Effects of psyllium hydrophilic mucilloid on LDL-cholesterol and bile acid synthesis in hypercholesterolemic men

Plantago consumption significantly reduces total cholesterol and low-density lipoprotein cholesterol in adults: A systematic review and meta-analysis

Plantago is rich in soluble fiber, known for its beneficial health effects. Given this, we hypothesized that Plantago consumption might positively influence blood lipid in adults. Researchers have conducted numerous randomized controlled trials (RCTs), revealing the impacts of Plantago consumption on various blood lipid parameters. However, findings regarding specific blood lipid parameters have shown variability. This study aimed to comprehensively assess the effect of Plantago consumption on blood lipid parameters. Eligible studies evaluating the effects of Plantago consumption on blood lipid were searched in 5 electronic databases published up to August 2023. Analysis used a random effects model to determine weighted mean difference and 95% confidence intervals. In total, 29 RCTs including 2769 participants were included. Compared with the control group, Plantago consumption significantly reduced total cholesterol (TC) by 0.28 mmol/L and low-density lipoprotein cholesterol (LDL-C) by 0.35 mmol/L, correlating to an estimated 7% decrease in cardiovascular event risk. Conversely, no substantial effects were observed on high-density lipoprotein cholesterol or triglycerides. Subgroup analyses of 29 RCTs revealed that TC concentrations were significantly lowered in studies that included male participants, those who were healthy, or had lipid disorders. Additionally, TC and LDL-C were significantly lower in participants consuming Plantago husk or psyllium, and soluble fiber intake was specifically effective in lowering TC, LDL-C, and triglycerides. In conclusion, Plantago consumption can significantly lower TC and LDL-C concentrations. The findings will provide crucial insights into the potential of Plantago in dietary strategies for blood lipid management.

Are all fibres created equal with respect to lipid lowering? Comparing the effect of viscous dietary fibre to non-viscous fibre from cereal sources: a systematic review and meta-analysis of randomised controlled trials

Although compelling evidence from observational studies supports a positive association between consumption of cereal fibre and CVD risk reduction, randomised controlled trials (RCT) often target viscous fibre type as the prospective contributor to lipid lowering to reduce CVD risk. The objective of our study is to compare the lipids-lowering effects of viscous dietary fibre to non-viscous, cereal-type fibre in clinical studies. RCT that evaluated the effect of viscous dietary fibre compared with non-viscous, cereal fibre on LDL cholesterol and alternative lipid markers, with a duration of ≥ 3 weeks, in adults with or without hypercholesterolaemia were included. Medline, EMBASE, CINAHL and the Cochrane Central Register were searched through October 19, 2021. Data were extracted and assessed by two independent reviewers. The generic inverse variance method with random effects model was utilised to pool the data which were expressed as mean differences (MD) with 95 % CI. Eighty-nine trials met eligibility criteria (n 4755). MD for the effect of viscous dietary fibre compared with non-viscous cereal fibre were LDL cholesterol (MD = -0·26 mmol/l; 95 % CI: -0·30, -0·22 mmol/l; P < 0·01), non-HDL cholesterol (MD = -0·33 mmol/l; 95 % CI: -0·39, -0·28 mmol/l; P < 0·01) and Apo-B (MD = -0·04 g/l; 95 % CI: -0·06, -0·03 g/l; P < 0·01). Viscous dietary fibre reduces LDL cholesterol and alternative lipid markers relative to the fibre from cereal sources, hence may be a preferred type of fibre-based dietary intervention targeting CVD risk reduction.

Global, distinctive, and personal changes in molecular and microbial profiles by specific fibers in humans

Dietary fibers act through the microbiome to improve cardiovascular health and prevent metabolic disorders and cancer. To understand the health benefits of dietary fiber supplementation, we investigated two popular purified fibers, arabinoxylan (AX) and long-chain inulin (LCI), and a mixture of five fibers. We present multiomic signatures of metabolomics, lipidomics, proteomics, metagenomics, a cytokine panel, and clinical measurements on healthy and insulin-resistant participants. Each fiber is associated with fiber-dependent biochemical and microbial responses. AX consumption associates with a significant reduction in LDL and an increase in bile acids, contributing to its observed cholesterol reduction. LCI is associated with an increase in Bifidobacterium. However, at the highest LCI dose, there is increased inflammation and elevation in the liver enzyme alanine aminotransferase. This study yields insights into the effects of fiber supplementation and the mechanisms behind fiber-induced cholesterol reduction, and it shows effects of individual, purified fibers on the microbiome.

A Guide to Recommending Fiber Supplements for Self-Care

The health benefits of dietary fiber are extensive and wide-ranging, yet most Americans do not consume the recommended amount of fiber from their diet. Fiber supplements may be used as a means to augment a low-fiber diet. But which, if any, of the benefits of dietary fiber are achieved through supplementation? And are all fiber supplements equally effective? An evidence-based approach to recommending fiber supplements for self-care will be discussed.

The effect of psyllium consumption on weight, body mass index, lipid profile, and glucose metabolism in diabetic patients: A systematic review and dose-response meta-analysis of randomized controlled trials

Water-soluble dietary fibers have been shown to improve lipid profile and glucose metabolism in diabetes. The aim of this study was to review the effects of psyllium consumption on weight, body mass index, lipid profiles, and glucose metabolism in diabetic patients in randomized controlled trials. A comprehensive systematic search was performed in PubMed/MEDLINE, Web of Sciences, Cochrane, and Scopus by two independent researchers up to August 2019 without any time and language restrictions. The DerSimonian and Laird random-effects model method performed to calculate the pooled results. Inclusion criteria were randomized controlled trial design, adult subjects, and studies reporting the mean differences with the 95% confidence interval for outcome. Eight studies containing nine arms with 395 participants were identified and included in final analysis. Combined results found a significant reduction in triglycerides, low-density lipoprotein, fasting blood sugar, and hemoglobin A1c following psyllium consumption (weighted mean differences [WMD]: -19.18 mg/dl, 95% CI [-31.76, -6.60], I² = 98%), (WMD: -8.96 mg/dl, 95% CI [-13.39, -4.52], I² = 97%), (WMD: -31.71 ml/dl, 95% CI [-50.04, -13.38], I² = 97%), and (WMD: -0.91%, 95% CI [-1.31, -0.51], I² = 99%), respectively. There was no significant change in high-density lipoprotein, body mass index, cholesterol, and weight. In conclusion, the results demonstrated a significant reduction in triglycerides, low-density lipoprotein, fasting blood sugar, and hemoglobin A1c by psyllium intervention among diabetic patients.

Dietary solutions to dyslipidemia: Milk protein-polysaccharide conjugates as liver biochemical enhancers

Protein-polysaccharide interactions have been a focus of scientific attention. This study aimed to improve the antioxidant and hepatoprotective effects of buffalo total milk proteins and whey protein hydrolysate (WPH) through noncovalent interactions with Psyllium husk (ispaghula) mucilage (PHM) and Nabq mucilage (NabM). Chemical composition, phenolic content, and antioxidant activities of milk protein-mucilage complexes were explored. The effects of resulting complexes on liver function, hyperlipidemia, and histopathology of the liver in rats fed high-fat diet (HFD) were investigated. The results showed that the complexes exerted significant effect on normalizing tested parameters; WPH-NabM had the most significantly decreased level of malondialdehyde content and the liver histopathological examination proved an improvement in all groups fed with these complexes. These complexes can be used as functional protection elements against the nonalcoholic fatty liver disease. PRACTICAL APPLICATIONS: PHM, NabM, and their complexes with milk proteins were proved to improve liver function, enhancing most of its measurable parameters and also diminishing the risk of cardiovascular disease. Mice with HFD achieved better health circumstances by combining these ingredients in their diet. Knowing how much these diseases proliferate in the western world and its correlation with high-fat consumption and modern lifestyle, its conjugation with PHM/NabM-MP complexes may reduce the negative impact of unhealthy food intake and, on some parameters, even improving the whole liver function. For that reason, the present study supports and pushes forward the dissemination and consumption of ispaghula or Nabq (the polysaccharides sources) or supplements originating from them. Although many interactions concerning milk proteins have already been analyzed, our study also proposes the interaction with bioactive polysaccharides as useful, opening a field of research aimed at the better application of milk proteins.

Aloe veraat the frontier of glycobiology and integrative medicine: Health implications of an ancient plant

Aloe vera plant extracts are ubiquitous in foods, cosmetics, and medicine. Like all plants, these extracts contain an array of potential bioactives or glycans, which may contribute to health when applied or consumed. In the Aloe vera plant, these bioactives are dominated by acemannan, a type of carbohydrate, and related complexes of saccharides, proteins, and lipids. Clinical data suggest aloe extracts may be beneficial in the management of cutaneous and some systemic conditions, such as some forms of immune dysfunction, atherogenesis, malignancy, and numerous cell functions. These extracts also contain an entourage of bioactive substances that may be allergenic and potentially toxic as well as salutary. These substances include aloin and a variety of anthracenes. The concentrations of potential allergens, aloin, and related compounds are markedly reduced through controlled decolorization processes that are utilized by leading Aloe products manufacturers. The entourage effects of contemporary Aloe vera when consumed or applied topically represent opportunities for clinical investigation which may be applied to commercial consumer products and therapeutic indications. Future research should fully explore the range of bioactive glycan components and their respective safety and efficacy. The history and ongoing popularity of Aloe vera products represent a pragmatic mandate for well-designed investigation into the diverse functional roles of glycans.

Effect of psyllium (Plantago ovata) fiber on LDL cholesterol and alternative lipid targets, non-HDL cholesterol and apolipoprotein B: a systematic review and meta-analysis of randomized controlled trials

Background

Studies have identified viscous dietary fiber as potentially attenuating cholesterol, including psyllium, which reduces LDL cholesterol and thus may complement cardiovascular disease (CVD) treatment.

Objectives

The aims of this study were to update evidence on the effect of psyllium on LDL cholesterol and to provide an assessment of its impact on alternate markers: non-HDL cholesterol and apolipoprotein B (apoB).

Design

Medline, EMBASE, CINAHL, and the Cochrane Central Register of Controlled Trials were searched through 3 October 2017. Independent reviewers extracted relevant data and assessed risk of bias. We included randomized controlled trials with a duration of ≥3 wk that assessed the effect of psyllium on blood lipids in individuals with or without hypercholesterolemia. Data were pooled by using the generic inverse variance method with random-effects models and expressed as mean differences (MDs) with 95% CIs. Heterogeneity was assessed by Cochran's Q statistic and quantified by the I2 statistic. Overall quality of the evidence was assessed by using the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) approach.

Results

We included 28 trials in our analysis (n = 1924). Supplementation of a median dose of ∼10.2 g psyllium significantly reduced LDL cholesterol (MD = -0.33 mmol/L; 95% CI: -0.38, -0.27 mmol/L; P < 0.00001), non-HDL cholesterol (MD = -0.39 mmol/L; 95% CI: -0.50, -0.27 mmol/L; P < 0.00001), and apoB (MD = -0.05 g/L; 95% CI: -0.08, -0.03 g/L; P < 0.0001). Effect estimates for LDL cholesterol and non-HDL cholesterol were graded as moderate quality on the basis of downgrades for inconsistency and graded as high quality for apoB.

Conclusion

Psyllium fiber effectively improves conventional and alternative lipids markers, potentially delaying the process of atherosclerosis-associated CVD risk in those with or without hypercholesterolemia. This trial is registered at www.clinicaltrials.gov as NCT03346733.

Meta-Analysis of Usefulness of Psyllium Fiber as Adjuvant Antilipid Therapy to Enhance Cholesterol Lowering Efficacy of Statins

Statins are usually well-tolerated drugs with a clear dose-dependent efficacy. However, manifestation of statin's side effects also bears a direct relation to higher doses necessary to achieve high impact cholesterol-lowering effects. Nevertheless, the reliance on statin efficacy alone has often left dietary intervention underutilized even though studies have shown a reduction in serum cholesterol levels when dietary fiber intake is increased. In this meta-analysis, we investigated whether the concomitant use of psyllium, a gel-forming viscous soluble fiber, would cause further overall cholesterol lowering in subjects already receiving statins. A systematic review of the medical literature was performed and identified three randomized, controlled clinical studies that evaluated the cholesterol lowering efficacy of statins when given concomitantly with psyllium as a fiber supplement. The duration of the studies ranged from 4 weeks to 12 weeks. The objective of the meta-analysis was to estimate the overall effect of psyllium plus statin versus statin alone. The results of the meta-analysis showed a clinically and statistically significant (p = 0.001) cholesterol lowering advantage for psyllium plus statin combination treatment over a statin alone. Adding psyllium fiber resulted in reductions in low-density lipoprotein-cholesterol equivalent to doubling the statin dose. In conclusion, the data support that psyllium fiber takenbefore meals adds to the efficacy of statins, providing an easy to implement dietary intervention for those who cannot tolerate side effects associated with higher-dose statins.

Understanding the Physics of Functional Fibers in the Gastrointestinal Tract: An Evidence-Based Approach to Resolving Enduring Misconceptions about Insoluble and Soluble Fiber

Enduring misconceptions about the physical effects of fiber in the gut have led to misunderstandings about the health benefits attributable to insoluble and soluble fiber. This review will focus on isolated functional fibers (eg, fiber supplements) whose effects on clinical outcomes have been readily assessed in well-controlled clinical studies. This review will also focus on three health benefits (cholesterol lowering, improved glycemic control, and normalizing stool form [constipation and diarrhea]) for which reproducible evidence of clinical efficacy has been published. In the small bowel, clinically meaningful health benefits (eg, cholesterol lowering and improved glycemic control) are highly correlated with the viscosity of soluble fibers: high viscosity fibers (eg, gel-forming fibers such as b-glucan, psyllium, and raw guar gum) exhibit a significant effect on cholesterol lowering and improved glycemic control, whereas nonviscous soluble fibers (eg, inulin, fructooligosaccharides, and wheat dextrin) and insoluble fibers (eg, wheat bran) do not provide these viscosity-dependent health benefits. In the large bowel, there are only two mechanisms that drive a laxative effect: large/coarse insoluble fiber particles (eg, wheat bran) mechanically irritate the gut mucosa stimulating water and mucous secretion, and the high water-holding capacity of gel-forming soluble fiber (eg, psyllium) resists dehydration. Both mechanisms require that the fiber resist fermentation and remain relatively intact throughout the large bowel (ie, the fiber must be present in stool), and both mechanisms lead to increased stool water content, resulting in bulky/soft/easy-to-pass stools. Soluble fermentable fibers (eg, inulin, fructooligosaccharide, and wheat dextrin) do not provide a laxative effect, and some fibers can be constipating (eg, wheat dextrin and fine/smooth insoluble wheat bran particles). When making recommendations for a fiber supplement, it is essential to recognize which fibers possess the physical characteristics required to provide a beneficial health effect, and which fiber supplements are supported by reproducible, rigorous evidence of one or more clinically meaningful health benefits.

Role of phytochemicals in the management of metabolic syndrome

BACKGROUND

The World Health Organization (WHO) for some years has been focusing on what is now commonly referred to as an "epidemic of obesity and diabetes" ("diabesity"): behind this outbreak, there are several risk factors grouped in what is called "metabolic syndrome" (MetS). The basis of this "epidemic" is either a diet too often characterized by excessive consumption of saturated and trans-esterified fatty acids, simple sugars and salt, either a sedentary lifestyle.

PURPOSE

The aim of this review is to focus on the phytochemicals that have a more positive effect on the treatment and/or prevention of MetS.

CHAPTERS

Treatment strategies for MetS include pharmacologic and non-pharmacologic options, with varying degrees of success rate. The first is indicated for patients with high cardiovascular risk, while the second one is the most cost-effective preventive approach for subjects with borderline parameters and for patients intolerant to pharmacological therapy. MetS non-pharmacological treatments could involve the use of nutraceuticals, most of which has plant origins (phytochemicals), associated with lifestyle improvement. The chapter will discuss the available evidence on soluble fibres from psyllium and other sources, cinnamaldehyde, cinnamic acid and other cinnamon phytochemicals, berberine, corosolic acid from banaba, charantin from bitter gourd, catechins and flavonols from green tea and cocoa. Vegetable omega-3 polyunsaturated fatty acids, alliin from garlic, soy peptides, and curcumin from curcuma longa.

CONCLUSION

Some nutraceuticals, when adequately dosed, should improve a number of the MetS components.

Hepatotoxic constituents and toxicological mechanism of Xanthium strumarium L. fruits

ETHNOPHARMACOLOGICAL RELEVANCE

In the recent years, the international community has attached increasing importance to possible toxicity associated with Traditional Chinese Medicine (TCM). And hepatotoxicity is one of the major concerns, a fundamental pathological process induced by toxicant. This paper is in an attempt to identify the hepatotoxic components in Xanthium strumarium L. fruits (XSF) and interpret the toxicological mechanism induced by XSF.

MATERIALS AND METHODS

XSF extract was prepared and seven characteristic components were isolated and identified in XSF water extracts. We evaluated their hepatotoxicity effect on cell proliferation and lactate dehydrogenase (LDH) activity in L-02 and BRL liver cell line. An integrated metabonomics study using high-resolution (1)H nuclear magnetic resonance ((1)H NMR) spectroscopy combined with multivariate statistical analysis was undertake to elucidate the hepatotoxicity mechanism induced in rats by XSF. The urine and serum metabolites were measured after treatment of rats with XSF (7.5, 15.0 and 30.0 g/kg/day) for 5 days.

RESULTS

The results showed that atractyloside, carboxyatractyloside, 4'-desulphate-atractyloside and XSF induced significant cytotoxic effects in both L-02 and BRL liver cell lines, indicating that atractyloside, carboxyatractyloside, and 4'-desulphate-atractyloside were the toxic components of XSF. When rats were treated with XSF at 30.0 g/kg the hepatotoxicity was reflected in the changes observed in serum biochemical profiles and by the histopathological examination of the liver. The levels of VLDL/LDL, 3-HB, lactate, acetate, acetone and glutamate in serum were increased in this group, while d-glucose, choline and valine were decreased. The elevation in the levels of succinate, citrate, 2-oxo-glutamate, glycine, 3-HB, acetate, lactate, hippurate, dimethylglycine, methylamine, dimethylamine, phenylalanine and tryptophan was observed in urine, in contrast a reduction in the intensities of taurine, d-glucose, N-acetyl-glucoprotein and trimethylamine-N-oxide (TMAO) was observed.

CONCLUSIONS

The results demonstrate that the major hepatotoxicity constituents are atractyloside, carboxyatractyloside and 4'-desulphate-atractyloside, and the hepatotoxicity of XSF involves mitochondrial inability, fatty acid metabolism, and some amino acids metabolism. This integrated (1)H NMR -based metabolic profiling approach has been able to capture and probe the metabolic alterations associated with the onset and progression of hepatotoxicity induced by XSF, and permits a comprehensive understanding of systemic toxicity for phytochemicals and other types of xenobiotic agents.

Viscous versus nonviscous soluble fiber supplements: mechanisms and evidence for fiber-specific health benefits

PURPOSE

This review focuses on the health benefits of viscous versus nonviscous soluble fibers, why symptoms can occur with increased fiber consumption, and how to avoid symptoms to improve adherence with a high-fiber diet.

DATA SOURCES

Review of scientific literature as well as evidence-based guidelines and resources.

CONCLUSIONS

While it is generally known that "fiber is good for you," it is less well known that specific health benefits are associated with specific fiber characteristics. Many of the health benefits of fiber can be directly correlated with the viscosity of soluble fibers when hydrated (i.e., gel-forming). A reduction in viscosity of a given fiber will attenuate these health benefits, and a nonviscous fiber does not exhibit these health benefits.

IMPLICATIONS FOR PRACTICE

Increasing the viscosity of chyme with a viscous soluble fiber has been shown clinically to lower cholesterol for cardiovascular health, improve glycemic control in type 2 diabetes, normalize stool form in both constipation (softens hard stool) and diarrhea (firms loose/liquid stool), and improve the objective clinical measures of metabolic syndrome (glycemic control, lipoprotein profile, body mass index/weight loss, and blood pressure).

Fruit and vegetable consumption and risk factors for cardiovascular disease

The international guidelines issued by the World Health Organization recommend reduction in dietary saturated fat and cholesterol intakes as means to prevent hypercholesterolemia and cardiovascular disease (CVD); however, only limited data are available on the benefits of fruit and vegetable consumption on CVD risk factors in a community-based population. The aim of this study was to examine whether, and to what extent, intake of fruits and vegetables is inversely associated with CVD risk factors in adults. In this population-based cross-sectional study, a representative sample of 840 Tehranian adults (male and female) aged 18 to 74 years was randomly selected in 1998. Multivariate logistic regression adjusted for lifestyle and nutritional confounders was used in 2 models. After adjusting for confounders, dietary fruit and vegetable were found to be significantly and inversely associated with CVD risk factors. Adjusted odds ratio for high low-density lipoprotein concentrations were 1.00, 0.88, 0.81, and 0.75 (P for trend < .01) in the first model, which was adjusted for age, sex, keys score, body mass index, energy intake, smoking status, dietary cholesterol, and history of diabetes mellitus and coronary artery disease, a trend which was not appreciably altered by additional adjustment for education, physical activity, and saturated, polyunsaturated, and total fat intakes. This association was observed across categories of smoking status, physical activity, and tertiles of the Keys score. Exclusion of subjects with prevalent diabetes mellitus or coronary artery disease did not alter these results significantly. Consumption of fruits and vegetables is associated with lower concentrations of total and low-density lipoprotein cholesterol and with the risk of CVD per se in a dose-response manner.

Cholesterol reduction using psyllium husks - do gastrointestinal adverse effects limit compliance? Results of a specific observational study

PURPOSE

Despite known cholesterol lowering effects the use of psyllium husk (Plantaginis ovatae testa) in Germany for hypercholesterolemia is limited compared to their use as a laxative. To investigate whether use in hypercholesterolemia is limited due to adverse effects on the gastrointestinal system, a prospective observational study was conducted.

METHODS

Sixty-two outpatients with documented hypercholesterolemia and complaints of constipation were identified from an academic clinical center. Treatment with 3.5g psyllium husk preparation administered three times daily was initiated and patients were monitored at weekly intervals. Gastrointestinal symptoms were quantified using a validated Nepean Dyspepsia Index modified to identify both upper and lower abdominal symptoms. Diaries and study medication records were used to evaluate compliance.

RESULTS

Fifty-four of 62 patients enrolled in the study completed the study protocol with 4 subjects discontinuing due to adverse reactions associated with psyllium husks. Total cholesterol was significantly decreased from 252+/-39mg/dl before treatment to 239+/-37mg/dl after 3 weeks of treatment. Similarly, low density lipoprotein (LDL)-cholesterol decreased from 174+/-34 to 162+/-31mg/dl during the study. Triglycerides and high density lipoprotein (HDL) were unchanged. Gastrointestinal symptoms were rated lower at the end than at the beginning of the study. In week 1 most of the patients reported gastrointestinal symptoms and also gastrointestinal adverse reactions, which however, showed a decrease from week 1 to weeks 2 and 3 in the diaries. Patient response to study medication was positive for patients completing the study.

CONCLUSIONS

Psyllium husk preparations may be a therapeutic option for patients with mild to moderately elevated cholesterol levels. Adverse gastrointestinal symptoms associated with the preparation appear to be transient in some of the patients. Compliance may be optimized with adequate patient counseling.

Beneficial health properties of psyllium and approaches to improve its functionalities

Psyllium is an excellent dietary source for both soluble and insoluble fibers and has been used in supplemental and food products for its beneficial health effects. The strong water-absorbing and gelling capacities have made it a great challenge to incorporate psyllium in foods at the level needed to claim health benefits on the label. This review is focused on the approaches to improve the functionality, sensory property, and bioactivity of psyllium. Also included is a brief summary of the health beneficial effects of psyllium, along with its possible adverse effects. The information may be useful for those in psyllium research and functional food development.

Hypolipidemic effect of Telfairia occidentalis (fluted pumpkin) in rats fed a cholesterol-rich diet

Telfairia occidentalis (fluted pumpkin) is one of the commonly consumed leafy vegetables in Nigeria. In order to justify its inclusion in herbal preparations in African traditional medicine, the possible hypolipidemic effect of this vegetable was investigated in rats fed a cholesterol-rich diet. The ability of Questran, a hypolipidemic drug, to attenuate hypercholesterolemia was also examined. Rats were fed with either a basal diet containing cholic acid (0.2%) or a supplemented diet with T. occidentalis at the 3% and 6% levels. Oral administration of cholesterol for 9 consecutive weeks resulted in a significant increase (P < .001) in the relative weight of the heart of cholesterol-fed rats. However, supplemented diets significantly (P < .001) ameliorated the cholesterol-induced enlargement of the heart. Rats fed on supplemented diets had a dose-dependent reduction in plasma and postmitochondrial supernatant fraction (PMF) cholesterol levels. In particular, supplemented diets containing 3% and 6% T. occidentalis decreased plasma and PMF cholesterol levels by 20% and 30% and by 30% and 45%, respectively. A similar decrease in plasma and PMF cholesterol levels was obtained in Questran-treated hypercholesterolemic rats. Furthermore, 3% and 6% T. occidentalis-supplemented diets significantly (P < .05) decreased the cholesterol-induced increase in plasma and PMF low-density lipoprotein (LDL) cholesterol levels by 24% and 48% and by 28% and 52%, respectively. In contrast, there was no significant difference (P > .05) in plasma and PMF triglyceride levels of rats fed on supplemented diets when compared with cholesterol-fed rats. There were significant decreases (P < .05) in lipid peroxidation levels in rats fed on the supplemented diets. Specifically, 3% and 6% T. occidentalis-supplemented diets decreased plasma and PMF lipid peroxidation by 24% and 20% and by 42% and 21%, respectively. This study demonstrates that T. occidentalis may be a useful therapy for hypercholesterolemia through reducing oxidative stress and cholesterol levels.

Aqueous extracts of husks of Plantago ovata reduce hyperglycaemia in type 1 and type 2 diabetes by inhibition of intestinal glucose absorption

Plantago ovata has been reported to reduce postprandial glucose concentrations in diabetic patients. In the present study, the efficacy and possible modes of action of hot-water extracts of husk of P. ovata were evaluated. The administration of P. ovata (0.5 g/kg body weight) significantly improved glucose tolerance in normal, type 1 and type 2 diabetic rat models. When the extract was administered orally with sucrose solution, it suppressed postprandial blood glucose and retarded small intestinal absorption without inducing the influx of sucrose into the large intestine. The extract significantly reduced glucose absorption in the gut during in situ perfusion of small intestine in non-diabetic rats. In 28 d chronic feeding studies in type 2 diabetic rat models, the extract reduced serum atherogenic lipids and NEFA but had no effect on plasma insulin and total antioxidant status. No effect of the extract was evident on intestinal disaccharidase activity. Furthermore, the extract did not stimulate insulin secretion in perfused rat pancreas, isolated rat islets or clonal beta cells. Neither did the extract affect glucose transport in 3T3 adipocytes. In conclusion, aqueous extracts of P. ovata reduce hyperglycaemia in diabetes via inhibition of intestinal glucose absorption and enhancement of motility. These attributes indicate that P. ovata may be a useful source of active components to provide new opportunities for diabetes therapy.

Hypocholesteremic and antioxidant effects of Withania somnifera (Dunal) in hypercholesteremic rats

Hypocholesteremic and antioxidant effects of Withania somnifera (WS) Dunal (Solanaceae) were investigated in hypercholesteremic male albino rats. When the root powder of WS was added to the diet at 0.75 and 1.5 gm/rat/day, hypercholesteremic animals registered significant decreases in total lipids (-40.54%; -50.69%), cholesterol (-41.58%; -53.01%) and triglycerides (-31.25%; - 44.85%) in plasma. On the other hand, significant increases in plasma HDL-cholesterol levels (+15.10%; +17.71%), HMG-CoA reductase activity (+19.51%; +26.02%) and bile acid content (+24.64%; +30.52%) of liver were noted in these animals. A similar trend was also noted in bile acid (+22.43%;+28.52%), cholesterol (+14.21%; +17.68%) and neutral sterol (+12.40%; +18.85%) excretion in the hypercholesteremic animals with WS administration. Further, a significant decrease in lipid-peroxidation (-35.29%; -36.52%) occurred in WS administered hypercholesteremic animals when compared to their normal counterparts. However, it appeared that WS root powder is also effective in normal subjects for decreasing lipid profiles.

The role of diet, exercise and smoking in dyslipidaemia in HIV-infected patients with lipodystrophy

BACKGROUND

Lipodystrophy in HIV-infected (LDHIV) patients receiving protease inhibitors (PIs) is associated with dyslipidaemia. Whether lifestyle factors play a role in dyslipidaemia in LDHIV subjects on PIs is not well characterized.

METHODS

A total of 45 LDHIV male and six LDHIV female patients on PIs were recruited, and data were collected on smoking, exercise, diet (by 3-day food record), and fasting levels of serum lipids and lipoproteins. The relationships between lifestyle factors and metabolic variables were analysed in male patients by Spearman's correlation test and the significant relationships were further analysed by adjusting for age, PI duration, and waist circumference by Spearman's partial correlation test.

RESULTS

In men, mean (+/-standard deviation) serum concentrations of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), and non-HDL-C were 212+/-70, 35+/-7.3, 325+/-230 and 169+/-44 mg/dL, respectively. Sixty-seven percent of the men exercised regularly and 31.1% smoked. The reported diet was high in cholesterol (390+/-212 mg) and percentage energy from saturated (12.2+/-3.3%) and trans (2.4+/-1.2%) fats, and low in soluble fibre (6.9+/-2.3 g) compared with recent dietary guidelines. Following adjustments for the confounding variables, percentage energy intake from total protein and animal protein was positively related to TC (r=0.44, P<0.01 and r=0.37, P<0.05, respectively), TG (r=0.40, P<0.01 and r=0.46, P<0.01, respectively) and non-HDL-C (r=0.56, P<0.001 and r=0.49, P<0.01, respectively), that from trans fat was positively related to TG (r=0.34, P<0.05), and soluble fibre was negatively related to non-HDL-C (r=-0.41, P<0.01). Moderate to heavy aerobic exercise tended to be associated with higher HDL-C (r=0.30, P=0.07) whereas smoking was not associated with any of the metabolic variables.

CONCLUSIONS

Increased intake of total protein, animal protein and trans fat, and reduced soluble fibre consumption contribute to dyslipidaemia in LDHIV subjects on PIs.

A diet supplemented with husks of Plantago ovata reduces the development of endothelial dysfunction, hypertension, and obesity by affecting adiponectin and TNF-alpha in obese Zucker rats

The aim of the present study was to analyze whether consumption of a fiber-supplemented diet containing 3.5% Plantago ovata husks prevented many of the abnormalities clustered in the metabolic syndrome, including obesity, dyslipidemia, hypertension and endothelial dysfunction. For this purpose, obese Zucker rats, a model of type 2 diabetes, and their lean littermates were studied. Rats consumed a standard control diet or that diet supplemented with 3.5% P. ovata husks for 25 wk. Body weights were measured weekly. Systolic blood pressure (SBP) was measured monthly. At the end of the treatment, plasma concentrations of triglycerides, total cholesterol, FFAs, glucose, insulin, adiponectin, and tumor necrosis factor alpha (TNF-alpha) were determined, and studies on vascular function were performed using aortic rings. Rats fed the P. ovata husk-supplemented diet had a significantly reduced body weight gain compared with those fed the standard diet. Decreased endothelium-dependent relaxation in response to acetylcholine (ACh) by aortic rings from obese Zucker rats was improved in those fed the fiber-supplemented diet. The greater SBP, higher plasma concentrations of triglycerides, total cholesterol, FFA, glucose, insulin, and TNF-alpha, and the hypoadinectinemia that occurred in obese Zucker rats that consumed the control diet were significantly improved in those fed the fiber-supplemented diet. We conclude that intake of a P. ovata husk-supplemented diet prevents endothelial dysfunction, hypertension, and obesity development, and ameliorates dyslipidemia and abnormal plasma concentrations of adiponectin and TNF-alpha in obese Zucker rats.

Effects of Psyllium on Plasma Total and Lipoprotein Cholesterol and Hepatic Cholesterol in Hamsters Fed n–3 PUFA or n–6 PUFA with High Cholesterol Levels

This study was conducted to determine whether psyllium is known to alter cholesterol metabolism modulate the hypercholesterolemic effect of a high cholesterol, n-3 polyunsaturated fatty acids (PUFA) diet in hamsters. Concentrations of plasma, hepatic total cholesterol and lipoprotein cholesterol were measured in male hamsters fed an n-3 PUFA plus psyllium (8%, wt/wt) diet combined with variable levels of cholesterol (0, 0.05, 0.1%, wt/wt) or a cholesterol-enriched (0.2%, wt/wt) n-3 PUFA or n-6 PUFA diet that contained either 8% methyl cellulose or psyllium for 4 weeks. In the n-3 PUFA-fed hamsters, we have found that psyllium was able to reduce plasma total cholesterol and low density lipoprotein (LDL)-cholesterol significantly when 0.1% cholesterol was added to the diet. In contrast, the effects of psyllium were not seen in the n-3 PUFA-fed hamsters without dietary cholesterol or with 0.05% dietary cholesterol. However, no matter in the presence of psyllium or not, the increase of plasma total cholesterol, very-low-density lipoprotein (VLDL)-cholesterol, LDL-cholesterol and high-density lipoprotein (HDL)-cholesterol levels was depend on the content of dietary cholesterol. Although the cholesterol diet increased the liver total cholesterol level, 80 g psyllium/kg diet resulted in a significantly lower concentration of liver total cholesterol in the cholesterol-fed hamsters. In the second experiment, we have also found that psyllium feeding lowered significantly plasma total cholesterol and VLDL-cholesterol concentrations in hamsters fed n-3 PUFA but not in those fed n-6 PUFA. However, the levels of plasma total cholesterol, VLDL-cholesterol and LDL-cholesterol levels of the (n-6) PUFA-fed hamsters were significantly lower than those in the (n-3) PUFA-fed hamsters in the absence or presence of dietary psyllium. Our data also showed that hamsters fed both high-cholesterol n-3 PUFA and n-6 PUFA diets had a significant decrease in hepatic cholesterol with intake of psyllium. Liver total cholesterol concentrations were significantly lower in n-3 PUFA-fed hamsters compared with the n-6 PUFA-fed groups. Therefore, these data may contribute to understanding the interactive effect of psyllium and cholesterol or the type of fat on plasma and liver cholesterol in hamsters.

Effect of time of administration on cholesterol-lowering by psyllium: a randomized cross-over study in normocholesterolemic or slightly hypercholesterolemic subjects

Background

Reports of the use of psyllium, largely in hypercholesterolemic men, have suggested that it lowers serum cholesterol as a result of the binding of bile acids in the intestinal lumen. Widespread advertisements have claimed an association between the use of soluble fibre from psyllium seed husk and a reduced risk of coronary heart disease. Given the purported mechanism of cholesterol-lowering by psyllium, we hypothesized that there would be a greater effect when psyllium is taken with breakfast than when taken at bedtime. Secondarily, we expected to confirm a cholesterol-lowering effect of psyllium in subjects with "average" cholesterol levels.

Methods

Sixteen men and 47 women ranging in age from 18 to 77 years [mean 53 +/- 13] with LDL cholesterol levels that were normal or slightly elevated but acceptable for subjects at low risk of coronary artery disease were recruited from general gastroenterology and low risk lipid clinics. Following a one month dietary stabilization period, they received an average daily dose of 12.7 g of psyllium hydrophilic mucilloid, in randomized order, for 8 weeks in the morning and 8 weeks in the evening. Change from baseline was determined for serum total cholesterol, LDL, HDL and triglycerides.

Results

Total cholesterol for the "AM first" group at baseline, 8 and 16 weeks was 5.76, 5.77 and 5.80 mmol/L and for the "PM first" group the corresponding values were 5.47, 5.61 and 5.57 mmol/L. No effect on any lipid parameter was demonstrated for the group as a whole or in any sub-group analysis.

Conclusion

The timing of psyllium administration had no effect on cholesterol-lowering and, in fact, no cholesterol-lowering was observed. Conclusions regarding the effectiveness of psyllium for the prevention of heart disease in the population at large may be premature.

Antithrombic and anti-atherogenic effects of partially defatted flaxseed meal using a laser-induced thrombosis test in apolipoprotein E and low-density lipoprotein receptor deficient mice

Atherothrombosis can be regarded as a 'life-style related disease' of which diet is one of the important risk factors. The prophylactic effect of partially defatted flaxseed meal (PDFM) on atherothrombosis has not yet been studied. The aim of this study was to assess the effect of PDFM and a lignan from flaxseed, secoisolariciresinol diglucoside (SDG), on thrombosis and atherogenesis. An earlier developed test, the quantitative assessment of laser-induced thrombus formation in the carotid artery of apolipoprotein E and low-density lipoprotein receptor deficient mice was used in this study. Thrombotic and atherosclerotic status was assessed in mice kept on a high-fat diet for 8 weeks (40% in energy). The diet contained 0.05% cholesterol alone (control) or the same cholesterol with added PDFM (5% w/w; 8.3 g/kg body weight per day) or SDG (0.06% w/w; 100 mg/kg body weight per day). PDFM showed antithrombotic (P < 0.01) and anti-atherogenic effect (P < 0.01). SDG did not affect either atherogenesis or thrombosis. This study suggests that dietary intake of PDFM can be beneficial in reducing the risk of high-fat-induced atherothrombosis.

Pulses and lipaemia, short- and long-term effect: potential in the prevention of cardiovascular disease

Cardiovascular disease (CVD) is the leading cause of death in most developed countries. Most CVD deaths are preventable through life-style measures such as diet, exercise and avoidance of cigarette smoking. Decreased intake of saturated fat and cholesterol and increased intake of cholesterol-reducing foods, such as pulses, deserve a high priority for activities designed to prevent CVD. Epidemiological and observational studies indicate that habitual intakes of large amounts of dietary fibre or of vegetables are associated with significantly lower rates of CVD. Studies over four decades document the hypocholesterolaemic effect of pulses and soyabeans. We performed a meta-analysis of eleven clinical trials that examined the effects of pulses (not including soyabeans) on serum lipoproteins. Intake of non-soya pulses was associated with these changes: fasting serum cholesterol, -7.2 %, 95 % CI -5.8, -8.6 %; LDL-cholesterol, -6.2 %, 95 % CI -2.8, -9.5 %; HDL-cholesterol, +2.6 %, 95 % CI +6.3, -1.0 %; triacylglycerols, -16.6 %, 95 % CI -11.8 %, -21.5 %; and body weight, -0.9 %, 95 % CI +2.2 %, -4.1 %. The hypocholesterolaemic effects of pulses appear related, in estimated order of importance, to these factors: soluble dietary fibre, vegetable protein, oligosaccharides, isoflavones, phospholipids and fatty acids, saponins and other factors. Intake of pulses may also reduce risk for CVD by favourable effects on blood pressure, glycaemia and risk for diabetes, and risk for obesity. Overall, the available evidence indicates that regular consumption of pulses may have important protective effects on risk for CVD.

A poorly fermented gel from psyllium seed husk increases excreta moisture and bile acid excretion in rats

Psyllium seed husk (PSH) increases stool output and lowers blood cholesterol levels in humans. PSH and three fractions isolated from it were meal-fed to colectomized rats and fermented in vitro to test the hypothesis that viscous, gel-forming fraction B was responsible for these physiological actions. Control rats were fed 50 g/kg cellulose. The concentration of each PSH fraction in the test meals was equivalent to its concentration in PSH. Yields of the fractions were: A, 171; B, 575; and C, 129 g/kg of PSH. The wet weight and moisture content of ileal excreta (IE) from rats fed test meals containing PSH or fraction B were greater than those measured in excreta from rats fed meals containing cellulose or the other two PSH fractions. Total bile acids in IE did not differ between rats fed PSH or fraction B and were greater in these groups than in the other groups. Fraction A was not fermented during 3 d of incubation; fraction B was poorly fermented, with approximately 30% of the constituent sugars disappearing; and fraction C was rapidly and nearly completely fermented. These results indicate that the gel-forming fraction we isolated from PSH is the physiologically active component of the husks.

Position of the American Dietetic Association: health implications of dietary fiber

Dietary fiber consists of the structural and storage polysaccharides and lignin in plants that are not digested in the human stomach and small intestine. A wealth of information supports the American Dietetic Association position that the public should consume adequate amounts of dietary fiber from a variety of plant foods. Recommended intakes, 20-35 g/day for healthy adults and age plus 5 g/day for children, are not being met, because intakes of good sources of dietary fiber, fruits, vegetables, whole and high-fiber grain products, and legumes are low. Consumption of dietary fibers that are viscous lowers blood cholesterol levels and helps to normalize blood glucose and insulin levels, making these kinds of fibers part of the dietary plans to treat cardiovascular disease and type 2 diabetes. Fibers that are incompletely or slowly fermented by microflora in the large intestine promote normal laxation and are integral components of diet plans to treat constipation and prevent the development of diverticulosis and diverticulitis. A diet adequate in fiber-containing foods is also usually rich in micronutrients and nonnutritive ingredients that have additional health benefits. It is unclear why several recently published clinical trials with dietary fiber intervention failed to show a reduction in colon polyps. Nonetheless, a fiber-rich diet is associated with a lower risk of colon cancer. A fiber-rich meal is processed more slowly, which promotes earlier satiety, and is frequently less calorically dense and lower in fat and added sugars. All of these characteristics are features of a dietary pattern to treat and prevent obesity. Appropriate kinds and amounts of dietary fiber for the critically ill and the very old have not been clearly delineated; both may need nonfood sources of fiber. Many factors confound observations of gastrointestinal function in the critically ill, and the kinds of fiber that would promote normal small and large intestinal function are usually not in a form suitable for the critically ill. Maintenance of body weight in the inactive older adult is accomplished in part by decreasing food intake. Even with a fiber-rich diet, a supplement may be needed to bring fiber intakes into a range adequate to prevent constipation. By increasing variety in the daily food pattern, the dietetics professional can help most healthy children and adults achieve adequate dietary fiber intakes.

A mixed green vegetable and fruit beverage decreased the serum level of low-density lipoprotein cholesterol in hypercholesterolemic patients

The effects of a canned mixed green vegetable and fruit beverage, containing broccoli (Brassica oleracea L. var. botrytis L.) and cabbage (Brassica oleracea L. var. capitata L.) as main materials, on serum lipid levels in hypercholesterolemic patients were investigated. Thirty-one adult subjects were administered two cans of the beverage (160 g/can) per day for 3 weeks. Their serum total cholesterol (TC) levels significantly decreased from 6.7 +/- 0.8 to 6.1 +/- 0.6 mmol/L, and, more strikingly, the level of low-density lipoprotein cholesterol (LDL-C) significantly decreased from 4.4 +/- 0.8 to 3.8 +/- 0.7 mmol/L. At 9 weeks after the cessation of the administration, these levels had returned to the preadministration levels. Furthermore, 14 other subjects who were administered one can of the sample for 12 weeks also showed a significant reduction in the levels of serum TC and LDL-C. Thus, daily consumption of this mixed green vegetable and fruit beverage may be useful in lowering serum TC and LDL-C levels in hypercholesterolemic patients.

Sex and hormonal status influence plasma lipid responses to psyllium

BACKGROUND

The primary mechanisms by which soluble fiber lowers plasma cholesterol are well known. However, specific effects of fiber on lipoprotein metabolism and how sex and hormonal status influence these effects are not well defined.

OBJECTIVE

The effects of a psyllium supplement in men, premenopausal women, and postmenopausal women were examined to determine the mechanisms by which psyllium lowers plasma LDL-cholesterol concentrations and affects lipoprotein remodeling in the intravascular compartment.

DESIGN

We designed a crossover trial in which 24 men, 23 premenopausal women, and 21 postmenopausal women were randomly assigned for 30 d to a fiber supplement (15 g psyllium/d) or a control. Plasma lipids and cholesteryl ester transfer protein and lecithin-cholesterol acyltransferase (phosphatidylcholine-sterol O-acyltransferase) activities were measured after each treatment.

RESULTS

When compared with the control, psyllium intake lowered plasma LDL-cholesterol concentrations by 7-9% (P < 0.0001) without affecting plasma HDL-cholesterol concentrations. An interactive effect between fiber and sex and hormonal status was observed for plasma triacylglycerol. Psyllium supplementation significantly lowered plasma triacylglycerol concentrations in men by 17% and raised triacylglycerol concentrations in postmenopausal women by 16% (P < 0.01). The dietary treatment did not significantly affect plasma triacylglycerol in premenopausal women. Lecithin-cholesterol acyltransferase was unaffected by psyllium intake whereas cholesteryl ester transfer protein activity was 18% lower after psyllium supplementation than after the control treatment (P < 0.0001).

CONCLUSIONS

This trial showed that the psyllium-induced responses to plasma lipids were associated with sex and hormonal status and that psyllium, through its action in the intestinal lumen, indirectly affected the intravascular processing of lipoproteins.

Gastrointestinal side effects of orlistat may be prevented by concomitant prescription of natural fibers (psyllium mucilloid)

OBJECTIVES

This placebo-controlled open study was designed to test the hypothesis that most of the gastrointestinal (GI) side events induced by treatment of obese patients with orlistat (a gastrointestinal lipase inhibitor) could be prevented or ameliorated by concomitant use of natural fibers (psyllium mucilloid).

DESIGN

Two groups of obese women (BMI>27 kg/m(2)) were treated with orlistat 120 mg three times a day. One group (A, n=30) was randomized to receive orlistat and, approximately 6.0 g of orange-flavored psyllium mucilloid dissolved in water and the other group (B, n=30) received orlistat and orange-flavored placebo. At the end of 30 days and 2 weeks of washout, group A switched to placebo and group B received psyllium while continuing orlistat three times a day.

SUBJECTS

Sixty professional women, more than 21-y-old with a body mass index (BMI) between 27.3 and 48.0 kg/m(2), who were not receiving any other medication.

MEASUREMENTS

Assessments included weekly visits to attending physician, filling a form in which GI events were recorded, monthly measurements of body weight, blood pressure and serum lipids. The frequency and severity of GI events were evaluated by a score system, based on information provided by the patients.

RESULTS

Both groups A and B significantly lost (P<0.01) weight after 60 days of orlistat (A=96.8 to 94.9 kg and B=98.7 to 96.5 kg). Similarly, BMI values declined significantly in both groups. While in the psyllium plus orlistat group (group A) the mean +/-s.e.m. of the scores reflecting GI events was 13.0+/-1.8, the placebo plus orlistat group (B) had a value of 35.9+/-2.7 (P<0.01). When the reverse situation was instituted the placebo and orlistat group presented a mean score of 36.1+/-3.6 and the psyllium plus orlistat a mean score of 8.9+/-1.5 (P<0.01).

CONCLUSIONS

Psyllium hydrophilic mucilloid concomitantly prescribed to obese patients receiving 120 mg of orlistat three times a day is an effective and safe adjunct therapy that is helpful in controlling the GI side effects of this pancreatic lipase inhibitor.

Role of oxidant stress in the permeability transition induced in rat hepatic mitochondria by hydrophobic bile acids

Hydrophobic bile acids may cause hepatocellular necrosis and apoptosis during cholestatic liver diseases. The mechanism for this injury may involve mitochondrial dysfunction and the generation of oxidant stress. The purpose of this study was to determine the relationship of oxidant stress and the mitochondrial membrane permeability transition (MMPT) in hepatocyte necrosis induced by bile acids. The MMPT was measured spectrophotometrically and morphologically in rat liver mitochondria exposed to glycochenodeoxycholic acid (GCDC). Freshly isolated rat hepatocytes were exposed to GCDC and hepatocellular necrosis was assessed by lactate dehydrogenase release, hydroperoxide generation by dichlorofluorescein fluorescence, and the MMPT in cells by JC1 and tetramethylrhodamine methylester fluorescence on flow cytometry. GCDC induced the MMPT in a dose- and Ca(2+)-dependent manner. Antioxidants significantly inhibited the GCDC-induced MMPT and the generation of hydroperoxides in isolated mitochondria. Other detergents failed to induce the MMPT and a calpain-like protease inhibitor had no effect on the GCDC-induced MMPT. In isolated rat hepatocytes, GCDC induced the MMPT, which was inhibited by antioxidants. Blocking the MMPT in hepatocytes reduced hepatocyte necrosis and oxidant stress caused by GCDC. Oxidant stress, and not detergent effects or the stimulation of calpain-like proteases, mediates the GCDC-induced MMPT in hepatocytes. We propose that reducing mitochondrial generation of reactive oxygen species or preventing increases in mitochondrial Ca(2+) may protect the hepatocyte against bile acid-induced necrosis.

Guinea pigs as models for cholesterol and lipoprotein metabolism

Guinea pigs carry the majority of their plasma cholesterol in LDL, making them a unique animal model with which to study hepatic cholesterol and lipoprotein metabolism. In this review, the benefits and advantages of using this particular model are discussed. How dietary factors such as soluble fiber, cholesterol and fatty acids that vary in saturation and chain length affect hepatic cholesterol homeostasis and influence the synthesis, intravascular processing and catabolism of lipoproteins is reviewed. In addition, alterations in hepatic cholesterol metabolism and plasma lipoproteins as affected by treatment with cholestyramine or 3-hydroxyl-3-methylglutaryl coenzyme A reductase inhibitors, exercise, marginal intake of vitamin C, ovariectomy (a model for menopause) and similarities to the human situation are addressed. A review of guinea pigs as models for early atherosclerosis development is also presented.

Hypercholesterolemia: a look at low-cost treatment and treatment adherence

PURPOSE

To determine whether a positive cholesterol-lowering effect could be achieved with a psyllium dose of 6 grams per day instead of the usual 10 grams per day as advocated by other researchers.

DATA SOURCES

Randomized trial of 46 males and females with hypercholesterolemia; multivariate analysis of variance with repeated measures on 1 factor done on 28 subjects (18 in treatment group, 10 in control group) remaining after 16 weeks of treatment.

CONCLUSIONS

Lipoprotein analysis at 2, 8, and 16 weeks indicated that a daily dose of 6 grams of psyllium hydrophilic mucilloid did not significantly affect serum total cholesterol nor low-density lipoproteins in either men or women with hypercholesterolemia. The effects of psyllium on hypercholesterolemia appear to be dose dependent.

PRACTICE IMPLICATIONS

Although it is a low cost option, the addition of psyllium to the diet has unpleasant side-effects, including abdominal distention, flatulence, and discomfort. Because these side effects are troublesome, the lowest effective dose of psyllium may be an important factor in improving treatment adherence.

Long-term cholesterol-lowering effects of psyllium as an adjunct to diet therapy in the treatment of hypercholesterolemia

BACKGROUND

Hypercholesterolemia is a major risk factor for coronary heart disease and nutrition management is the initial therapeutic approach.

OBJECTIVE

This multicenter study evaluated the long-term effectiveness of psyllium husk fiber as an adjunct to diet in the treatment of persons with primary hypercholesterolemia.

DESIGN

Men and women with hypercholesterolemia were recruited. After following an American Heart Association Step I diet for 8 wk (dietary adaptation phase), eligible subjects with serum LDL-cholesterol concentrations between 3.36 and 4.91 mmol/L were randomly assigned to receive either 5.1 g psyllium or a cellulose placebo twice daily for 26 wk while continuing diet therapy.

RESULTS

Serum total and LDL-cholesterol concentrations were 4.7% and 6.7% lower in the psyllium group than in the placebo group after 24-26 wk (P < 0.001). Other outcome measures did not differ significantly between groups.

CONCLUSIONS

Treatment with 5.1 g psyllium twice daily produces significant net reductions in serum total and LDL-cholesterol concentrations in men and women with primary hypercholesterolemia. Psyllium therapy is an effective adjunct to diet therapy and may provide an alternative to drug therapy for some patients.

Gender and hormonal status affect the hypolipidemic mechanisms of dietary soluble fiber in guinea pigs

The objective of this study was to assess the effects of gender on the secondary mechanisms by which dietary soluble fiber lowers plasma LDL cholesterol. For that purpose, male, female and ovariectomized (to mimic menopause) guinea pigs (8-10 per group) were allocated to two dietary treatments. Diets were identical in composition except for the fiber source: the control diet contained 10 g/100 of cellulose and 2.5 g/100 g of guar gum, while the soluble fiber (SF) diet contained 5 g/100 of psyllium, 5 g/100 of pectin and 2.5 g/100 g of guar gum. SF intake resulted in 44% lower plasma LDL cholesterol, 64% lower apo B and 22% lower plasma triacylglycerol (TAG) concentrations (P < 0.01) compared to guinea pigs fed the control diet. However, ovariectomized guinea pigs had higher plasma cholesterol, apo B and TAG concentrations (P < 0.01) compared to males and females, even those fed SF. Plasma HDL-cholesterol was higher in females than in males (P < 0.05). LDL size, as measured by LDL composition and fast protein liquid chromatography, was larger in females than males. Guinea pigs fed SF had smaller LDL than controls. LDL susceptibility to oxidation was 80% lower in male and females fed the SF diet (P < 0.001) than in controls, while there was no effect of diet in ovariectomized guinea pigs. Hepatic free cholesterol and TAG were lower, and activities of 3-hydroxy-3-methyl-glutaryl coenzyme A (HMG-CoA) reductase and cholesterol 7alpha-hydroxylase were higher in guinea pigs fed SF (P < 0.05) than in controls. These results indicate that gender plays an important role in the metabolic responses to dietary soluble fiber and that estrogen deprivation leads to a detrimental lipoprotein profile.

Cholesterol-lowering effects of psyllium intake adjunctive to diet therapy in men and women with hypercholesterolemia: meta-analysis of 8 controlled trials

BACKGROUND

Soluble fibers, including those from psyllium husk, have been shown to augment the cholesterol-lowering effects of a low-fat diet in persons with hypercholesterolemia. As evidence of this, the US Food and Drug Administration recently authorized the use of health claims on food products containing soluble fiber from psyllium that state that they are associated with a decreased risk of coronary heart disease.

OBJECTIVE

This meta-analysis was conducted to more precisely define the hypolipidemic effects and safety of psyllium when used adjunctive to a low-fat diet in men and women with hypercholesterolemia.

DESIGN

The 8 studies in the meta-analysis included a total of 384 and 272 subjects receiving psyllium or cellulose placebo, respectively. All studies evaluated the hypocholesterolemic effects of 10.2 g psyllium/d adjunctive to a low-fat diet for >/=8 wk in individuals with mild-to-moderate hypercholesterolemia after a low-fat diet lead-in phase lasting >/=8 wk. The safety and adverse events associated with psyllium consumption were summarized from pooled data of 19 clinical studies ranging from 6 wk to 6 mo in duration.

RESULTS

Consumption of 10.2 g psyllium/d lowered serum total cholesterol by 4% (P < 0.0001), LDL cholesterol by 7% (P < 0.0001), and the ratio of apolipoprotein (apo) B to apo A-I by 6% (P < 0.05) relative to placebo in subjects already consuming a low-fat diet, with no effect on serum HDL or triacylglycerol concentrations.

CONCLUSIONS

Psyllium supplementation significantly lowered serum total and LDL-cholesterol concentrations in subjects consuming a low-fat diet. Psyllium is well tolerated and safe when used adjunctive to a low-fat diet in individuals with mild-to-moderate hypercholesterolemia.