Dietary reduction of serum cholesterol concentration: time to think again

Measuring and Leveraging Motives and Values in Dietary Interventions

Why measure and leverage food motives and values? Every failure and every success in dietary change can be connected to motivation. Therefore, this research question naturally arises: How can food motives and values be measured and leveraged to improve diet outcomes from the individual to populations? There are four ways that food motives and values (FMVs) can assist researchers and health professionals. First, FMVs can help to create a personalized approach to dietary change. Second, FMVs can inform content for dietary interventions. Third, these FMV measures can be used in data analysis to elucidate differences in adherence and outcomes among participants. Fourth, public health nutrition messages can be tailored using information on FMVs. Each of these uses has the potential to further the literature and inform future efforts to improve diet. A central aim of our study is to provide specific examples and recommendations on how to measure and leverage FMVs. To do so, we reviewed 12 measures included in the literature citing the Food Choice Questionnaire by Steptoe, Pollard, and Wardle, which was identified as the earliest, highly cited article appearing under the search terms “food motives” AND “food values” AND “eating behavior” AND “measure”. Specific details on how articles were selected from the citing literature are described in the Methods section. We also expound on our reasoning for including the Three-Factor Eating Questionnaire, which made for 13 measures in total. Our main finding is that each measure has strengths and shortcomings to consider in using FMVs to inform nutritional recommendations at different levels.

The anti-cholesterolaemic effect of a consortium of probiotics: An acute study in C57BL/6J mice

Hypercholesterolaemia is a major risk factor for cardiovascular disease and it has been found that some probiotic bacteria possess cholesterol-lowering capabilities. In this study, the ability of the Lab4 probiotic consortium to hydrolyse bile salts, assimilate cholesterol and regulate cholesterol transport by polarised Caco-2 enterocytes was demonstrated. Furthermore, in wild-type C57BL/6J mice fed a high fat diet, 2-weeks supplementation with Lab4 probiotic consortium plus Lactobacillusplantarum CUL66 resulted in significant reductions in plasma total cholesterol levels and suppression of diet-induced weight gain. No changes in plasma levels of very low-density lipoprotein/low-density lipoprotein, high-density lipoprotein, triglycerides, cytokines or bile acids were observed. Increased amounts of total and unconjugated bile acids in the faeces of the probiotic-fed mice, together with modulation of hepatic small heterodimer partner and cholesterol-7α-hydroxylase mRNA expression, implicates bile salt hydrolase activity as a potential mechanism of action. In summary, this study demonstrates the cholesterol-lowering efficacy of short-term feeding of the Lab4 probiotic consortium plus L. plantarum CUL66 in wild-type mice and supports further assessment in human trials.

Egg consumption and heart health: A review

Cardiovascular disease is the leading cause of death in the United States. Until recently, reducing dietary cholesterol has been a part of the American Heart Association (AHA) and American College of Cardiology (ACC) guidelines on lifestyle management, despite inconclusive evidence to support the recommendation. Considering eggs are a rich source of dietary cholesterol (typically containing 141-234 mg per egg), individuals with increased risk for CVD are advised not to consume eggs. Furthermore, based on the 2012 AHA/ACC guidelines, individuals with lower risk for CVD have previously been advised to avoid consuming eggs due to the high content of dietary cholesterol. Rather than strictly limiting cholesterol intake, the AHA and ACC guidelines now recommend dietary patterns that emphasize fruits, vegetables, whole grains, low-fat dairy products, poultry, fish, and nuts as an approach to favorably alter blood lipid levels. Of note, the 2015-2020 Dietary Guidelines for Americans have removed the recommendation of limiting cholesterol intake to no more than 300 mg per day; however, the guidelines advise that individuals should eat as little dietary cholesterol as possible while consuming a healthy eating pattern. The purpose of this review is to summarize the documented health risks of egg consumption in individuals with low and high risk for CVD and determine whether current recommendations are warranted based on the available literature. We also aim to provide guidance for future studies that will help further elucidate the health modulating effect of eggs.

State of the Art Reviews: Relationship Between Diet/ Physical Activity and Health

Obesity and 4 of the leading causes of death—heart disease, cancer, stroke, and type 2 diabetes mellitus—are related to lifestyle. The combination of a healthy weight, prudent diet, and daily physical activity clearly plays a role in primary, secondary, and tertiary prevention of these and other chronic diseases. Because nearly 65% of the adult population is overweight or obese, weight loss and maintenance are central to this review article. Improved lipid profiles, blood pressure, insulin sensitivity, and euglycemia are associated with weight loss or a normal body weight; thus, maintaining a healthy weight is a universal recommendation for health. The methods for improving lifestyle described in the section on obesity include assessing nutritional status and stages of change of the client, setting realistic goals, eating a diet high in fruits and vegetables with low-fat sources of dairy and protein, and achieving appropriate physical activity levels. The importance of physicians discussing weight with clients and vice versa is stressed. The common features of lifestyle-related diseases make them amenable to similar lifestyle interventions.

Understanding patients' perspective of statin therapy: can we design a better approach to the management of dyslipidaemia? A literature review

INTRODUCTION

Dyslipidaemia leads to atherosclerosis and is a major risk factor for cardiovascular diseases. In clinical trials, 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors, or statins, have been shown to effectively reduce dyslipidaemia. Despite the availability and accessibility of statins, myocardial infarctions and cerebrovascular accidents remain among the top causes of mortality in developed countries, including Singapore. This enigma could be attributed to suboptimal adherence to statin therapy. The present literature review aimed to evaluate patients' perceptions of statin therapy.

METHODS

We searched PubMed and other databases for articles published in English from October 1991 to May 2012 containing keywords such as 'patient', 'views', 'perceptions', 'adherence', 'statin' and 'dyslipidaemia'. Of the 122 eligible studies retrieved, 58 were reviewed. The findings were categorised and framed in accordance with the Health Belief Model.

RESULTS

Patients with dyslipidaemia appeared to underestimate their susceptibility to dyslipidaemia-related complications, partly due to their demographic profiles. Failure to appreciate the severity of potential complications was a major hindrance toward adherence to statin therapy. Other factors that affected a patient's adherence included lack of perceived benefits, perceived side effects, the cost of statins, poor physician-patient relationship, and overestimation of the effectiveness of diet control as a treatment modality.

CONCLUSION

Existing evidence suggests that the cause of poor adherence to statin therapy is multifactorial. The use of the Health Belief Model to present the results of our literature review provides a systematic framework that could be used to design a patient-centric approach for enhancing adherence to statin therapy.

Dietary advice for reducing cardiovascular risk

BACKGROUND

Changes in population diet are likely to reduce cardiovascular disease and cancer, but the effect of dietary advice is uncertain. This review is an update of a previous review published in 2007.

OBJECTIVES

To assess the effects of providing dietary advice to achieve sustained dietary changes or improved cardiovascular risk profile among healthy adults.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials, the Database of Abstracts of Reviews of Effects (DARE) and the HTA database on The Cochrane Library (Issue 4, 2010). We searched MEDLINE (Ovid) (1950 to week 2 October 2010) and EMBASE (Ovid) (1980 to Week 42 2010). Additional searches were done on CAB Health (1972 to December 1999), CVRCT registry (2000), CCT (2000) and SIGLE (1980 to 2000). Dissertation abstracts and reference lists of articles were checked and researchers were contacted.

SELECTION CRITERIA

Randomised studies with no more than 20% loss to follow-up, lasting at least three months and involving healthy adults comparing dietary advice with no advice or minimal advice. Trials involving children, trials to reduce weight or those involving supplementation were excluded.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. Study authors were contacted for additional information.

MAIN RESULTS

Forty-four trials with 52 intervention arms (comparisons) comparing dietary advice with no advice were included in the review; 18,175 participants or clusters were randomised. Twenty-nine of the 44 included trials were conducted in the USA. Dietary advice reduced total serum cholesterol by 0.15 mmol/L (95% CI 0.06 to 0.23) and LDL cholesterol by 0.16 mmol/L (95% CI 0.08 to 0.24) after 3 to 24 months. Mean HDL cholesterol levels and triglyceride levels were unchanged. Dietary advice reduced blood pressure by 2.61 mm Hg systolic (95% CI 1.31 to 3.91) and 1.45 mm Hg diastolic (95% CI 0.68 to 2.22) and 24-hour urinary sodium excretion by 40.9 mmol (95% CI 25.3 to 56.5) after 3 to 36 months but there was heterogeneity between trials for the latter outcome. Three trials reported plasma antioxidants, where small increases were seen in lutein and β-cryptoxanthin, but there was heterogeneity in the trial effects. Self-reported dietary intake may be subject to reporting bias, and there was significant heterogeneity in all the following analyses. Compared to no advice, dietary advice increased fruit and vegetable intake by 1.18 servings/day (95% CI 0.65 to 1.71). Dietary fibre intake increased with advice by 6.5 g/day (95% CI 2.2 to 10.82), while total dietary fat as a percentage of total energy intake fell by 4.48% (95% CI 2.47 to 6.48) with dietary advice, and saturated fat intake fell by 2.39% (95% CI 1.4 to 3.37).Two trials analysed incident cardiovascular disease (CVD) events (TOHP I/II). Follow-up was 77% complete at 10 to 15 years after the end of the intervention period and estimates of event rates lacked precision but suggested that sodium restriction advice probably led to a reduction in cardiovascular events (combined fatal plus non-fatal events) plus revascularisation (TOHP I hazards ratio (HR) 0.59, 95% CI 0.33 to 1.08; TOHP II HR 0.81, 95% CI 0.59 to 1.12).

AUTHORS' CONCLUSIONS

Dietary advice appears to be effective in bringing about modest beneficial changes in diet and cardiovascular risk factors over approximately 12 months, but longer-term effects are not known.

Dietary advice for reducing cardiovascular risk

BACKGROUND

Changes in population diet are likely to reduce cardiovascular disease and cancer, but the effect of dietary advice is uncertain. This review is an update of a previous review published in 2007.

OBJECTIVES

To assess the effects of providing dietary advice to achieve sustained dietary changes or improved cardiovascular risk profile among healthy adults.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials, the Database of Abstracts of Reviews of Effects (DARE) and the HTA database on The Cochrane Library (Issue 4, 2010). We searched MEDLINE (Ovid) (1950 to week 2 October 2010) and EMBASE (Ovid) (1980 to Week 42 2010). Additional searches were done on CAB Health (1972 to December 1999), CVRCT registry (2000), CCT (2000) and SIGLE (1980 to 2000). Dissertation abstracts and reference lists of articles were checked and researchers were contacted.

SELECTION CRITERIA

Randomised studies with no more than 20% loss to follow-up, lasting at least three months and involving healthy adults comparing dietary advice with no advice or minimal advice. Trials involving children, trials to reduce weight or those involving supplementation were excluded.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. Study authors were contacted for additional information.

MAIN RESULTS

Forty-four trials with 52 intervention arms (comparisons) comparing dietary advice with no advice were included in the review; 18,175 participants or clusters were randomised. Twenty-nine of the 44 included trials were conducted in the USA. Dietary advice reduced total serum cholesterol by 0.15 mmol/L (95% CI 0.06 to 0.23) and LDL cholesterol by 0.16 mmol/L (95% CI 0.08 to 0.24) after 3 to 24 months. Mean HDL cholesterol levels and triglyceride levels were unchanged. Dietary advice reduced blood pressure by 2.61 mm Hg systolic (95% CI 1.31 to 3.91) and 1.45 mm Hg diastolic (95% CI 0.68 to 2.22) and 24-hour urinary sodium excretion by 40.9 mmol (95% CI 25.3 to 56.5) after 3 to 36 months but there was heterogeneity between trials for the latter outcome. Three trials reported plasma antioxidants, where small increases were seen in lutein and β-cryptoxanthin, but there was heterogeneity in the trial effects. Self-reported dietary intake may be subject to reporting bias, and there was significant heterogeneity in all the following analyses. Compared to no advice, dietary advice increased fruit and vegetable intake by 1.18 servings/day (95% CI 0.65 to 1.71). Dietary fibre intake increased with advice by 6.5 g/day (95% CI 2.2 to 10.82), while total dietary fat as a percentage of total energy intake fell by 4.48% (95% CI 2.47 to 6.48) with dietary advice, and saturated fat intake fell by 2.39% (95% CI 1.4 to 3.37).Two trials analysed incident cardiovascular disease (CVD) events (TOHP I/II). Follow-up was 77% complete at 10 to 15 years after the end of the intervention period and estimates of event rates lacked precision but suggested that sodium restriction advice probably led to a reduction in cardiovascular events (combined fatal plus non-fatal events) plus revascularisation (TOHP I hazards ratio (HR) 0.59, 95% CI 0.33 to 1.08; TOHP II HR 0.81, 95% CI 0.59 to 1.12).

AUTHORS' CONCLUSIONS

Dietary advice appears to be effective in bringing about modest beneficial changes in diet and cardiovascular risk factors over approximately 12 months, but longer-term effects are not known.

Effect of combining viscous fibre with lovastatin on serum lipids in normal human subjects

OBJECTIVES

Soluble fibre supplements are recommended to reduce the levels of low-density lipoprotein cholesterol (LDL-C). Limited information exists on the interaction between fibre and hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins). The purpose of the present study was to evaluate the per se effect of psyllium (10 g/day) and lovastatin (20 mg/day) alone and in combination on serum lipids in normal human volunteers.

METHODS

In a 4-week open label, randomised, parallel study, subjects were randomised to receive 20 mg of lovastatin, 10 g of psyllium or 20 mg of lovastatin plus 10 g of psyllium in evening daily. Levels of total cholesterol (TC), LDL-C, high-density lipoprotein cholesterol (HDL-C), TC/LDL-C ratio, LDL-C/HDL-C ratio and triglycerides were determined after 1, 2, 3 and 4 weeks of treatment.

RESULTS

The study group comprised 36 adult, male subjects. All treatments were well tolerated, and after 4 weeks the mean LDL-C, TC and TG levels in the group receiving 20 mg of lovastatin plus 10 g of psyllium fell by 30.88%, 26.88% and 26.21% from baseline, compared with 24.78%, 19.55% and 32.88% in the group receiving 20 mg of lovastatin and 3.58%, 2.90% and 10.95% in the group receiving 10 g of psyllium respectively. Although additive effect was observed in the group receiving combination compared with group receiving lovastatin, the observed difference was not statistically significant. No significant changes from baseline in HDL-C levels occurred.

CONCLUSIONS

Psyllium soluble fibre should be considered as a safe and well-tolerated dietary supplement option to enhance cholesterol lowering.

State of the Art Reviews: Relationship Between Diet/ Physical Activity and Health

Obesity and 4 of the leading causes of death—heart disease, cancer, stroke, and type 2 diabetes mellitus—are related to lifestyle. The combination of a healthy weight, prudent diet, and daily physical activity clearly plays a role in primary, secondary, and tertiary prevention of these and other chronic diseases. Because nearly 65% of the adult population is overweight or obese, weight loss and maintenance are central to this review article. Improved lipid profiles, blood pressure, insulin sensitivity, and euglycemia are associated with weight loss or a normal body weight; thus, maintaining a healthy weight is a universal recommendation for health. The methods for improving lifestyle described in the section on obesity include assessing nutritional status and stages of change of the client, setting realistic goals, eating a diet high in fruits and vegetables with low-fat sources of dairy and protein, and achieving appropriate physical activity levels. The importance of physicians discussing weight with clients and vice versa is stressed. The common features of lifestyle-related diseases make them amenable to similar lifestyle interventions.

Dietary advice for reducing cardiovascular risk

BACKGROUND

Changes in population diet are likely to reduce cardiovascular disease and cancer, but the effect of dietary advice is uncertain.

OBJECTIVES

To assess the effects of providing dietary advice to achieve sustained dietary changes or improved cardiovascular risk profile among healthy adults.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials, DARE and HTA databases on The Cochrane Library (Issue 4 2006), MEDLINE (1966 to December 2000, 2004 to November 2006) and EMBASE (1985 to December 2000, 2005 to November 2006). Additional searches were done on CAB Health (1972 to December 1999), CVRCT registry (2000), CCT (2000) and SIGLE (1980 to 2000). Dissertation abstracts and reference lists of articles were checked and researchers were contacted.

SELECTION CRITERIA

Randomised studies with no more than 20% loss to follow-up, lasting at least 3 months involving healthy adults comparing dietary advice with no advice or minimal advice. Trials involving children, trials to reduce weight or those involving supplementation were excluded.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data. Study authors were contacted for additional information.

MAIN RESULTS

Thirty-eight trials with 46 intervention arms (comparisons) comparing dietary advice with no advice were included in the review. 17,871 participants/clusters were randomised. Twenty-six of the 38 included trials were conducted in the USA. Dietary advice reduced total serum cholesterol by 0.16 mmol/L (95% CI 0.06 to 0.25) and LDL cholesterol by 0.18 mmol/L (95% CI 0.1 to 0.27) after 3-24 months. Mean HDL cholesterol levels and triglyceride levels were unchanged. Dietary advice reduced blood pressure by 2.07 mmHg systolic (95% CI 0.95 to 3.19) and 1.15 mmHg diastolic (95% CI 0.48 to 1.85) and 24-hour urinary sodium excretion by 44.2 mmol (95% CI 33.6 to 54.7) after 3-36 months. Three trials reported plasma antioxidants where small increases were seen in lutein and beta-cryptoxanthin, but there was heterogeneity in the trial effects. Self-reported dietary intake may be subject to reporting bias, and there was significant heterogeneity in all the following analyses. Compared to no advice, dietary advice increased fruit and vegetable intake by 1.25 servings/day (95% CI 0.7 to 1.81). Dietary fibre intake increased with advice by 5.99 g/day (95% CI 1.12 to 10.86), while total dietary fat as a percentage of total energy intake fell by 4.49 % (95% CI 2.31 to 6.66) with dietary advice and saturated fat intake fell by 2.36 % (95% CI 1.32 to 3.39).

AUTHORS' CONCLUSIONS

Dietary advice appears to be effective in bringing about modest beneficial changes in diet and cardiovascular risk factors over approximately 10 months but longer term effects are not known.

Cholesterol-lowering effects of a new isolated soy protein with high levels of nondenaturated protein in hypercholesterolemic patients

This study was undertaken to compare the effects on plasma cholesterol concentration of a new isolated soy protein in which the protein structure is kept in its native, nondenaturated form (verum 1) versus a conventional isolated soy protein (verum 2) and milk protein (placebo). This prospective, randomized, double-blind, placebo-controlled study was conducted in an outpatient clinical study center in Berlin, Germany. Over 8 wk, 120 patients (total cholesterol, 5.2-7.8 mmol/L) were given verum 1, verum 2, or placebo at a dosage of 25 g protein daily. At the end of the treatment period, total cholesterol levels were significantly reduced by 10.7% in the verum 1 group compared with placebo (P<.001), and levels were reduced by 5.8% in the verum 2 group (P=.008). The difference between the 2 verum groups was statistically significant (P=.008). Low-density lipoprotein cholesterol levels were significantly reduced with nondenaturated isolated soy protein only: levels were reduced by 9.4% in the verum 1 group (P=.002) and by 4.9% in the verum 2 group (P=.107). Again, the difference between the verum groups was significant (P=.05). The results of this study confirm that supplementation with isolated soy protein can lead to significant reductions in plasma concentrations of total and low-density lipoprotein cholesterol. These reductions are significantly more pronounced with an isolated soy protein that maintains the native protein structure than with a commercially available reference isolated soy protein.

Plasma fatty acids and lipoproteins in type 2 diabetic patients

BACKGROUND

The dyslipidemia of type 2 diabetic patients is characterized by high VLDL, abnormal LDL composition and low HDL cholesterol concentrations. The aim of this study was to establish whether the type of dietary fats affects LDL size and density and HDL cholesterol concentrations in these patients.

METHODS

Plasma phospholipid fatty acid composition, which reflects the type of dietary fatty acids, was quantified by gas chromatography. LDL relative flotation (LDL-Rf), a measure of LDL particle size and density, was determined by single vertical spin density gradient ultracentrifugation in 97 type 2 diabetic patients.

RESULTS

By linear regression analysis of the data, plasma fatty acids were associated neither with LDL-cholesterol levels nor with LDL-Rf. The HDL cholesterol concentrations were negatively related with saturated fatty acids (r = -0.23; p = 0.02) but positively related with monounsaturated fatty acids (r = +0.20; p = 0.00). Furthermore, higher HDL concentrations were associated with large and buoyant LDL particles (HDL cholesterol vs LDL-Rf: r = +0.47; p = 0.00). In the multiple regression analysis, the LDL-Rf was significantly related both to triglycerides (beta coefficient = -0.55, p = 0.000) and HDL cholesterol (beta coefficient = 0.19, p = 0.034) concentrations. In a stepwise regression analysis including both triglycerides and HDL cholesterol, triglycerides alone explained the 43.0% of the LDL-Rf variability.

CONCLUSIONS

A reduction of the dietary saturated fats and an increment of monounsaturated fats might increase HDL cholesterol concentrations in type 2 diabetic patients. Modifications of LDL composition might be expected from interventions aimed to reduce plasma triglycerides.

Effect of soya protein on serum lipid profile and lipoprotein concentrations in patients undergoing hypercholesterolaemic haemodialysis

Clinical trials have shown that soya protein reduces the concentrations of some atherogenic lipids in subjects with normal renal function. The present study examined the effects of soya protein on serum lipid concentrations and lipoprotein metabolism in patients on hypercholesterolaemic haemodialysis. Twenty-six hypercholesterolaemic (total cholesterol > or =6.21 mmol/l) patients on haemodialysis were studied in a randomized, double-blind, placebo-controlled clinical trial. After a 4-week run-in phase, the subjects were randomly assigned to two groups. Isolated soya protein or milk protein 30 g was consumed daily as a beverage at breakfast or post-dialysis for 12 weeks. Soya protein substitution resulted in significant reductions in total cholesterol (17.2 (sd 8.9 )%), LDL-cholesterol (15.3 (sd 12.5 )%), apo B (14.6 (sd 12.1 )%) and insulin (23.8 (sd 18.7) %) concentrations. There were no significant changes in HDL-cholesterol or apo A-I. These results indicate that replacing part of the daily protein intake with soya protein has a beneficial effect on atherogenic lipids and favourably affects lipoprotein metabolism in hypercholesterolaemic patients undergoing haemodialysis.

Assessment of the longer-term effects of a dietary portfolio of cholesterol-lowering foods in hypercholesterolemia

BACKGROUND

Cholesterol-lowering foods may be more effective when consumed as combinations rather than as single foods.

OBJECTIVES

Our aims were to determine the effectiveness of consuming a combination of cholesterol-lowering foods (dietary portfolio) under real-world conditions and to compare these results with published data from the same participants who had undergone 4-wk metabolic studies to compare the same dietary portfolio with the effects of a statin.

DESIGN

For 12 mo, 66 hyperlipidemic participants were prescribed diets high in plant sterols (1.0 g/1000 kcal), soy protein (22.5 g/1000 kcal), viscous fibers (10 g/1000 kcal), and almonds (23 g/1000 kcal). Fifty-five participants completed the 1-y study. The 1-y data were also compared with published results on 29 of the participants who had also undergone separate 1-mo metabolic trials of a diet and a statin.

RESULTS

At 3 mo and 1 y, mean (+/-SE) LDL-cholesterol reductions appeared stable at 14.0 +/- 1.6% (P < 0.001) and 12.8 +/- 2.0% (P < 0.001), respectively (n = 66). These reductions were less than those observed after the 1-mo metabolic diet and statin trials. Nevertheless, 31.8% of the participants (n = 21 of 66) had LDL-cholesterol reductions of >20% at 1 y (x +/- SE: -29.7 +/- 1.6%). The LDL-cholesterol reductions in this group were not significantly different from those seen after their respective metabolically controlled portfolio or statin treatments. A correlation was found between total dietary adherence and LDL-cholesterol change (r = -0.42, P < 0.001). Only 2 of the 26 participants with <55% compliance achieved LDL-cholesterol reductions >20% at 1 y.

CONCLUSIONS

More than 30% of motivated participants who ate the dietary portfolio of cholesterol-lowering foods under real-world conditions were able to lower LDL-cholesterol concentrations >20%, which was not significantly different from their response to a first-generation statin taken under metabolically controlled conditions.

Plant sterols as dietary adjuvants in the reduction of cardiovascular risk: theory and evidence

Plant sterol-enriched foods are an effective dietary adjuvant in reducing cardiovascular risk by lowering total cholesterol and low density lipoprotein-cholesterol (LDL-C) in serum by up to approximately 15%. The mechanism of action of plant sterols is different from those of 3-hydroxy-3-methylglutaryl coenzyme A inhibitors (statins) and thus their effect is additive. Combining plant sterols with other dietary components known to reduce cholesterol in a portfolio approach has proven to be most effective for reduction of hypercholesterolemia and provide an alternative treatment option for clinicians. Plant sterol-enriched foods provides clinicians with a relatively cheap, safe, and effective way to help patients manage their cardiovascular risk.

Dietary advice for reducing cardiovascular risk

BACKGROUND

Changes in population diet are likely to reduce cardiovascular disease and cancer, but the effect of dietary advice is uncertain.

OBJECTIVES

To assess the effects of providing dietary advice to achieve sustained dietary changes or improved cardiovascular risk profile among healthy adults.

SEARCH STRATEGY

We searched the Cochrane Controlled Trials Register on The Cochrane Library (Issue 2 2000), MEDLINE (January 1966 to December 2000), EMBASE (January 1985 to December 2000), DARE (December 2000), CAB Health (December 1999), dissertation abstracts, and reference lists of articles. We contacted researchers in the field.

SELECTION CRITERIA

Randomised studies with no more than 20% loss to follow-up, lasting at least three months involving healthy adults comparing dietary advice with no advice or less intensive advice. Trials involving children, trials to reduce weight or those involving supplementation were excluded.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data. Study authors were contacted for additional information.

MAIN RESULTS

Twenty-three trials with 29 intervention arms (comparisons) comparing dietary advice with no advice were included in the review. Dietary advice reduced total serum cholesterol by 0.13 mmol/l (95% CI 0.03 to 0.23) and LDL cholesterol by 0.13 mmol/l (95% CI 0.01 to 0.25) after 3-12 months. Mean HDL cholesterol levels were unchanged. Dietary advice reduced blood pressure by 2.10 mmHg systolic (95% CI 1.37 to 2.83) and 1.63 mmHg diastolic (95% CI 0.56 to 2.71) and 24-hour urinary sodium excretion by 44.2 mmol (95% CI 33.6 to 54.7) after 3-36 months. Plasma triglycerides, ss-carotene and red cell folate were each measured in one small study which suggested no significant effect. Self-reported dietary intake may be subject to reporting bias, and there was significant heterogeneity in all the following analyses. Compared to no advice, dietary advice increased fruit and vegetable intake by 1.24 servings/day (95% CI 0.43 to 2.05). Dietary fibre intake increased with advice by 7.22 g/day (95% CI 2.84 to 11.60), while total dietary fat as a percentage of total energy intake fell by 6.18 % (95% CI 4.00 to 8.36) with dietary advice and saturated fat intake fell by 3.28 % (95% CI 1.92 to 4.64).

AUTHORS' CONCLUSIONS

Dietary advice appears to be effective in bringing about modest beneficial changes in diet and cardiovascular risk factors over approximately 9 months but longer term effects are not known.

Direct comparison of a dietary portfolio of cholesterol-lowering foods with a statin in hypercholesterolemic participants

BACKGROUND

3-Hydroxy-3-methyl-glutaryl-coenzyme A (HMG-CoA) reductase inhibitors reduce serum cholesterol and are increasingly advocated in primary prevention to achieve reductions in LDL cholesterol. Newer dietary approaches combining cholesterol-lowering foods may offer another option, but these approaches have not been compared directly with statins in the same persons.

OBJECTIVE

The objective was to compare, in the same subjects, the cholesterol-lowering potential of a dietary portfolio with that of a statin.

DESIGN

Thirty-four hyperlipidemic participants underwent all three 1-mo treatments in random order as outpatients: a very-low-saturated-fat diet (control diet), the same diet plus 20 mg lovastatin (statin diet), and a diet high in plant sterols (1.0 g/1000 kcal), soy-protein foods (including soy milks and soy burgers, 21.4 g/1000 kcal), almonds (14 g/1000 kcal), and viscous fibers from oats, barley, psyllium, and the vegetables okra and eggplant (10 g/1000 kcal) (portfolio diets). Fasting blood samples were obtained at 0, 2, and 4 wk.

RESULTS

LDL-cholesterol concentrations decreased by 8.5+/-1.9%, 33.3+/-1.9%, and 29.6+/-1.3% after 4 wk of the control, statin, and portfolio diets, respectively. Although the absolute difference between the statin and the portfolio treatments was significant at 4 wk (P=0.013), 9 participants (26%) achieved their lowest LDL-cholesterol concentrations with the portfolio diet. Moreover, the statin (n=27) and the portfolio (n=24) diets did not differ significantly (P=0.288) in their ability to reduce LDL cholesterol below the 3.4-mmol/L primary prevention cutoff.

CONCLUSIONS

Dietary combinations may not differ in potency from first-generation statins in achieving current lipid goals for primary prevention. They may, therefore, bridge the treatment gap between current therapeutic diets and newer statins.

Metabolic syndrome: dietary interventions

PURPOSE OF REVIEW

Metabolic syndrome affects almost a quarter of the adult American population and its incidence is rising in the rest of the world. Its treatment involves both pharmacologic and nonpharmacologic interventions. In this review the authors focus on foods with potential benefits for this disease.

RECENT FINDINGS

Metabolic syndrome is associated with the risk of diabetes, and thus cardiovascular disease. In recent years, many scientific studies have evaluated the role of different foods and diets in the treatment of the components of metabolic syndrome, especially atherogenic dyslipidemia.

SUMMARY

It is imperative to identify strategies that favorably impact this deadly syndrome. Here the authors review how different nutrients in food can modify metabolic syndrome, potentially altering its natural history, and related consequences. Although there is no "all-inclusive" diet yet, it seems plausible that a Mediterranean-style diet exhibits most of the desired attributes.

A shift in myocardial substrate, improved endothelial function, and diminished sympathetic activity may contribute to the anti-anginal impact of very-low-fat diets

A new category of anti-anginal drug - exemplified by ranolazine - is believed to work by partially inhibiting cardiac oxidation of fatty acids; oxidation of glucose requires less oxygen per mol of ATP generated, and thus is preferable to fat oxidation when oxygen availability is limiting in underperfused cardiac tissue. Unfortunately, there is no reason to believe that these drugs inhibit fat oxidation selectively in the heart; thus, chronic use of these drugs can be expected to increase body fat stores until the original rate of fat oxidation is restored by mass action - presumably negating the therapeutic benefit in angina, while exacerbating the manifold adverse effects of insulin resistance syndrome. The rational way to decrease cardiac metabolic reliance on fatty acids is to consume a very-low-fat quasi-vegan diet (i.e., 10% fat calories). Indeed, such diets are known to have a rapid and substantial therapeutic impact on anginal symptoms, while concurrently benefiting insulin sensitivity, markedly improving serum lipid profile, promoting leanness, and lessening coronary risk. A reduction in diurnal insulin secretion might also be achieved, which would be expected to decrease sympathetic activity. While reduced myocardial demand for oxygen doubtless contributes to the beneficial impact of such diets on angina, it is likely that improved cardiac perfusion consequent to improved endothelium-dependent vasodilation also plays a role in this regard. Supplemental carnitine, also beneficial in angina, appears to improve utilization of glucose in the ischemic myocardium by lowering elevated acetyl-coA levels and thereby disinhibiting pyruvate dehydrogenase. Certain other nutraceuticals may aid control of angina by improving endothelial function. In the longer term, these measures have the potential to slow or reverse the progression of stenotic lesions that underlie most cases of angina. These safe and relatively inexpensive nutritional strategies for coping with angina deserve far more attention than orthodox medical practice has thus far accorded them.

Statin therapy after acute myocardial infarction: are we adequately treating high-risk patients?

After acute myocardial infarction, patients remain at high risk for recurrent cardiovascular events and mortality. Despite the compelling scientific and clinical trial evidence that lipid-lowering medications reduce mortality in patients after acute myocardial infarction, this life-saving therapy continues to be underutilized. A number of studies in a variety of clinical settings have documented that a significant proportion of patients after myocardial infarction are not receiving treatment with lipid-lowering medications when guided by conventional care. It has recently been demonstrated that implementation of a hospital-based system for initiation of statins prior to hospital discharge results in a marked increase in treatment rates, improved long-term patient compliance, more patients reaching low-density lipoprotein levels of less than 100 mg/dL, and improved clinical outcomes. Adopting in-hospital initiation of lipid-lowering medications as the standard of care for patients hospitalized with acute myocardial infarction could dramatically improve treatment rates and thus substantially reduce the risk of future coronary events and prolong life in the large number of patients hospitalized each year.

Population implications of lipid lowering for prevention of coronary heart disease: data from the 1995 Scottish health survey

OBJECTIVE

To determine the proportion of the population, firstly, with cholesterol >/= 5.0 mmol/l and, secondly, with any cholesterol concentration, who might benefit from statin treatment for the following: secondary prevention of coronary heart disease (CHD); primary prevention at CHD risk 30%, 20%, 15%, and 6% over 10 years; and primary prevention at projected CHD risk 20% over 10 years (CHD risk at age 60 years if actual age < 60 years).

SUBJECTS

Random stratified sample of 3963 subjects aged 35-64 years from the Scottish health survey 1995.

RESULTS

For secondary prevention 7.8% (95% confidence interval (CI) 6.9% to 8.6%) of the population with cholesterol >/= 5.0 mmol/l would benefit from statins. For primary prevention, the prevalence of people at CHD risk 30%, 20%, 15%, and 6% over 10 years is 1.5% (95% CI 1.2% to 1.9%), 5.4% (95% CI 4.7% to 6.1%), 9.7% (95% CI 8.8% to 10.6%), and 32.9% (95% CI 31.5% to 34.4%), respectively. At projected CHD risk 20% over 10 years, 12.4% (95% CI 11.4% to 13.5%) would be treated with statins. Removing the 5.0 mmol/l cholesterol threshold makes little difference to population prevalence at high CHD risk.

CONCLUSIONS

Statin treatment would be required for 7.8% of the population for secondary prevention. For primary prevention, among other factors, guidelines should take into account the number of patients needing treatment at different levels of CHD risk when choosing the CHD risk to target. The analysis supports a policy of targeting treatment at CHD risk 30% over 10 years as a minimum, as recommended in current British guidelines, with a move to treating at CHD risk 15% over 10 years as resources permit.

Carob pulp preparation for treatment of hypercholesterolemia

The lipid-lowering effect of a carob pulp preparation rich in insoluble dietary fiber and polyphenols was investigated in a noncomparative, open-label pilot study. Over 8 weeks, 47 volunteers with moderate hypercholesterolemia (total cholesterol 232-302 mg/dL) consumed 15 g of carob per day in three products (breakfast cereal, fruit muesli bar, powdered drink) as a supplement to their regular diet. After 4 weeks, reductions of 7.1% in mean total cholesterol and 10.6% in LDL cholesterol were noted; respective decreases after 6 weeks were 7.8% and 12.2% (all P<.001). HDL cholesterol and triglyceride levels remained unchanged. Overall compliance was good. Only 3 volunteers (6%) reported a sensation of fullness, which led to 2 of the 3 dropouts. The carob preparation may have value in the dietary treatment of hypercholesterolemia.

Cholesterol risk management: a systematic examination of the gap from evidence to practice

Hypercholesterolemia is a major risk factor for coronary heart disease, and data indicate that aggressive cholesterol reduction decreases mortality and morbidity associated with this disease. Many patients with hypercholesterolemia, however, are not screened, prescribed appropriate lipid-lowering therapy, or treated to target cholesterol levels. Practice patterns are particularly inadequate for those patients at highest risk for having a cardiac event. We performed a literature search to identify studies of practice patterns in the management of patients with hypercholesterolemia with regard to screening, implementing lipid-lowering therapy, and treating to lipid goals. The findings highlight the potential for substantial opportunities to improve patient outcomes. Future studies should evaluate reasons for suboptimal cholesterol management as well as provide steps to improve management.

Hypocholesterolemic effect of an enteric-coated garlic supplement

OBJECTIVE

To evaluate the hypocholesterolemic effect of an enteric-coated garlic supplement standardized for allicin-releasing potential in mild to moderate hypercholesterolemic patients.

METHODS

A double-blind randomized, placebo-controlled intervention study was conducted in 46 hypercholesterolemic subjects who had failed or were not compliant with drug therapy. Each subject was given dietary counseling to lower fat intake and enteric-coated Australian garlic powder tablets with 9.6 mg allicin-releasing potential or matching placebo tablets.

RESULTS

After 12 weeks, the garlic supplement group (n=22) had a significant reduction in total cholesterol (TC, -0.36 mmol/L. -4.2%) and LDL-cholesterol (LDL-C, -0.44 mmol/L, -6.6%) while the placebo group (n=24) had a non-significant increase in TC (0.13 mmol/L, 2.0%) and LDL-C (0.18 mmol/L, 3.7%). HDL-cholesterol was significantly increased in the placebo group (0.09 mmol/L, 9.1%), compared to the garlic group (-0.02 mmol/L, -0.9%). and no significant difference in triglycerides or in LDL/HDL ratio was observed between groups.

CONCLUSIONS

The study demonstrates that enteric-coated garlic powder supplements with 9.6 mg allicin-releasing potential may have value in mild to moderate hypercholesterolemic patients when combined with a low fat diet. Taken with other evidence, the efficacy of garlic for lipoprotein metabolism might require allicin bioavailability to be enhanced through the use of, for example, an enteric-coated dose form. If this is the case, the possibility remains that greater hypocholesterolemic efficacy may be evident at a higher allicin dose. Also noteworthy in this study was a small reduction in energy intake with garlic compared with placebo, attributable to reduction in fat, carbohydrate and alcohol intakes. This may also have contributed to the effects on blood lipids. This study suggests that garlic supplementation has a cholesterol-lowering effect, which may be mediated by direct action of a biologically active compound or compounds and in part through the effect on food and nutrient intake.

Use of lipid-lowering medications at discharge in patients with acute myocardial infarction: data from the National Registry of Myocardial Infarction 3

BACKGROUND

The present study aimed to assess use of lipid-lowering medication at discharge in a current national sample of patients hospitalized with acute myocardial infarction and to evaluate factors associated with prescribing patterns.

METHODS AND RESULTS

Demographic, procedural, and discharge medication data were collected from 138 001 patients with acute myocardial infarction discharged from 1470 US hospitals participating in the National Registry of Myocardial Infarction 3 from July 1998 to June 1999. Lipid-lowering medications were part of the discharge regimen in 31. 7%. Among patients with prior history of CAD, revascularization, or diabetes, less than one half of the patients were discharged on treatment. In multivariate analysis, factors independently related to lipid-lowering use included history of hypercholesterolemia (odds ratio [OR] 4.93; 95% CI 4.79 to 5.07), cardiac catheterization during hospitalization (OR 1.29; 95% CI 1.24 to 1.34), care provided at a teaching hospital, (OR 1.26; 95% CI 1.22 to 1.32), use of ss-blocker (OR 1.43; 95% CI 1.39 to 1.48), and smoking cessation counseling (OR 1.51; 95% CI 1.44 to 1.59). Lipid-lowering medications were given less often to patients who were older (65 to 74 versus <55 years of age; OR 0.82; 95% CI 0.78 to 0.86), those with a history of hypertension (OR 0.92; 95% CI 0.89 to 0.95), and those undergoing coronary artery bypass graft surgery (OR 0.58; 95% CI 0.55 to 0.60).

CONCLUSIONS

Analysis of current practice patterns for the use of lipid-lowering medications in patients hospitalized with acute myocardial infarction reveals that a significant proportion of high-risk patients did not receive treatment at time of discharge.

Do polymorphisms of apoB, LPL or apoE affect the hypocholesterolemic response to weight loss?

To assess whether there is a differential hypocholesterolemic response to weight loss for subjects carrying polymorphisms of the apolipoprotein B and other genes. A before and after comparison of lipid parameters following a calorie controlled diet for an intervention period of 12 weeks. A lipid clinic based in a large teaching hospital. The difference in slope coefficients relating the percentage change in lipid parameters to the change in body weight (adjusted for age, gender and initial body mass index (BMI)), for genotype subgroups defined by polymorphisms of the 5'VNTR apoB gene, two mutations of the LPL gene and ApoE. One hundred and forty six subjects completed the intervention diet. While, on average, the intervention was successful (mean weight loss 3.9%), there was no statistically significant difference in the slope coefficients relating lipid change to weight loss for most of the genotypes tested. The slope difference for long versus short 5'VNTR alleles of the apoB gene was 0.445 (-1.307, 2.198) for apolipoprotein B and -0. 104 (-1.486, 1.278) for total cholesterol. However, subjects carrying at least one varepsilon4 allele were significantly hypo-responsive to weight loss, difference in slope coefficients -1.087 (-2.09, -0.084) and -1.320 (-2.589, 0.051) for total cholesterol and apoB, respectively. Although, this study is one of the largest of its kind, it has not replicated the findings of other smaller studies. These findings do not provide support for the use of genotype-targeted dietary advice in routine practice.

Identifying patients at risk for coronary heart disease: implications from trials of lipid-lowering drug therapy

Abnormal lipid levels contribute significantly to the risk of coronary heart disease (CHD), which is increased further in the presence of other risk factors. The association between elevated low-density lipoprotein (LDL) cholesterol and CHD risk is well established, and large primary and secondary prevention studies of HMG-CoA reductase inhibitors (statins) have shown conclusively that lowering LDL cholesterol levels reduces CHD events and total mortality. Regardless of the intervention used (diet, surgery, drugs), reduction of plasma cholesterol has consistently produced a reduction in cardiovascular risk. Absolute benefit is greatest in those who are at highest risk initially, and trial results suggest that the lower the LDL cholesterol level achieved, at least down to LDL of 3.0 mmol/l, then the lower is the CHD event risk. Epidemiological data also point to the negative impact of other lipids on CHD risk. Low levels of high-density lipoprotein (HDL) and high levels of triglycerides (particularly in conjunction with an LDL/HDL ratio >5) are particularly strong risk factors for CHD. Thus, although prevention trials to date have primarily assessed the impact of LDL lowering on CHD events, the initial assessment of CHD risk should consider a more detailed atherogenic profile including HDL and triglyceride levels. A general approach to preventing cardiovascular disease should include strategies to reduce the overall CHD risk by lifestyle modification and management of modifiable risk factors such as smoking, hypertension and diabetes. Based on data from recent prevention studies, and because they are the most potent lipid-lowering agents available for lowering LDL cholesterol, statins have appropriately become the drug of choice for most patients with hyperlipidaemia who require drug therapy.

The cost-effectiveness of lipid lowering in patients with ischaemic heart disease: an intervention and evaluation in primary care

BACKGROUND

There has been a major revolution in the recommended treatment of hyperlipidaemia in patients with ischaemic heart disease following the publication of the Scandinavian Simvastatin Survival Study. This was the first major study to demonstrate that lipid-lowering drugs reduced mortality and morbidity in patients with ischaemic heart disease.

AIM

To evaluate the feasibility and cost-effectiveness of screening and treating hyperlipidaemia in patients with ischaemic heart disease in primary care.

METHOD

A study conducted in a rural dispensing training practice on the border of Nottinghamshire and Lincolnshire involving 327 patients with ischaemic heart disease who were registered with the practice on 1 January 1996.

RESULTS

Eighty per cent of patients with ischaemic heart disease were considered eligible for screening and 80% of those attended for screening. The majority of patients who were screened had hyperlipidaemia that persisted after dietary advice. Despite lipid-lowering drugs, few patients had serum lipid concentrations in the target range at the end of six months. The costs of identifying and treating 83 patients with lipid-lowering drugs over five years is estimated at 105,318 Pounds at 1996 prices, or 94,257 Pounds assuming a 6% discount rate per annum. Two-thirds of this is owing to the cost of lipid-lowering drugs. The discounted cost per coronary event prevented would be 17,138 Pounds (95% CI = 12,568 Pounds-26,183 Pounds). The discounted cost per coronary death prevented would be 32,502 Pounds (95% CI = 23,564 Pounds-55,445 Pounds). There were no important adverse effects of lipid-lowering drugs on quality of life or mood.

CONCLUSION

Such a programme is feasible and acceptable within primary care, although the ongoing cost implications need to be considered against the costs and benefits of other interventions.

Implication of recent trials with b-hydroxy-b-methylglutaryl coenzyme A reductase inhibitors for hypertension management

BACKGROUND

There is broad agreement that statin treatment should be targeted at absolute coronary heart disease (CHD) risk but no consensus on the level of risk to target. We have examined the implications of adopting three different treatment policies for the management of hypertensive patients in the UK using data from treated hypertensives aged 35-69 years included in the Health Survey for England (1993).

METHODS

We calculated the proportion of hypertensive patients with existing atherosclerotic cardiovascular disease requiring statin treatment for secondary prevention of CHD. For those without atherosclerotic cardiovascular disease (primary prevention), we estimated CHD risk from the Framingham equation and examined the proportion with CHD risk exceeding thresholds of 4.5, 3 and 1.5% per year.

RESULTS

Twenty-one percent of treated hypertensives would require statin treatment for secondary prevention of CHD. When the CHD event threshold for statin treatment was set at > or =4.5% per year [equivalent to a number needed to treat (NNT) in 5 years of 13] a further 0.6% of hypertensive patients were identified for treatment; at a threshold of 3.0% per year (NNT = 20) 5.5% of patients were identified for primary prevention; and at a threshold of 1.5% per year (NNT = 40) 28.5% of patients were identified for primary prevention.

CONCLUSIONS

Those needing secondary prevention are first priority for statins and 21% of hypertensive patients will require treatment Formulation of guidelines for primary prevention should take into account the NNT; the proportion of patients targeted for treatment; the cost-effectiveness and the total cost of treatment. Current British guidance will entail treating an additional 5.5% of hypertensive patients for primary prevention and therefore 27% of hypertensive patients.

Under-reporting of dietary intake by smoking and non-smoking subjects counselled for hypercholesterolaemia

OBJECTIVES

We asked whether under-reporting of energy and cigarette smoking were associated with choice of foods and dietary composition amongst subjects with hypercholesterolaemia who had received dietary instruction to lower serum cholesterol.

DESIGN, SETTING AND SUBJECTS

Dietary intake was assessed with a 4-day weighed food record in 205 women and 141 men, aged 20-73 years, being treated at a lipid clinic (tertiary referral centre). Under-reporting was assessed by calculating the ratio of energy intake (EI) to estimated basal metabolic rate (BMR).

RESULTS

The median EI/BMR was 1.1 for both men and women. EI/BMR did not differ according to smoking status, but correlated negatively with body mass index (Spearman's rho = -0.32, P = 0.0001). EI/BMR was inversely associated with energy-adjusted intakes of potatoes, vegetables, fish and low-fat meats, and positively associated with intakes of nuts, potato crisps, chocolate, sour and ice cream, oils, fatty meat spreads, cakes and biscuits, and with alcohol. Thus, low EI/BMR was associated with increased energy-adjusted intakes of protein, thiamine, riboflavin, niacin, iron and cholesterol and with decreased intakes of sugar, poly- and monounsaturated fats and vitamin E (all P < 0.05). Cigarette smokers had a higher energy percentage (E%) from fat than non-smokers (29 +/- 6 vs. 26 +/- 6), a lower E% from carbohydrates (50 +/- 7 vs. 54 +/- 7) and a lower intake of vitamin C (11 +/- 7 vs. 16 +/- 9 mg MJ-1; all P = 0.0001), reflecting an increased intake of fatty meats and a decreased intake of skimmed cheese, fruit, rice and pasta, and cakes and biscuits (all P < 0.05).

CONCLUSION

Weighed dietary records reflected a 'healthier' intake of fat, protein, sugar, alcohol and some micronutrients amongst under-reporters, suggesting that self-reported dietary intakes are biased in patients with hypercholesterolaemia. Lack of responsiveness to the diet should not be assumed when dietary data are based on self-report. Smokers report a higher intake of fat and lower intake of vitamin C than non-smokers, even after dietary counsel, and may require more intensive interventions to optimize the diet.

Diet and pravastatin in moderate hypercholesterolaemia: a randomized trial in 215 middle-aged men free from cardiovascular disease

OBJECTIVE

To evaluate the effect of diet and drug intervention separately and combined in the treatment of primary hypercholesterolemia.

DESIGN

The study was conducted as a randomized, placebo-controlled factorial trial, double-blinded for drug intervention.

SETTING

Subjects were recruited from a population-based cholesterol screening programme.

SUBJECTS

215 middle-aged men with primary hypercholesterolemia, free from cardiovascular disease.

INTERVENTIONS

Subjects were randomized to one of four intervention groups: (1) placebo and US National Cholesterol Education Program step 1 diet; (2) placebo and step 2 diet; (3) pravastatin 20 mg day-1 and step 1 diet; or (4) pravastatin 20 mg day-1 and step 2 diet. The intervention period was 6 months.

MAIN OUTCOME MEASUREMENTS

Efficacy measurements included: serum total cholesterol, HDL cholesterol, triglycerides, apolipoproteins A1 and B. LDL cholesterol was calculated. For safety, values of ALAT, ASAT and CK were measured.

RESULTS

In the group receiving the step 1 diet only, lipid values were stable during the study period. In the placebo group on the step 2 diet, total cholesterol decreased by 6.3% (0.47 mmol L-1 (95% CI: 0.28, 0.67)) during 6 months. In the group receiving both pravastatin and the step 1 diet, there was a mean reduction in serum total cholesterol of 19.4% (1.46 mmol L-1 (95% CI: 1.20, 1.72)). In the group treated with pravastatin and the step 2 diet, the 6 months of data show a reduction of 20.7% (1.55 mmol L-1 (95% CI: 1.30, 1.80)).

CONCLUSIONS

If drug therapy with a HMG-CoA reductase inhibitor is considered necessary, a step 2 diet has no additional lipid-lowering effect compared with a step 1 diet in men with primary hypercholesterolaemia. However, favourable 'side-effects' of a lipid-lowering diet, such as weight loss and lowering of blood pressure, may still warrant a low-fat diet in these cases.

Dietary intervention for cholesterol reduction in public clinic patients

OBJECTIVES

To test the feasibility and effectiveness of a diet intervention (consisting of interactive mailings, computer-generated phone calls, and classes) in hypercholesterolemic low-income public clinic patients.

METHODS

Clinic patients with serum cholesterol > 200 mg/dl, referred by their primary care physician were randomized to a 6-month special intervention (SI) or usual care (UC). The intervention included mailings, computer phone calls, and four 1-hour classes. Serum total cholesterol (TC) was measured before and after intervention, and participation was monitored.

RESULTS

One hundred sixty-five of the 212 patients referred (77.8%) agreed to participate. A medical records review revealed 123 (74.5%) met eligibility criteria. Eligible subjects had a mean age of 56.7 years, 80.0% were African American, 74.8% were female, 33.6% were married, and 89.4% had a high school or lower education. Subjects were randomized with 80.5% (99) completing follow-up cholesterol measures. SI subjects were encouraged to use all three components, with 84.6% (55 of 65) actively participating in at least one component. Seventy-two percent (47 of 65) returned at least one mailing, 49.1% (28 of 57) of those with touch-tone phones accessed the computer system, and 43.1% (28 of 65) attended classes. The TC in SI decreased from 273.2 mg/dl to 265.0 mg/dl (P = 0.05) and in UC 272.4 mg/dl to 267.6 mg/dl (P = 0.32). The net reduction in SI compared with UC was 3.4 mg/dl (P = 0.58).

CONCLUSIONS

(1) Low-income public clinic patients will participate in diet interventions, (2) computer-generated interactive phone calls are feasible in this population, and (3) clinically meaningful decreases in serum cholesterol are difficult to achieve with interventions of practical intensity.

The potential role of soluble fibre in the treatment of hypercholesterolaemia

The three major modifiable coronary risk factors are smoking, hypertension, and hypercholesterolaemia. Serum cholesterol levels are above the desirable level of 5.2 mmol/l in 79% of men and 65% of women aged between 35 and 50 years and thus are an important target for intervention. In this paper, the role of nonpharmacological intervention with soluble fibre in treating mild to moderate primary hypercholesterolaemia is reviewed. Evidence from controlled studies shows that soluble fibre can be effective in lowering cholesterol by clinically significant amounts. It is stressed, however, that risk factors for coronary heart disease are interactive and attention is shifting to addressing multiple rather that individual factors.

Broadening the evidence base for evidence-based guidelines. A research agenda based on the work of the U.S. Preventive Services Task Force

Evidence-based evaluations of clinical preventive services help define priorities for research in prevention as part of primary health care. In this article, we draw on our experiences with the U.S. Preventive Services Task Force (USPSTF) to outline some major areas where research is needed to define the appropriate use of specific screening tests, counseling interventions, immunizations, and chemoprophylaxis. Areas of particular importance included research to: (1) Identify effective and practical primary care interventions for modifying personal health practices of patients, especially around issues such as diet, exercise, alcohol and drug use, and risky sexual behavior; (2) Clarify the optimal periodicity for certain screening tests and counseling interventions; (3) Identify practical ways to allow patients to share decision-making about preventive care, especially for services of possible but uncertain benefit; (4) Examine the most sensitive and efficient ways to identify high-risk groups who may need different services than the average population; and (5) Expand the use of decision-analysis and cost-effectiveness analysis to help identify optimal use of clinical preventive services. Given the difficulty of large, prospective trials, we discuss the use of alternative research designs to fill in critical gaps in the evidence for the effectiveness of specific services. Finally, we note several issues of increasing importance that may need to be addressed by future work of the USPSTF: what are the most reliable and effective ways to (1) measure and (2) improve the delivery and quality of preventive care provided in the primary care setting.

Systematic review of dietary intervention trials to lower blood total cholesterol in free-living subjects

OBJECTIVES

To estimate the efficacy of dietary advice to lower blood total cholesterol concentration in free-living subjects and to investigate the efficacy of different dietary recommendations.

DESIGN

Systematic overview of 19 randomised controlled trials including 28 comparisons.

SUBJECTS

Free-living subjects.

INTERVENTIONS

Individualised dietary advice to modify fat intake.

MAIN OUTCOME MEASURE

Percentage difference in blood total cholesterol concentration between the intervention and control groups.

RESULTS

The percentage reduction in blood total cholesterol attributable to dietary advice after at least six months of intervention was 5.3% (95% confidence interval 4.7% to 5.9%). Including both short and long duration studies, the effect was 8.5% at 3 months and 5.5% at 12 months. Diets equivalent to the step 2 diet of the American Heart Association were of similar efficacy to diets that aimed to lower total fat intake or to raise the polyunsaturated to saturated fatty acid ratio. These diets were moderately more effective than the step 1 diet of the American Heart Association (6.1% v 3.0% reduction in blood total cholesterol concentration; P<0.0001). On the basis of reported food intake, the targets for dietary change were seldom achieved. The observed reductions in blood total cholesterol concentrations in the individual trials were consistent with those predicted from dietary intake on the basis of the Keys equation.

CONCLUSIONS

Individualised dietary advice for reducing cholesterol concentration is modestly effective in free-living subjects. More intensive diets achieve a greater reduction in serum cholesterol concentration. Failure to comply fully with dietary recommendations is the likely explanation for this limited efficacy.

Resource utilisation in the management of dyslipidaemia

In Western countries, cardiovascular disease accounts for substantial morbidity and mortality. In the US, where medical costs and intervention rates are the highest in the world, the direct and indirect costs of cardiovascular disease and stroke have been estimated at $US274 billion (1998 dollars), with the costs of hospitalisation ($US119.9 billion) and lost productivity because of early mortality ($US77.9 billion) representing the largest proportions of this amount. Dyslipidaemia is an important risk factor for coronary heart disease (CHD), a condition which accounts for $US39.3 billion and $US37.9 billion (1998 dollars) in hospitalisation/nursing home costs and lost productivity, respectively, annually in the US. Similarly, the UK National Health Service spends more than 500 million pounds sterling annually on the treatment of CHD. Numerous studies have shown the benefit of lowering cholesterol levels in terms of decreasing CHD-associated morbidity and mortality; however, drug therapy costs for dyslipidaemia can be high. US and European treatment guidelines for dyslipidaemia recommend aggressive treatment for those at highest CHD event risk. Because of the high prevalence of dyslipidaemia in Western countries, these recommendations impact on a substantial proportion of the population and have increased the use of cholesterol-lowering medications. In a limited number of economic studies using clinical data from large prevention trials, the cost of drug therapy was nearly offset by the reduction in costs associated with hospitalisation and revascularisation procedures. Therefore, it appears that the strategy of identifying and treating individuals at highest risk for CHD, although expensive in terms of drug costs, would be expected to reduce the substantial direct and indirect costs associated with this condition.

Can dietary interventions change diet and cardiovascular risk factors? A meta-analysis of randomized controlled trials

OBJECTIVES

This study evaluated the effectiveness of dietary advice in primary prevention of chronic disease.

METHODS

A meta-analysis was conducted of 17 randomized controlled trials of dietary behavior interventions of at least 3 months' duration. Results were analyzed as changes in reported dietary fat intakes and biomedical measures (serum cholesterol, urinary sodium, systolic and diastolic blood pressure) in the intervention group minus changes in the control group at 3 to 6 months and 9 to 18 months of follow-up.

RESULTS

After 3 to 6 months, mean net changes in each of the five outcomes favored intervention. For dietary fat as a percentage of food energy, the change was -2.5% (95% confidence interval [CI] = -3.9%, -1.1%). Mean net changes over 9 to 18 months were as follows: serum cholesterol, -0.22 (95% CI = -0.39, -0.05) mmol/L; urinary sodium, -45.0 (95% CI = -57.1, -32.8) mmol/24 hours; systolic blood pressure, -1.9 (95% CI = -3.0, 0.8) mm Hg; and diastolic blood pressure, -1.2 (95% CI = -2.6, 0.2) mm Hg.

CONCLUSIONS

Individual dietary interventions in primary prevention can achieve modest improvements in diet and cardiovascular disease risk status that are maintained for 9 to 18 months.