Effects of policosanols and phytosterols on lipid levels and cholesterol biosynthesis in hamsters

What is the influence of policosanol supplementation on liver enzymes? A systematic review and dose-response meta-analysis of randomized controlled trials

OBJECTIVE

Policosanol is a mixture of long chain alcohols refined from sugar cane. Significant reductions in liver enzymes have been observed in some studies. However, the impact of policosanol on liver enzymes remained controversial. The current meta-analysis aims to evaluate the effect of policosanol supplementation on the levels of alanine transaminase (ALT) and aspartate transaminase (AST).

METHODS

The literature was systematically searched for studies published up to November 2023 in PubMed/Medline, Google Scholar, EMBASE, and Scopus. Randomized controlled trial (RCT) studies were included to evaluate the intervention effect of policosanol compared to placebo on ALT and AST. DerSimonian and Laird models were used to calculate effect sizes.

RESULTS

Twenty-three trials including 2535 participants were included in the study. The combination of effect sizes, regarding the random-effects model, demonstrated significant changes in ALT serum levels after intervention (WMD: -1.48 U/L; 95% CI: -2.33 to -0.64; P = 0.001), and AST (WMD: -1.10 U/L; 95% CI: -1.70 to -0.51; P < 0.001). Subgroup analysis of AST and ALT showed that this reduction effect was most often observed at the dose of 20 mg/d. The dose-response analysis represented a non-significant non-linear connection between the dosage and duration of policosanol intervention in ALT and AST serum reduction.

CONCLUSION

Policosanol supplementation exerts a beneficial effect on liver enzymes as well as ALT and AST concentrations in adults. However, further long-term and well-designed RCTs with better quality are needed to further assess and confirm these results.

Effect of raw and encapsulated policosanol on lipid profiles, blood biochemistry, activity, energy expenditure and macronutrient metabolism of adult cats

OBJECTIVES

The objective of this study was to verify the safety of policosanol supplementation for domestic cats. The effects of raw and encapsulated policosanol were compared with positive (L-carnitine) and negative (no supplementation) controls on outcomes of complete blood count, serum biochemistry, energy expenditure, respiratory quotient and physical activity in healthy young adult cats.

METHODS

The study was a replicated 4 × 4 complete Latin square design. Eight cats (four castrated males, four spayed females; mean age 3.0 ± 1.0 years; mean weight 4.36 ± 1.08 kg; mean body condition score 5.4 ± 1.4) were blocked by sex and body weight then randomized to treatment groups: raw policosanol (10 mg/kg body weight), encapsulated policosanol (50 mg/kg body weight), L-carnitine (200 mg/kg body weight) or no supplementation. Treatments were supplemented to a basal diet for 28 days with a 1-week washout between periods. Food was distributed equally between two offerings to ensure complete supplement consumption (first offering) and measure consumption time (second offering). Blood collection (lipid profile, complete blood count, serum biochemistry) and indirect calorimetry (energy expenditure, respiratory quotient) were conducted at days 0, 14 and 28 of each period. Activity monitors were worn 7 days prior to indirect calorimetry and blood collection. Data were analyzed using a repeated measures mixed model (SAS, v.9.4).

RESULTS

Food intake and body weight were similar among treatments. There was no effect of treatment on lipid profile, serum biochemistry, activity, energy expenditure or respiratory quotient (P >0.05); however, time to consume a second meal was greatest in cats fed raw policosanol (P <0.05).

CONCLUSIONS AND RELEVANCE

These data suggest that policosanol is safe for feline consumption. Further studies with cats demonstrating cardiometabolic risk factors are warranted to confirm whether policosanol therapy is an efficacious treatment for hyperlipidemia and obesity.

Semi-synthetic diet versus diet using natural ingredients-Comparative study in female Golden Syrian hamsters

Semi-synthetic diets (SSD) are recommended and are widely used to carry out experiments in rodents. However, in our experiments planned to carry out generation studies in female Golden Syrian hamsters using semi-synthetic diets, it was observed that the hamsters did not conceive as a result of decreased food intake. In this paper, we present the effects of both semi-synthetic diets and natural source diets (NSD) on food intake, body weight and reproductive performance of this species. Four-week-old female hamsters were equally divided into 3 groups and initially acclimatized for 2 weeks on natural chow diet (NCD). Thereafter, they were fed either control diet, high fat diet (HFD) or low protein diet (LPD) based on semi-synthetic/natural source ingredients until 12 weeks. Daily food intake and weekly body weights were monitored. Hamsters were kept for mating for about 2 weeks from 10th week onwards, during which the pregnancy confirmation test was done using standard vaginal smear examination. In all the groups fed SSD, the food intake was very poor, hamsters lost body weight and did not conceive, thus preventing us from carrying out further experiments. Hamsters fed NCD/NSD ingested more than twice as much as hamsters fed SSD (7-8 g/day/hamster against 3 g/day/hamster on average respectively). Based on the results of the current research, we conclude that the routinely used semi-synthetic diet is not suitable for carrying out studies in female hamsters. We suggest that scientists must also consider the unusual biological characteristics of a given species besides other biological factors. It is therefore critical to select appropriate biological models and diets that provide optimal sensitivity and specificity to accomplish the research objectives.

Anti-Aging and Tissue Regeneration Ability of Policosanol Along with Lipid-Lowering Effect in Hyperlipidemic Zebrafish via Enhancement of High-Density Lipoprotein Functionality

We investigated the tissue regeneration and lipid-lowering effects of policosanol (PCO) by employing a hyperlipidemic zebrafish model. A reconstituted high-density lipoprotein containing policosanol (PCO-rHDL) facilitated greater cell growth and replication with less apoptosis and reactive oxygen species (ROS) production in BV-2 microglial cell lines. From in vivo study, injection of rHDL containing apolipoprotein A-I (ApoA-I) caused 76 ± 4% (p = 0.01) greater tissue regeneration activity than the phosphate-buffered saline (PBS) control, whereas PCO-rHDL caused 94 ± 7% (p = 0.002) increased regeneration. PCO in ethanol (EtOH) showed lower cholesteryl ester transfer protein (CETP) inhibitory ability than did anacetrapib, whereas PCO-rHDL showed higher inhibitory ability than anacetrapib, suggesting a synergistic effect between PCO and rHDL. Following 9 weeks of PCO consumption, the PCO group (0.003% PCO in Tetrabit) showed the highest survivability (80%), whereas normal diet (ND) and high-cholesterol diet (HCD) control groups showed 67% and 70% survival rates, respectively. Supplementation with a HCD resulted in two-fold elevation of CETP activity along with 3- and 2.5-fold increases in serum total cholesterol (TC) and triglycerides (TGs) levels, respectively. Consumption of PCO for 9 weeks resulted in 40 ± 5% (p = 0.01 vs. HCD) and 33 ± 4% (p = 0.02 vs. HCD) reduction of TC and TGs levels, respectively. Serum high-density lipoprotein cholesterol (HDL-C) level increased up to 37 ± 2 mg/dL (p = 0.004), whereas the percentage of HDL-C/TC increased up to 20 ± 2% from 5 ± 1% compared to the HCD control. The serum glucose level was reduced to 47 ± 2% (p = 0.002) compared to the HCD control. Fatty liver change and hepatic inflammation levels were remarkably increased upon HCD consumption and were two-fold higher than that under ND. However, the PCO group showed 58 ± 5% (p = 0.001) and 50 ± 3% (p = 0.006) reduction of inflammation enzyme levels and lipid content in hepatic tissue under HCD. In conclusion, PCO supplementation showed lipid-lowering and HDL-C-elevating effects with ameliorating fatty liver change. These in vivo anti-atherosclerotic and anti-diabetic effects of PCO are well associated with in vitro anti-apoptotic activities.

Berberine decreases cholesterol levels in rats through multiple mechanisms, including inhibition of cholesterol absorption

OBJECTIVE

The objective was to determine the mechanisms of action of berberine (BBR) on cholesterol homeostasis using in vivo and in vitro models.

METHODS

Male Sprague-Dawley rats were fed the AIN-93G diet (normal control) or modified AIN-93G diet containing 28% fat, 2% cholesterol and 0.5% cholic acid with treatment of 0 (atherogenic control), 50, 100, and 150 mg/kg·d of BBR, respectively by gavaging in water for 8 weeks. Cholesterol absorption rate was measured with the dual stable isotope ratio method, and plasma lipids were determined using the enzymatic methods. Gene and protein expressions of Acyl-coenzyme A:cholesterol acyltransferase-2 were analyzed in vivo and in vitro. Cholesterol micellarization, uptake and permeability were determined in vitro.

RESULTS

Rats on the atherogenic diet showed significantly hypercholesterolemic characteristics compared to normal control rats. Treatment with BBR in rats on the atherogenic diet reduced plasma total cholesterol and nonHDL cholesterol levels by 29%-33% and 31%-41%, respectively, with no significant differences being observed among the three doses. The fractional dietary cholesterol absorption rate was decreased by 40%-51%. Rats fed the atherogenic diet showed lower plasma triacylglycerol levels, and no changes were observed after the BBR treatment. BBR interfered with cholesterol micellarization, decreased cholesterol uptake by Caco-2 cells and permeability through Caco-2 monolayer. BBR also inhibited the gene and protein expressions of acyl-coenzyme A cholesterol acyltransferease-2 in the small intestine and Caco-2 cells.

CONCLUSION

BBR lowered blood cholesterol levels at least in part through inhibiting the intestinal absorption and further by interfering with intraluminal cholesterol micellarization and decreasing enterocyte cholesterol uptake and secretion.

Effects of high molecular weight alcohols from sugar cane fed alone or in combination with plant sterols on lipid profile and antioxidant status of Wistar rats

The effect of feeding a mixture of high molecular weight alcohols derived from sugarcane (SCA), both alone and in combination with phytosterols (PS), on changes in plasma lipids, organ cholesterol accumulation, and antioxidant status of Wistar rats was undertaken. Three separate experiments were conducted and each experiment had 3 subsets. In experiment 1, rats were fed on an AIN-76, semi-synthetic diet supplemented with 0%, 0.5%, and 5% SCA w/w. The second experiment consisted of feeding rats an atherogenic diet (AIN-76+0.5% cholesterol) containing 0%, 0.5%, and 5% SCA w/w. The third experiment consisted of feeding rats an atherogenic diet that contained 2% PS in combination with 0%, 0.5%, and 5% SCA. Rats fed the atherogenic diet exhibited significant elevations in total and low-density lipoprotein cholesterol, and significant reductions in the high-density lipoprotein/total cholesterol ratio, regardless of the presence of 0.5% or 5% SCA mixture. Serum cholesterol increased 29% to 35% in these animals compared with animals fed the nonatherogenic diets. In contrast, animals fed atherogenic diets that contained 2% PS exhibited no difference in serum lipids compared with counterparts fed nonatherogenic diets. The combined presence of SCA with PS had no effect on further lowering plasma cholesterol. No changes in C-reactive protein were observed, but plasma oxygen radical scavenging capacity values significantly (p < 0.05) decreased when rats were fed the atherogenic diets that contained the combination of PS and SCA. This result corresponded to an apparent greater (p < 0.05) susceptibility of red blood cells to oxidative stress.

Metabolic and genetic factors modulating subject specific LDL-C responses to plant sterol therapy1This article is an invited review for the Journal's Made In Canada section. The authors gratefully acknowledge the training that was acquired at the Richardson Centre for Functional Foods and Nutraceuticals, University of Manitoba. We would specifically like to thank Dr. Peter Jones for his mentorship and significant contribution to the research contained within this manuscript

Reducing intestinal cholesterol absorption with plant sterol consumption is a well-characterized strategy to lower LDL-C and potentially reduce cardiovascular disease risk. However, over 50 years of clinical research demonstrate that there is significant heterogeneity in the individual LDL-C lowering response to plant sterol therapy. A clear understanding of why plant sterols work effectively in some individuals but not in others will ensure optimal integration of plant sterols in future personalized nutritional lipid-lowering strategies. This review will examine the current knowledge base surrounding the metabolic and genetic determinants of LDL-C lowering in response to plant sterol consumption.

Cholesterol ester and free fatty acids are modulated by policosanol in CaCo-2 intestinal cells

OBJECTIVE

To investigate policosanol absorption by brush border membrane (BBM), metabolism in CaCo-2 enterocytes, and transport of policosanol metabolites across the basolateral membrane (BLM). It was hypothesized that policosanol is partially oxidized into fatty acids and then is incorporated into other lipids.

METHODS

Policosanol was emulsified with phosphatidylcholine in the culture medium. The viability of cells was assessed via an MTT (3-[4,5]dimethylthiazol-2-yl-2,5-diphenyltetrazolim) assay. Control cells received only the same amount of "vehicle" (phosphatidylcholine) without policosanol. CaCo-2 cell monolayer and medium were collected; lipid was extracted and analyzed by thin-layer chromatography (TLC) and gas liquid chromatography (GLC).

RESULTS

Eighty-six percent of policosanol added to the cell culture medium was absorbed after 48 hours' incubation. The amount of cholesterol ester fatty acid was significantly increased both in the cells and in the basolateral medium, and was reduced in the apical medium. Policosanol increased the quantity of free fatty acids in the basolateral medium and reduced the free fatty acid content of CaCo-2 cells. Further evaluation of lipid profiles indicated that policosanol modulated the fatty acid profile of cholesterol ester in the basolateral medium.

CONCLUSION

It was concluded that policosanol or policosanol metabolites may modulate lipid metabolism and/or transport following absorption by the BBM, partial oxidation by the intestinal epithelium, and transport of policosanol metabolites across the BLM.

Astragalus polysaccharides lowers plasma cholesterol through mechanisms distinct from statins

To determine the efficacy and underlying mechanism of Astragalus polysaccharides (APS) on plasma lipids in hypercholesterolemia hamsters. The effect of APS (0.25g/kg/d) on plasma and liver lipids, fecal bile acids and neutral sterol, cholesterol absorption and synthesis, HMG-CoA reductase activity, and gene and protein expressions in the liver and small intestine was investigated in twenty-four hypercholesterolemia hamsters. Treatment periods lasted for three months. APS significantly lowered plasma total cholesterol by 45.8%, triglycerides by 30%, and low-density lipoprotein-cholesterol by 47.4%, comparable to simvastatin. Further examinations revealed that APS reduced total cholesterol and triglycerides in the liver, increased fecal bile acid and neutral sterol excretion, inhibited cholesterol absorption, and by contrast, increased hepatic cholesterol synthesis and HMG-CoA reductase activity. Plasma total cholesterol or low-density lipoprotein-cholesterol levels were significantly correlated with cholesterol absorption rates. APS up-regulated cholesterol-7α-hydroxylase and LDL-receptor gene expressions. These new findings identify APS as a potential natural cholesterol lowering agent, working through mechanisms distinct from statins.

Activation of AMP-kinase by policosanol requires peroxisomal metabolism

Policosanol, a well-defined mixture of very long chain primary alcohols that is available as a nutraceutical product, has been reported to lower blood cholesterol levels. The present studies demonstrate that policosanol promotes the phosphorylation of AMP-kinase and HMG-CoA reductase in hepatoma cells and in mouse liver after intragastric administration, providing a possible means by which policosanol might lower blood cholesterol levels. Treatment of hepatoma cells with policosanol produced a 2.5-fold or greater increase in the phosphorylation of AMP-kinase and HMG-CoA reductase, and increased the phosphorylation of Ca(++)/calmodulin-dependent kinase kinase (CaMKK), an upstream AMP-kinase kinase. Intragastric administration of policosanol to mice similarly increased the phosphorylation of hepatic HMG-CoA reductase and AMP-kinase by greater than 2-fold. siRNA-mediated suppression of fatty aldehyde dehydrogenase, fatty acyl-CoA synthetase 4, and acyl-CoA acetyltransferase expression in hepatoma cells prevented the phosphorylation of AMP-kinase and HMG-CoA reductase by policosanol, indicating that metabolism of these very long chain alcohols to activated fatty acids is necessary for the suppression of cholesterol synthesis, presumably by increasing cellular AMP levels. Subsequent peroxisomal β-oxidation probably augments this effect.

High basal fractional cholesterol synthesis is associated with nonresponse of plasma LDL cholesterol to plant sterol therapy

BACKGROUND

The cholesterol-lowering effectiveness of plant sterol (PS) therapy is hindered by wide-ranging variability in LDL-cholesterol responsiveness across individuals. To capitalize on the LDL-cholesterol-lowering potential of PS in the clinical setting, it is paramount to characterize the metabolic factors that underlie this heterogeneity of responsiveness.

OBJECTIVE

The objective was to investigate the relation between cholesterol synthesis and plasma LDL-cholesterol reductions in response to PS consumption.

DESIGN

We evaluated previously conducted clinical PS interventions incorporating stable-isotope measures of cholesterol synthesis and conducted feeding studies in animal models of response (Syrian Golden hamsters) and nonresponse (C57BL/6J mice) to PS consumption.

RESULTS

From our clinical study population (n = 113), we identified 47 nonresponders (3.73 +/- 1.10% change in LDL cholesterol) and 66 responders (-15.16 +/- 1.04% change in LDL cholesterol) to PS therapy. The basal cholesterol fractional synthesis rate (FSR) as measured by direct deuterium incorporation was 23% higher (P = 0.003) in the nonresponder subgroup than in responders to PS therapy. The basal cholesterol FSR correlated (r = 0.22, P = 0.02) with the percentage change in LDL cholesterol after PS intervention. In support of our clinical observations, nonresponding mice showed a 77% higher (P = 0.001) basal cholesterol FSR than that of responding hamsters. Compared with control mice, PS-fed mice showed an increase in hepatic nuclear sterol regulatory element binding protein 2 abundance (1.3-fold of control, P = 0.04) and beta-hydroxy-beta-methylglutaryl coenzyme A reductase-mRNA expression (2.4-fold of control, P = 0.00).

CONCLUSION

The results suggest that subjects with high basal cholesterol synthesis are less responsive to PS treatment than are subjects with low basal cholesterol synthesis.

Policosanols as nutraceuticals: fact or fiction

Policosanols (PC) are very long chain aliphatic alcohols derived from the wax constituent of plants. In the early 1990s, researchers at Dalmer Laboratories in La Habana Cuba isolated and produced the first PC supplement from sugarcane wax. The original PC supplement has been approved as a cholesterol-lowering drug in over 25 countries throughout the Caribbean and South America. Cuban studies claim that 1 to 20 mg/day of the original PC supplement are effective at producing significant reductions in total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C). These studies also show that PC supplements are potent antioxidants, promote proper arterial endothelial cell function, inhibit platelet aggregation and thrombosis, and serve as effective treatments for intermittent claudication. However, for the most part, those studies reporting therapeutic efficacy of PC were carried out by one research group situated in Cuba. Conversely, research groups outside of Cuba have failed to validate the cholesterol-lowering and antioxidant efficacy of PC. Cuban researchers, however, continue to claim that the efficacy is attributed to the unique purity and composition of the original PC preparation, a mixture not found in PC products used by external research groups. The absence of independent and external studies confirming the therapeutic benefits of PC in disease prevention and treatment raises questions regarding their true efficacy.

Berberine and plant stanols synergistically inhibit cholesterol absorption in hamsters

The present study was conducted to determine the efficacy and underlying mechanism of berberine (BBR), plant stanols (PS) and their combination on plasma lipids. Male Golden Syrian hamsters were randomly divided into 4 groups (n=15/group) and fed a cornstarch-casein-sucrose-based diet containing 0.15% cholesterol and 5% fat. Three treatment groups were supplemented with 0.17% (equivalent to 100mgkg(-1)d(-1)) BBR, 1% PS, or a combination of both (BBRPS) for 4wk. At the end of the study, plasma lipids were analyzed with enzymatic methods, cholesterol absorption and synthesis using stable isotope tracer methodology, and gene and protein expressions in the liver and small intestine using real-time PCR and Western blot, respectively. BBR and PS significantly lowered plasma total- and nonHDL-cholesterol levels, and BBRPS markedly improved cholesterol-lowering efficacy compared to BBR or PS alone. Further examinations revealed that BBR and PS both inhibited cholesterol absorption and by contrast, increased cholesterol synthesis, and exerted a synergistic action when they were combined. Plasma total or nonHDL-cholesterol levels were significantly correlated with cholesterol absorption rates. BBR upregulated sterol 27-hydroxlase gene expression and BBRPS increased both cholesterol-7alpha-hydroxylase and sterol 27-hydroxlase gene expressions. BBR and PS also synergistically decreased plasma triacylglycerides. These findings suggest that the cholesterol-lowering action of BBR might involve a combination of inhibition of cholesterol absorption and stimulation of bile acid synthesis. The combination of BBR and PS improves cholesterol-lowering efficacy through a synergistic action on cholesterol absorption, in addition to synergistically reducing plasma triacylglycerols in hamsters.

Effect of sugar cane policosanol on lipid profile in primary hypercholesterolemia

Policosanol, a mixture of long-chain aliphatic primary alcohols, is used as a cholesterol-lowering supplement. The effectiveness of policosanol is still questionable. To determine the lipoprotein-lowering effects of Cuban sugar cane-derived policosanol a double-blind, randomized, placebo controlled trial was performed. Sixty-eight primary hypercholesterolemic subjects were enrolled and randomly assigned to the treatment or to the control group. The first group received sugar cane policosanol 20 mg daily for 8 weeks, while the control group was treated with placebo. All subjects followed a normocaloric diet. The content of policosanol in the supplement tablets was assessed by gas chromatography. A total of 32 subjects in the policosanol group and 31 subjects in the control group completed the study. Body mass index, total cholesterol, HDL-cholesterol, LDL-cholesterol and triglyceride plasma levels did not change significantly in either group. In conclusion, sugar cane policosanol at doses of 20 mg daily showed no lipid lowering effects in subjects with primary hypercholesterolemia.

Cholesterol-lowering nutraceuticals and functional foods

Epidemiological studies have demonstrated that elevated levels of plasma total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) are the major risk factors for coronary heart disease (CHD), whereas high concentrations of plasma high-density lipoprotein cholesterol (HDL-C) and a low ratio of TC to HDL-C are protective against CHD. A relationship between plasma TC and the risk of CHD is well established at concentrations above 240 mg/dL. In addition to the use of three main classes of cholesterol-lowering medications, including HMG-CoA reductase inhibitors, anion-exchange resins, and fibrates, a nutritionally balanced diet that reduces saturated fat and cholesterol intake has traditionally been the first goal of dietary therapy in lowering plasma TC. In recent years, nutraceuticals and functional foods have attracted much interest as possible alternative therapies for lowering plasma TC, especially for hypercholesterolemia patients, whose blood cholesterol level is marginally high (200-240 mg/dL) but not high enough to warrant the prescription of cholesterol-lowering medications. This review summarizes the findings of recent studies on the production, application, efficacy, and mechanisms of popular cholesterol-lowering nutraceuticals and functional foods.

Changes in cholesterol kinetics following sugar cane policosanol supplementation: a randomized control trial

Background

Sugar cane policosanols (SCP) have been shown to exert cholesterol-modulating properties in various studies conducted in Cuba by substantially reducing cholesterol synthesis. Independent research examining changes in cholesterol kinetics in response to SCP is limited to few studies, none of which was able to replicate findings of the original research. Moreover, no data are available on the effect of SCP on cholesterol absorption to date. The present study was undertaken to determine effects on cholesterol kinetics, namely synthesis and absorption, within hypercholesterolemic individuals consuming a SCP treatment. Twenty-one otherwise healthy hypercholesterolemic subjects participated in a randomized double-blind crossover study where they received 10 mg/day of policosanols or a placebo incorporated in margarine as an evening snack for a period of 28 days. The last week of the study phase, subjects were given ¹³C labelled cholesterol and deuterated water for the measurement of cholesterol absorption and synthesis respectively. Blood was collected on the first two and last five days of the trial. Cholesterol absorption and synthesis were determined by measuring red cell cholesterol ¹³C and deuterium enrichment, respectively.

Results

There was no significant change in LDL cholesterol levels as compared to control. In addition, the area under the curve for red cell cholesterol ¹³C enrichment across 96 hours was not significantly different in the SCP group as compared to control. Similarly, no difference was observed in the fractional rate of cholesterol synthesis over the period of 24 hours between the two treatment groups.

Conclusion

The findings of the present study fail to support previous research concerning efficacy and mechanism of action for policosanols.

Octacosanol administration to humans decreases neutral sterol and bile acid concentration in feces

To investigate octacosanol (OC) metabolism in humans and its influence on cholesterol metabolism, two studies were conducted. In the first study ten healthy women received daily 30 mg OC for a period of 4 weeks. Blood and feces samples were collected at baseline and after the intervention. Serum concentrations of total cholesterol, LDL cholesterol, and HDL cholesterol were not altered following OC administration. Concentrations of excreted cholesterol end products decreased with the intervention (neutral sterols: 24.6 +/- 9.7 mg/g vs. 20.3 +/- 7.5 mg/g dry matter, P < 0.05; bile acids: 6.47 +/- 3.89 mg/g vs. 4.03 +/- 2.26 mg/g dry matter, P < 0.05). OC was not detected in serum samples, but the fecal OC concentration increased after the intervention period (11 +/- 7 microg/g vs. 817 +/- 179 microg/g dry matter, P < 0.05). In the second kinetic study on three participants, OC was identified in serums after oral application of 50 mg OC within 8 h. The decrease in the concentration of fecal cholesterol end products may underline a systemic effect of OC on cholesterol metabolism, even though the serum cholesterol levels were not influenced.

Comparison of composition and absorption of sugarcane policosanols

Policosanols (PC) exist as very-long-chain alcohols derived from sugarcane currently used in many countries as a cholesterol-lowering therapy. PC purity and relative percentage composition have been suggested as primary reasons why the original Cuban PC (OPC) supplements possess lipid-lowering efficacy. The purpose of the present study was, first, to compare the relative percentage purity and PC composition of both OPC and alternative sources of PC (APC). A second objective was to feed Syrian hamsters a diet containing 0.275 mg PC/g of either the OPC or an APC product (APC1) and compare subsequent tissue, plasma and faecal PC levels. Five animals from the APC1 dietary group received a diet containing ten times the original amount of PC. Results indicate that the APC formulations have a composition that is highly consistent with the OPC supplement, with octacosanol being present within the cited 60-70 % range. PC were undetectable in the small intestine, liver, adipose or plasma in animals fed either source. Hamsters fed OPC excreted octacosanol (C28) more rapidly (P < 0.05) than hamsters receiving APC1. If the cholesterol-lowering efficacy of PC mixtures is dependent on their purity and composition, then sugarcane-derived APC products should possess similar therapeutic properties as the OPC supplement.

Effects of a policosanol supplement on serum lipid concentrations in hypercholesterolaemic and heterozygous familial hypercholesterolaemic subjects

Policosanol is a mixture of higher aliphatic primary alcohols that is extracted from purified sugar cane wax or a variety of other plant sources, and has been shown to have beneficial effects on serum lipid concentrations. The objective of this study was to investigate the effects of a policosanol supplement (Octa-60) on lipid profiles of hypercholesterolaemic and heterozygous familial hypercholesterolaemic subjects. Nineteen hypercholesterolaemic and familial hypercholesterolaemic subjects completed this randomised, placebo-controlled, double-blind study. The subjects received either a daily dose of 20 mg policosanol or placebo for 12 weeks. After a wash-out period of 4 weeks, the interventions were crossed over. Lipid levels were measured at baseline and at the end of each intervention period. No significant differences in total cholesterol and LDL-cholesterol from baseline to end or between policosanol and placebo were seen in the hypercholesterolaemic or familial hypercholesterolaemic groups. There were small reductions in total cholesterol and LDL-cholesterol from baseline to end in the hypercholesterolaemic group, but these changes did not differ significantly from the changes with the placebo, indicating that the observed decrease in cholesterol in the policosanol group was not due to the specific effect of policosanol treatment. The differences in response may be ascribed to the differences in composition of the higher aliphatic primary alcohols in the previously used products, compared with the local policosanol supplement. An intake of 20 mg/d policosanol for 12 weeks had no significant effect on serum lipid levels in hypercholesterolaemic and heterozygous familial hypercholesterolaemic patients when compared with placebo intake.

Policosanol is ineffective in the treatment of hypercholesterolemia: a randomized controlled trial

BACKGROUND

Policosanol is one of the fastest growing over-the-counter supplements sold in the United States. The use of policosanol to treat elevated cholesterol is based on clinical trials conducted in Cuba, which showed sugar cane-derived policosanol to be similar in efficacy to statins. Recent studies have challenged these findings, but there have been no trials conducted in North America that have examined the ability of sugar cane-derived policosanol to lower cholesterol.

OBJECTIVES

This study investigated the efficacy of sugar cane-derived policosanol in healthy adults with mild hypercholesterolemia. The primary outcome was the percentage change in LDL cholesterol after 8 wk of therapy. Secondary outcome measures included changes in total cholesterol, HDL cholesterol, triacylglycerols, C-reactive protein, and nuclear magnetic resonance-determined lipoprotein profile. Dietary habits, weight, and blood pressure were also monitored.

DESIGN

Ambulatory, community-dwelling healthy adults with mild hypercholesterolemia (n = 40) were assigned to receive oral policosanol (20 mg) or placebo once daily for 8 wk. This was a double-blind, randomized controlled trial conducted from January through August 2005.

RESULTS

No significant differences in the change in LDL cholesterol were observed between the placebo (n = 20) and policosanol (n = 20) groups. Also, no significant changes in secondary outcome measures, including total cholesterol, HDL cholesterol, triacylglycerol, C-reactive protein, and nuclear magnetic resonance spectroscopy-determined profiles were observed. Policosanol was well tolerated, and no significant adverse events were noted.

CONCLUSION

Policosanol does not alter the serum lipid profile over an 8-wk period in adults with mild hypercholesterolemia.

Lack of effect of sugar cane policosanol on plasma cholesterol in Golden Syrian hamsters

Policosanol is a mixture of higher aliphatic alcohols shown to have beneficial effects on plasma lipid levels in animals and humans. Over 50 studies have reported significant reductions in plasma cholesterol using policosanol obtained from Cuban sugar cane (Dalmer, La Havana, Cuba). However, other research groups using policosanol from alternative sources have failed to reproduce the efficacy of these alcohols observed in earlier studies. Therefore, the objective of the present study was to compare the cholesterol-lowering effect of the Dalmer sugar cane policosanol (SCP) product versus an alternative mixture of similar policosanol composition. Forty-eight male Golden Syrian hamsters were randomly assigned to four groups and fed experimental diets ad libitum for a period of 4 weeks: (i) non-cholesterol control, (ii) 0.1% cholesterol control, (iii) 0.1% cholesterol diet supplemented with 275 mg/kg diet of Dalmer Cuban sugar cane policosanol and (iv) 0.1% cholesterol diet supplemented with 275 mg/kg diet of alternative sugar cane policosanol. Hamsters were sacrificed and blood was collected at the end of the feeding period. Body weights and food intakes were similar across study groups. Neither of the two policosanol treatments had any significant effect on plasma lipid levels, as compared to cholesterol control. The outcome of the present study questions the clinical usefulness of policosanol mixtures as cholesterol-lowering nutraceuticals.

Comparative lipid-lowering effects of policosanol and atorvastatin: a randomized, parallel, double-blind, placebo-controlled trial

BACKGROUND

Policosanol, commonly derived from purified sugar cane wax, has been reported to exert lipid-lowering effects. Policosanol is available in the United States as a nutritional supplement despite no US research clinical experience. This trial was designed to rigorously establish the lipid-lowering efficacy of policosanol as monotherapy and its potential additive and possibly synergistic effects when added to statin therapy.

METHODS

A randomized, parallel, double-blind, double-dummy, placebo-controlled design was used. Patients with low-density lipoprotein cholesterol (LDL-C) levels from 140 to 189 mg/dL were assigned into 1 of 4 groups to receive policosanol 20 mg, atorvastatin 10 mg, combination therapy, or placebo for 12 weeks.

RESULTS

A total of 99 patients were examined. Baseline characteristics were similar among all treatment groups. Policosanol (20 mg/d for 12 weeks) did not significantly change plasma total cholesterol, LDL-C, high-density lipoprotein cholesterol, or triglyceride levels when compared with baseline values or with values of placebo-treated patients. Atorvastatin (10 mg/d for 12 weeks) reduced total cholesterol by 27% and LDL-C by 35%. Addition of policosanol to atorvastatin failed to produce any further reduction in lipid levels above that of atorvastatin alone. Policosanol was safe and did not affect liver enzyme or creatinine phosphokinase levels.

CONCLUSIONS

Policosanol did not reduce LDL-C or total cholesterol levels either alone or in combination with atorvastatin. This observation supports the need for systematic evaluation of available products containing policosanol to determine their clinical lipid-lowering efficacy under rigorous experimental conditions. We propose that policosanol should be added to the list of nutritional supplements lacking scientific validity to support their use.

Policosanol Inhibits Cholesterol Synthesis in Hepatoma Cells by Activation of AMP-Kinase

Policosanol is a mixture of long-chain primary alcohols that has been shown to decrease serum cholesterol in animals and in humans. The hypocholesterolemic effect results from a decrease in cholesterol synthesis by suppression of HMG-CoA reductase activity, but the mechanism of this suppression and the active components of policosanol have not been established. In the present study, we investigated the ability of policosanol and its principal components to inhibit cholesterol synthesis in cultured rat hepatoma cells. Maximal inhibition by policosanol yielded a 30% decrease in [(14)C]acetate incorporation without evidence of cellular toxicity. Octacosanol (C28, the major constituent of policosanol), heptacosanol (C27), and hexacosanol (C26) yielded smaller and statistically insignificant decreases in cholesterol synthesis, whereas triacontanol (1-hydroxytriacontane; C30) replicated the inhibition obtained with policosanol. At pharmacological concentrations (<5 microg/ml), policosanol and triacontanol decreased [(14)C]acetate incorporation into cholesterol without affecting the incorporation of [(14)C]mevalonate, indicating that these compounds act at or above HMG-CoA reductase. Policosanol and triacontanol did not directly inhibit HMG-CoA reductase, and incubation of these compounds with hepatoma cells did not affect reductase enzyme levels. However, reductase activity was decreased by up to 55% in lysates prepared from these cells, suggesting that HMG-CoA reductase activity was down-regulated by policosanol treatment. Consistent with this hypothesis, a 3-fold increase in AMP-kinase phosphorylation was noted in policosanol-treated cells. Because AMP-kinase is activated by phosphorylation and is well established to suppress HMG-CoA reductase activity, these results suggest that policosanol or a metabolite decreases HMG-CoA reductase activity by activating AMP-kinase.

Fish oil fatty acid esters of phytosterols alter plasma lipids but not red blood cell fragility in hamsters

In an attempt to combine the hypocholesterolemic properties of plant sterols with the hypotriglyceridemic action of fish oil FA, plant sterols have recently been esterified to fish oil n-3 PUFA. The objective of this study was to determine the effects of plant sterols esterified to n-3 PUFA on plasma lipid levels and erythrocyte fragility. For 5 wk, male Golden Syrian hamsters were fed diets varying in cholesterol and plant sterol content: (i) Non-cholesterol (semipurified diet with no added cholesterol or plant sterols) (ii), Cholesterol (0.25% cholesterol) (iii), Sterols (0.25% cholesterol plus 1% nonesterified plant sterols), or (iv) Fish oil esters of plant sterols (0.25% cholesterol plus 1.76% EPA and DHA sterol esters, providing 1% plant sterols). The addition of fish oil esters of plant sterols to the cholesterol diet decreased (P = 0.001) plasma total cholesterol levels by 20%, but nonesterified plant sterols did not have such a beneficial impact. In addition, non-HDL cholesterol concentrations were 29% lower in hamsters fed fish oil esters of plant sterols than in hamsters fed nonesterified plant sterols (P < 0.0001). Despite higher (P < 0.0001) plant sterol levels in whole erythrocytes of hamsters fed nonesterified plant sterols and fish oil esters of plant sterols compared with hamsters fed no plant sterols, no difference was observed in erythrocyte fragility. The present results show that EPA and DHA esters of plant sterols have a hypocholesterolemic effect in hamsters, and that these new esters of plant sterols exert no detrimental effect on erythrocyte fragility.

Grain sorghum lipid extract reduces cholesterol absorption and plasma non-HDL cholesterol concentration in hamsters

Grain sorghum is a rich source of phytochemicals that could potentially benefit human health. In this study, male hamsters were fed AIN-93M diets supplemented with a hexane-extractable lipid fraction from grain sorghum whole kernels. The grain sorghum lipids (GSL) comprised 0.0, 0.5, 1.0, or 5.0% of the diet by weight. After 4 wk, dietary GSL significantly reduced plasma non-HDL cholesterol concentration in a dose-dependent manner with reductions of 18, 36, and 69% in hamsters fed 0.5, 1.0, and 5.0% GSL, respectively, compared with controls. Liver cholesteryl ester concentration was also significantly reduced in hamsters fed GSL. Plasma HDL cholesterol concentration was not altered (P > 0.05) by dietary treatment. Cholesterol absorption efficiency was significantly reduced by GSL in a dose-dependent manner. Cholesterol absorption was also directly correlated with plasma non-HDL cholesterol concentration (r = 0.97, P < 0.05), suggesting that dietary GSL lowers non-HDL cholesterol, at least in part, by inhibiting cholesterol absorption. TLC and GLC analyses of the GSL extract revealed the presence of plant sterols and policosanols at concentrations of 0.35 and 8.0 g/100 g GSL, respectively. Although plant sterols reduce cholesterol absorption, policosanols may inhibit endogenous cholesterol synthesis. The data suggest that these components of GSL extract may work collectively in lowering plasma and liver cholesterol concentrations. Our findings further indicate that grain sorghum contains beneficial components that could be used as food ingredients or dietary supplements to manage cholesterol levels in humans.

Very long chain fatty acids (policosanols) and phytosterols affect plasma lipid levels and cholesterol biosynthesis in hamsters

The aim of the current study was to examine the effects of very long chain fatty acids (VLCFA) alone at 2 dietary levels, or in combination of VLCFA at the lower level with lecithin (LT) or phytosterols (PS), on lipid profiles and cholesterol biosynthesis in hamsters. Seventy-five male Golden Syrian hamsters, weighing 100 to 120 g, were fed a regular rodent chow for 2 weeks before being randomly assigned into 5 groups of 15 animals each fed semisynthetic diets for 4 weeks. Group 1 was given a control diet that contained 0.25% cholesterol and 5% fat with a polyunsaturated to saturated fatty acids ratio of 0.4. Groups 2 to 5 were fed the control diet and given 25 mg/kg BW per day of VLCFA (Licowax) (VLCFA25), 50 mg/kg BW per day of VLCFA (VLCFA50), 25 mg/kg BW per day of VLCFA+1000 mg/kg BW per day of LT (VLCFA25/LT), and 25 mg/kg BW per day of VLCFA+1000 mg/kg BW per day of PS (Cholestatin, VLCFA25/PS), respectively. Results showed that HDL-cholesterol (HDL-C) levels were not changed by VLCFA25, although increased by VLCFA50 (P<.05) relative to control. Total cholesterol (T-C) and non-HDL-C levels were not affected by VLCFA25 and VLCFA50 as compared with control. VLCFA25/LT had higher (P<.02) T-C and HDL-C levels than any other treatments and increased (P<.05) liver weight relative to control. In contrast, VLCFA25/PS reduced T-C (P=.0004) and non-HDL-C (P=.007) without effect on HDL-C levels compared with control. Triglyceride levels were not affected by any treatment. Cholesterol biosynthesis rate was higher (P<.05) in animals fed VLCFA25 and VLCFA50 than those fed control or VLCFA25/LT or VLCFA25/PS. Results suggest that PSs can decrease total and non-HDL-C cholesterol, whereas VLCFA may increase HDL-C in hamsters.

Wheat germ policosanol failed to lower plasma cholesterol in subjects with normal to mildly elevated cholesterol concentrations

Sugar cane policosanol, a mixture of long-chain primary alcohols (approximately 67% as octacosanol), has been reported to lower plasma low-density lipoprotein (LDL)-cholesterol. We investigated the effect of wheat germ policosanol (WGP) on plasma lipid profiles in 58 adults (30 men and 28 women, aged 49 +/- 11 years) with normal to mildly elevated plasma cholesterol concentrations in a double-blind, randomized, parallel placebo-controlled study. Subjects consumed chocolate pellets with or without 20 mg/d WGP for 4 weeks. Plasma lipid concentrations, routine blood chemistry and hematology were determined at the start and the end of the study. The initial plasma total, LDL-cholesterol, high-density lipoprotein (HDL)-cholesterol, and triacylglycerol concentrations in the WGP and the control groups were identical. Over the 4 weeks, neither the WGP nor the control treatment significantly changed plasma total cholesterol, LDL- and HDL-cholesterol, or triacylglycerol concentrations when compared to baseline values. In addition, there was no significant difference in plasma lipid profiles between the WGP and the control groups at the end of the study. WGP did not result in any adverse effects as indicated by plasma activities of L-gamma-glutamyltransferase (gamma-GT), ALT, AST, bilirubin concentrations, and blood cell profiles. Chemical analysis showed that WGP consists of 8% hexacosanol, 67% octacosanol, 12% triacosanol, and 13% other long-chain alcohols, which is similar to the composition of sugar cane policosanol. In conclusion, WGP at 20 mg/d had no beneficial effects on blood lipid profiles. It therefore seems unlikely that the long chain (C24-34) alcohols have any cholesterol-lowering activity.

Nutritional significance and metabolism of very long chain fatty alcohols and acids from dietary waxes

Very long chain fatty alcohols obtained from plant waxes and beeswax have been reported to lower plasma cholesterol in humans. This review discusses nutritional or regulatory effects produced by wax esters or aliphatic acids and alcohols found in unrefined cereal grains, beeswax, and many plant-derived foods. Reports suggest that 5-20 mg per day of mixed C24-C34 alcohols, including octacosanol and triacontanol, lower low-density lipoprotein (LDL) cholesterol by 21%-29% and raise high-density lipoprotein cholesterol by 8%-15%. Wax esters are hydrolyzed by a bile salt-dependent pancreatic carboxyl esterase, releasing long chain alcohols and fatty acids that are absorbed in the gastrointestinal tract. Studies of fatty alcohol metabolism in fibroblasts suggest that very long chain fatty alcohols, fatty aldehydes, and fatty acids are reversibly inter-converted in a fatty alcohol cycle. The metabolism of these compounds is impaired in several inherited human peroxisomal disorders, including adrenoleukodystrophy and Sjögren-Larsson syndrome. Reports on dietary management of these diseases confirm that very long chain fatty acids (VLCFA) are normal constituents of the human diet and are synthesized endogenously. Concentrations of VLCFA in blood plasma increase during fasting and when children are placed on ketogenic diets to suppress seizures. Existing data support the hypothesis that VLCFA exert regulatory roles in cholesterol metabolism in the peroxisome and also alter LDL uptake and metabolism.