A combination of psyllium and plant sterols alters lipoprotein metabolism in hypercholesterolemic subjects by modifying the intravascular processing of lipoproteins and increasing LDL uptake

Modification of High-Density Lipoprotein Functions by Diet and Other Lifestyle Changes: A Systematic Review of Randomized Controlled Trials

High-density lipoprotein (HDL) functional traits have emerged as relevant elements that may explain HDL antiatherogenic capacity better than HDL cholesterol levels. These properties have been improved in several lifestyle intervention trials. The aim of this systematic review is to summarize the results of such trials of the most commonly used dietary modifications (fatty acids, cholesterol, antioxidants, alcohol, and calorie restriction) and physical activity. Articles were screened from the Medline database until March 2021, and 118 randomized controlled trials were selected. Results from HDL functions and associated functional components were extracted, including cholesterol efflux capacity, cholesteryl ester transfer protein, lecithin-cholesterol acyltransferase, HDL antioxidant capacity, HDL oxidation status, paraoxonase-1 activity, HDL anti-inflammatory and endothelial protection capacity, HDL-associated phospholipase A2, HDL-associated serum amyloid A, and HDL-alpha-1-antitrypsin. In mainly short-term clinical trials, the consumption of monounsaturated and polyunsaturated fatty acids (particularly omega-3 in fish), and dietary antioxidants showed benefits to HDL functionality, especially in subjects with cardiovascular risk factors. In this regard, antioxidant-rich dietary patterns were able to improve HDL function in both healthy individuals and subjects at high cardiovascular risk. In addition, in randomized trial assays performed mainly in healthy individuals, reverse cholesterol transport with ethanol in moderate quantities enhanced HDL function. Nevertheless, the evidence summarized was of unclear quality and short-term nature and presented heterogeneity in lifestyle modifications, trial designs, and biochemical techniques for the assessment of HDL functions. Such findings should therefore be interpreted with caution. Large-scale, long-term, randomized, controlled trials in different populations and individuals with diverse pathologies are warranted.

The beneficial effects of nutraceuticals and natural products on small dense LDL levels, LDL particle number and LDL particle size: a clinical review

Cardiovascular diseases (CVDs) are globally the major causes of morbidity and mortality. Evidence shows that smaller and denser low-dense lipoprotein (sdLDL) particles are independent atherogenic risk factors for CVD due to their greater susceptibility to oxidation, and permeability in the endothelium of arterial walls. sdLDL levels are an independent risk factor and of more predictive value than total LDL-C for the assessment of coronary artery disease and metabolic syndrome. Functional food ingredients have attracted significant attention for the management of dyslipidemia and subsequently increase cardio-metabolic health. However, to date there is no study that has investigated the effect of these bioactive natural compounds on sdLDL levels. Therefore, the aim of the present review is to summarize the evidence accrued on the effect of special dietary ingredients such as omega-3 polyunsaturated fatty acids, nutraceuticals and herbal medicines on the levels of sdLDL, LDL particle number, and LDL particle size. Based on the results of the existing clinical trials this review suggests that natural products such as medicinal plants, nutraceuticals and omega-3 fatty acids can be used as adjunct or complementary therapeutic agents to reduce sdLDL levels, LDL particle numbers or increase LDL particle size and subsequently may prevent and treat CVD, with the advantage that theses natural agents are generally safe, accessible, and inexpensive.

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.

Critical Evaluation of Gene Expression Changes in Human Tissues in Response to Supplementation with Dietary Bioactive Compounds: Moving Towards Better-Quality Studies

Pre-clinical cell and animal nutrigenomic studies have long suggested the modulation of the transcription of multiple gene targets in cells and tissues as a potential molecular mechanism of action underlying the beneficial effects attributed to plant-derived bioactive compounds. To try to demonstrate these molecular effects in humans, a considerable number of clinical trials have now explored the changes in the expression levels of selected genes in various human cell and tissue samples following intervention with different dietary sources of bioactive compounds. In this review, we have compiled a total of 75 human studies exploring gene expression changes using quantitative reverse transcription PCR (RT-qPCR). We have critically appraised the study design and methodology used as well as the gene expression results reported. We herein pinpoint some of the main drawbacks and gaps in the experimental strategies applied, as well as the high interindividual variability of the results and the limited evidence supporting some of the investigated genes as potential responsive targets. We reinforce the need to apply normalized procedures and follow well-established methodological guidelines in future studies in order to achieve improved and reliable results that would allow for more relevant and biologically meaningful results.

Fiber supplements and clinically proven health benefits: How to recognize and recommend an effective fiber therapy

BACKGROUND

Only 5% of adults consume the recommended level of dietary fiber. Fiber supplements appear to be a convenient and concentrated source of fiber, but most do not provide the health benefits associated with dietary fiber.

PURPOSE

This review will summarize the physical effects of isolated fibers in small and large intestines, which drive clinically meaningful health benefits.

DATA SOURCES

A comprehensive literature review was conducted (Scopus and PubMed) without limits to year of publication (latest date included: October 31, 2016).

CONCLUSIONS

The physical effects of fiber in the small intestine drive metabolic health effects (e.g., cholesterol lowering, improved glycemic control), and efficacy is a function of the viscosity of gel-forming fibers (e.g., psyllium, β-glucan). In the large intestine, fiber can provide a laxative effect if (a) it resists fermentation to remain intact throughout the large intestine, and (b) it increases percentage of water content to soften/bulk stool (e.g., wheat bran and psyllium).

IMPLICATIONS FOR PRACTICE

It is important for nurse practitioners to understand the underlying mechanisms that drive specific fiber-related health benefits, and which fiber supplements have rigorous clinical data to support a recommendation.

CLINICAL PEARL

For most fiber-related beneficial effects, "Fiber needs to gel to keep your patients well."

Combinations of phytomedicines with different lipid lowering activity for dyslipidemia management: The available clinical data

BACKGROUND

Cardiovascular diseases are the primary cause of death and the leading cause of disability in industrialized countries. Dyslipidemia is a major independent and reversible risk factor for these diseases: it is estimated that a reduction of 1 mmol/l (38 mg/dl) of LDL cholesterol is associated with a risk of developing a cardiovascular complication reduced by 25%, a reduction potentially achieved by life-style improvement associated to adequate dietary supplementation with bioactive substances.

AIM

The aim of this review is to focus on the major phytochemical nutraceuticals combinations supported by clinical trials that have demonstrated positive effects in the treatment of dyslipidemia.

MAIN TEXT

There are many nutraceuticals with significant lipid-lowering properties: most of them are used in association with a low dosage, because that permits to reduce the risk of side effects and theoretically to improve efficacy. In fact, natural products with different synergetic lipid-lowering could be combined: they can reduce the absorption of lipids from the bowel and/or increase their excretion (soluble fibers, plant sterols, probiotics), enhance the hepatic uptake of cholesterol (berberine, soybean proteins), inhibit Hydroxy-Methil-Gglutaryl Coenzyme A reductase enzyme and consequently the hepatic synthesis of cholesterol (monacolins, policosanols, allicin, soybean proteins, bergamot); furthermore some products are able to reduce the oxidation of the LDL and increase the thermogenesis and lipid metabolism (chlorogenic acid).

CONCLUSION

Rational combinations of nutraceuticals with different lipid-lowering activities, whether associated with an appropriate lifestyle, should provide an alternative to drug treatment in patients in primary cardiovascular disease prevention with mildly added cardiovascular risk and in some statin-intolerant patients.

Evidence-Based Approach to Fiber Supplements and Clinically Meaningful Health Benefits, Part 1: What to Look for and How to Recommend an Effective Fiber Therapy

Dietary fiber that is intrinsic and intact in fiber-rich foods (eg, fruits, vegetables, legumes, whole grains) is widely recognized to have beneficial effects on health when consumed at recommended levels (25 g/d for adult women, 38 g/d for adult men). Most (90%) of the US population does not consume this level of dietary fiber, averaging only 15 g/d. In an attempt to bridge this “fiber gap,” many consumers are turning to fiber supplements, which are typically isolated from a single source. Fiber supplements cannot be presumed to provide the health benefits that are associated with dietary fiber from whole foods. Of the fiber supplements on the market today, only a minority possess the physical characteristics that underlie the mechanisms driving clinically meaningful health benefits. The first part (current issue) of this 2-part series will focus on the 4 main characteristics of fiber supplements that drive clinical efficacy (solubility, degree/rate of fermentation, viscosity, and gel formation), the 4 clinically meaningful designations that identify which health benefits are associated with specific fibers, and the gel-dependent mechanisms in the small bowel that drive specific health benefits (eg, cholesterol lowering, improved glycemic control). The second part (next issue) of this 2-part series will focus on the effects of fiber supplements in the large bowel, including the 2 mechanisms by which fiber prevents/relieves constipation (insoluble mechanical irritant and soluble gel-dependent water-holding capacity), the gel-dependent mechanism for attenuating diarrhea and normalizing stool form in irritable bowel syndrome, and the combined large bowel/small bowel fiber effects for weight loss/maintenance. The second part will also discuss how processing for marketed products can attenuate efficacy, why fiber supplements can cause gastrointestinal symptoms, and how to avoid symptoms for better long-term compliance.

Hypolipidemic activity of a natural mineral water rich in calcium, magnesium, and bicarbonate in hyperlipidemic adults

PURPOSE

This study compared the effects of a mineral water rich in calcium, magnesium, bicarbonate, and sulfate and a marketed mineral water with a composition similar to that of urban water on the lipid profile of dyslipidemic adults.

METHODS

In a randomized controlled trial, 32 adults received one liter of "rich mineral water" daily for one month, and 37 adults drank the same amount of normal mineral water for the same period. Changes in lipid profiles were compared separately in each studied group at the end of one month.

RESULTS

RESULTS showed that mean cholesterol and low density lipoprotein LDL levels were significantly decreased in both studied groups after one month of drinking mineral water (P<0.05); however, no significant differences in high density lipoprotein (HDL) and triglyceride (TG) levels were seen in either group one month after drinking. There were no statistically significant differences between the "rich mineral water" and the normal mineral water groups in any of the above-mentioned lipid levels ( P>0.05).

CONCLUSION

A one-month intake of mineral water rich in calcium, magnesium bicarbonate, and sulfate decreased cholesterol and LDL levels but not TG or HDL levels in dyslipidemic adults.

Xanthohumol, a prenylated chalcone from Humulus lupulus L., inhibits cholesteryl ester transfer protein

High density lipoprotein (HDL)-cholesterol levels are correlated with a low risk of atherosclerosis. The inhibition of cholesteryl ester transfer protein (CETP), which catalyses cholesterol transfer between lipoproteins, leads to an increase in HDL-cholesterol and is expected to be the next anti-atherogenic target. This study revealed that xanthohumol, a prenylated chalcone, showed the highest inhibition against CETP from screening of natural products in various plants. We investigated the inhibitory activity of some chalcones and flavanones. Naringenin chalcone showed weak CETP inhibition compared with xanthohumol. In addition, isoxanthohumol and naringenin drastically decreased the inhibitory activity. These results suggest that the prenyl group and chalcone structure of xanthohumol were responsible for the CETP inhibitory activity.

Chinese herbal medicines for hypercholesterolemia

BACKGROUND

Hypercholesterolemia is an important key contributory factor for ischemic heart disease and is associated with age, high blood pressure, a family history of hypercholesterolemia, and diabetes. Chinese herbal medicines have been used for a long time as lipid-lowering agents.

OBJECTIVES

To assess the effects of Chinese herbal medicines on hypercholesterolemia.

SEARCH STRATEGY

We searched the following databases: The Cochrane Library (issue 8, 2010), MEDLINE (until July 2010), EMBASE (until July 2010 ), Chinese BioMedical Database (until July 2010), Traditional Chinese Medical Literature Analysis and Retrieval System (until July 2010), China National Knowledge Infrastructure (until July 2010), Chinese VIP Information (until July 2010), Chinese Academic Conference Papers Database and Chinese Dissertation Database (until July 2010), and Allied and Complementary Medicine Database (until July 2010).

SELECTION CRITERIA

We considered randomized controlled clinical trials in hypercholesterolemic participants comparing Chinese herbal medicines with placebo, no treatment, and pharmacological or non-pharmacological interventions.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed the risk of bias. We resolved any disagreements with this assessment through discussion and a decision was achieved based by consensus. We assessed trials for the risk of bias against key criteria: random sequence generation, allocation concealment, blinding of participants, incomplete outcome data, selective outcome reporting and other sources of bias.

MAIN RESULTS

We included 22 randomized trials (2130 participants). The mean treatment duration was 2.3 ± 1.3 months (ranging from one to six months). Twenty trials were conducted in China and 18 trials were published in Chinese. Overall, the risk of bias of included trials was high or unclear. Five different herbal medicines were evaluated in the included trials, which compared herbs with conventional medicine in six comparisons (20 trials), or placebo (two trials). There were no outcome data in any of the trials on cardiovascular events and death from any cause. One trial each reported well-being (no significant differences) and economic costs. No serious adverse events were observed. Xuezhikang was the most commonly used herbal formula investigated. A significant effect on total cholesterol (two trial, 254 participants) was shown in favor of Xuezhikang when compared with inositol nicotinate (mean difference (MD) -0.90 mmol/L, 95% confidence interval (CI) -1.13 to -0.68) .

AUTHORS' CONCLUSIONS

Some herbal medicines may have cholesterol-lowering effects. Our findings have to be interpreted with caution due to high or unclear risk of bias of the included trials.

Evaluation of cardiovascular risk and oxidative stress parameters in hypercholesterolemic subjects on a standard healthy diet including low-fat milk enriched with plant sterols

A healthy diet and plant sterols (PS) are recommended for reducing low-density lipoprotein (LDL) cholesterol and, subsequently, the risk of premature cardiovascular disease. PS mediate a decrease in fat-soluble vitamin concentration, which can lead to a general impairment of antioxidative defenses and an increase in oxidative stress. Thus, we evaluated the effects of a healthy diet, including PS-enriched low-fat milk, on cardiovascular risk and oxidative stress parameters in hypercholesterolemic subjects. This was a randomized parallel trial employing 40 subjects and consisting of two 3-month intervention phases. After 3 months on a standard healthy diet, subjects were divided into two intervention groups: a diet group and a diet+PS group (2 g/day). Lipid profile, apolipoproteins, high-sensitivity C-reactive protein and oxidative stress parameters were analyzed. Diet significantly reduced total and LDL cholesterol (4.0% and 4.7%, respectively), produced an increase in the level of beta-carotene (23%) and improved the antioxidant capacity of LDL cholesterol particles (4.6%). PS induced a significant decrease in total cholesterol (6.4%), LDL (9.9%) and the apolipoprotein B100/apolipoprotein A1 ratio (4.9%), but led to a decrease in cryptoxanthin level (29%) without any change being observed in the antioxidant capacity of LDL cholesterol particles, total antioxidant status or lipid peroxidation. After 3 months, we observed the positive effect of including a PS supplement in dietary measures, as the lipoprotein-mediated risk of cardiovascular disease was reduced. Despite a decrease in the concentration of cryptoxanthin, no evidence of a global impairment of antioxidative defenses or an enhancement of oxidative stress parameters was found.

Correlates for healthful snacking among middle-income midwestern women

OBJECTIVE

To assess snacking patterns, self-efficacy, barriers, stage of change, and awareness of healthful snacks among middle-income midwestern women.

DESIGN

Self-administered questionnaire.

SETTING

An urban church.

PARTICIPANTS

Convenience sample of 56 women, mean age 43.9 years and mean body mass index (BMI) 25.9 kg/m(2).

MAIN OUTCOME MEASURES

A snack quality index (SQI) assessed healthfulness of snack choices; subscales identified self-efficacy and barriers; and a test measured knowledge of healthful snacks.

ANALYSIS

SQI scores were based on energy density and frequency of consumption. Correlations identified associations between SQI scores and self-efficacy and barriers. Analysis of variance identified significant differences between subscale scores for self-efficacy and barriers. Statistical significance was P < .05.

RESULTS

The mean SQI score was 64.9%. Participants felt least confident to choose healthful snacks when experiencing negative emotions, and the most important barrier to healthful snacking was an unfavorable taste perception. The majority of the women (86%) were in the pre-action and 14% in the action stages of change for healthful snacking. The mean score on the snack knowledge test was 84.2%.

CONCLUSIONS AND IMPLICATIONS

These women need information concerning snacks high in fiber and low in trans fat, and interventions for enhancing self-confidence for healthful snack selection under challenging circumstances and for overcoming barriers.

Lifestyle approaches and dietary strategies to lower LDL-cholesterol and triglycerides and raise HDL-cholesterol

This article discusses specific dietary factors as well as dietary patterns that affect the major coronary heart disease (CHD) lipid risk factors (ie, LDL-C, HDL-C, and TG). Based on a very large evidence base, it is clear that diet and lifestyle practices can markedly affect these major CHD lipid risk factors, and consequently decrease CHD risk substantively.

Effects of soluble dietary fiber on low-density lipoprotein cholesterol and coronary heart disease risk

Strong epidemiologic and experimental data suggest that increasing dietary fiber may help to lower low-density lipoprotein cholesterol (LDL-C) and decrease the risk of coronary heart disease. Recent studies have highlighted the role of dietary fiber, particularly water-soluble varieties, in decreasing the risk of cardiovascular disease. Several types of soluble fiber, including psyllium, beta-glucan, pectin, and guar gum, have been shown to decrease LDL-C in well-controlled intervention studies, whereas the soluble fiber content of legumes and vegetables has also been shown to decrease LDL-C. Current investigations continue to explore this area in depth and examine potential synergies between dietary fiber and other phytochemicals that may lower cholesterol. These studies, along with recent analyses of ongoing prospective cohort studies, have provided new insights into the probable protective role of dietary fiber in the development of coronary heart disease and other cardiovascular diseases.

Raisins and walking alter appetite hormones and plasma lipids by modifications in lipoprotein metabolism and up-regulation of the low-density lipoprotein receptor

The purpose of this study was to determine the effects of consuming raisins, increasing steps walked, or a combination of these interventions on lipoprotein metabolism and appetite hormones by assessing plasma apolipoprotein concentrations, cholesterol ester transfer protein activity, low-density lipoprotein (LDL) receptor messenger RNA (mRNA) abundance, and plasma ghrelin and leptin concentrations. Thirty-four subjects (17 men and 17 postmenopausal women) were matched for weight and sex and randomly assigned to consume 1 cup raisins per day (RAISIN), increase the amount of steps walked per day (WALK), or a combination of both interventions (RAISIN + WALK). The subjects completed a 2-week run-in period, followed by a 6-week intervention. Ribonucleic acid was extracted from mononuclear cells, and LDL receptor mRNA abundance was quantified by use of reverse transcriptase polymerase chain reaction. Plasma apolipoproteins were measured by Luminex (Austin, TX) technology. Apoproteins A-1, B, C-II, and E and cholesterol ester transfer protein activity were not altered for any of the groups. In contrast, apolipoprotein C-III was significantly decreased by 12.3% only in the WALK group (P < .05). Low-density lipoprotein receptor mRNA abundance was increased for all groups after the intervention (P < .001). There was a significant group effect for plasma leptin (P = .026). Plasma concentrations increased for RAISIN and RAISIN + WALK. Similarly, plasma ghrelin concentrations were elevated postintervention for both groups consuming raisins (P < .05). These data suggest that walking and raisin consumption decrease plasma LDL cholesterol by up-regulating the LDL receptor and that raisin consumption may reduce hunger and affect dietary intake by altering hormones influencing satiety.

Carbohydrate restriction alters hepatic cholesterol metabolism in guinea pigs fed a hypercholesterolemic diet

The current study was undertaken to evaluate the effect of carbohydrate restriction on hepatic cholesterol metabolism in guinea pigs fed a hypercholesterolemic diet. Hartley male guinea pigs (n = 10 per group) were fed 1 of 3 diets: a diet with a percent energy distribution of 42:23:35 carbohydrate:protein:fat and 0.04% cholesterol (control), a diet with the same macronutrient distribution but with 0.25% cholesterol (HChol), or a carbohydrate-restricted (CR) diet with a percent energy distribution of 11:30:59 carbohydrate:protein:fat and 0.25% cholesterol for 12 wk. There was more accumulation of hepatic cholesterol and triglycerides as well as lower 3-hydroxy-3-methyl glutaryl-CoA reductase messenger RNA abundance in guinea pigs fed the high-cholesterol diets (HChol and CR) (P < 0.01). Guinea pigs fed the CR diet had lower concentrations of hepatic total cholesterol and cholesteryl ester than those fed the HChol diet (P < 0.05). There was no diet effect on hepatic LDL receptor expression. Hepatic acyl CoA cholesteryl acyltransferase (ACAT) activity was lowest in guinea pigs fed the low-cholesterol diet (9.7 +/- 4.8 pmol.min(-1).mg(-1)), intermediate in those fed the CR diet (37.3 +/- 12.4 pmol.min(-1).mg protein(-1)), and highest in guinea pigs fed the HChol diet (55.9 +/- 11.2 pmol.min(-1).mg(-1)). ACAT activity was significantly correlated with hepatic cholesterol (r = 0.715; P < 0.01) and LDL cholesterol (r = 0.59; P < 0.01) for all dietary groups, suggesting a major role of this enzyme in hepatic cholesterol homeostasis and in lipoprotein concentrations. These results indicate that dietary cholesterol increases hepatic lipid accumulation and affects hepatic cholesterol homeostasis. Carbohydrate restriction in the presence of high cholesterol is associated with lower hepatic ACAT activity and an attenuation of hepatic cholesterol accumulation.