A summary of the science supporting the new National Cholesterol Education Program dietary recommendations: what dietitians should know

Effects of supercritical fluid extraction pressure on chemical composition, microbial population, polar lipid profile, and microstructure of goat cheese

The consumer trend for healthier food choices and preferences for low-fat products has increased the interest in low-fat cheese and nutraceutical dairy products. However, consumer preference is still for delicious food. Low- and reduced-fat cheeses are not completely accepted because of their unappealing properties compared with full-fat cheeses. The method reported here provides another option to the conventional cheese-making process to obtain lower fat cheese. Using CO(2) as a supercritical fluid offers an alternative to reduce fat in cheese after ripening, while maintaining the initial characteristics and flavor. The aim of this experiment was to evaluate the effect of pressure (10, 20, 30, and 40 × 10(6) Pa) of supercritical CO(2) on the amount of fat extracted, microbial population, polar lipid profile, and microstructure of 2 varieties of goat cheese: Majorero, a protected denomination of origin cheese from Spain, and goat Gouda-type cheese. The amount of fat was reduced 50 to 57% and 48 to 55% for Majorero and goat Gouda-type cheeses, respectively. Higher contents (on a fat basis) of sphingomyelin and phosphatidylcholine were found in Majorero cheese compared with control and goat Gouda-type cheeses. The microbial population was reduced after supercritical fluid extraction in both cheeses, and the lethality was higher as pressure increased in Majorero cheese, most noticeably on lactococcus and lactobacillus bacteria. The Gouda-type cheese did not contain any lactobacilli. Micrographs obtained from confocal laser scanning microscopy showed a more open matrix and whey pockets in the Majorero control cheese. This could explain the ease of extracting fat and reducing the microbial counts in this cheese after treatment with supercritical CO(2). Supercritical fluid extraction with CO(2) has great potential in the dairy industry and in commercial applications. The Majorero cheese obtained after the supercritical fluid extraction treatment was an excellent candidate as a low-fat goat cheese, lower in triglycerides and cholesterol but still with all the health benefits inherent in goat milk.

Effect of plant sterols on the lipid profile of patients with hypercholesterolaemia. Randomised, experimental study

BACKGROUND

Studies have been conducted on supplementing the daily diet with plant sterol ester-enriched milk derivatives in order to reduce LDL-cholesterol levels and, consequently, cardiovascular risk. However, clinical practice guidelines on hypercholesterolaemia state that there is not sufficient evidence to recommend their use in subjects with hypercholesterolaemia. The main objective of this study is to determine the efficacy of the intake of 2 g of plant sterol esters a day in lowering LDL-cholesterol levels in patients diagnosed with hypercholesterolaemia. The specific objectives are: 1) to quantify the efficacy of the daily intake of plant sterol esters in lowering LDL-cholesterol, total cholesterol and cardiovascular risk in patients with hypercholesterolaemia; 2) to evaluate the occurrence of adverse effects of the daily intake of plant sterol esters; 3) to identify the factors that determine a greater reduction in lipid levels in subjects receiving plant sterol ester supplements.

METHODS/DESIGN

Randomised, double-blind, placebo controlled experimental trial carried out at family doctors' surgeries at three health centres in the Health Area of Albacete (Spain). The study subjects will be adults diagnosed with "limit" or "defined" hypercholesterolaemia and who have LDL cholesterol levels of 130 mg/dl or over. A dairy product in the form of liquid yoghurt containing 2 g of plant sterol ester per container will be administered daily after the main meal, for a period of 24 months. The control group will receive a daily unit of yogurt not supplemented with plant sterol esters that has a similar appearance to the enriched yoghurt. The primary variable is the change in lipid profile at 1, 3, 6, 12, 18 and 24 months. The secondary variables are: change in cardiovascular risk, adherence to the dairy product, adverse effects, adherence to dietary recommendations, frequency of food consumption, basic physical examination data, health problems, lipid-lowering medication, physical activity, smoking habits and socio-demographic variables.

DISCUSSION

If plant sterol ester supplements were effective a sounder recommendation for the consumption of plant sterols in subjects with hypercholesterolaemia could be made.

A Diet Rich in Monounsaturated Fatty Acids Improves the Lipid Profile of Mice Previously on a Diet Rich in Saturated Fatty Acids

This study investigated whether switching from a diet rich in saturated fatty acids (SAFAs) to a diet rich in monounsaturated fatty acids (MUFAs) or to one with equal amounts of MUFAs-SAFAs favorably affects the lipid profile of hypercholesterolemic mice. C57BL/6 mice (n = 82) were allocated into 4 groups. The first group (control, n = 10) was fed standard chow. The 3 remaining groups (n = 24 mice/group) were fed a SAFA-rich diet for 8 weeks and were then allocated for 16 weeks to either a MUFA-rich diet, an equal in MUFAs-SAFAs-rich diet, or continued the previous SAFA-rich diet. After 8 weeks, mice consuming SAFA-rich diet had increased weight, total cholesterol (TC), and high-density lipoprotein cholesterol (HDL-C) levels ( P < .05 vs baseline). At week 24, MUFA-rich and MUFA-SAFA rich diets decreased TC and low-density lipoprotein cholesterol (LDL-C) levels ( P < .05) compared with week 8. In conclusion, switching to MUFA-rich diets or substituting half of the SAFAs with MUFAs can reverse diet-induced-hypercholesterolemia.

Enhancement on the Europium emission band of Europium chlortetracycline complex in the presence of LDL

Low-density lipoprotein (LDL) particles are the major cholesterol-carrying lipoprotein in the human circulation from the liver to peripheral tissues. High levels of LDL-Cholesterol (LDL-C) are known risk factor for the development of coronary artery disease (CAD). The most common approach to determine the LDL-C in the clinical laboratory involves the Friedewald formula. However, in certain situations, this approach is inadequate. In this paper we report on the enhancement on the Europium emission band of Europium chlortetracycline complex (CTEu) in the presence of LDL. The emission intensity at 615 nm of the CTEu increases with increasing amounts of LDL. This phenomenon allowed us to propose a method to determine the LDL concentration in a sample composed by an aqueous solution of LDL. With this result we obtained LDL calibration curve, LOD (limit of detection) of 0.49 mg/mL and SD (standard deviation) of 0.003. We observed that CTEu complex provides a wider dynamic concentration-range for LDL determination than that from Eu-tetracycline previously. The averaged emission lifetimes of the CTEu and CTEu with LDL (1.5 mg/mL) complexes were measured as 15 and 46 micros, respectively. Study with some metallic interferents is presented.

NMR analysis of lipoprotein particle size does not increase sensitivity to the effect of soy protein on CVD risk when compared with the traditional lipid profile

The traditional lipid profile compared with nuclear magnetic resonance (NMR) may underestimate the risk for cardiovascular disease and may explain some of the discrepancies in results between studies analyzing the salubrious effects of soy. Our purpose was to compare the traditional lipid profile with NMR quantification of the number of lipoprotein particles, subclasses, and diameters or sizes in 30 sedentary males, between 18 and 30 years of age, consuming 1 of the following 3 supplements daily for 28 days: milk protein (Milk), isoflavone-poor soy protein (Soy–), or isoflavone-rich soy protein (Soy+). The study used a double-blind, parallel-arm design with random assignment to 1 of the 3 protein supplement groups. Fasting EDTA blood samples were collected at baseline and after 28 days of supplementation and analyzed for the number and size of very low-density lipoprotein (VLDL), low-density lipoprotein (LDL), and high-density lipoprotein (HDL) particles, respectively. Fasting serum samples were analyzed for concentrations of total cholesterol (TC), LDL cholesterol (LDL-C), total HDL cholesterol (HDL-C), HDL2-C, HDL3-C, triglycerides (TGs), free fatty acids (FFAs), and glucose. Fasting heparin blood samples were collected at baseline and after supplementation and analyzed for apolipoproteins A-I, A-II, B, C-II, C-III, and E, as well as hepatic and lipoprotein lipase concentrations. HDL3-C increased by 47.2% after Soy+ supplementation and hepatic lipase decreased 19.2% after Soy– supplementation (p < 0.05). HDL-C and apolipoproteins A-I and A-II were found to increase in all 3 groups (p < 0.05). Results support that NMR analysis of lipoprotein particle number and size are not more sensitive to the effect of soy protein on CVD risk compared with the traditional lipid profile. Furthermore, the lack of isoflavones in soy protein seems to have a deleterious effect on hepatic lipase.

The evidence for dietary prevention and treatment of cardiovascular disease

During the past few decades numerous studies have reported the atherogenic potential of saturated fatty acids, trans-fatty acids, and cholesterol, and beneficial effects of fiber, phytostanols/phytosterols, n-3 fatty acids, a Mediterranean diet, and other plant-based approaches. The purpose of this article is to provide a comprehensive and systematic review of the evidence associated with key dietary factors and risk of cardiovascular disease-an umbrella term encompassing diseases that affect the heart and blood vessels, including coronary heart disease, coronary artery disease, dyslipidemia, and hypertension-in conjunction with the work of the American Dietetic Association Evidence Analysis Library review on diet and lipids, updated with new evidence from the past 2 years. The criteria used and results cited provide scientific rationale for food and nutrition professionals and other health professionals for counseling patients. Details of these searches are available within the American Dietetic Association Evidence Analysis Library online (http://adaevidencelibrary.com). Potential mechanisms and needs for future research are summarized for each relevant nutrient, food, or food component.

Meta-analysis of the health effects of using the glycaemic index in meal-planning

Diabetes mellitus and CVD are some of the leading causes of mortality and morbidity. Accumulating data indicate that a diet characterised by low-glycaemic index (GI) foods may improve the management of diabetes or lipid profiles. The objective of the present meta-analysis was to critically analyse the scientific evidence that low-GI diets have beneficial effects on carbohydrate and lipid metabolism compared with high-GI diets. We searched for randomised controlled trials with a crossover or parallel design published in English between 1981 and 2003, investigating the effect of low-GI v. high-GI diets on markers for carbohydrate and lipid metabolism. Unstandardised differences in mean values were examined using the random effects model. The main outcomes were fructosamine, glycated Hb (HbA1c), HDL-cholesterol, LDL-cholesterol, total cholesterol and triacylglycerol. Literature searches identified sixteen studies that met the strict inclusion criteria. Low-GI diets significantly reduced fructosamine by –0·1 (95 % CI –0·20, 0·00) mmol/l (P=0·05), HbA1c by 0·27 (95 % CI –0·5, –0·03) % (P=0·03), total cholesterol by –0·33 (95 % CI –0·47, –0·18) mmol/l (P>0·0001) and tended to reduce LDL-cholesterol in type 2 diabetic subjects by –0·15 (95 % CI –0·31, –0·00) mmol/l (P=0·06) compared with high-GI diets. No changes were observed in HDL-cholesterol and triacylglycerol concentrations. No substantial heterogeneity was detected, suggesting that the effects of low-GI diets in these studies were uniform. Results of the present meta-analysis support the use of the GI as a scientifically based tool to enable selection of carbohydrate-containing foods to reduce total cholesterol and to improve overall metabolic control of diabetes.

Position of the American Dietetic Association: the roles of registered dietitians and dietetic technicians, registered in health promotion and disease prevention

It is the position of the American Dietetic Association (ADA) that primary prevention is the most effective, affordable course of action for preventing and reducing risk for chronic disease. Registered dietitians and dietetic technicians, registered, are leaders in delivering preventive services in both clinical and community settings, including advocating for funding and inclusion of these services in programs and policy initiatives at local, state, and federal levels. In addition, registered dietitians are leaders in facilitating and participating in research in chronic disease prevention and health promotion. Diet, nutrition, and physical activity are important factors in the promotion and maintenance of good health throughout the life cycle. Cost-effective interventions that produce a change in personal health practices are likely to lead to substantial reductions in the incidence and severity of the leading causes of disease in the United States. In an era of increasing health care expenditures and relative decreases in availability of federal funds, there is increasing demand on health promotion and disease prevention to be economically viable. Through clinical involvement and rigorous participation in research on chronic disease prevention and health promotion, the field of dietetics can lead the way to effectively translate the impact of nutrition on all ages.

Eficacia hipocolesterolemiante de un yogur que contiene ésteres de estanol vegetal

This clinical trial was carried out with the objective of a preliminar evaluation of the hypocholesteremic effectiveness of a dietary dairy product currently marketed in Spain in the form of drinkable yogurt. Thirty-two adult male and female patients with LDL cholesterol higher than 120 mg/dl were recruited in a pilot, randomized as parallel groups, double-blind, and placebo-controlled clinical trial. Patients consumed during 3 weeks (a bottle a day) Kaiku's Benecol containing 2 g/bottle of plant stanol esters, or a placebo consisting of the same product without plant stanol. Furthermore, all participants carried out some dietary standards. At the beginning and the end of the treatment LDL cholesterol, total cholesterol, and HDL cholesterol were assessed; LDL/HDL index was also calculated. At the end of the treatment in the active group a significant decline (p < 0.01) with regard to the initial levels was observed in LDL cholesterol (157 +/- 30 to 140 +/- 34, mg/dl, mean +/- SD) levels, total cholesterol (235 +/- 34 to 219 +/- 35) levels, and LDL/HDL index (3,2 +/- 1,0 to 3,0 +/- 1,2), without significant changes in HDL cholesterol (48 +/- 15 to 53 +/- 29); in the placebo group there were no significant changes (LDL cholesterol: 168 +/- 25 to 164 +/- 23; total cholesterol: 245 +/- 31 to 237 +/- 23; HDL cholesterol: 51 +/- 12 to 51 +/- 12; LDL/HDL index: 3,4 +/- 0,6 to 3,3 +/- 0,8). In short, consumption of a yogurt a day containing 2 g of stanol reduces significantly the cholesterol levels and this effect is not observed with the placebo.

Plant sterol/stanol prescription is an effective treatment strategy for managing hypercholesterolemia in outpatient clinical practice

OBJECTIVE

To determine the effectiveness of prescribing 2 g plant sterols/stanols per day as an addition to standard practice in a dietary outpatient clinic.

DESIGN

A randomized parallel design of comparative 12-week interventions.

SUBJECTS/SETTING

Patients referred by a general practitioner to a dietary outpatient clinic for the management of hyperlipidemia were eligible. Twenty-five patients (15 women and 10 men) completed the study.

INTERVENTION

Counseling regarding diet for hyperlipidemia was based on the National Cholesterol Education Program guidelines. The intervention group was instructed to incorporate approximately 25 g/day of margarine, containing plant sterols/stanols, which delivered approximately 2 g plant sterols/stanols.

MAIN OUTCOME MEASURE

Changes in diet, body weight, and serum total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglycerides were measured.

STATISTICAL ANALYSIS PERFORMED

Changes in dietary and biochemical outcomes were assessed using Student's t test. For nonnormally distributed data, Wilcoxon signed rank test was used, and Mann-Whitney U tests were conducted to determine the proportion of subjects reaching defined goals. The number needed to treat index was used to report effectiveness of the intervention.

RESULTS

Five of 14 subjects in the intervention group compared with 0 of 11 in the control group achieved a reduction in serum cholesterol of >/=15% ( P <.05). Using the number needed to treat index, for each 2.8 patients counseled with routine prescription of plant sterols/stanols, one additional patient would obtain a reduction in cholesterol by >/=15% compared with conventional management. This was achieved without any detrimental effects on the dietary fatty acid profile.

CONCLUSIONS

Routine prescription of margarine containing plant sterol/stanol is an effective strategy in the management of hypercholesterolemic patients in the clinical setting.

Effects of plant-based diets high in raw or roasted almonds, or roasted almond butter on serum lipoproteins in humans

OBJECTIVE

To compare the lipid-altering effect of roasted salted almonds and roasted almond butter with that of raw almonds, as part of a plant-based diet.

METHODS

Thirty-eight free-living, hypercholesterolemic men (n = 12) and women (n = 26) with a mean total serum cholesterol (TC) of 245 + 29 mg/dL (mean + SD) followed a heart-healthy diet including 100g of one of three forms of almonds: roasted salted almonds, roasted almond butter or raw almonds for four weeks. Measurements of serum TC, triglycerides (TG), selected lipoproteins and blood pressure were taken at baseline and after four weeks.

RESULTS

All three forms of almonds in the context of a heart-healthy diet significantly lowered low-density lipoprotein-cholesterol (LDL) from baseline to the completion of the study. Both raw and roasted almonds significantly lowered TC, whereas the decrease by almond butter (in a smaller cohort) did not reach statistical significance. High-density lipoprotein-cholesterol (HDL) did not significantly change with raw or roasted almonds but slightly increased with almond butter. At the end of the study, blood pressure did not change significantly from baseline values for any of the groups.

CONCLUSION

These results suggest that unblanched almonds-whether raw, dry roasted, or in roasted butter form-can play an effective role in cholesterol-lowering, plant-based diets.