesis. In an 8-week, parallel-arm trial, 84 subjects were randomized to 1 of 4 interventions: plant sterols combined with exercise, plant sterols, exercise, or control. Diets were not controlled. Total cholesterol and triglyceride levels decreased (P<0.01) by 7.7% and 11.8%, respectively, whereas high-density lipoprotein (HDL) cholesterol levels increased (P<0.01) by 7.5% in the combination group. Mean posttreatment low-density lipoprotein (LDL) cholesterol levels decreased (P<0.01) by 0.30 mmol/L in the combination group. Cholesterol absorption was 16% lower (P<0.01) in the combination group and 18% lower (P<0.01) in the plant sterol group, when compared with control. Exercise had no effect on cholesterol absorption. Nonsignificant increases in cholesterol synthesis rates of 63% (0.084+/-0.014 pools/day), 59% (0.075+/-0.013 pools/day), and 57% (0.072+/-0.011 pools/day) were observed in the combination, exercise, and plant sterol groups, respectively, relative to the control group (0.031+/-0.019 pools/day). LDL cholesterol levels correlated with cholesterol absorption, as represented by the area under the deuterium enrichment curve (r=0.23, P=0.05), and with percent absorption relative to control (r=0.25, P=0.03). These findings suggest that exercise does not modulate lipid levels by altering to cholesterol absorption or synthesis, whereas plant sterols favorably alter levels of LDL cholesterol by suppressing intestinal absorption.

Cocoa flavanol-enriched snack bars containing phytosterols effectively lower total and low-density lipoprotein cholesterol levels

BACKGROUND

Dietary intervention studies incorporating phytosterol-enriched margarine spreads have reported significant decreases in total and low-density lipoprotein (LDL) cholesterol in populations with both normal lipid levels and those with hypercholesterolemia. There is emerging support for more diverse and lower-fat phytosterol-enriched matrixes. Controversy exists, however, over whether phytosterol-enriched foods affect serum fat-soluble vitamins.

OBJECTIVE

We investigated whether a flavanol-rich cocoa snack food containing phytosterols would decrease total and LDL cholesterol levels in subjects with hypercholesterolemia and significantly affect serum fat-soluble vitamins and carotenoids.

DESIGN

A randomized, double-blind parallel arm study design was used. Subjects were randomized to one of two dietary treatments: a cocoa flavanol-enriched snack bar containing 1.5 g phytosterol (n=32), or a control product containing no phytosterols (n=35). Subjects consumed two servings per day.

RESULTS

Consumption of the phytosterol-enriched snack bars but not control bars for 6 weeks was associated with significant reductions in plasma total (4.7%; P<0.01) and LDL cholesterol (6%; P<0.01), and the ratio of total to high-density lipoprotein cholesterol (7.4%; P<0.001). There were no changes in high-density lipoprotein cholesterol, triglycerides, or lipid-adjusted lycopene, beta-cryptoxanthin, lutein/zeaxanthin, alpha-carotene levels, or levels of serum vitamins A or E. A significant reduction in lipid-adjusted serum beta-carotene was observed in the phytosterol but not the no-phytosterol-added group (P<0.05).

CONCLUSIONS

This study supports the use of a novel phytosterol-enriched snack bar to effectively reduce plasma total and LDL cholesterol levels in a population with hypercholesterolemia. The data suggest that the incorporation of this snack food into a balanced diet represents a practical dietary strategy in the management of serum cholesterol levels.

Improvement of cholesterol levels and reduction of cardiovascular risk via the consumption of phytosterols

Hypercholesterolaemia is one of the main factors contributing to the appearance and progression of CVD, which is the main cause of death in the adult population of industrialized societies. By 2020, projections suggest that it will continue to hold first place, by then causing 37 % of all deaths. Therapeutic life-style changes to reduce cardiovascular risk include dietary modifications, such as the inclusion of phytosterols or plant sterols (known since the 1950s to reduce cholesterol levels). These help prevent the absorption of cholesterol and thus condition a reduction in total cholesterol and LDL-cholesterol levels, and ultimately in cardiovascular mortality. The fat-soluble nature of these sterols rendered margarine one of the best vehicles by which to supply them in the diet. Indeed, margarine was the first food to contain cholesterol-reducing phytosterols to be approved by the EU (in agreement with its regulations on new foods and food ingredients, 258/97/CE). Presently, phytosterols can be emulsified with lecithin and thus delivered in non-fat or low-fat foods and beverages. Margarine and dairy products (yoghurt and milk) enriched in phytosterols have proved better at lowering total cholesterol and LDL-cholesterol levels than have enriched cereals and their derivatives, although all can be of help, depending on the characteristics of each subject. The reduction in carotenoid bioavailability caused by sterols is minimized by increasing fruit and vegetable consumption. Individuals who habitually consume phytosterols should also follow traditional advice such as eating less dietary fat and increasing their physical activity. Phytosterols have been shown to be safe and effective in lowering cholesterol levels in many rigorous studies. In few areas of nutrition is there such consensus. Diet professionals should feel comfortable in prescribing phytosterols/stanols for the treatment of hypercholesterolaemia. They are safe whether taken alone or in combination with cholesterol-reducing drugs, such as statins and fibrates. Reinforcement counselling is essential, as therapy is effective only if compliance is good.

Plasma Concentrations of Plant Sterols: Physiology and Relationship with Coronary Heart Disease

Recently, it has been questioned whether elevated levels of circulating plant sterols increase the risk of coronary heart disease (CHD). To date, no definitive conclusions regarding such a relationship have been reached, nor have there been any studies summarizing the factors that contribute to the observed elevations in plant sterol concentrations in plasma. Thus, the purpose of this review is to systematically compare the plant sterol levels of subjects from the general population and to describe factors that contribute to the variations observed. The question of whether elevated plasma concentrations of plant sterols are associated with an increased risk of CHD was also assessed. Results indicate that the key factors accounting for variations in circulating plant sterol concentrations include: apolipoprotein E phenotypes, ATP-binding cassette transporter polymorphisms, use of statin drugs, presence of metabolic syndrome, dietary intake of plant sterols, gender, and analytical techniques used in the measurement of plant sterols in the plasma. An analysis of the studies examining the relationship between circulating levels of plant sterols and CHD risk in non-sitosterolemic populations revealed no clear associations. Furthermore, it was shown that the above-mentioned factors play an important role in determining the levels of plant sterols in plasma. Since these factors may act as potential confounders, they must be controlled for before more solid conclusions can be reached.

Effect of plant sterols and glucomannan on lipids in individuals with and without type II diabetes

OBJECTIVE

The purpose of this study was to determine whether supplements of plant sterols and/or glucomannan improve lipid profile and cholesterol biosynthesis in mildly hypercholesterolemic type II diabetic and non-diabetic subjects and to compare the response of these two subject groups to the treatments.

DESIGN

A randomized, crossover study consisting of four phases of 21 days, with each phase separated by a 28-day washout.

SETTING

The Mary Emily Clinical Nutrition Research Unit of McGill University.

SUBJECTS

Eighteen non-diabetic individuals and 16 type II diabetic individuals aged 38-74 years.

INTERVENTIONS

Subjects were supplemented with plant sterols (1.8 g/day), glucomannan (10 g/day), a combination of glucomannan and plant sterols, and a placebo, provided in the form of bars.

RESULTS

Overall plasma cholesterol concentrations were lowered (P<0.05) after combination treatment (4.72+/-0.20 mmol/l) compared to control (5.47+/-0.18 mmol/l). Plasma low-density lipoprotein (LDL) cholesterol concentrations were decreased (P<0.05) after glucomannan (3.16+/-0.14 mmol/l) and combination treatments (2.95+/-0.16 mmol/l) compared to control (3.60+/-0.16 mmol/l). The results of lipid profiles did not differ between subject groups. Overall plasma lathosterol concentrations, an index of cholesterol biosynthesis, were lowered (P<0.05) after the combination treatment compared to the plant sterol treatment.

CONCLUSIONS

The results suggest that glucomannan and a combination of glucomannan and plant sterols substantially improves plasma LDL cholesterol concentrations.

SPONSORSHIP

Forbes Medi-Tech Inc., Vancouver, British Columbia, Canada.

Blood lipid responses to plant stanol ester supplementation and aerobic exercise training

The purpose of this study was to determine the independent and combined effects of plant stanol ester (PSE) margarine and aerobic exercise on blood lipid concentrations and related intravascular enzymes in 26 healthy sedentary, middle-aged men and postmenopausal women (age, 53 +/- 8 years; body mass index, 27 +/- 1.0, % fat, 28.5 +/- 2). In a stratified double-blind manner, participants were randomly assigned to either a PSE (n = 17) or a placebo (CON, n = 9) margarine group. Participants supplemented their daily diets with 42 g of margarine spread (PSE = 3 g; CON, PSE = 0 g, of approximately equal energy content) for 9 weeks. During the last 4 weeks of margarine supplementation (MS), participants expended 400 kcal on a treadmill 5 d/wk at 65% of VO(2) reserve (2000 kcal/wk). Fasting blood samples were obtained before initiating and after 4 weeks of MS and after exercise training. All blood samples were analyzed for total cholesterol, low-density lipoprotein cholesterol, triglyceride, high-density lipoprotein cholesterol (HDL-C), hepatic lipase, lipoprotein lipase, and cholesterol ester transfer protein activities. Total cholesterol (-10%), low-density lipoprotein cholesterol (-13%), and triglyceride (-18%) concentrations decreased after 4 weeks of MS in the PSE group, but not in the CON group (P < .05 for all). Four weeks of aerobic exercise increased HDL-C by 21% in the CON group (P < .05) and by 4% in the PSE group (P > .05). Total cholesterol-HDL-C ratio decreased significantly (P < .05) in the PSE group, but not in the CON group. No other significant alterations were observed with either PSE or exercise. Our findings suggest that PSE is effective in reducing blood cholesterol concentrations and that exercise can increase HDL-C in middle-aged men and postmenopausal women. Our findings also suggest that PSE supplementation may attenuate the exercise-induced increase in HDL-C.

Plant sterols combined with exercise for the treatment of hypercholesterolemia: overview of independent and synergistic mechanisms of action

At present, dyslipidemia is most commonly treated with lipid-altering pharmacological therapies. However, safety concerns regarding the use of these agents have prompted the need for safe and efficacious nonpharmacological lipid-altering interventions. One such natural therapy is the combination of plant sterols and endurance training. This combination lifestyle intervention has been shown to decrease total cholesterol, low-density lipoprotein (LDL) cholesterol and triglyceride concentrations while increasing high-density lipoprotein (HDL) cholesterol concentrations. However, the mechanisms that underlie these positive lipid alterations have yet to be clarified. Thus, the purpose of this review is to evaluate individual effects of plant sterols and exercise training on lipid levels while attempting to elucidate the possible independent and synergistic mechanisms of action responsible for these modulations. Results reveal that plant sterols decrease both total and LDL cholesterol levels by reducing exogenous cholesterol absorption by way of cholesterol displacement in the intestinal lumen. Additionally, the intestinal membrane transport proteins, ABCG5, ABCG8, as well as NPC1L1, have also been implicated in plant sterol-mediated cholesterol lowering. Conversely, exercise decreases triglyceride levels by reducing hepatic very low-density lipoprotein secretion and increasing skeletal lipoprotein lipase activity. In addition, endurance training was shown to increase HDL cholesterol levels by way of HDL subfraction alterations, in conjunction with changing reverse cholesterol transport enzyme activities. Moreover, plant sterols and exercise may work synergistically to alter lipid levels by modulating lipoprotein transport, composition, release and metabolism. In sum, the present review lends further insight as to the metabolic benefits of adopting a healthy lifestyle, including plant sterols and endurance training, in the treatment of dyslipidemia.

Physical Activity and High-Sensitivity C-Reactive Protein

Cardiovascular disease (CVD) remains one of the leading causes of death and disability in developed countries around the world despite the documented success of lifestyle and pharmacological interventions. This illustrates the multifactorial nature of atherosclerosis and the use of novel inflammatory markers as an adjunct to risk factor reduction strategies. As evidence continues to accumulate that inflammation is involved in all stages of the development and progression of atherosclerosis, markers of inflammation such as high-sensitivity C-reactive protein (CRP) may provide additional information regarding the biological status of the atherosclerotic lesion. Recent investigations suggest that physical activity reduces CRP levels. Higher levels of physical activity and cardiorespiratory fitness are consistently associated with 6-35% lower CRP levels. Longitudinal training studies that have demonstrated reductions in CRP concentrations range from 16% to 41%, an effect that may be independent of baseline levels of CRP, body composition or weight loss. The average change in CRP associated with physical activity appears to be at least as good, if not better, than currently prescribed pharmacological interventions in similar populations. The primary purpose of this review will be to present evidence from both cross-sectional and longitudinal investigations that physical activity lowers CRP levels in a dose-response manner. Finally, this review will examine factors such as body composition, sex, blood sample timing, diet and smoking, which may influence the CRP response to physical activity.

Efficacy and safety of sitosterol in the management of blood cholesterol levels

Elevated levels of plasma LDL cholesterol (LDL-C) represent a major risk factor for cardiovascular disease. Treatments aimed at reducing levels of circulating LDL are regarded, therefore, as cardioprotective. The cholesterol lowering properties of plant sterols have been known for some time and many clinical studies have confirmed the efficacy of sitosterol in lowering plasma LDL-C concentrations. Animal studies have also shown reductions in LDL by sitosterol. The use of animal models has been useful in facilitating the elucidation of specific mechanisms by which this sterol exerts its hypocholesterolemic action. It is well known that plant sterols compete with cholesterol for space within bile salt micelles in the intestinal lumen thereby reducing cholesterol absorption. The understanding of the function of plant sterols in impeding cholesterol absorption has been clarified with the discovery of the adenosine binding cassette transporters, ABCG5/8, involved in the regulation of sterol absorption and secretion into the enterocyte and hepatocyte. Compared to cholesterol and other sterols, sitosterol is preferentially pumped out to the intestinal lumen by the ABCG5/8 transporters. This selective binding of sitosterol to the transporters ultimately results in significant lowering of plasma cholesterol. However, some findings support the hypothesis that plant sterols might be an additional risk factor for coronary heart disease. From the review of these studies, it is apparent that sitosterol is a useful dietary supplement for the lowering of plasma cholesterol. Nevertheless, this plant sterol should be used with caution in certain individuals who have a higher absorption rate of sitosterol.

Effect of plant sterols and endurance training on LDL particle size and distribution in previously sedentary hypercholesterolemic adults

BACKGROUND

Plant sterols and exercise favourably alter lipid profiles in a way that protect against future coronary heart disease (CHD). However, their effects on other indicators of CHD risk, such as LDL particle size, still need further clarification.

OBJECTIVE

This study examined the effect of plant sterols, exercise, and the combination of plant sterols and exercise, on LDL particle size and distribution in previously sedentary, hypercholesterolemic adults.

DESIGN

In an 8-week, placebo-controlled, parallel-arm clinical trial, 84 subjects were randomized to one of four intervention groups: (1) combination of sterols and exercise, (2) exercise, (3) sterol, or (4) control.

RESULTS

Exercise significantly (P < 0.05) reduced post-treatment LDL peak particle size from 255 to 253 A. Additionally, exercise significantly (P < 0.05) decreased the proportion of large LDL particles within plasma. Sterol supplementation significantly (P < 0.05) decreased the estimated cholesterol concentrations within small, medium, and large LDL particles by 13.4, 13.5, and 14.4%, respectively, yet had no effect on the distribution of cholesterol among various LDL particle sizes. Furthermore, decreased body weight post-training was associated with increased cholesterol in small LDL particles (r = -0.52, P < 0.0001). Decrease in body fat percent (BF%) post-training was associated with increased cholesterol concentrations in small LDL particles (r = -0.29, P < 0.01).

CONCLUSION

On the basis of modulating LDL electrophoretic characteristics, the present study demonstrates that plant sterols have no effect on CHD risk, while short-term exercise may potentially increase CHD risk by decreasing LDL peak particle size.

SPONSORSHIP

This study was sponsored by The Heart and Stroke Foundation of Canada.

Combination diet and exercise interventions for the treatment of dyslipidemia: an effective preliminary strategy to lower cholesterol levels?

At present, dyslipidemia is most commonly treated with drug therapy. However, because safety concerns regarding the use of pharmaceutical agents have arisen, a need for alternative nonpharmacological therapies has become increasingly apparent. The National Cholesterol Education Program (NCEP) Adult Treatment Panel III (ATP III) recommends lifestyle therapies, which include a combination of diet and exercise modifications, in place of drug treatment for patients who fall into an intermediate range of coronary heart disease (CHD) risk. This review examined the cholesterol lowering efficacy of the following 2 NCEP-recommended combination therapies: 1) low saturated fat diets combined with exercise, and 2) nutritional supplementation, i.e., fish oil, oat bran, or plant sterol supplementation, combined with exercise, in the treatment of dyslipidemia. Combination therapies are particularly advantageous because diet and exercise elicit complementary effects on lipid profiles. More specifically, diet therapies, with some exceptions, lower total (TC) and LDL cholesterol (LDL-C) concentrations, whereas exercise interventions increase HDL cholesterol (HDL-C) while decreasing triglyceride (TG) levels. With respect to specific interventions, low saturated fat diets combined with exercise lowered TC, LDL-C, and TG concentrations by 7-18, 7-15, and 4-18%, respectively, while increasing HDL-C levels by 5-14%. Alternatively, nutritional supplements combined with exercise, decreased TC, LDL-C, and TG concentrations by 8-26, 8-30, and 12-39%, respectively, while increasing HDL-C levels by 2-8%. These findings suggest that combination lifestyle therapies are an efficacious, preliminary means of improving cholesterol levels in those diagnosed with dyslipidemia, and should be implemented in place of drug therapy when cholesterol levels fall just above the normal range.