Differential effect of National Cholesterol Education Program (NCEP) Step II diet on HDL cholesterol, its subfractions, and apoprotein A-I levels in hypercholesterolemic women and men after 1 year: the beFIT Study

Reduction in saturated fat intake for cardiovascular disease

BACKGROUND

Reducing saturated fat reduces serum cholesterol, but effects on other intermediate outcomes may be less clear. Additionally, it is unclear whether the energy from saturated fats eliminated from the diet are more helpfully replaced by polyunsaturated fats, monounsaturated fats, carbohydrate or protein.

OBJECTIVES

To assess the effect of reducing saturated fat intake and replacing it with carbohydrate (CHO), polyunsaturated (PUFA), monounsaturated fat (MUFA) and/or protein on mortality and cardiovascular morbidity, using all available randomised clinical trials.

SEARCH METHODS

We updated our searches of the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (Ovid) and Embase (Ovid) on 15 October 2019, and searched Clinicaltrials.gov and WHO International Clinical Trials Registry Platform (ICTRP) on 17 October 2019.

SELECTION CRITERIA

Included trials fulfilled the following criteria: 1) randomised; 2) intention to reduce saturated fat intake OR intention to alter dietary fats and achieving a reduction in saturated fat; 3) compared with higher saturated fat intake or usual diet; 4) not multifactorial; 5) in adult humans with or without cardiovascular disease (but not acutely ill, pregnant or breastfeeding); 6) intervention duration at least 24 months; 7) mortality or cardiovascular morbidity data available.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed inclusion, extracted study data and assessed risk of bias. We performed random-effects meta-analyses, meta-regression, subgrouping, sensitivity analyses, funnel plots and GRADE assessment.

MAIN RESULTS

We included 15 randomised controlled trials (RCTs) (16 comparisons, 56,675 participants), that used a variety of interventions from providing all food to advice on reducing saturated fat. The included long-term trials suggested that reducing dietary saturated fat reduced the risk of combined cardiovascular events by 17% (risk ratio (RR) 0.83; 95% confidence interval (CI) 0.70 to 0.98, 12 trials, 53,758 participants of whom 8% had a cardiovascular event, I² = 67%, GRADE moderate-quality evidence). Meta-regression suggested that greater reductions in saturated fat (reflected in greater reductions in serum cholesterol) resulted in greater reductions in risk of CVD events, explaining most heterogeneity between trials. The number needed to treat for an additional beneficial outcome (NNTB) was 56 in primary prevention trials, so 56 people need to reduce their saturated fat intake for ~four years for one person to avoid experiencing a CVD event. In secondary prevention trials, the NNTB was 53. Subgrouping did not suggest significant differences between replacement of saturated fat calories with polyunsaturated fat or carbohydrate, and data on replacement with monounsaturated fat and protein was very limited. We found little or no effect of reducing saturated fat on all-cause mortality (RR 0.96; 95% CI 0.90 to 1.03; 11 trials, 55,858 participants) or cardiovascular mortality (RR 0.95; 95% CI 0.80 to 1.12, 10 trials, 53,421 participants), both with GRADE moderate-quality evidence. There was little or no effect of reducing saturated fats on non-fatal myocardial infarction (RR 0.97, 95% CI 0.87 to 1.07) or CHD mortality (RR 0.97, 95% CI 0.82 to 1.16, both low-quality evidence), but effects on total (fatal or non-fatal) myocardial infarction, stroke and CHD events (fatal or non-fatal) were all unclear as the evidence was of very low quality. There was little or no effect on cancer mortality, cancer diagnoses, diabetes diagnosis, HDL cholesterol, serum triglycerides or blood pressure, and small reductions in weight, serum total cholesterol, LDL cholesterol and BMI. There was no evidence of harmful effects of reducing saturated fat intakes.

AUTHORS' CONCLUSIONS

The findings of this updated review suggest that reducing saturated fat intake for at least two years causes a potentially important reduction in combined cardiovascular events. Replacing the energy from saturated fat with polyunsaturated fat or carbohydrate appear to be useful strategies, while effects of replacement with monounsaturated fat are unclear. The reduction in combined cardiovascular events resulting from reducing saturated fat did not alter by study duration, sex or baseline level of cardiovascular risk, but greater reduction in saturated fat caused greater reductions in cardiovascular events.

Sex differences in the effects of the moon on ischemic stroke incidence: new findings from Beijing, China

Stroke is a major cause of death and disability in China, and no therapies have proven effective to prevent it. Popular belief holds that the lunar cycle affects human physiology, behavior, and health. The aim of our study is to determine whether the lunar cycle impacts the incidence of stroke subtypes [intracerebral hemorrhage (ICH), transient ischemic attack (TIA) and ischemic stroke (IS)]. We retrospectively extracted the discharge registry data of all patients with first-ever acute stroke hospitalized in the affiliated hospital of Beijing University of Traditional Chinese Medicine during 2002-2015. The onset times of stroke were assigned to four primary lunar phases based on NASA definitions. Chi-square tests and multiple logistic regression analyses were used to estimate the association between the lunar cycle and stroke incidence with adjustment for age, sex and season. A total of 5,965 patients with stroke (4,909 admissions for ischemic stroke IS, 754 admissions for ICH, and 302 admissions for TIA) were evaluated in our study. Subgroup analysis indicated that the admission rates of different sexes for IS tended to have opposite variation during the four moon phases. More female patients were admitted during the new moon than in the first and third quarters, while fewer male patients were admitted during the new moon than in the first and third quarters (χ2 = 15.589, P = .001). Multiple logistic regression analyses revealed that men were more likely to be admitted for IS in the first quarter than during the new moon (odds ratio [OR] = 1.252, 95% confidence interval [CI] = 1.076-1.456) (P = .004), and a corresponding trend was also identified for the third quarter (OR = 1.235, 95% CI = 1.062-1.437) (P = .006). No significant gender differences were shown in ICH or TIA. No sex difference is obvious during the full moon. Moon phases seem to affect both genders, but in very different ways. It seems that the new moon is a protective factor for male ischemic stroke patients and a risk factor for female ones. Woman tends to be more vulnerable than ever at the new moon, so deserves more attention and care. The mechanisms underlying this observation are worth studying further.

Effects of total fat intake on body fatness in adults

BACKGROUND

The ideal proportion of energy from fat in our food and its relation to body weight is not clear. In order to prevent overweight and obesity in the general population, we need to understand the relationship between the proportion of energy from fat and resulting weight and body fatness in the general population.

OBJECTIVES

To assess the effects of proportion of energy intake from fat on measures of body fatness (including body weight, waist circumference, percentage body fat and body mass index) in people not aiming to lose weight, using all appropriate randomised controlled trials (RCTs) of at least six months duration.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, Clinicaltrials.gov and the WHO International Clinical Trials Registry Platform (ICTRP) to October 2019. We did not limit the search by language.

SELECTION CRITERIA

Trials fulfilled the following criteria: 1) randomised intervention trial, 2) included adults aged at least 18 years, 3) randomised to a lower fat versus higher fat diet, without the intention to reduce weight in any participants, 4) not multifactorial and 5) assessed a measure of weight or body fatness after at least six months. We duplicated inclusion decisions and resolved disagreement by discussion or referral to a third party.

DATA COLLECTION AND ANALYSIS

We extracted data on the population, intervention, control and outcome measures in duplicate. We extracted measures of body fatness (body weight, BMI, percentage body fat and waist circumference) independently in duplicate at all available time points. We performed random-effects meta-analyses, meta-regression, subgrouping, sensitivity, funnel plot analyses and GRADE assessment.

MAIN RESULTS

We included 37 RCTs (57,079 participants). There is consistent high-quality evidence from RCTs that reducing total fat intake results in small reductions in body fatness; this was seen in almost all included studies and was highly resistant to sensitivity analyses (GRADE high-consistency evidence, not downgraded). The effect of eating less fat (compared with higher fat intake) is a mean body weight reduction of 1.4 kg (95% confidence interval (CI) -1.7 to -1.1 kg, in 53,875 participants from 26 RCTs, I² = 75%). The heterogeneity was explained in subgrouping and meta-regression. These suggested that greater weight loss results from greater fat reductions in people with lower fat intake at baseline, and people with higher body mass index (BMI) at baseline. The size of the effect on weight does not alter over time and is mirrored by reductions in BMI (MD -0.5 kg/m², 95% CI -0.6 to -0.3, 46,539 participants in 14 trials, I² = 21%), waist circumference (MD -0.5 cm, 95% CI -0.7 to -0.2, 16,620 participants in 3 trials; I² = 21%), and percentage body fat (MD -0.3% body fat, 95% CI -0.6 to 0.00, P = 0.05, in 2350 participants in 2 trials; I² = 0%). There was no suggestion of harms associated with low fat diets that might mitigate any benefits on body fatness. The reduction in body weight was reflected in small reductions in LDL (-0.13 mmol/L, 95% CI -0.21 to -0.05), and total cholesterol (-0.23 mmol/L, 95% CI -0.32 to -0.14), with little or no effect on HDL cholesterol (-0.02 mmol/L, 95% CI -0.03 to 0.00), triglycerides (0.01 mmol/L, 95% CI -0.05 to 0.07), systolic (-0.75 mmHg, 95% CI -1.42 to -0.07) or diastolic blood pressure(-0.52 mmHg, 95% CI -0.95 to -0.09), all GRADE high-consistency evidence or quality of life (0.04, 95% CI 0.01 to 0.07, on a scale of 0 to 10, GRADE low-consistency evidence).

AUTHORS' CONCLUSIONS

Trials where participants were randomised to a lower fat intake versus a higher fat intake, but with no intention to reduce weight, showed a consistent, stable but small effect of low fat intake on body fatness: slightly lower weight, BMI, waist circumference and percentage body fat compared with higher fat arms. Greater fat reduction, lower baseline fat intake and higher baseline BMI were all associated with greater reductions in weight. There was no evidence of harm to serum lipids, blood pressure or quality of life, but rather of small benefits or no effect.

Reduction in saturated fat intake for cardiovascular disease

BACKGROUND

Reducing saturated fat reduces serum cholesterol, but effects on other intermediate outcomes may be less clear. Additionally, it is unclear whether the energy from saturated fats eliminated from the diet are more helpfully replaced by polyunsaturated fats, monounsaturated fats, carbohydrate or protein.

OBJECTIVES

To assess the effect of reducing saturated fat intake and replacing it with carbohydrate (CHO), polyunsaturated (PUFA), monounsaturated fat (MUFA) and/or protein on mortality and cardiovascular morbidity, using all available randomised clinical trials.

SEARCH METHODS

We updated our searches of the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (Ovid) and Embase (Ovid) on 15 October 2019, and searched Clinicaltrials.gov and WHO International Clinical Trials Registry Platform (ICTRP) on 17 October 2019.

SELECTION CRITERIA

Included trials fulfilled the following criteria: 1) randomised; 2) intention to reduce saturated fat intake OR intention to alter dietary fats and achieving a reduction in saturated fat; 3) compared with higher saturated fat intake or usual diet; 4) not multifactorial; 5) in adult humans with or without cardiovascular disease (but not acutely ill, pregnant or breastfeeding); 6) intervention duration at least 24 months; 7) mortality or cardiovascular morbidity data available.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed inclusion, extracted study data and assessed risk of bias. We performed random-effects meta-analyses, meta-regression, subgrouping, sensitivity analyses, funnel plots and GRADE assessment.

MAIN RESULTS

We included 15 randomised controlled trials (RCTs) (16 comparisons, ~59,000 participants), that used a variety of interventions from providing all food to advice on reducing saturated fat. The included long-term trials suggested that reducing dietary saturated fat reduced the risk of combined cardiovascular events by 21% (risk ratio (RR) 0.79; 95% confidence interval (CI) 0.66 to 0.93, 11 trials, 53,300 participants of whom 8% had a cardiovascular event, I² = 65%, GRADE moderate-quality evidence). Meta-regression suggested that greater reductions in saturated fat (reflected in greater reductions in serum cholesterol) resulted in greater reductions in risk of CVD events, explaining most heterogeneity between trials. The number needed to treat for an additional beneficial outcome (NNTB) was 56 in primary prevention trials, so 56 people need to reduce their saturated fat intake for ~four years for one person to avoid experiencing a CVD event. In secondary prevention trials, the NNTB was 32. Subgrouping did not suggest significant differences between replacement of saturated fat calories with polyunsaturated fat or carbohydrate, and data on replacement with monounsaturated fat and protein was very limited. We found little or no effect of reducing saturated fat on all-cause mortality (RR 0.96; 95% CI 0.90 to 1.03; 11 trials, 55,858 participants) or cardiovascular mortality (RR 0.95; 95% CI 0.80 to 1.12, 10 trials, 53,421 participants), both with GRADE moderate-quality evidence. There was little or no effect of reducing saturated fats on non-fatal myocardial infarction (RR 0.97, 95% CI 0.87 to 1.07) or CHD mortality (RR 0.97, 95% CI 0.82 to 1.16, both low-quality evidence), but effects on total (fatal or non-fatal) myocardial infarction, stroke and CHD events (fatal or non-fatal) were all unclear as the evidence was of very low quality. There was little or no effect on cancer mortality, cancer diagnoses, diabetes diagnosis, HDL cholesterol, serum triglycerides or blood pressure, and small reductions in weight, serum total cholesterol, LDL cholesterol and BMI. There was no evidence of harmful effects of reducing saturated fat intakes.

AUTHORS' CONCLUSIONS

The findings of this updated review suggest that reducing saturated fat intake for at least two years causes a potentially important reduction in combined cardiovascular events. Replacing the energy from saturated fat with polyunsaturated fat or carbohydrate appear to be useful strategies, while effects of replacement with monounsaturated fat are unclear. The reduction in combined cardiovascular events resulting from reducing saturated fat did not alter by study duration, sex or baseline level of cardiovascular risk, but greater reduction in saturated fat caused greater reductions in cardiovascular events.

Dairy consumption is associated with a lower incidence of the metabolic syndrome in middle-aged and older Korean adults: the Korean Genome and Epidemiology Study (KoGES)

This cohort study examined the association between total and individual dairy products and the risk of developing the metabolic syndrome (MetS) and its components in Korean adults from the Korean Genome and Epidemiology Study. We prospectively analysed 5510 participants aged 40-69 years without the MetS at baseline during a 10-year follow-up period. Dairy consumption was assessed with a semi-quantitative FFQ at baseline and after 4 years. The MetS was defined according to the criteria by the National Cholesterol Education Program Adult Treatment Panel III. The Cox's proportional hazard model was used to examine the association between consumption of total dairy products, milk and yogurt in servings per week and the risk of incident MetS or individual components. A total of 2103 subjects developed the MetS (38·2 %) during an average follow-up of 67·4 months (range 17-104 months). Frequent dairy consumption (>7 servings of total dairy and milk/week, ≥4 servings of yogurt/week) was associated with a reduced risk of incident MetS and its components. In the multivariable adjusted model, hazard ratios for the MetS were 0·51 (95 % CI 0·43, 0·61) for total dairy products, 0·50 (95 % CI 0·38, 0·66) for milk and 0·67 (95 % CI 0·57, 0·78) for yogurt in frequent consumers compared with non-consumers. An inverse association between milk/yogurt and low HDL-cholesterol was shown only in women. In conclusion, high consumption of individual dairy products including milk and yogurt as well as total dairy were associated with a reduced risk of incident MetS and individual components in Korean adults.

Effects of total fat intake on body weight

BACKGROUND

In order to prevent overweight and obesity in the general population we need to understand the relationship between the proportion of energy from fat and resulting weight and body fatness in the general population.

OBJECTIVES

To assess the effects of proportion of energy intake from fat on measures of weight and body fatness (including obesity, waist circumference and body mass index) in people not aiming to lose weight, using all appropriate randomised controlled trials (RCTs) and cohort studies in adults, children and young people

SEARCH METHODS

We searched CENTRAL to March 2014 and MEDLINE, EMBASE and CINAHL to November 2014. We did not limit the search by language. We also checked the references of relevant reviews.

SELECTION CRITERIA

Trials fulfilled the following criteria: 1) randomised intervention trial, 2) included children (aged ≥ 24 months), young people or adults, 3) randomised to a lower fat versus usual or moderate fat diet, without the intention to reduce weight in any participants, 4) not multifactorial and 5) assessed a measure of weight or body fatness after at least six months. We also included cohort studies in children, young people and adults that assessed the proportion of energy from fat at baseline and assessed the relationship with body weight or fatness after at least one year. We duplicated inclusion decisions and resolved disagreement by discussion or referral to a third party.

DATA COLLECTION AND ANALYSIS

We extracted data on the population, intervention, control and outcome measures in duplicate. We extracted measures of weight and body fatness independently in duplicate at all available time points. We performed random-effects meta-analyses, meta-regression, subgrouping, sensitivity and funnel plot analyses.

MAIN RESULTS

We included 32 RCTs (approximately 54,000 participants) and 30 sets of analyses of 25 cohorts. There is consistent evidence from RCTs in adults of a small weight-reducing effect of eating a smaller proportion of energy from fat; this was seen in almost all included studies and was highly resistant to sensitivity analyses. The effect of eating less fat (compared with usual diet) is a mean weight reduction of 1.5 kg (95% confidence interval (CI) -2.0 to -1.1 kg), but greater weight loss results from greater fat reductions. The size of the effect on weight does not alter over time and is mirrored by reductions in body mass index (BMI) (-0.5 kg/m(2), 95% CI -0.7 to -0.3) and waist circumference (-0.3 cm, 95% CI -0.6 to -0.02). Included cohort studies in children and adults most often do not suggest any relationship between total fat intake and later measures of weight, body fatness or change in body fatness. However, there was a suggestion that lower fat intake was associated with smaller increases in weight in middle-aged but not elderly adults, and in change in BMI in the highest validity child cohort.

AUTHORS' CONCLUSIONS

Trials where participants were randomised to a lower fat intake versus usual or moderate fat intake, but with no intention to reduce weight, showed a consistent, stable but small effect of low fat intake on body fatness: slightly lower weight, BMI and waist circumference compared with controls. Greater fat reduction and lower baseline fat intake were both associated with greater reductions in weight. This effect of reducing total fat was not consistently reflected in cohort studies assessing the relationship between total fat intake and later measures of body fatness or change in body fatness in studies of children, young people or adults.

Reduction in saturated fat intake for cardiovascular disease

BACKGROUND

Reducing saturated fat reduces serum cholesterol, but effects on other intermediate outcomes may be less clear. Additionally it is unclear whether the energy from saturated fats that are lost in the diet are more helpfully replaced by polyunsaturated fats, monounsaturated fats, carbohydrate or protein. This review is part of a series split from and updating an overarching review.

OBJECTIVES

To assess the effect of reducing saturated fat intake and replacing it with carbohydrate (CHO), polyunsaturated (PUFA) or monounsaturated fat (MUFA) and/or protein on mortality and cardiovascular morbidity, using all available randomised clinical trials.

SEARCH METHODS

We updated our searches of the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (Ovid) and EMBASE (Ovid) on 5 March 2014. We also checked references of included studies and reviews.

SELECTION CRITERIA

Trials fulfilled the following criteria: 1) randomised with appropriate control group; 2) intention to reduce saturated fat intake OR intention to alter dietary fats and achieving a reduction in saturated fat; 3) not multifactorial; 4) adult humans with or without cardiovascular disease (but not acutely ill, pregnant or breastfeeding); 5) intervention at least 24 months; 6) mortality or cardiovascular morbidity data available.

DATA COLLECTION AND ANALYSIS

Two review authors working independently extracted participant numbers experiencing health outcomes in each arm, and we performed random-effects meta-analyses, meta-regression, subgrouping, sensitivity analyses and funnel plots.

MAIN RESULTS

We include 15 randomised controlled trials (RCTs) (17 comparisons, ˜59,000 participants), which used a variety of interventions from providing all food to advice on how to reduce saturated fat. The included long-term trials suggested that reducing dietary saturated fat reduced the risk of cardiovascular events by 17% (risk ratio (RR) 0.83; 95% confidence interval (CI) 0.72 to 0.96, 13 comparisons, 53,300 participants of whom 8% had a cardiovascular event, I² 65%, GRADE moderate quality of evidence), but effects on all-cause mortality (RR 0.97; 95% CI 0.90 to 1.05; 12 trials, 55,858 participants) and cardiovascular mortality (RR 0.95; 95% CI 0.80 to 1.12, 12 trials, 53,421 participants) were less clear (both GRADE moderate quality of evidence). There was some evidence that reducing saturated fats reduced the risk of myocardial infarction (fatal and non-fatal, RR 0.90; 95% CI 0.80 to 1.01; 11 trials, 53,167 participants), but evidence for non-fatal myocardial infarction (RR 0.95; 95% CI 0.80 to 1.13; 9 trials, 52,834 participants) was unclear and there were no clear effects on stroke (any stroke, RR 1.00; 95% CI 0.89 to 1.12; 8 trials, 50,952 participants). These relationships did not alter with sensitivity analysis. Subgrouping suggested that the reduction in cardiovascular events was seen in studies that primarily replaced saturated fat calories with polyunsaturated fat, and no effects were seen in studies replacing saturated fat with carbohydrate or protein, but effects in studies replacing with monounsaturated fats were unclear (as we located only one small trial). Subgrouping and meta-regression suggested that the degree of reduction in cardiovascular events was related to the degree of reduction of serum total cholesterol, and there were suggestions of greater protection with greater saturated fat reduction or greater increase in polyunsaturated and monounsaturated fats. There was no evidence of harmful effects of reducing saturated fat intakes on cancer mortality, cancer diagnoses or blood pressure, while there was some evidence of improvements in weight and BMI.

AUTHORS' CONCLUSIONS

The findings of this updated review are suggestive of a small but potentially important reduction in cardiovascular risk on reduction of saturated fat intake. Replacing the energy from saturated fat with polyunsaturated fat appears to be a useful strategy, and replacement with carbohydrate appears less useful, but effects of replacement with monounsaturated fat were unclear due to inclusion of only one small trial. This effect did not appear to alter by study duration, sex or baseline level of cardiovascular risk. Lifestyle advice to all those at risk of cardiovascular disease and to lower risk population groups should continue to include permanent reduction of dietary saturated fat and partial replacement by unsaturated fats. The ideal type of unsaturated fat is unclear.

Associations between macronutrient intake and serum lipid profile depend on body fat in European adolescents: the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study

The present study aimed to investigate the relationships between macronutrient intake and serum lipid profile in adolescents from eight European cities participating in the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) cross-sectional study (2006-7), and to assess the role of body fat-related variables in these associations. Weight, height, waist circumference, skinfold thicknesses, total cholesterol, HDL-cholesterol (HDL-C), LDL-cholesterol, TAG, apoB and apoA1 were measured in 454 adolescents (44% boys) aged 12.5-17.5 years. Macronutrient intake (g/4180 kJ per d (1000 kcal per d)) was assessed using two non-consecutive 24 h dietary recalls. Associations were evaluated by multi-level analysis and adjusted for sex, age, maternal education, centre, sum of four skinfolds, moderate-to-vigorous physical activity, sedentary behaviours and diet quality index for adolescents. Carbohydrate intake was inversely associated with HDL-C (β = - 0.189, P< 0.001). An inverse association was found between fat intake and TAG (β = - 0.319, P< 0.001). Associations between macronutrient intake and serum lipids varied according to adiposity levels, i.e. an inverse association between carbohydrate intake and HDL-C was only observed in those adolescents with a higher waist:height ratio. As serum lipids and excess body fat are the major markers of CVD, these findings should be considered when developing strategies to prevent the risk of CVD among adolescents.

Disruption of ldlr causes increased LDL-c and vascular lipid accumulation in a zebrafish model of hypercholesterolemia

Hyperlipidemia and arterial cholesterol accumulation are primary causes of cardiovascular events. Monogenic forms of hyperlipidemia and recent genome-wide association studies indicate that genetics plays an important role. Zebrafish are a useful model for studying the genetic susceptibility to hyperlipidemia owing to conservation of many components of lipoprotein metabolism, including those related to LDL, ease of genetic manipulation, and in vivo observation of lipid transport and vascular calcification. We sought to develop a genetic model for lipid metabolism in zebrafish, capitalizing on one well-understood player in LDL cholesterol (LDL-c) transport, the LDL receptor (ldlr), and an established in vivo model of hypercholesterolemia. We report that morpholinos targeted against the gene encoding ldlr effectively suppressed its expression in embryos during the first 8 days of development. The ldlr morphants exhibited increased LDL-c levels that were exacerbated by feeding a high cholesterol diet. Increased LDL-c was ameliorated in morphants upon treatment with atorvastatin. Furthermore, we observed significant vascular and liver lipid accumulation, vascular leakage, and plaque oxidation in ldlr-deficient embryos. Finally, upon transcript analysis of several cholesterol-regulating genes, we observed changes similar to those seen in mammalian systems, suggesting that cholesterol regulation may be conserved in zebrafish. Taken together, these observations indicate conservation of ldlr function in zebrafish and demonstrate the utility of transient gene knockdown in embryos as a genetic model for hyperlipidemia.

The effect of nutritional supplements on serum high-density lipoprotein cholesterol and apolipoprotein A-I

One of the factors contributing to the increased risk of developing premature atherosclerosis is low plasma concentrations of high-density lipoprotein (HDL) cholesterol. Multiple potential mechanisms account for the cardioprotective effects of HDL and its main protein apolipoprotein A-I (apo A-I). Diet has an important role in modulating HDL cholesterol level. The widespread use of nutritional supplements may also alter the biology of HDL. In this review, we discuss the effect of select nutritional supplements on serum HDL cholesterol and apo A-I levels. Some nutritional supplements, such as phytosterols, soy proteins, and black seed extracts, may increase HDL cholesterol levels, while others such as cholic acid and high doses of commonly used antioxidant vitamins may downregulate HDL cholesterol levels and reduce its cardioprotection. Multiple mechanisms are involved in the regulation of HDL levels, so changes in production and clearance of HDL may have different clinical implications. The clinical relevance of the changes in HDL and apo A-I caused by nutrient supplementation needs to be tested in controlled clinical trials.

Dietary macronutrients, genetic variation, and progression of coronary atherosclerosis among women

BACKGROUND

Previous studies observed the surprising finding that saturated fat was inversely associated with atherosclerosis progression in postmenopausal women, whereas polyunsaturated fat (PUFA) and carbohydrates were positively associated. Whether certain genes modify the association of diet with atherosclerotic progression is unknown.

METHODS

Using Haplotype-tagging single nucleotide polymorphisms, we evaluated gene-diet interactions with 3 preselected genes involved in fatty acid and carbohydrate metabolism: sterol regulatory element binding protein-1 (SREBP1), insulin-induced gene-1 (INSIG1), and SREBP cleavage-activating protein (SCAP). Diet was assessed at baseline. Quantitative coronary angiography was performed at baseline and after a mean of follow-up of 3.09 years in 2,227 coronary segments in 234 postmenopausal women.

RESULTS

Global effects of each gene and gene-diet interactions for different fats, total fat, and carbohydrate were evaluated. Global tests revealed no main effects between SCAP, INSIG1, and SREBP1 haplotypes and progression of atherosclerosis (P = .87, P = .58, and P = .44). After correction for 5 nutrients evaluated (Bonferroni-corrected 2-tailed α = .01), no significant gene-nutrient interactions were seen, except for a borderline global interaction between SREBP1 and PUFA intake (P interaction = .013). This interaction was specific to the G-C haplotype (frequency 35%) and was driven by n-6 rather than n-3 PUFA (P for interaction < .0001). The interaction was robust to estimated isocaloric replacement of PUFA with any other nutrient. Per each 5% energy from n-6 PUFA, a 0.21-mm greater decline in mean minimal coronary artery diameter was seen among women per each copy of the second most frequent haplotype of SREBP1.

CONCLUSIONS

We observed an interaction between SREBP1 and PUFA consumption that might explain the positive association of PUFA with atherosclerosis progression in this cohort.

Intake and serum profile of fatty acids are weakly correlated with global dietary quality in European adolescents

OBJECTIVE

The present study assessed whether compliance with the Food-Based Dietary Guidelines is related to habitual fatty acid (FA) intake and blood lipid parameters.

METHODS

Dietary information was collected by two non-consecutive 24-h recalls in 1804 European adolescents. Compliance with the Food-Based Dietary Guidelines was expressed by calculating the Diet Quality Index for Adolescents (DQI-A). Blood samples were collected in a randomly selected subset (n = 552). Relations between FA intake/serum concentrations and DQI-A were tested with multilevel regression analysis to correct for the study design (clustering within cities). Analyses were stratified for gender; age was entered as a covariate.

RESULTS

Better DQI-A scores were related to increased proportional intakes of energy from total fat, saturated FA, monounsaturated FA, and cholesterol (P < 0.001), whereas no significant association was observed with polyunsaturated FA intakes. In adolescents with higher compared with lower DQI-A scores, dairy products contributed more (21.0% versus 12.7%) and low-nutrient, energy-dense items contributed less (17.2% versus 26.3%) to the intake of total fat. A positive association was observed between the DQI-A scores and serum concentrations of eicosapentaenoic acid and docosahexaenoic acid (all P < 0.005). The latter, however, was significant only in girls. In boys, higher DQI-A scores were inversely associated with serum cholesterol concentrations (P < 0.05).

CONCLUSION

Although compliance with the Food-Based Dietary Guidelines was not always associated with a favorable FA intake pattern, a significant favorable association with some serum biomarkers was observed. This outcome underlines the importance of considering dietary habits instead of single-nutrient intakes.

Lipid and lipoprotein responses of dyslipidemic patients to exclusive nutritional counseling by gender and age

OBJECTIVE: The aim of the present study was to evaluate the plasma lipid responses of dyslipidemic patients to nutritional counseling according to gender and age. METHODS: One-hundred and twenty nine dyslipidemic subjects comprised the study, 56 men and 73 women, aged 20 to 73 years, treated at the Dyslipidemia Outpatient Clinic of the Universidade Estadual de Campinas Clinic Hospital. The inclusion criteria established that no lipid-lowering medication had been used in the 30 days prior to and during the nutritional counseling. Blood samples were collected in the morning after a 12 hour fast. The participants were divided into groups according to gender and age (age <60 and > 60 years). The hypercholesterolemic patients were instructed to restrict saturated fats (<7%) and cholesterol (<200mg/day). Those presenting with high triglyceride levels (>300mg/dL) were asked to consume a low fat diet. Those with mixed hyperlipidemia were instructed to do both. Statistical analyses included the Wilcoxon, Mann-Whitney, Chi-square and Fisher's exact tests and Analysis of Covariance. RESULTS: After nutritional counseling, total cholesterol and triglycerides decreased by 16% and 36% in males, and by 12% and 26% in females, respectively, and Low Density Lipoprotein-cholesterol decreased by 12% in females. Only triglycerides decrease significantly. In the mixed hyperlipidemia group, the male and female triglyceride (-44% and -29%), Low Density Lipoprotein-cholesterol (+12% and -15%) and High Density Lipoprotein-cholesterol (+7% and -3%) levels differed significantly. Between the age groups, only triglyceride levels differed significantly, with adults experiencing the highest reductions (33%). CONCLUSION: Nutritional counseling effectively lowered plasma lipid and lipoprotein levels, reinforcing the benefits of dietary interventions for the treatment of dyslipidemia.

Effect of reducing total fat intake on body weight: systematic review and meta-analysis of randomised controlled trials and cohort studies

OBJECTIVE

To investigate the relation between total fat intake and body weight in adults and children.

DESIGN

Systematic review and meta-analysis of randomised controlled trials and cohort studies.

DATA SOURCES

Medline, Embase, CINAHL, and the Cochrane Central Register of Controlled Trials to June 2010.

INCLUSION CRITERIA

Randomised controlled trials and cohort studies of adults or children that compared lower versus usual total fat intake and assessed the effects on measures of body fatness (body weight, body mass index, or waist circumference) after at least six months (randomised controlled trials) or one year (in cohorts). Randomised controlled trials with any intention to reduce weight in participants or confounded by additional medical or lifestyle interventions were excluded.

DATA EXTRACTION

Data were extracted and validity was assessed independently and in duplicate. Random effects meta-analyses, subgroups, sensitivity analyses, and metaregression were done.

RESULTS

33 randomised controlled trials (73,589 participants) and 10 cohort studies were included, all from developed countries. Meta-analysis of data from the trials suggested that diets lower in total fat were associated with lower relative body weight (by 1.6 kg, 95% confidence interval -2.0 to -1.2 kg, I(2)=75%, 57,735 participants). Lower weight gain in the low fat arm compared with the control arm was consistent across trials, but the size of the effect varied. Metaregression suggested that greater reduction in total fat intake and lower baseline fat intake were associated with greater relative weight loss, explaining most of the heterogeneity. The significant effect of a low fat diet on weight was not lost in sensitivity analyses (including removing trials that expended greater time and attention on low fat groups). Lower total fat intake also led to lower body mass index (-0.51 kg/m(2), 95% confidence interval -0.76 to -0.26, nine trials, I(2)=77%) and waist circumference (by 0.3 cm, 95% confidence interval -0.58 to -0.02, 15,671 women, one trial). There was no suggestion of negative effects on other cardiovascular risk factors (lipid levels or blood pressure). GRADE assessment suggested high quality evidence for the relation between total fat intake and body weight in adults. Only one randomised controlled trial and three cohort studies were found in children and young people, but these confirmed a positive relation between total fat intake and weight gain.

CONCLUSIONS

There is high quality, consistent evidence that reduction of total fat intake has been achieved in large numbers of both healthy and at risk trial participants over many years. Lower total fat intake leads to small but statistically significant and clinically meaningful, sustained reductions in body weight in adults in studies with baseline fat intakes of 28-43% of energy intake and durations from six months to over eight years. Evidence supports a similar effect in children and young people.

Developing culturally congruent weight maintenance programs for African American church members

OBJECTIVES

Developing community-based and culturally congruent weight loss maintenance programs is an important component of weight reduction interventions in high-risk populations. This qualitative investigation was conducted to guide development of faith-based weight maintenance programs for African American church members.

DESIGN

Twenty African American church members who previously participated in a church-based group weight loss program were recruited to participate in focus groups. This qualitative inquiry focused on the role of faith in maintaining healthy lifestyle behaviors, such as healthy eating and regular physical activity. Within these groups, a nominal group process was used to identify activities and language to be included within a faith-based maintenance program.

RESULTS

Content analysis identified seven conceptual domains that participants thought were important aspects of a faith-based weight maintenance program: (1) accountability for change targets, (2) programmatic tools, (3) group benefits and support, (4) keys to successful behavior change, (5) keys to church and programmatic level success, (6) addressing barriers, and (7) faith. The faith sub-domains included faith in the Lord, using the body for God, and a spiritual focus. The nominal group process resulted in 11 recommended components for a faith-based weight maintenance program. The top four included scriptures and prayers are 'walk of faith,' healthy diet, exercise, and focusing on God.

CONCLUSIONS

The results suggest that integrating faith themes into a weight loss maintenance program may increase its long-term impact on participants' health behavior change.

Reduced or modified dietary fat for preventing cardiovascular disease

BACKGROUND

Reduction and modification of dietary fats have differing effects on cardiovascular risk factors (such as serum cholesterol), but their effects on important health outcomes are less clear.

OBJECTIVES

To assess the effect of reduction and/or modification of dietary fats on mortality, cardiovascular mortality, cardiovascular morbidity and individual outcomes including myocardial infarction, stroke and cancer diagnoses in randomised clinical trials of at least 6 months duration.

SEARCH METHODS

For this review update, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE, were searched through to June 2010. References of Included studies and reviews were also checked.

SELECTION CRITERIA

Trials fulfilled the following criteria: 1) randomised with appropriate control group, 2) intention to reduce or modify fat or cholesterol intake (excluding exclusively omega-3 fat interventions), 3) not multi factorial, 4) adult humans with or without cardiovascular disease, 5) intervention at least six months, 6) mortality or cardiovascular morbidity data available.

DATA COLLECTION AND ANALYSIS

Participant numbers experiencing health outcomes in each arm were extracted independently in duplicate and random effects meta-analyses, meta-regression, sub-grouping, sensitivity analyses and funnel plots were performed.

MAIN RESULTS

This updated review suggested that reducing saturated fat by reducing and/or modifying dietary fat reduced the risk of cardiovascular events by 14% (RR 0.86, 95% CI 0.77 to 0.96, 24 comparisons, 65,508 participants of whom 7% had a cardiovascular event, I(2) 50%). Subgrouping suggested that this reduction in cardiovascular events was seen in studies of fat modification (not reduction - which related directly to the degree of effect on serum total and LDL cholesterol and triglycerides), of at least two years duration and in studies of men (not of women). There were no clear effects of dietary fat changes on total mortality (RR 0.98, 95% CI 0.93 to 1.04, 71,790 participants) or cardiovascular mortality (RR 0.94, 95% CI 0.85 to 1.04, 65,978 participants). This did not alter with sub-grouping or sensitivity analysis.Few studies compared reduced with modified fat diets, so direct comparison was not possible.

AUTHORS' CONCLUSIONS

The findings are suggestive of a small but potentially important reduction in cardiovascular risk on modification of dietary fat, but not reduction of total fat, in longer trials. Lifestyle advice to all those at risk of cardiovascular disease and to lower risk population groups, should continue to include permanent reduction of dietary saturated fat and partial replacement by unsaturates. The ideal type of unsaturated fat is unclear.

Reduced or modified dietary fat for preventing cardiovascular disease

BACKGROUND

Reduction and modification of dietary fats have differing effects on cardiovascular risk factors (such as serum cholesterol), but their effects on important health outcomes are less clear.

OBJECTIVES

To assess the effect of reduction and/or modification of dietary fats on mortality, cardiovascular mortality, cardiovascular morbidity and individual outcomes including myocardial infarction, stroke and cancer diagnoses in randomised clinical trials of at least 6 months duration.

SEARCH STRATEGY

For this review update, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE, were searched through to June 2010. References of Included studies and reviews were also checked.

SELECTION CRITERIA

Trials fulfilled the following criteria: 1) randomised with appropriate control group, 2) intention to reduce or modify fat or cholesterol intake (excluding exclusively omega-3 fat interventions), 3) not multi factorial, 4) adult humans with or without cardiovascular disease, 5) intervention at least six months, 6) mortality or cardiovascular morbidity data available.

DATA COLLECTION AND ANALYSIS

Participant numbers experiencing health outcomes in each arm were extracted independently in duplicate and random effects meta-analyses, meta-regression, sub-grouping, sensitivity analyses and funnel plots were performed.

MAIN RESULTS

This updated review suggested that reducing saturated fat by reducing and/or modifying dietary fat reduced the risk of cardiovascular events by 14% (RR 0.86, 95% CI 0.77 to 0.96, 24 comparisons, 65,508 participants of whom 7% had a cardiovascular event, I(2) 50%). Subgrouping suggested that this reduction in cardiovascular events was seen in studies of fat modification (not reduction - which related directly to the degree of effect on serum total and LDL cholesterol and triglycerides), of at least two years duration and in studies of men (not of women). There were no clear effects of dietary fat changes on total mortality (RR 0.98, 95% CI 0.93 to 1.04, 71,790 participants) or cardiovascular mortality (RR 0.94, 95% CI 0.85 to 1.04, 65,978 participants). This did not alter with sub-grouping or sensitivity analysis.Few studies compared reduced with modified fat diets, so direct comparison was not possible.

AUTHORS' CONCLUSIONS

The findings are suggestive of a small but potentially important reduction in cardiovascular risk on modification of dietary fat, but not reduction of total fat, in longer trials. Lifestyle advice to all those at risk of cardiovascular disease and to lower risk population groups, should continue to include permanent reduction of dietary saturated fat and partial replacement by unsaturates. The ideal type of unsaturated fat is unclear.

Relation of omega-3 fatty acid and dietary fish intake with brachial artery flow-mediated vasodilation in the Multi-Ethnic Study of Atherosclerosis

BACKGROUND

The relation between dietary fish intake and brachial artery measures, including brachial artery flow-mediated dilation (FMD), has not been well established across sex and racial-ethnic groups.

OBJECTIVE

We hypothesized that consumption of nonfried fish and plasma phospholipid measures of long-chain omega-3 (n-3) fatty acids would be positively associated with larger FMD in men and women across racial-ethnic groups.

DESIGN

We investigated cross-sectional associations of brachial artery measures with fish intake (ascertained with a food-frequency questionnaire) and plasma phospholipid omega-3 concentrations in 3045 adults, aged 45-84 y, who were free of clinical cardiovascular disease.

RESULTS

In overall multivariate-adjusted analyses, there were no significant associations between fish intake or any brachial artery measures. However, when stratified by sex, there was an association between the highest quartile of nonfried fish consumption and a 0.10-mm lower (1 SD) brachial artery diameter in men (P = 0.01) and a 0.27% smaller FMD in women (P = 0.02) compared with the lowest quartile of nonfried fish intake in each respective sex strata. When stratified by race-ethnicity and race-ethnicity by sex, additional heterogeneity was noted, but results were difficult to interpret because of small sample sizes. Plasma phospholipid omega-3 concentrations showed a similar directionality of association with brachial artery measures observed for nonfried fish consumption, although statistical significance was not achieved in fully adjusted models.

CONCLUSION

This study indicates that the association between nonfried fish intake and baseline brachial artery size varies by sex, with suggestive evidence of sex differences in the association between nonfried fish intake and FMD.

Dietary total fat intake and ischemic stroke risk: the Northern Manhattan Study

BACKGROUND

Dietary fat intake is associated with coronary heart disease risk, but the relationship between fat intake and ischemic stroke risk remains unclear. We hypothesized that total dietary fat as part of a Western diet is associated with increased risk of ischemic stroke.

METHODS

As part of the prospective Northern Manhattan Study, 3,183 stroke-free community residents over 40 years of age underwent evaluation of their medical history and had their diet assessed by a food-frequency survey. Cox proportional hazard models calculated risk of incident ischemic stroke.

RESULTS

The mean age of participants was 69 years, 63% were women, 21% were white, 24% black and 52% Hispanic. During a mean of 5.5 years of follow-up, 142 ischemic strokes occurred. After adjusting for potential confounders, risk of ischemic stroke was higher in the upper quintile of total fat intake compared to the lowest quintile (HR 1.6, 95% CI 1.0-2.7). Total fat intake >65 g was associated with increased risk of ischemic stroke (HR 1.6, 95% CI 1.2-2.3). Risk was attenuated after controlling for caloric intake.

CONCLUSIONS

The results suggest that increased daily total fat intake, especially above 65 g, significantly increases risk of ischemic stroke.

Combined hyperlipidemia in relation to race/ethnicity, obesity, and insulin resistance in the Multi-Ethnic Study of Atherosclerosis

We have asked whether the prevalence of combined hyperlipidemia (CHL) differs by race/ethnicity, obesity, and insulin resistance in a contemporary, multiethnic, US cohort. We determined the prevalence and adjusted odds of CHL in a cohort of 5923 men and women free of clinically recognized cardiovascular disease and diabetes according to race/ethnicity (white, Chinese, African American, and Hispanic), obesity, and insulin resistance. Untreated lipid values were imputed for those on lipid-lowering therapy. Combined hyperlipidemia was defined using age- and sex-specific greater than or equal to 75th percentile cut points for low-density lipoprotein cholesterol and triglycerides obtained from a predominantly white North American population study. Compared with whites, adjusted odds ratios for CHL were 0.48 in African Americans (95% confidence interval [CI], 0.30-0.75), 1.33 in Hispanics (95% CI, 0.93-1.91), and 1.06 in Asians (95% CI, 0.62-1.82). Within the entire population, the adjusted odds of CHL were over 2-fold higher in overweight and obese participants compared with normal-weight participants and more than 4-fold higher in quartiles 2 through 4 of insulin resistance compared with quartile 1. African Americans had lower odds for CHL than whites despite higher body mass index and abdominal adiposity. Hispanics had a nonsignificantly higher trend, and Asians had no significantly different odds than whites. Modest increases in weight and insulin resistance were associated with significantly higher odds of CHL in a multiethnic US population. Further research is needed to determine the most efficacious diet, exercise, and drug management to decrease the risk of CHL and coronary heart disease among racial/ethnic groups in the United States.

Obesity-related changes in high-density lipoprotein metabolism

Obesity is associated with a 3-or-more-fold increase in the risk of fatal and nonfatal myocardial infarction (1,2,3,4,5,6). The American Heart Association has reclassified obesity as a major, modifiable risk factor for coronary heart disease (7). The increased prevalence of premature coronary heart disease in obesity is attributed to multiple factors (8,9,10). A principal contributor to this serious morbidity is the alterations in plasma lipid and lipoprotein levels. The dyslipidemia of obesity is commonly manifested as high plasma triglyceride levels, low high-density lipoprotein cholesterol (HDLc), and normal low-density lipoprotein cholesterol (LDLc) with preponderance of small dense LDL particles (7,8,9,10). However, there is a considerable heterogeneity of plasma lipid profile in overweight and obese people. The precise cause of this heterogeneity is not entirely clear but has been partly attributed to the degree of visceral adiposity and insulin resistance. The emergence of glucose intolerance or a genetic predisposition to familial combined hyperlipidemia will further modify the plasma lipid phenotype in obese people (11,12,13,14,15).

Particle size of LDL is affected by the National Cholesterol Education Program (NCEP) step II diet in dyslipidaemic adolescents

The objective was to determine the effects of the National Cholesterol Education Program (NCEP) step II diet on LDL and HDL particle size in dyslipidaemic adolescents. Forty-four dyslipidaemic adolescents, aged 10–18 years, participated in this case-control study. The control diet was a diet similar to what most Tehranian adolescents eat. NCEP step II diet was a diet with 30 % of energy as total fat, less than 7 % saturated fat, less than 200 mg cholesterol/d, less than 15 % of energy as MUFA and less than 10 % as PUFA. Lipoprotein particle size was the major outcome variable, which was measured after 3 months of intervention. Comparison was made by the repeated measurement ANOVA. The mean BMI was 26·3 (sd4·2) kg/m2. There were no significant changes in weight or physical activity in the two groups during the study. The NCEP diet resulted in higher reduction in total cholesterol ( − 13 (sd4)v.− 2 (sd0·3) mg/dl,P < 0·001) and LDL ( − 9 (sd2)v.3 (sd0·6) mg/dl,P < 0·01), and higher increase in size of the LDL (1·7 (sd0·4)v.0·1 (sd0·4) nanometer,P < 0·001). HDL particle size did not change significantly. NCEP step II diet had a favourable effect on the LDL particle size. The related mechanism needs to be studied in future experimental designs.

Sex differences in lipoprotein metabolism and dietary response: basis in hormonal differences and implications for cardiovascular disease

The transport of fat in the blood stream is approximately twice as fast in women as men. Disease states such as obesity and diabetes are associated with greater lipoprotein abnormalities in women compared with men. A greater increment in cardiovascular disease risk in women is linked to these abnormalities. A greater change in triglyceride level and a lesser change in low-density lipoprotein are observed in women than men with high-carbohydrate or high-fat feeding. Most consistent are greater changes in high-density lipoprotein (HDL), HDL(2), and apolipoprotein A-I levels in women compared with men with high-carbohydrate or high-fat feeding. Dietary fat restriction in women appears to have a less beneficial lipoprotein effect than in men. Dietary fat restriction for heart disease prevention may be less ideal in women than in men.

The effect of select nutrients on serum high-density lipoprotein cholesterol and apolipoprotein A-I levels

One of the factors contributing to the increased risk of developing premature atherosclerosis is low plasma concentrations of high-density lipoprotein (HDL) cholesterol (HDLc). Multiple potential mechanisms account for the cardioprotective effects of HDL and its main protein apolipoprotein A-I (apo A-I). The low plasma concentrations of HDL could be the result of increased fractional clearance and reduced expression of apo A-I. To this end, nutrients play an important role in modulating the fractional clearance rate, as well as the rate of apo A-I gene expression. Because medical nutrition therapy constitutes the cornerstone of management of dyslipidemias, it is essential to understand the mechanisms underlying the changes in HDL level in response to alterations in dietary intake. In this review, we will discuss the effect of select nutrients on serum HDLc and apo A-I levels. Specifically, we will review the literature on the effect of carbohydrates, fatty acids, and ketones, as well as some of the nutrient-related metabolites, such as glucosamine and the prostanoids, on apo A-I gene expression. Because there are multiple mechanisms involved in the regulation of serum HDLc levels, changes in gene transcription do not necessarily correlate with clinical observations on serum levels of HDLc.

Effects of dietary fats versus carbohydrates on coronary heart disease: A review of the evidence

Recommendations arising from the traditional diet-coronary heart disease (CHD) paradigm, which focuses on effects of total and saturated fat on serum total and low-density lipoprotein cholesterol, may have failed to reduce CHD risk and inadvertently exacerbated dyslipidemia, insulin resistance, and weight gain, particularly among individuals who are older, female, sedentary, or obese. A suitable dietary paradigm must consider types and qualities of fats and carbohydrates consumed, their effects on a range of intermediary risk factors, and characteristics that may modify individual susceptibility. Based on current evidence, replacement of total, unsaturated, and even possibly saturated fats with refined, high-glycemic index carbohydrates is unlikely to reduce CHD risk and may increase risk in persons predisposed to insulin resistance. In contrast, a diet that is 1) rich in whole grains and other minimally processed carbohydrates; 2) includes moderate amounts of fats (approximately 30%-40% of total energy), particularly unsaturated fats and omega-3 polyunsaturated fats from seafood and plant sources; 3) is lower in refined grains and carbohydrates; and 4) eliminates packaged foods, baked goods, and fast foods containing trans fatty acids, will likely reduce the risk of CHD.

Gender differences in lipoprotein metabolism and dietary response: Basis in hormonal differences and implications for cardiovascular disease

The transport of fat in the blood stream is approximately twice as fast in women as men. Disease states such as obesity and diabetes are associated with greater lipoprotein abnormalities in women compared with men. A greater increment in cardiovascular disease risk in women is linked to these abnormalities. A greater change in triglyceride level and a lesser change in low-density lipoprotein are observed in women than men with high-carbohydrate or high-fat feeding. Most consistent are greater changes in high-density lipoprotein (HDL), HDL2, and apolipoprotein A-I levels in women compared with men with high-carbohydrate or high-fat feeding. Dietary fat restriction in women appears to have a less beneficial lipoprotein effect than in men. Dietary fat restriction for heart disease prevention may be less ideal in women than in men.

Dietary fats, carbohydrate, and progression of coronary atherosclerosis in postmenopausal women

BACKGROUND

The influence of diet on atherosclerotic progression is not well established, particularly in postmenopausal women, in whom risk factors for progression may differ from those for men.

OBJECTIVE

The objective was to investigate associations between dietary macronutrients and progression of coronary atherosclerosis among postmenopausal women.

DESIGN

Quantitative coronary angiography was performed at baseline and after a mean follow-up of 3.1 y in 2243 coronary segments in 235 postmenopausal women with established coronary heart disease. Usual dietary intake was assessed at baseline.

RESULTS

The mean (+/-SD) total fat intake was 25 +/- 6% of energy. In multivariate analyses, a higher saturated fat intake was associated with a smaller decline in mean minimal coronary diameter (P = 0.001) and less progression of coronary stenosis (P = 0.002) during follow-up. Compared with a 0.22-mm decline in the lowest quartile of intake, there was a 0.10-mm decline in the second quartile (P = 0.002), a 0.07-mm decline in the third quartile (P = 0.002), and no decline in the fourth quartile (P < 0.001); P for trend = 0.001. This inverse association was more pronounced among women with lower monounsaturated fat (P for interaction = 0.04) and higher carbohydrate (P for interaction = 0.004) intakes and possibly lower total fat intake (P for interaction = 0.09). Carbohydrate intake was positively associated with atherosclerotic progression (P = 0.001), particularly when the glycemic index was high. Polyunsaturated fat intake was positively associated with progression when replacing other fats (P = 0.04) but not when replacing carbohydrate or protein. Monounsaturated and total fat intakes were not associated with progression.

CONCLUSIONS

In postmenopausal women with relatively low total fat intake, a greater saturated fat intake is associated with less progression of coronary atherosclerosis, whereas carbohydrate intake is associated with a greater progression.

Men and Women Differ in Lipoprotein Response to Dietary Saturated Fat and Cholesterol Restriction

A diet restricted in saturated fat and cholesterol is recommended for subjects with elevated LDL cholesterol concentrations before and during drug therapy. Gender differences in lipoprotein subspecies response to such diets have not been studied in detail. We examined the effects of a diet low in total fat, saturated fat and cholesterol (Therapeutic Lifestyle Changes, TLC, diet: 26% of energy as fat, 4% as saturated fat, and 45 mg cholesterol/4.2 MJ), compared with an average American diet (AAD: 35% of energy as fat, 14% as saturated fat, and 147 mg cholesterol/4.2 MJ), on plasma lipoprotein subspecies in men and women. Each diet period lasted 6 wk. Body weight was kept constant during each diet period. Men (n = 19) and postmenopausal women (n = 14) >40 y old with moderate hypercholesterolemia participated in this study. Plasma lipoprotein concentrations were assessed by standardized methodology, and lipoprotein sizes were determined by gradient gel electrophoresis and NMR spectroscopy. The TLC diet resulted in greater reductions in total cholesterol and plasma apolipoprotein B concentrations in men than in women (-19% vs. -12%, P < 0.05, and -18% vs. -9%, P < 0.05, respectively). Postprandial triacylglycerol and LpAI:AII concentrations were reduced in men, but not in women (-15% vs. 8%, P < 0.05, and -9% vs. -2%, respectively, P < 0.05). Similar decreases in LpAI concentrations and LDL and HDL particle size were observed in men and women. These data are consistent with the concept that middle aged/elderly men may have a more favorable lipoprotein response to a low fat, low cholesterol diet than postmenopausal women.

Effects of a low-carbohydrate diet on weight loss and cardiovascular risk factor in overweight adolescents

OBJECTIVES

To compare the effects of a low-carbohydrate (LC) diet with those of a low-fat (LF) diet on weight loss and serum lipids in overweight adolescents.

DESIGN

A randomized, controlled 12-week trial.

SETTING

Atherosclerosis prevention referral center.

METHODS

Random, nonblinded assignment of participants referred for weight management. The study group (LC) (n = 16) was instructed to consume <20 g of carbohydrate per day for 2 weeks, then <40 g/day for 10 weeks, and to eat LC foods according to hunger. The control group (LF) (n = 14) was instructed to consume <30% of energy from fat. Diet composition and weight were monitored and recorded every 2 weeks. Serum lipid profiles were obtained at the start of the study and after 12 weeks.

RESULTS

The LC group lost more weight (mean, 9.9 +/- 9.3 kg vs 4.1 +/- 4.9 kg, P <.05) and had improvement in non-HDL cholesterol levels (P <.05). There was improvement in LDL cholesterol levels (P <.05) in the LF group but not in the LC group. There were no adverse effects on the lipid profiles of participants in either group.

CONCLUSIONS

The LC diet appears to be an effective method for short-term weight loss in overweight adolescents and does not harm the lipid profile.

Dietary intake and changes in lipoprotein lipids in obese, postmenopausal women placed on an American Heart Association Step 1 diet

BACKGROUND

Dietary intake and changes in lipoprotein lipids in obese, postmenopausal women placed on an American Heart Association Step 1 diet.

OBJECTIVE

The purpose of this study was to determine the specific dietary factors associated with the commonly observed decrease in HDL-C concentration in obese, postmenopausal women placed on a low-fat diet. DESIGN/SUBJECTS/INTERVENTION: Dietary intake, lipoprotein lipid concentrations, and body weight were measured before and after 10 weeks of instruction in the principles of the American Heart Association (AHA) Step 1 diet in 55 overweight and obese (body mass index=33+/-4 kg/m2), sedentary, postmenopausal women (mean age 59+/-5 years).

RESULTS

The percent of energy obtained from total fat, monounsaturated, polyunsaturated, saturated fat, and dietary cholesterol decreased significantly after dietary intervention, while the polyunsaturated:saturated ratio and the percent of energy obtained from total carbohydrate, complex carbohydrate, and simple carbohydrate increased. On average, the women lost a small, but significant, amount of body weight (2%+/-3%, P<.0001). Adherence to the AHA diet reduced total cholesterol (-8%+/-8%), LDL-C (-6%+/-11%), and HDL-C (-16%+/-10%). The only dietary change that predicted decreases in HDL-C concentrations was the increase in the percent of energy from simple sugar (r=-0.32, P<.05). There were no relationships between changes in HDL-C and changes in percent of energy from fat (r=0.16), saturated fat (r=0.07), polyunsaturated fat (r=0.04), or monounsaturated fat (r=0.09).

APPLICATIONS/CONCLUSIONS

In postmenopausal women, a dietary reduction in total fat, saturated fat, and cholesterol reduces body weight, total cholesterol, and LDL-C, but substitution of simple sugar for dietary fat may lead to a reduction in HDL-C. Further research is needed to determine which specific simple sugars are contributing to diet-induced reductions in HDL-C in older women placed on a low-fat diet.

Lifestyle and health status in long-term cardiac transplant recipients

OBJECTIVE

The purpose of this pilot study was to describe the lifestyle and health status of long-term cardiac transplant recipients.

DESIGN AND SETTING

The study was a descriptive correlational design at a health sciences center.

MEASURES

We measured lifestyle, using the Health-Promoting Lifestyle Profile-II, and indicators of health status (eg, number of medications, infections, and rejections; systolic and diastolic blood pressure; lipid profile; and percent ideal body weight) in 47 patients after an annual evaluation or follow-up visit after patients received cardiac transplantation.

RESULTS

Patients were primarily male, white, 56.5 years old and 75.6 months after transplant. Spiritual growth was the most frequently reported lifestyle characteristic (mean, 27.4; SD, 4.9). The least frequently reported lifestyle characteristic was engagement in physical activity (mean, 18.4; SD, 5.7). Factorial between-subjects analysis of variance demonstrated that women had a higher high-density lipoprotein level (P =.0001) and reported healthier dietary habits (P =.02) and greater spiritual growth (P =.006) than men. African Americans reported poorer stress management behaviors (P =.04). Recipients whose heart failure was due to ischemic cardiomyopathy had a lower percent ideal body weight than those with a nonischemic cause (P =.01). Recipients with cardiac allograft vasculopathy had a higher low-density lipoprotein cholesterol level (P =.05) and lower high-density lipoprotein cholesterol level (P =.05) than those without cardiac allograft vasculopathy, and those persons who required maintenance corticosteroid therapy reported poorer interpersonal relationships than those persons not receiving corticosteroids (P =.04).

CONCLUSION

Cardiac transplant recipients did not consistently include health-promoting behaviors in their lifestyles although some of the behaviors were associated with a better health status. Future research should be aimed at identifying factors that affect the ability to make and sustain changes in lifestyle and improve health status.

Flow-mediated vasodilation is not impaired when HDL-cholesterol is lowered by substituting carbohydrates for monounsaturated fat

Low-fat diets, in which carbohydrates replace some of the fat, decrease serum cholesterol. This decrease is due to decreases in LDL-cholesterol but in part to possibly harmful decreases in HDL-cholesterol. High-oil diets, in which oils rich in monounsaturated fat replace some of the saturated fat, decrease serum cholesterol mainly through LDL-cholesterol. We used these two diets to investigate whether a change in HDL-cholesterol would change flow-mediated vasodilation, a marker of endothelial function. We fed thirty-two healthy volunteers two controlled diets in a weeks' randomised cross-over design to eliminate variation in changes due to differences between subjects. The low-fat diet contained 59.7 % energy (en%) as carbohydrates and 25.7 en% as fat (7.8 en% as monounsaturates); the oil-rich diet contained 37.8 en% as carbohydrates and 44.4 en% as fat (19.3 en% as monounsaturates). Average (sd) serum HDL-cholesterol after the low-fat diet was 0.21 (sd 0.12) mmol/l (8.1 mg/dl) lower than after the oil-rich diet. Serum triacylglycerols were 0.22 (sd 0.28) mmol/l (19.5 mg/dl) higher after the low-fat diet than after the oil-rich diet. Serum LDL and homocysteine concentrations remained stable. Flow-mediated vasodilation was 4.8 (SD 2.9) after the low-fat diet and 4.1 (SD 2.7) after the oil-rich diet (difference 0.7 %; 95 % CI -0.6, 1.9). Thus, although the low-fat diet produced a lower HDL-cholesterol than the high-oil diet, flow-mediated vasodilation, an early marker of cardiovascular disease, was not impaired.

Prevention of coronary heart disease by raising high-density lipoprotein cholesterol?

Consistent with several potentially anti-atherogenic activities of high-density lipoproteins in vitro, low plasma levels of high-density lipoprotein cholesterol are associated with an increased risk of coronary heart disease. In addition to genes, lifestyle factors (e.g. smoking, being overweight and physical inactivity) strongly affect plasma high-density lipoprotein cholesterol levels. Moreover, a low level of high-density lipoprotein cholesterol interacts with other risk factors. Raising of high-density lipoprotein cholesterol by either adjustments of lifestyle or drug intervention as well as elimination of additional risk factors are thus thought to affect coronary risk. Here, we summarize the outcomes of observational and interventional studies as well as genetic and experimental research which have recently much advanced our understanding of the function and regulation of high-density lipoprotein metabolism. We conclude from the data that changes in the kinetics and functionality of high-density lipoprotein rather than changes in plasma high-density lipoprotein cholesterol levels per se will affect the anti-atherogenicity of therapeutic interference with high-density lipoprotein metabolism.

One-year effects of increasingly fat-restricted, carbohydrate-enriched diets on lipoprotein levels in free-living subjects

Restriction of all dietary fat is a popular strategy for restricting saturated fat intake to lower LDL cholesterol. Some authorities advise the restriction of fat intake to the extreme of less than 10% of daily energy on the assumption that more fat restriction is better. The two studies described herein address questions relating to whether increasing fat restriction produces proportionally increasing benefit on cardiovascular risk factors in hyperlipidemic subjects. The first study is the Dietary Alternatives Study (DAS). The DAS was conducted in 531 male Boeing employees over a 2-year period. Subjects were defined as hypercholesterolemic (HC) or combined hyperlipidemic (CHL) based on age-specific 75th percentiles for plasma LDL-C and triglyceride levels. Hypothesis test analyses were performed at 1 year. HC subjects were randomized to diets taught to attain fat intakes of 30, 26, 22, and 18% (Diets levels 1-4, respectively). CHL subjects (slightly fewer in number) were randomized to Diets 1-3. After 1 year, subjects' total fat intakes were 27, 26, 25, and 22% of energy (en%), resulting in saturated fat intakes of 8, 7, 7, and 6%, respectively. In HC subjects the greatest LDL-C decrease was with Diet 2 (mean of 13.4%) and in CHL subjects with Diet 1 (7.0%). Surprisingly, plasma triglyceride concentrations rose in HC subjects 20% and 40% above baseline on Diets 3 and 4, respectively, with reciprocal reductions in HDL cholesterol of 2.5% and 3%, respectively. Furthermore, apo B reductions were attenuated below Diet 2 in HC subjects and Diet 1 in CHL subjects, and no further reductions were seen in plasma glucose and insulin concentrations, blood pressure, or body weight. Measurements of plasma total fatty acid composition showed a slight increase in plasma palmitate, whereas stearate decreased slightly, supporting the idea that de novo synthesis of palmitic acid was increased in the chronic high-carbohydrate feeding condition. The second study asked if the most effective diet in HC subjects, Diet 2, has an equivalent effect in women and men. To answer this question, men and women Boeing employees were taught the closely similar National Cholesterol Education Program (NCEP) Step II diet. After 6 and 12 months, equivalent reductions in LDL cholesterol were observed in women compared with men. HDL cholesterol levels in men were unchanged from baseline at 6 and 12 months, but were reduced 8% in HC women, with accompanying decreases of 18% in HDL2-cholesterol and 5% in apoprotein A-I (all P < 0.01). These data indicate that intakes of fat below about 25 en% and carbohydrate intake above approximately 60 en% yield no further LDL-C lowering in HC and CHL male subjects and can be counterproductive to triglyceride, HDL-C, and apo B levels. This lack of benefit appears to be explained by an enhanced endogenous synthesis of palmitic acid, which negates the benefit of further saturated fat restriction. The HDL-C decrease in HC women may have a similar cause and points to an underlying male-female difference. Alternative dietary approaches to limit saturated fat intake deserve intensive study.