Magnitude of dietary effects on plasma cholesterol concentration: role of sex and apolipoprotein E phenotype

Saturated fat intake and alcohol consumption modulate the association between the APOE polymorphism and risk of future coronary heart disease: a nested case-control study in the Spanish EPIC cohort

The association is still not clear between the common APOE polymorphism and coronary heart disease (CHD) risk, nor its modulation by diet. Thus, our aim was to study the association between the APOE genotypes and incident CHD and how dietary fat and alcohol consumption modify these effects. We performed a nested case-control study in the Spanish European Prospective Investigation into Cancer and Nutrition cohort. Healthy men and women (41,440, 30-69 years) were followed up over a 10-year period, with the incident CHD cases being identified. We analyzed 534 incident CHD cases and 1123 controls. APOE, dietary intake and plasma lipids were determined at baseline. The APOE polymorphism was significantly associated with low-density lipoprotein cholesterol (LDL-C), and gene-alcohol interactions in determining LDL-C were detected. In the whole population, the E2 allele was significantly associated with a lower CHD risk than E3/E3 subjects [odds ratio (OR), 0.58; 95% confidence interval (CI), 0.38-0.89]. The E4 allele did not reach statistical significance vs. E3/E3 (OR, 1.17; 95% CI, 0.88-1.58). However, saturated fat intake modified the effect of the APOE polymorphism in determining CHD risk. When saturated fat intake was low (<10% of energy), no statistically significant association between the APOE polymorphism and CHD risk was observed (P=.682). However, with higher intake (≥10%), the polymorphism was significant (P=.005), and the differences between E2 and E4 carriers were magnified (OR for E4 vs. E2, 3.33; 95% CI, 1.61-6.90). Alcohol consumption also modified the effect of the APOE on CHD risk. In conclusion, in this Mediterranean population, the E2 allele is associated with lower CHD risk, and this association is modulated by saturated fat and alcohol consumption.

A 12-week worksite health promotion program reduces cardiovascular risk factors in male workers with the apolipoprotein E2 and apolipoprotein E3 genotypes, but not in apolipoprotein E4 genotype

Worksite health promotion programs focusing on diet and lifestyle modification have been shown to improve health outcomes in workers. The purpose of this study was to investigate whether a 12-week worksite health promotion program shows different response of cardiovascular risk factors in subjects according to apolipoprotein E (Apo E) genotype and obesity level in 141 male Korean industrial workers. We hypothesized that the health changes of a 12-week intervention may not be the same within Apo E genotypes in nonobese and obese subjects. They received 5 face-to-face meetings based on their health profiles. In obese group carrying Apo E3 genotype, body mass index, body fat (%), waist circumference, waist-hip ratio, and systolic blood pressure were decreased, as well as intakes of energy (P = .000) and carbohydrate (P = .005). High-density lipoprotein cholesterol (P = .004) level was improved in individuals with the Apo E2 genotype. These beneficial effects were only observed in individuals with the Apo E2 or Apo E3 genotype. Multiple linear regression revealed that obesity was strongly correlated with waist circumference (P = .002), plasma total cholesterol (P = .037), and changes in dietary cholesterol intake (P = .011) in individuals with the Apo E3 genotype, whereas only changes in dietary fat intake (P = .044) was correlated in those with the Apo E4 genotype. Overall, the results of this study suggest that a health promotion program can be a useful method of improving cardiovascular risk factors and dietary intake in industrial workers with certain genotypes only. Therefore, further research is needed to develop a tailored, long-term worksite health promotion program based on genetic background.

Serum concentration of 27-hydroxycholesterol predicts the effects of high-cholesterol diet on plasma LDL cholesterol level

AIM

The effect of dietary cholesterol on plasma cholesterol concentrations varies widely among individuals. Recent studies suggest that the synthesis of oxysterols is up-regulated when tissue cholesterol is saturated. The present study was undertaken to test the hypothesis that a serum high concentration of 27-hydroxycholesterol, one of the oxysterols, reflects positive cholesterol balance in the body and predicts intolerance to a high-cholesterol diet.

METHODS

In 30 subjects, 750 mg/day of cholesterol was added for 4 weeks to the ordinary diet. Blood samples were collected at the start and finish of the supplementation. Serum sterol and oxysterol concentrations were measured by high-resolution GC-MS.

RESULTS

A receiver operating characteristic curve was drawn and the cutoff point (80 ng/mg cholesterol) was chosen to maximize sensitivity (81.3%) and specificity (64.3%) for predicting a positive change of LDL cholesterol concentration after cholesterol loading. Subjects with higher serum 27-hydroxycholesterol concentrations (>/= 80 ng/mg cholesterol) showed significantly (P < 0.05) high values for the change of LDL cholesterol concentration (+7.4 +/- 3.4%, mean +/- SEM, n = 17) compared with those with lower 27-hydroxycholesterol levels (-5.3 +/- 2.7%, n = 13).

CONCLUSIONS

In subjects with high serum 27-hydroxycholesterol concentrations were unable to adapt to a high-cholesterol diet. The concentration of serum 27-hydroxycholesterol appears to reflect cholesterol saturation in the body and predicts to some extent a responsiveness to dietary cholesterol.

Estimation of VLDL, IDL, LDL, HDL2, apoA-I, and apoB from the Friedewald inputs--apoB and IDL, but not LDL, are associated with mortality in type 1 diabetes

BACKGROUND

There is an unmet need for a straightforward and cost-effective assessment of multiple lipoprotein risk factors for vascular diseases.

AIMS

1) To study the relation of various lipoprotein lipid and apolipoprotein (apo) measures on the Friedewald inputs, i.e. plasma triglycerides (TG), cholesterol (TC), and high-density lipoprotein cholesterol (HDL-C). 2) To build up regression models for the appropriate measures based solely on the Friedewald inputs.

METHODS

Data were available for 1,775 plasma samples, from which very-low-density lipoprotein (VLDL), intermediate-density lipoprotein (IDL), low-density lipoprotein (LDL), and HDL were also isolated by ultracentrifugation. For HDL(2)-C and apolipoproteins, 343 and 247 samples were available, respectively.

RESULTS

Accurate models were obtained for VLDL-TG (cross-validation r=0.98), LDL-C (r=0.91), HDL(2)-C (r=0.92), apoA-I (r=0.92), and apoB (r=0.95). A semi-quantitative model was obtained for IDL-C (r=0.78). Due to the anticipated role of IDL-C in atherosclerosis, it was still kept within the accepted models and pursued further. The associations of the estimates with premature deaths were studied in 4,084 patients with type 1 diabetes. The associations of IDL-C and LDL-C were markedly different, the best predictors of mortality being apoB, apoB to apoA-I ratio, and IDL-C.

CONCLUSIONS

The new models allow identification of clinically relevant lipoprotein profiles with no added cost to the conventional Friedewald formula.

Apolipoprotein E polymorphisms in Mexican patients with coronary artery disease

BACKGROUND

Apolipoprotein E polymorphisms have important effects on plasma lipid levels and in the genetic susceptibility to development of cardiovascular diseases. Thus, the purpose of this study was to investigate the association of apolipoprotein E polymorphisms with coronary artery disease and with plasma lipid levels in a group of Mexican Mestizo patients.

METHODS

Apolipoprotein E polymorphisms were determined in 156 Mexican patients with coronary artery disease and 200 non-related healthy controls using the restriction fragment length polymorphism technique. The correlation of these polymorphisms with lipid profile (total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol and triglycerides) in the patient group was determined.

RESULTS

A similar distribution of allele and genotype frequencies in coronary artery disease patients and healthy controls was found. Higher serum levels of high-density lipoprotein cholesterol and lower levels of low-density lipoprotein cholesterol, triglycerides and glucose were found in patients with the APOE*2/3 genotype when compared to patients with the APOE*3/4 and APOE*3/3 genotypes, although these differences were not significant.

CONCLUSIONS

Our data suggest that genetic variation at the APOE is not a genetic factor related to the genetic susceptibility to coronary artery disease in Mexican individuals, but the role of this polymorphism in determining the lipid profile cannot be excluded.

Gene–nutrient interactions: dietary behaviour associated with high coronary heart disease risk particularly affects serum LDL cholesterol in apolipoprotein E ε4-carrying free-living individuals

Apolipoprotein E (ApoE) genotype influence on the relationship between dietary risk factors for cardiovascular disease and blood serum lipid levels was investigated in 132 free-living individuals participating in the European Prospective Investigation of Cancer (EPIC) study. All subjects (age 40–69) were clinically healthy and provided information on their usual diet. ApoE genotype and serum lipid concentrations were determined in all subjects. Relationships of intake of dietary constituents with serum lipid levels were compared in different genotype groups. There was a significant correlation between total serum cholesterol and intake of energy derived from total fat (r 0·195; P 0·025) and saturated fat (r 0·174; P 0·046) in the cohort as a whole. However, individuals with the ApoE ε3/ε4 genotype displayed a much stronger positive correlation between LDL cholesterol level and the percentage of energy derived from intake of saturated fat (r 0·436; P 0·043). There were no significant associations in the groups with ε3/ε3 or ε2/ε2 & ε2/ε3 genotype. A significant positive correlation between alcohol consumption and HDL cholesterol level was present in individuals bearing ApoE ε2 allele. These findings support current public health recommendations that saturated fat consumption should be reduced in order to reduce coronary heart disease risk. Total cholesterol concentrations were positively related to saturated fat intake in the cohort as a whole, but elevated LDL cholesterol levels associated with high saturated fat intake can be expected particularly in those individuals who combine a ‘risky’ dietary behaviour with the presence of the ε4 variant of ApoE.

Endothelial Function in Healthy 11-Year-Old Children After Dietary Intervention With Onset in Infancy

Background— Early childhood introduction of nutritional habits aimed at atherosclerosis prevention reduces children’s serum total cholesterol concentration, but its effect on vascular endothelial function is unknown.

Methods and Results— Between 1990 and 1992, we randomized healthy 7-month-old infants (n=1062) to intervention (low-saturated-fat diet) and control (unrestricted diet) groups. At the age of 11 years, endothelium-dependent (flow-mediated) and endothelium-independent (nitrate-mediated) vasodilatory responses of the brachial artery were measured with high-resolution ultrasound in 179 intervention and 190 control children. The effect of intervention on endothelial function was significant in boys ( P =0.0034) but not in girls ( P =0.69). The maximum endothelium-dependent dilation response (mean±SD) was 9.62±3.53% and 8.36±3.85% in intervention boys and control boys and 8.84±4.00% and 8.44±3.60% in intervention girls and control girls, respectively. Intervention had no effect on nitrate-mediated dilation. The difference in endothelial function in boys remained significant after adjustment for current serum total or LDL cholesterol but became nonsignificant after adjustment for mean cholesterol measured under 3 years of age (adjusted means: 9.46% [CI 8.68% to 10.24%] versus 8.54% [CI 7.75% to 9.32%], P =0.11).

Conclusions— A low-saturated-fat diet introduced in infancy and maintained during the first decade of life is associated with enhanced endothelial function in boys. The effect is explained in part by the diet-induced reduction in serum cholesterol concentration.

Genetic analysis of diet-induced hypercholesterolemia in exogenously hypercholesterolemic rats

The exogenously hypercholesterolemic (ExHC) rat is an established strain that exhibits a polygenic syndrome of hypercholesterolemia after feeding on a cholesterol-containing diet, and the extent of this differs between male and female rats in the strain. The present study was performed to determine the genetic background of diet-induced hypercholesterolemia in ExHC rats. We used quantitative trait locus (QTL) analyses of the F2 progeny derived from ExHC and Brown-Norway rats. Rats were fed a diet containing 1% cholesterol, and a genome-wide scan was then performed. Significant QTLs for serum total cholesterol levels were revealed on chromosomes 5 and 14 in the vicinity of markers D5Rat95 and D14Rat43, having maximum logarithm of the odds scores of 6.0 and 5.8, respectively. A suggestive QTL for the trait was also detected on chromosome 3 at D3Rat140. In particular, the QTL on chromosome 5 was specific for female rats. These loci were novel QTLs for post-dietary serum total cholesterol levels. In addition, cross-mating analysis in F1 generations suggested that the responsiveness to dietary cholesterol in ExHC rats is partly attributable to X-linked inheritance. Identifying such genetic factors may be useful in predicting the risks associated with diet-induced hypercholesterolemia in humans.

Dietary intake and gene variation influence the response of plasma lipids to dietary intervention

We have examined whether variation at the apolipoprotein (apo) B, apo E, apo AII, and apo AI-CIII-AIV genes affected the relationship between dietary intake and serum lipid traits in individuals who had participated in dietary intervention from a basal high fat diet to a low fat diet followed by a return to their natural diet, the switchback. On both the basal and switchback diets where the variance of dietary intake was great, there was a significant correlation between P/S ratio and serum total, low-density lipoprotein (LDL) cholesterol, and apo AI levels. In addition dietary cholesterol (dchol) levels correlated significantly with serum apo AI levels on the basal diet. Comparing the difference between basal and intervention (delta 1) and between switchback and intervention diets (delta 2), changes in dchol and P/S ratio correlated significantly with changes in serum total, high-density lipoprotein (HDL) and LDL cholesterol, and apo B levels. There was a significant correlation between monounsaturated fatty acid (MUFA) and apo AI levels during both changes. Furthermore we have examined whether the relationship between variables was homogeneous among genotypes of candidate gene polymorphisms. A heterogeneous effect (P less than 0.01) was seen among genotypes of the PvuII-AIV restriction fragment length polymorphism (RFLP) on the correlation of serum LDL cholesterol levels and dietary MUFA during both dietary changes (delta 1 and delta 2). A heterogeneous effect among genotypes of the apo B XbaI RFLP on the correlation between dchol versus total and LDL cholesterol during the change delta 1, but not delta 2, was observed. Thus our results show that both dietary components and genetic variation affect the response of serum lipid, lipoprotein, and apolipoprotein levels to dietary change.

Diet, genes and disease: implications for nutrition policy

There is extensive evidence to show that there is considerable variation in diet and disease patterns in Europe and that many of the dietary patterns are predictive of chronic disease. Increasingly, there is evidence that this dietary effect is mediated by genetic background. The present paper examines the role of polymorphisms within three genes, those responsible for the synthesis of apoE, 5,10-methylenetetrahydrofolate reductase (MTHFR) and PPARgamma. There is clear evidence to support the concept that the diet-disease link is moderated by genetic variation. The paper then considers whether this moderating effect will have implications for dietary recommendations. In the formulation of dietary reference values it has long been recognized that these values cannot cover the needs of all individuals. By setting the upper level at the mean value +2 sd, the needs of 97.5% of the population are covered. Setting a hypothetical scenario of a nutrient requirement of 200 mg/d and a polymorphism with an allelic frequency in the general population in the range of 0, 10, 20 and 30% that causes an increased nutrient requirement of 25%, there was no evidence that the traditional approach requires revision. Whilst it is recognized that genetic variability may not influence population goals, genetic variability will have to be taken into account in the clinical nutrition management of disease. To knowingly assign a patient to life-long treatment with a diet that for genetic reasons will have no success is both unethical and uneconomical. Once accepted in clinical nutrition, the diet-gene interaction will filter into the prevention of disease in public health nutrition.

Double-blind, randomized feedback control fails to improve the hypocholesterolemic effect of a plant-based low-fat diet in patients with moderately elevated total cholesterol levels

OBJECTIVE

To determine whether the cholesterol-lowering effect of a plant-based low-fat diet can be improved by a flexible control design that controls the extent of fat reduction based on the individual response of blood cholesterol.

DESIGN

Randomized, double-blind intervention study.

SETTING

A hotel in Prerow, Germany.

SUBJECTS

A total of 32 participants (21 female and 11 male participants) with total cholesterol level > 5.7 mmol/l.

INTERVENTION

The control group consumed a plant-based low-fat diet with constantly 20% of energy as fat; the intervention group received a diet with either 20 or 15% of energy as fat, depending on the serum cholesterol response of the preceding week. A flexible control design based on the individual cholesterol response during a run-in period of 1 week was used within a low-fat intervention.

RESULTS

During the run-in period, the consumption of a plant-based low-fat diet led to a reduction in total cholesterol by 18+/-6 mmol/l (P < 0.001), in LDL cholesterol by 19+/-9 mmol/l (P < 0.001) and triglycerides by 13+/-3 mmol/l (P < 0.001). During the feedback control period, an additional reduction in total cholesterol by 13+/-8 (P < 0.001) and in LDL cholesterol by 17+/-11 (P < 0.001) was observed compared to 15+/-15 and 7+/-18 in the control group. The effect of an additional feedback control was only marginal and not statistically significant compared to the effect of the low-fat diet alone.

CONCLUSIONS

On a level of fat intake already reduced to 20% of energy, the use of a feedback control to adapt the fat content of the diet depending on the individual serum cholesterol response was not more effective in reducing blood cholesterol levels than a plant-based low-fat diet alone.

A biochanin-enriched isoflavone from red clover lowers LDL cholesterol in men

OBJECTIVE

To determine whether the two major isoflavones in red clover differ in their effect on low-density lipoprotein cholesterol (LDL-C).

DESIGN

A randomised, placebo-controlled, double-blind trial; two parallel groups taking one of the two isoflavones within which treatment and placebo were administered in a crossover design.

SETTING

Free-living volunteers.

SUBJECTS

A total of 46 middle-aged men and 34 postmenopausal women.

INTERVENTION

Two mixtures of red clover isoflavones enriched in either biochanin (n=40) or formononetin (n=40) were compared. Placebo and active treatment (40 mg/day) were administered for 6 weeks each in a crossover design within the two parallel groups.

MAIN OUTCOME MEASURES

Plasma lipids were measured twice at the end of each period.

RESULTS

Baseline LDL-C concentrations did not differ significantly between men (n=46) and women (n=34), nor between those randomised to biochanin or formononetin. Interaction between time and treatments, biochanin, formononetin and corresponding placebos (two-way ANOVA) on LDL-C showed a significant effect of biochanin treatment alone. The biochanin effect was confined to men; median LDL-C was 3.61 (3.05-4.14) mmol/l with biochanin and 3.99 (3.16-4.29) mmol/l with the corresponding placebo (RM ANOVA with Dunnett's adjustment P<0.05). The difference between placebo and biochanin effects on LDL-C was 9.5%. No other lipid was affected and women failed to respond significantly to treatment.

CONCLUSION

Isolated isoflavones from red clover enriched in biochanin (genistein precursor) but not in formononetin (daidzein precursor), lowered LDL-C in men. This may partly explain the previous failure to demonstrate cholesterol-lowering effects with mixed isoflavones studied predominantly in women.

SPONSORSHIP

Novogen Ltd, North Ryde NSW, Australia, provided partial support including provision of tablets and outside monitoring.

Influences of apolipoprotein E polymorphism on the response of plasma lipids to the ad libitum consumption of a high-carbohydrate diet compared with a high-monounsaturated fatty acid diet

The purpose of this study was to assess the contribution of the apolipoprotein E (apoE) polymorphism and factors, such as age and waist circumference, to variations in plasma low-density lipoprotein-cholesterol (LDL-C) response following ad libitum consumption of a diet rich in complex carbohydrates (high-CHO: 58% of energy as CHO) versus a diet rich in fat and monounsaturated fatty acids (high-MUFA: fat, 40% of energy and 22% as MUFA). Sixty-five men participated in this parallel 6- to 7-week study involving either a high-CHO or a high-MUFA diet. Fasting plasma lipid profile and anthropometry were determined at the beginning and at the end of the dietary period. The high-CHO and high-MUFA diets both induced significant (P<.01) and comparable reductions in body weight and waist circumference. These changes were associated with a significant (P<.01) and comparable decrease in LDL-C (-19% and -16%, respectively). Stepwise multiple regression analyses showed that 32% of the variation in the LDL-C response to the high-CHO diet was attributable to the apoE polymorphism (18.5%, P=.04) and waist circumference (13.5%, P=.03) indicating that men with a waist circumference greater than 100 cm and the E2 allele had the greatest reduction in plasma LDL-C after the high-CHO diet. On the other hand, in the high-MUFA group, waist circumference was the only significant contributing factor to the LDL-C response and accounted for 44.5% of its variance. In conclusion, the plasma LDL-C response to ad libitum comsumption of a high-CHO and a high-MUFA diets are not modulated to the same extent by the apoE polymorphism and waist circumference.

Genetic variation and the lipid response to dietary intervention: a systematic review

There is wide interindividual variation in the lipid and lipoprotein responses to dietary change, and the existence of consistent hypo- and hyperresponders supports the hypothesis that responsiveness is related to genetic variation. Many studies have investigated the possibility that the heterogeneity in responsiveness to changes in dietary fat, cholesterol, and fiber intake is explained by variation in genes whose products affect lipoprotein metabolism, eg, apolipoproteins, enzymes, and receptors. A systematic review of the literature was carried out to investigate the effect of genetic variation on the lipid response to dietary intervention. A search strategy for the MEDLINE database retrieved 2540 articles from 1966 to February 2002. This strategy was adapted and performed on the EMBASE database, which retrieved 2473 articles from 1980 to week 9, 2002. Reference lists from relevant journal articles were also checked. This is the first systematic review of the literature, and it summarizes results available from 74 relevant articles. There is evidence to suggest that variation in the genes for apolipoprotein (apo) A-I, apo A-IV, apo B, and apo E contributes to the heterogeneity in the lipid response to dietary intervention. However, the effects of genetic variation are not consistently seen and are sometimes conflicting. Future studies need to have much larger sample sizes based on power calculations and carefully controlled dietary interventions and should investigate the effects of polymorphisms in multiple genes instead of the effects of polymorphisms in single genes.

Pharmacogenomics of drugs affecting the cardiovascular system

The variability in drug response originates partly from genetics, with possible consequences for drug efficacy, adverse effects, and toxicity. Until now, pharmacogenetics mainly indicated the best known source of variability, that is, the variability caused by drug metabolism. However, simultaneous progress in the knowledge of biochemical targets of drugs and of the human genome, together with the development of new technologies, revealed many new sources of human genetic variation, e.g., in receptors or transporters. Drugs are metabolized by various polymorphic phase I enzymes, including cytochromes P450 (CYP). Among them, the most relevant for the metabolism of cardiovascular drugs are CYP3A4, CYP2C9 or CYP2C19, and CYP2D6. The role of phase II enzymes is limited with regard to cardiovascular drugs biotransformation, but some polymorphisms (glutathion-S-transferase; GSH-T) are linked to cardiovascular risk. Phase III proteins or transporters, especially from the ABC family, must also be considered, as their polymorphisms affect cholesterol and other sterols transport. Among pharmacological targets, some proteins were identified as involved in interindividual variations in the response to cardiovascular drugs. Some examples are apolipoprotein E, angiotensin-converting enzyme, and the beta-adrenergic receptor. From the risk concept emphasizing impaired metabolism and adverse effects, we now moved to an approach, which is a personalized, genotype-dependent adaptation of therapy.

Apolipoprotein E polymorphism and serum lipid response to plant sterols in humans

BACKGROUND

The apolipoprotein E polymorphism may influence the absorption of cholesterol from the intestine and thus the response of serum cholesterol to diet. We decided to use plant sterols to investigate this and studied whether the cholesterol-lowering effect of plant sterols differed between subjects with different apolipoprotein E genotyes.

DESIGN

Thirty-one healthy subjects with the E3/4 or E4/4 genotype and 57 with the E3/3 genotype were fed sterol-enriched margarine or control margarine for 3 weeks each in a blind randomised cross-over design. The sterol margarine provided 3.2 g of plant sterols daily, was low-fat, and had the same fatty acid composition as the control margarine. Subjects used the margarines as part of their usual diet, which was fairly low in cholesterol (mean, 175 mg per day). The mean (+/- standard deviation) age of the subjects was 25 (+/- 11) years.

RESULTS

The apolipoprotein E polymorphism did not significantly affect the responses of total and LDL cholesterol. The decrease in total cholesterol was 0.36 mmol L-1 (7.4%) in the E3/3 subjects and 0.31 mmol L-1 (5.7%) in the epsilon 4 subjects (P = 0.50) and that in LDL cholesterol was 0.34 mmol L-1 (12.2%) in the E3/3 subjects and 0.32 mmol L-1 (9.8%) in the epsilon 4 subjects (P = 0.68).

CONCLUSION

The serum cholesterol response to plant sterols is not affected by the apolipoprotein E polymorphism in healthy subjects who consume a low-cholesterol diet.

One-year community-based education program for hypercholesterolemia in middle-aged Japanese: a long-term outcome at 8-year follow-up

To examine a long-term effect of community-based education program for hypercholesterolemia and an effect modification by apolipoprotein E polymorphism, we conducted a 1-year randomized clinical trial with 8 year-follow-up. One hundred four persons aged 40-64 years who had serum total cholesterol levels between 6.21 and 7.73 mmol/l (240 and 299 mg/dl) in 1988-89 cardiovascular risk surveys were enrolled in the trial. The intervention group (n=51, 82% for women) attended eight education classes in 1 year, while the control group (n=53, 85% for women) attended only two classes. Both groups were invited to the subsequent annual surveys. The mean serum cholesterol was 0.24-0.26 mmol/l less in the intervention than in the control group at both 6 month and 1 year (P=0.03, each) while the proportion of subjects using hypolipidemic agents was 0 and 6% in both groups, respectively. During 8-year follow-up, the probability of using hypolipidemic agents and/or total cholesterol > or =7.76 mmol/l was 51% in the education group and 69% in the control group; the risk ratio in the intervention vs control groups was 0.62 (95% CI: 0.36-1.06). When stratified by the apolipoprotein E polymorphism examined for 78% of the subjects, the risk ratio was 0.61 (0.31-1.18) among subjects without e4 allele (n=59) and 0.55 (0.14-2.14) among those with e4 allele (n=22). The intervention group had reduced intake of egg, fish egg, butter, mayonnaise and fatty meat compared to the control group at 6-month, 1- and 8-year follow-up. In conclusion, our community-based program was effective in reducing serum total cholesterol levels non-pharmacologically during the first year, and also reduced the likelihood of progressive worsening of hypercholesterolemia during the subsequent 8 years, regardless of the apolipoprotein E polymorphism.

Apolipoprotein E and diets: a case of gene-nutrient interaction?

Apolipoprotein E has key functions in lipoprotein metabolism, and polymorphisms in the apolipoprotein E gene are associated with distinct lipoprotein patterns. The possibility of gene-nutrient interactions for apolipoprotein E has been addressed in many studies. Although results have generally been mixed, the indications for such an interaction have been more common in studies employing a metabolic challenge. Studies directly designed to examine apolipoprotein E gene-nutrient interactions are needed.

DIETARY ANDGENETICEFFECTS ONLOW-DENSITYLIPOPROTEINHETEROGENEITY

We have tested whether differences in distribution and dietary responsiveness of low-density lipoprotein (LDL) subclasses contribute to the variability in the magnitude of LDL-cholesterol reduction induced by diets low in total and saturated fat and high in carbohydrate. Our studies have focused on a common, genetically influenced metabolic profile, characterized by a predominance of small, dense LDL particles (subclass pattern B), that is associated with a two- to threefold increase in risk for coronary artery disease. We have found that healthy normolipidemic individuals with this trait show a greater reduction in LDL cholesterol and particle number in response to low-fat, high-carbohydrate diets than do unaffected individuals (subclass pattern A). Moreover, such diets result in reduced LDL particle size, with induction of pattern B in a substantial proportion of pattern A men. Recent studies have indicated that this response is under genetic influence. Future identification of the specific genes involved may lead to improved targeting of dietary therapies aimed at reducing cardiovascular disease risk.

APOE polymorphism and the hypertriglyceridemic effect of dietary sucrose

BACKGROUND

The E4 allele of the apolipoprotein gene (APOE) is associated with a greater serum cholesterol response to dietary changes in fat and cholesterol. However, less is known about the interaction between APOE polymorphism and other macronutrients in the diet.

OBJECTIVE

We evaluated the interaction between APOE polymorphism and dietary fat and carbohydrate, particularly sucrose, in relation to serum lipid concentrations.

DESIGN

A total of 284 men and 130 women with coronary artery disease (mean age: 61 y; range: 33-74 y) participated in the cross-sectional EUROASPIRE study. Serum lipids and fatty acids in cholesteryl esters (CEs) were measured and APOE genotypes were determined. Dietary intake was examined by using a 4-d food record.

RESULTS

Patients were grouped by APOE genotype: E2 (E2/E2 and E2/E3; n = 21), E3 (E3/E3; n = 245), and E4 (E4/E2, E4/E3, and E4/E4; n = 148). Patients with the E2 allele had lower LDL-cholesterol concentrations and tended to have higher triacylglycerol concentrations than did patients with the E3 or E4 allele; concentrations were not significantly different between the last 2 groups. In regression analysis, significant predictors of serum triacylglycerol were the interaction between sucrose intake and the E2 allele, proportion of n-3 fatty acids in CEs, body mass index, and diabetes. A high sucrose intake was associated with high triacylglycerol concentrations only in patients with the E2 allele. Interaction between saturated fat intake and the E2 allele, proportion of linoleic acid in CEs, and fiber intake predicted serum cholesterol.

CONCLUSION

Coronary artery disease patients with the E2 allele will likely have a greater triacylglycerol response to high dietary sucrose intakes than will patients with the E3 or E4 allele.

Apoprotein E genotype and the response of serum cholesterol to dietary fat, cholesterol and cafestol

Previous studies on the effect of apoprotein E (APOE) polymorphism on the response of serum lipids to diet showed inconsistent results. We therefore studied the effect of apoprotein E polymorphism on responses of serum cholesterol and lipoproteins to various dietary treatments. We combined data on responses of serum cholesterol and lipoproteins to saturated fat, to trans-fat, to dietary cholesterol, and to the coffee diterpene cafestol with newly obtained data on the apoprotein E polymorphism in 395 mostly normolipidemic subjects. The responses of low-density lipoprotein (LDL-) cholesterol to saturated fat were 0.08 mmol/l larger in subjects with the APOE3/4 or E4/4 genotype than in those with the APOE3/3 genotype (95% confidence interval: -0.01-0.18 mmol/l). In contrast, responses of LDL-cholesterol to cafestol were 0.11 mmol/l smaller in subjects with the APOE3/4 or E4/4 genotype than in those with the APOE3/3 genotype (95% confidence interval: -0.29-0.07 mmol/l). Responses to dietary cholesterol and trans-fat did not differ between subjects with the various APOE genotypes. In conclusion, the APOE genotype may affect the response of serum cholesterol to dietary saturated fat and cafestol in opposite directions. However, the effects are small. Therefore, knowledge of the APOE genotype by itself may be of little use in the identification of subjects who respond to diet.

Gene-diet interactions and plasma lipoproteins: role of apolipoprotein E and habitual saturated fat intake

To test whether plasma lipoprotein levels and low density lipoprotein (LDL) particle size are modulated by an interaction between habitual saturated fat intake and apolipoprotein E (APOE) genotype, we studied 420 randomly selected free-living Costa Ricans. The APOE allele frequencies were 0.03 for APOE2, 0.91 for APOE3, and 0.06 for APOE4. The median saturated fat intake, 11% of energy, was used to divide the population into two groups, LOW-SAT (mean intake 8.6% energy) represents those below median intake, and HIGH-SAT (mean intake 13.5%) represents those above median intake. Significant interactions between APOE genotype and diet were found for VLDL (P = 0.03) and HDL cholesterol (P = 0.02). Higher saturated fat intake was associated with higher VLDL cholesterol (+29%) and lower HDL cholesterol (-22%) in APOE2 carriers, while the opposite association was observed in APOE4 carriers (-31% for VLDL cholesterol and +10% for HDL cholesterol). Higher saturated fat intake was associated with smaller LDL particles (-2%, P < 0.05) in APOE2 carriers, and larger LDL particles (+2%, P < 0.05) in APOE4 carriers, but the gene-diet interaction was not statistically significant (P = 0.09). Higher saturated fat intake was associated with higher LDL cholesterol in all genotypes (mean +/- SEM, LOW-SAT 2.61 +/- 0.05 vs. HIGH-SAT 2.84 +/- 0.05 mmol/L, P = 0.009). These data suggest that the APOE2 allele could modulate the effect of habitual saturated fat on VLDL cholesterol and HDL cholesterol in a population with an average habitual total fat intake of less than 30%.

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

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

Genetic determinants of plasma lipid response to dietary intervention: the role of the APOA1/C3/A4 gene cluster and the APOE gene

Polymorphisms at the APOA1/C3/A4 gene cluster and the APOE gene have been extensively studied in order to examine their potential association with plasma lipid levels, coronary heart disease risk and more recently with inter-individual variability in response to dietary therapies. Although the results have not been uniform across studies, the current research supports the concept that variation at these genes explains a significant, but still rather small, proportion of the variability in fasting and postprandial plasma lipid responses to dietary interventions. This information constitutes the initial frame to develop panels of genetic markers that could be used to predict individual responsiveness to dietary therapy for the prevention of coronary heart disease. Future progress in this complex area will come from experiments carried out using animal models, and from carefully controlled dietary protocols in humans that should include the assessment of several other candidate gene loci coding for products that play a relevant role in lipoprotein metabolism (i.e. APOB, CETP, LPL, FABP2, SRBI, ABC1 and CYP7).

Apolipoprotein B gene polymorphisms and serum lipids: meta-analysis of the role of genetic variation in responsiveness to diet

BACKGROUND

The genetic variance determining plasma lipid and lipoprotein concentrations may modify individual responsiveness to alterations in dietary fat and cholesterol content.

OBJECTIVE

The aim was to examine the role of apolipoprotein (apo) B DNA polymorphisms in responsiveness of plasma lipids and lipoproteins to diet.

DESIGN

A controlled dietary intervention study was conducted in 44 healthy, middle-aged subjects with a 3-mo baseline, a 1-mo fat-controlled, a 1-mo high-fat, and a 1-mo habitual diet period. We also conducted a meta-analysis of all published dietary trials, including our own.

RESULTS

In our own dietary study, the apo B XbaI restriction-site polymorphism affected the responsiveness to diet of the plasma LDL-cholesterol concentration (P < 0.05, repeated-measures analysis of variance). Especially during the high-fat diet, homozygous absence of the XbaI restriction site (X(-)/X(-)) was associated with a greater increase in LDL cholesterol (44 +/- 5%) than was X(+)/X(+) (27 +/- 7%) or X(+)/X(-) (40 +/- 5%). The high-fat diet also induced a larger increase in plasma LDL cholesterol in subjects with the R(-)/R(-) genotype (homozygous absence of the EcoRI restriction site) (59 +/- 10%) than in those with the R(+)/R(-) (39 +/- 6%) or R(+)/R(+) (36 +/- 4%) genotype. The M(+)/M(+) genotype (homozygous presence of the MspI restriction site) was also more responsive (41 +/- 3% increase in LDL cholesterol) than the M(+)/M(-) genotype (27 +/- 10% increase). The meta-analysis supported the finding of the significant role of the EcoRI and MspI polymorphisms, but not that of the XbaI polymorphism.

CONCLUSIONS

The present study indicated that the apo B EcoRI and MspI polymorphisms are associated with responsiveness to diet.

Differences between men and women in the response of serum cholesterol to dietary changes

BACKGROUND

Hypercholesterolaemia is initially treated by diet. However, most studies of diet and cholesterol response have been carried out in men, and it is not known whether women react to diet to the same extent as men do. We therefore studied sex differences in the response of serum cholesterol and lipoproteins to diet.

MATERIALS AND METHODS

We measured the responses of serum cholesterol to a decrease in dietary saturated fat in seven trials involving 126 men and 147 women, to a decrease in dietary trans fat in two trials (48 men and 57 women) and to a decrease in dietary cholesterol in eight trials (74 men and 70 women). We also measured responses to the coffee diterpene cafestol, which occurs in unfiltered coffee, in nine trials (72 men and 61 women). All subjects were lean and healthy.

RESULTS

The response of total cholesterol (+/- standard deviation) to a decrease in the intake of saturated fat was greater in men (-0.62 +/- 0.39 mmol L-1) than in women (-0.48 +/- 0.39 mmol L-1; 95% confidence interval, 0.04-0.23 mmol L-1). The response of total cholesterol to a decrease in the intake of cafestol was also larger in men (-1.01 +/- 0.49 mmol L-1) than in women (-0.80 +/- 0.49 mmol L-1; 95% confidence interval, 0. 04-0.39 mmol L-1). Responses to trans fat and to dietary cholesterol did not differ between men and women.

CONCLUSION

Men have larger responses of total and low-density lipoprotein cholesterol to saturated fat and cafestol than women do.

Variation of apolipoprotein B as a possible cause of decreased low density lipoprotein clearance and hypercholesterolemia

The fractional catabolic rate (FCR) for low density lipoprotein (LDL) apolipoprotein B (apo B) was studied to explore the variations in apo B as a possible cause of hypercholesterolemia. The FCR of radioiodine labelled autologous LDL and homologous LDL isolated from a normocholesterolemic subject were compared in forty-nine type II hypercholesterolemic males and females with the mean plasma concentration of total cholesterol of 7.78 mmol/l, LDL-cholesterol 5.41 mmol/l and triglycerides 2.09 mmol/l. In most patients the autologous LDL was catabolized at an equal rate and sometimes even faster than the homologous LDL. However, twelve out of forty-nine patients catabolized homologous LDL 0.8-19.3% faster than autologous LDL and several apo B polymorphisms were determined. No apo B-3500 or apo B-3531 mutations were detected. Patients with XbaI -/- (absence of cutting site) had lower total, IDL and LDL cholesterol and LDL apoB than the other genotypes. Patients with EcoRI +/+ (presence of cutting site) had higher total, VLDL and LDL cholesterol and slower FCR for autologous LDL, and their VLDL was richer in cholesterol than that of patients with the EcoRI +/-. The MspI and ins/del polymorphisms were not associated with variations in the measured parameters. The apo E 4 was associated with higher VLDL and IDL cholesterol, higher triglycerides and LDL apo B than E 3/3. Overall, the determined apo B polymorphisms were not related to the slow clearance of autologous LDL among the 12 patients, in whom autologous LDL was cleared at a slower rate than homologous LDL. In conclusion, hypercholesterolemia can be due to particle-related slow clearance of LDL in some patients. However, this is not a common cause of hypercholesterolemia.

Use of hierarchical models for meta-analysis: experience in the metabolic ward studies of diet and blood cholesterol

Overviews that combine single effect estimates from published studies generally use a summary statistic approach where the effect of interest is first estimated within each study and then averaged across studies in an appropriately weighted manner. Combining multiple regression coefficients from publications is more problematic, particularly when there are differences in study design and inconsistent reporting of effect sizes and standard errors. This paper describes the use of a hierarchical model in such circumstances. Its use is illustrated in a meta-analysis of the metabolic ward studies that have investigated the effect of changes in intake of various dietary lipids on blood cholesterol. These studies all reported average blood cholesterol for groups of individuals who were studied on one or more diets. Thirty-one studies had randomized cross-over designs, 12 had matched parallel group designs, 12 had non-randomized Latin square designs and 16 had other uncontrolled designs. The hierarchical model allowed the different types of comparison (within-group between-diet, between matched group) that were made in the various studies to each contribute to the overall estimates in an appropriately weighted manner by distinguishing between-study variation, within-study between-matched-group variation and within-group between-diet variation. The hierarchical models do not require consistent specification of effect sizes and standard errors and hence have particular utility in combining results from published studies where the relationships between a dependent variable and two or more predictors have been investigated using heterogeneous methods of analysis.

The genetics of serum lipid responsiveness to dietary interventions

CHD is a multifactorial disease that is associated with non-modifiable risk factors, such as age, gender and genetic background, and with modifiable risk factors, including elevated total cholesterol and LDL-cholesterol levels. Lifestyle modification should be the primary treatment for lowering cholesterol values. The modifications recommended include dietary changes, regular aerobic exercise, and normalization of body weight. The recommended dietary changes include restriction in the amount of total fat, saturated fat and cholesterol together with an increase in the consumption of complex carbohydrate and dietary fibre, especially water-soluble fibre. However, nutrition scientists continue to question the value of these universal concepts and the public health benefits of low-fat diets, and an intense debate has been conducted in the literature on whether to focus on reduction of total fat or to aim efforts primarily towards reducing the consumption of saturated and trans fats. Moreover, it is well known that there is a striking variability between subjects in the response of serum cholesterol to diet. Multiple studies have examined the gene-diet interactions in the response of plasma lipid concentrations to changes in dietary fat and/or cholesterol. These studies have focused on candidate genes known to play key roles in lipoprotein metabolism. Among the gene loci examined, APOE has been the most studied, and the current evidence suggests that this locus might be responsible for some of the inter-individual variability in dietary response. Other loci, including APOA4, APOA1, APOB, APOC3, LPL and CETP have also been found to account for some of the variability in the fasting and fed states.

The apolipoprotein E4 allele is not associated with an abnormal lipid profile in a Native American population following its traditional lifestyle

The apolipoprotein E4 allele is associated in industrialized countries with an elevated LDL cholesterol concentration and an increased cardiovascular risk. Our purpose in this study was to assess the influence of the genetic variation at the APOE gene locus on the lipid profile of a Native American rural population. We examined plasma lipid levels and the common apo E alleles in 142 healthy randomly selected adults living in their native communities in western Mexico. Their age was 38+/-17 years and the BMI 25.7+/-4.5 kg/m2. Plasma cholesterol, triglycerides, LDL C and HDL C were 165+/-29.6, 126+/-83, 98+/-26 and 42+/-12.7 mg/dl respectively. Ninety-one per cent of the subjects had Lp(a) concentrations below 20 mg/dl and 30% had levels lower than 2 mg/dl. The most common APOE genotype was E3/3 (63%), followed by E3/4 (30.1%). The prevalence of the E2 allele was very low (2.3%). No difference was observed in LDL C concentrations between the E3/E3 and E3/E4 subjects; however carriers of the E2/3 genotype had lower LDL C levels. Similar results were obtained for cholesterol and apo B levels. In summary, the increased LDL C levels associated with the E4 allele in previous studies were not observed in a population with non-westernized habits. Environmental factors, such as diet and lifestyle, could outweigh the hypercholesterolemic predisposition resulting from the presence of the apo E4 allele.

The apolipoprotein E phenotype has a strong influence on tracking of serum cholesterol and lipoprotein levels in children: a follow-up study from birth to the age of 11 years

The extent to which an individual maintains his position relative to the rest of the population is called tracking. The objective of this study was to examine the effect of the apolipoprotein E (apoE) phenotype on the tracking of serum cholesterol and lipoproteins from birth to the age of 11 y. In a longitudinal follow-up study of healthy children, concentrations of total serum cholesterol and triglyceride were determined at birth (n = 193), and at the ages of 2 (n = 192), 4 (n = 192), 6 (n = 190), 9 (n = 188), and 12 mo (n = 196), and 5 (n = 162) and 11 y (n = 153). Concentrations of total HDL, HDL2, and HDL3, VLDL, and LDL cholesterol were determined at 2, 6, 9, and 12 mo (n = 36), and 5 (n = 162) and 11 y (n = 153). The apoE phenotype was determined in 151 children. The children had the following apoE phenotypes: 4 had type 4/4 and 40 type 3/4 (group apoE4), 94 had type 3/3 (group apoE3), and 11 had type 2/3 and 2 type 2/4 (group apoE2). The correlation coefficients for total cholesterol levels during childhood compared with the level at 11 y of age were: 0.03 at birth, 0.26 (p < 0.001) at 2 mo, 0.24 (p < 0.001) at 4 mo, 0.24 (p < 0.001) at 6 mo, 0.28 (p < 0.001) at 9 mo, 0.41 (p < 0.001) at 12 mo, and 0.60 (p < 0.001) at 5 y. When the children were divided into three groups according to their apoE phenotypes, these three groups had the following correlation coefficients at 4 mo, 12 mo, or 5 y of age compared with the level at the age of 11 y; group apoE2: r = 0.65 (p < 0.01), r = 0.59 (p < 0.01), and r = 0.72 (p < 0.01); group apoE3: r = 0.27 (p < 0.01), 0.43 (p < 0.001), and r = 0.64 (p < 0.001); and group apoE4: r = 0.14 (p = NS), r = 0.33 (p < 0.05), and 0.42 (p < 0.01). The apoE phenotype also strongly influenced the tracking of the LDL cholesterol levels; the correlation coefficients between 5 and 11 y of age were for group apoE2 r = 0.84 (p < 0.001), for group apoE3 r = 0.70 (p < 0.001), and for group apoE4 r = 0.37 (p < 0.05). Our results indicate that the apoE phenotype strongly influences the tracking of lipids. The children having apoE 2/3, 2/4, and 3/3 phenotypes maintained their relative cholesterol and lipoprotein levels better than the others throughout the first 11 y of age. Because the apoE phenotype strongly affects the tracking of serum cholesterol, the usefulness of cholesterol screening in predicting future cholesterol values should be analyzed, keeping the apoE phenotype in mind.

Serum lipids and apolipoprotein E phenotypes in identical twins reared apart

Lipid and lipoprotein metabolism is controlled by genes, the environment and the gene environment interaction. We studied monozygotic twin pairs reared apart (MZA) and an age sex matched group of twins reared together (MZT) to evaluate the effects of the genotype and the rearing environment on lipids. The intraclass correlations for low density lipoprotein (LDL) cholesterol were 0.21 and 0.50 for the MZA and MZT groups, respectively, suggesting that the rearing environment possibly had an impact on the variability in LDL cholesterol later in life. The intraclass correlations for total cholesterol (0.26 and 0.47 for the MZA and MZT groups, respectively) reflected those for LDL cholesterol. The intraclass correlations for high density lipoprotein (HDL) cholesterol did not show any difference between the twin groups, suggesting that the rearing environment does not have major long-term effects on the variability of HDL levels. The intrapair differences for LDL cholesterol were smallest in the twins heterozygous for the apolipoprotein E allele epsilon2 (E2/3 and E2/4 phenotypes), intermediate in the pairs with the common E3/3 phenotype and enhanced in the pairs with E4/3 phenotype. To conclude, these data suggest that the rearing environment may play a role in the variability of LDL cholesterol levels, although variance difference between MZAs and MZTs, and the small number of available monozygotic twins reared apart limits the generalizability of the results.

Effect of apolipoprotein E polymorphism on serum lipoprotein response to saturated fatty acids

This report summarizes two studies which investigated the effects of apolipoprotein E (apoE) polymorphism on the serum total cholesterol (TC) and lipoprotein cholesterol responses to 8:0 + 10:0 and 12:0 diets (Study I) and 14:0, 16:0 and 18:0 diets (Study II). Eighteen healthy premenopausal women (3 apoE 3/2, 12 apoE 3/3, 3 apoE 4/3) in study I and another 18 healthy premenopausal women (4 apoE 3/2, 10 apoE 3/3, 3 apoE 4/3, 1 apoE 4/2) in study II consumed a baseline diet providing 40 en% total fat, 11 en% 18:2, 15 en% 18:1, 11.5 en% saturated fat for the first week of each 5-wk period. The experimental diets for both studies provided 40 en% total fat, 13-14 en% as one of five test saturated fatty acids (SFA), 14-16 en% 18:1, and 3-4 en% 18:2. Analysis by apoE phenotypes showed that both the 8:0 + 10:0 diet and the 12:0 diet in Study I induced significant increases in serum TC in subjects with different apoE phenotypes with the exception of apoE 3/2 in the medium-chain triglyceride group. In contrast, in Study II, individuals with apoE 4/3 consuming the 14:0 diet showed significant increases in serum TC, high density lipoprotein-cholesterol (HDL-C), and HDL2-C, but the same subjects consuming the 16:0 diet showed significant increases in serum TC and low density lipoprotein-cholesterol. The findings from both studies indicated serum lipoprotein responses to SFA were different and the variation of responsiveness may be regulated, at least in part, by apoE polymorphism, especially when 14:0, 16:0, or 18:0 was consumed.

ApoE genotype does not predict lipid response to changes in dietary saturated fatty acids in a heterogeneous normolipidemic population. The DELTA Research Group. Dietary Effects on Lipoproteins and Thrombogenic Activity

Recent studies have suggested that variations in apoE genotypes may influence the magnitude of plasma lipid changes in response to dietary interventions. We examined the ability of apoE genotype to predict plasma lipid response to reductions in percent of calories from total fat (TF) and saturated fat (SF) in a normolipidemic study population (n = 103) heterogeneous with respect to age, gender, race, and menopausal status. Three diets, an average American diet (34.3% TF, 15.0% SF), an AHA Step 1 diet (28.6% TF, 9.0% SF), and a low saturated fat (Low-Sat) diet (25.3% TF, 6.1% SF) were each fed for a period of 8 weeks in a three-way crossover design. Cholesterol was kept constant at 275 mg/d; monounsaturated and polyunsaturated fat were kept constant at approximately 13% and 6.5% of calories, respectively. Fasting lipid levels were measured during each of the final 4 weeks of each diet period. Participants were grouped by apoE genotype: E2 (E2/2, E2/3, E2/4); E3 (E3/3); E4 (E3/4, E4/4). Relative to the average American diet, both the Step 1 and Low-Sat diets significantly reduced total cholesterol, LDL cholesterol, and HDL cholesterol in all three apoE genotype groups. No evidence of a significant diet by genotype interaction, however, could be identified for any of the measured lipid and lipoprotein end points. Additional analysis of the data within individual population subgroup (men and women, blacks and whites) likewise provided no evidence of a significant diet by genotype interaction. Thus, in a heterogeneous, normolipidemic study population, apoE genotype does not predict the magnitude of lipid response to reductions in dietary saturated fat.

Preliminary report of a genetic basis for cognitive decline after cardiac operations. The Neurologic Outcome Research Group of the Duke Heart Center

BACKGROUND

Changes in memory and cognition frequently follow cardiac operations. We hypothesized that patients with the apolipoprotein E-epsilon 4 allele are genetically predisposed to cognitive dysfunction after cardiac operations.

METHODS

The apolipoprotein E-epsilon 4 allele was evaluated as a predictor variable for postoperative cognitive dysfunction in 65 patients undergoing cardiac bypass grafting at Duke University Medical Center. The primary outcome measure was performance on a cognitive battery administered preoperatively and at 6 weeks postoperatively.

RESULTS

In a multivariable logistic regression analysis including apolipoprotein E-epsilon 4, preoperative score, age, and years of education, a significant association was found between apolipoprotein E-epsilon 4 and change in cognitive test score in measures of short-term memory at 6 weeks postoperatively. Patients with lower educational levels were more likely to show a decline in cognitive function associated with the apolipoprotein E-epsilon 4 allele.

CONCLUSIONS

This study suggests that apolipoprotein E genotype is related to cognitive dysfunction after cardiopulmonary bypass. Cardiac surgical patients may be susceptible to deterioration after physiologic stress as a result of impaired genetically determined neuronal mechanisms of maintenance and repair.

Interactions between lifestyle-related factors and the ApoE polymorphism on plasma lipids and apolipoproteins. The EARS Study. European Atherosclerosis Research Study

To elucidate how the apolipoprotein (apo) E polymorphism and modifiable factors interact in explaining plasma lipid and apolipoprotein levels, we studied 1448 young adults (18 to 26 years old), participating in the European Atherosclerosis Research Study (EARS). Venous blood was collected after an overnight fast. Modifiable factors, eg, body mass index (BMI), waist-to-hip ratio (WHR), tobacco and alcohol consumption, and physical activity, were determined by using standardized protocols. Associations of modifiable factors with apoE levels were homogeneous across apoE phenotypes. In contrast, correlations of BMI with total cholesterol and apoB levels, as well as correlations between WHR and apoB, were significantly (P < .05 to P < .01) stronger in E2 carriers than in subjects with other phenotypes. Total cholesterol and apoB levels were comparable in E2 carriers in the upper tertile of BMI or WHR to those in E3/3 subjects, suggesting that the lowering effect of the E2 allele was no longer present. The inverse association between the plasma cholesteryl linoleate-to-oleate ratio, a marker for the dietary polyunsaturated-to-saturated fatty acid ratio, and triglycerides was also stronger in E2 carriers (-0.33 versus -0.17 in E3/3 and -0.24 in E4 carriers). Associations with other modifiable factors were notably consistent across apoE phenotypes. Gender and modifiable factors explained three times more (31%) of the interindividual variation in apoB levels in E2 carriers than in E3/3 subjects (9%) or E4 carriers (14%), mainly due to a larger variance explained by BMI. Our results suggest that the apoE polymorphism acts in a relatively uniform manner, independently of lifestyle. However, the associations of adiposity to total cholesterol and apoB levels appear to be stronger in apoE2 carriers.

A dietary and behavioral intervention designed to lower coronary heart disease. Risk factors are unaffected by variation at the APOE gene locus

Variation at the apolipoprotein E (APOE) gene locus has demonstrated a consistent impact on lipoprotein levels. APOE typing was performed for 488 healthy, caucasian, premenopausal women participating in the Women's Healthy Lifestyle Project (WHLP) aimed at reducing total fat, saturated fat and cholesterol intake and promoting physical activity. Women in both the intervention and control groups were included in the trial. The purpose of the present study was to determine whether the magnitude of the changes in total cholesterol (Tc), low density lipoprotein cholesterol (LDLc) and high density lipoprotein cholesterol (HDLc) due to the dietary intervention were dependent on the variation in APOE. Weight, body mass index (BMI), and lipoprotein levels were measured at baseline and at a 6 month follow-up. ANOVA was used to determine whether the change in Tc and LDLc was dependent on dietary intervention and variation at APOE levels. The levels of Tc and LDLc were higher in women with the APOE*4 genotype. There were no statistically significant effects of APOE genotype and changes in Tc and LDLc (P > 0.1). Adjusted Tc and LDLc changes were comparable in the 3 APOE subgroups (Tc = -14.3, -12.9 and -11.7 mg/dl; LDLc = -12.1, -10.7 and -10.7 mg/dl, respectively as above). In conclusion, the genetic (APOE) background of premenopausal women in this study did not have a significant effect on their response to dietary intervention.

LDL subclass patterns and lipoprotein response to a low-fat, high-carbohydrate diet in women

A predominance of small, dense LDL particles (subclass pattern B) characterizes a metabolic trait that is associated with higher levels of triglyceride-rich lipoproteins and lower levels of HDL compared with those of individuals with predominantly larger LDL (pattern A). This trait appears to be under the influence of one or more genes, with maximal expression in adult males and reduced expression in premenopausal females. In a previous study, men with LDL subclass pattern B had significantly greater reductions in LDL cholesterol (LDL-C) and apolipoprotein B than men with pattern A. We hypothesized that despite the low prevalence of pattern B in premenopausal women, genetic predisposition to this trait could affect dietary responsiveness. Specifically, we predicted that LDL-C reduction on a low-fat, high-carbohydrate diet would be greatest in daughters of two pattern B parents, intermediate in daughters with one pattern B parent, and least in daughters with no pattern B parents. When 72 premenopausal women were placed on a 20% fat diet for 8 weeks, the changes in LDL-C (mmol/L) compared with levels on basal diets were significantly related to the number of pattern B parents (two B parents: -0.92 +/- 0.61, one B parent: -0.23 +/- 0.10, no B parents: -0.05 +/- 0.06) and could not be explained by diet adherence or baseline characteristics including initial lipoprotein profile or body mass index. The number of pattern B parents was also related to reductions in plasma mass concentrations of IDL, total LDL, and large LDL and to increases in plasma triglycerides. There was a significant inverse correlation between changes in triglyceride and LDL-C induced by the low-fat, high-carbohydrate diet. Thus, genetic and metabolic factors underlying LDL subclass pattern B may result in enhanced LDL and triglyceride responsiveness to substitution of dietary carbohydrate for fat in premenopausal women.

Effects of apo B and apo E gene polymorphisms on lipid and apolipoprotein concentrations after a test meal

The role of apo B signal peptide and apo E polymorphisms, and individual factors (age, sex, etc.) have been investigated on the interindividual variability of the postprandial response of 274 subjects ingesting a 1.260-KJ milkshake. The mean postprandial response, observed during 4 h, is significantly positive for total cholesterol (P < 0.005), LDL-cholesterol (P < 0.0001), triglycerides (P < 0.001), apo E (P < 0.0001) and glucose (P < 0.0001), whereas HDL-cholesterol, apo A-I and apo B do not present mean postprandial variation. Independently of the mean response, some parameters present a large interindividual variability of response, which is significantly influenced by cofactors, such as weight or BMI, for total and LDL-cholesterol, apo B and apo E or tobacco use for HDL-cholesterol. Sex has no effect on any lipid levels. Total, LDL-cholesterol and apo E responses are correlated with their corresponding fasting values. ApoB signal peptide polymorphism is not involved in the postprandial responses, whereas apo E polymorphism explains a significant part of the variability of HDL-cholesterol and apo A-I responses.

Apolipoprotein E and complement C3 polymorphism and their role in the response to gemfibrozil and low fat low cholesterol therapy

Three different allelic variants of apolipoprotein E determine, in concert with other gene products, the levels of plasma lipoproteins. Recently, cleavage products of the complement C3 molecule have also been implicated in determining plasma triacylglycerol concentrations. This study presents data of an ongoing study to dissect the role of the apolipoprotein E gene locus in the response to low fat/low cholesterol diet combined with gemfibrozil treatment. In addition, for the first time, the significance of C3 allelic variants to such hypolipidaemic therapy response was analysed. To this end data from 81 obese hyperlipoproteinaemic patients (Fredrickson type II/A and B and type IV and V) confirmed the usefulness of the combined gemfibrozil/diet treatment and unveiled apolipoprotein E allele group specific therapy responses. The mean changes of lipid properties due to combined treatment was 15% for total cholesterol, 48% for triacylglycerols and 28% for atherogenic index. Division into hyperlipidaemia types according to Fredrickson and subgrouping into E2, E3 and E4 groups (apolipoprotein E2/2 and 2/3, apolipoprotein E3/3 and apolipoprotein E4/2 and 4/3 phenotype groups respectively) exposed pronounced differences from these mean changes, suggesting substantial influence of apolipoprotein E variants on this therapy. We observed triacylglycerol reductions of from 17% in type IIA-apolipoprotein E3 group patients up to 78% in the type IV and V-apolipoprotein E2 group. Thus it might be concluded the apolipoprotein E genotyping aides therapy success prediction. Although, low sample number in some subgroups obscures significance in this pilot study, significant therapy success emerges for the E3 and E4 group in type IV and V hyperlipidaemia and type IIB-apolipoprotein E3 homozygous patients can be predicted to respond better than apolipoprotein E2 carriers. Finally, we present evidence that positive changes of lipid properties are also determined by the "fast" complement C3 allel (C3-F). Patients with complement factor C3-FS pattern respond better to treatment than patients with C3-SS configuration. In summary these data endorse the genotyping of apolipoprotein E alleles to predict maximal success of "fibrate" treatment. In addition they argue strongly for further assessment of the involvement of complement C3 allelic variations in lipid homeostasis.

Body fat distribution is a determinant of the high-density lipoprotein response to dietary fat and cholesterol in women

We have conducted a dietary trial that addressed the factors influencing the variability in plasma lipids in response to dietary fat and cholesterol with a focus on the effects of gender and body fat distribution. Sixty-seven women and 53 men were selected so that overall men and women had a similar mean age, LDL cholesterol, and body mass index. After a 2-week low-fat period subjects were given two liquid supplements for 3 weeks each, one that contained 31 to 40 g fat and 650 to 845 mg cholesterol, and one that was fat free. Measurements included plasma lipids and lipoproteins, glucose, insulin, hepatic triglyceride lipase activity, apolipoprotein E polymorphism, and three indexes of body fat (body mass index, waist girth, and waist-hip ratio). In response to dietary fat and cholesterol supplementation only the changes in HDL cholesterol, especially in HDL2, differed between the sexes. Although on univariate analysis lipoprotein changes were predicted by baseline lipoprotein levels, body mass index, waist girth, waist-hip ratio, hepatic triglyceride lipase activity, and insulin, multiple regression showed only waist-hip ratio to predict changes in HDL2 cholesterol in women and body mass index and baseline HDL2 cholesterol in men. Changes in LDL were predicted by baseline LDL cholesterol in women and apolipoprotein E phenotype and age in men. These studies explain much of the variability that individuals show in lipoprotein changes, especially in the more desirable changes in cholesterol transport in HDL2, in response to eating saturated fat and cholesterol.

Effect of apolipoprotein E and A-IV phenotypes on the low density lipoprotein response to HMG CoA reductase inhibitor therapy

Our purpose was to assess the effect of apolipoprotein (apo) E and apo A-IV isoform variation on low density lipoprotein (LDL) cholesterol lowering response to the HMG CoA reductase inhibitor, pravastatin. Plasma samples were obtained from participants (apo E, n = 97; apo A-IV, n = 144) in the PLAC-I (Pravastatin Limitation of Atherosclerosis in Coronary Arteries Study-1). The mean LDL cholesterol reduction in these subjects who were randomized to pravastatin 40 mg/day was 28%. Subjects with the APOE*2 allele (n = 12) had significantly (P = 0.04) greater reductions at 36% than subjects homozygous for the APOE*3 allele (n = 66, 27%) or those with the APOE*4 allele (n = 19, 26%). No significant effect of apo A-IV phenotype on LDL cholesterol lowering in response to pravastatin was noted. A meta-analysis utilizing published data from 4 previously published studies as well as our own data with a total sample size of 625 subjects was carried out. This analysis indicates that the presence of the APOE*2 allele was associated with a significantly greater (P < 0.05) LDL-cholesterol lowering response at 37% than those subjects homozygous for the APOE*3 allele at 35%, while those with the APOE*4 allele had a significantly lower response (P < 0.05), at 33%. These data are consistent with the concept that apo E phenotype modulates the LDL cholesterol lowering response observed with the use of HMG CoA reductase inhibitors.

Apolipoprotein E isoform phenotype and LDL subclass response to a reduced-fat diet

We investigated the association of apolipoprotein (apo) E isoform phenotype with lipoprotein response to reduced dietary fat intake in 103 healthy men (apoE3/2, n = 10; apoE3/3, n = 65; and apoE4/3, 4/4, n = 28). In a randomized, crossover design, subjects consumed high-fat (46%) and low-fat (24%) diets for 6 weeks each. High-fat LDL cholesterol differed among phenotypes, with apoE4/3, 4/4 > apoE3/3 > apoE3/2. Reduction of LDL cholesterol on the low-fat diet was greater for apoE4/3, 4/4 than apoE3/3 (P < .05). There was no significant change in plasma apoB level within any of the apoE phenotype groups on the low-fat diet. This result, together with measurements of LDL subfraction mass by analytical ultracentrifugation, indicated that the primary basis for the diet-induced reduction in LDL cholesterol was not reduced LDL particle number but rather a shift from large, buoyant, cholesterol-rich LDL particles (flotation rate, 7 to 12) to smaller, denser LDL particles (flotation rate, 0 to 7). The magnitude of this effect was related to apoE phenotype, with progressively greater reductions in levels of large LDL (P < .01) from apoE3/2 to apoE3/3 to apoE4/3, 4/4. These results indicate that reduced dietary fat lowers levels of large, buoyant LDL particles by an apoE-dependent mechanism.

Gender and diet interactions with simvastatin treatment

Twelve men and thirteen women with hypercholesterolaemia participated in a 20-week controlled cross-over trial to assess the interaction between dietary fat intake, gender and an HMGCoA reductase inhibitor, simvastatin. Subjects were matched for total cholesterol, age, body mass index (BMI) and plasma triglyceride. Gender-drug interactions were noted with men demonstrating only a 27% fall in LDL cholesterol with simvastatin when consuming a high fat (40% energy) diet compared to women with a 35% fall. In men, the lowest LDL/HDL ratio was achieved with simvastatin on a low fat diet (22% energy). Gender differences in the effect of simvastatin on HDL were confined to HDL3 cholesterol, although the drug raised HDL2 in both sexes on the low fat diet. Simvastatin was responsible for an 11% increase in HDL3 cholesterol in men particularly when on a low fat diet but did not affect HDL3 in women. An important diet-drug interaction was seen in triglyceride response, with a lowering of 17%-20% only when subjects were on a low fat diet. There was a gender difference in response to dietary fat change with men demonstrating a 19% decrease in triglycerides with dietary fat reduction while on simvastatin, whereas women showed a 9% increase which did not reach significance. Men also responded more favourably to dietary fat reduction with at least two-fold greater falls in plasma cholesterol than was seen in women.(ABSTRACT TRUNCATED AT 250 WORDS)