Apolipoprotein E genotype modulates the effect of black tea drinking on blood lipids and blood coagulation factors: a pilot study

Potential therapeutic effects of green tea on obese lipid profile - a systematic review

Background: Green tea, obtained from the plant Camellis sinensis, is one of the oldest drinks in the world and contains numerous bioactive compounds. Studies have demonstrated the efficacy of green tea in preventing obesity and cardiovascular diseases that may be related to the reduction of lipid levels. Aim: This study aimed to evidence, through a systematic review, the therapeutic potential of green tea on the lipid profile in preclinical studies in obese animals and clinical studies in obese individuals. Methods: This systematic review follows the recommendations of the preferred report items for systematic reviews and meta-analyses. The electronic databases, PubMed (Medline), Science Direct, Scopus, and Web of Science were consulted. Articles from January 2009 to December 2019 were selected. Results: This search resulted in twenty-nine articles were included cirtically reviewed. In experimental studies, green tea administration has been shown to reduce total cholesterol, triglycerides and low-density lipoprotein cholesterol in animals exposed to obesity-inducing diet. In humans' studies green tea was not shown to be effective for obese lipid control. Because supplementation with green tea extract reduced total cholesterol, triglycerides, low-density lipoprotein for three months at a specific dose. Conclusion: Therefore, green tea appears to act as a protective agent for dyslipidemia in obesity-induced animals. In human studies, green tea has not been shown to be effective in controlling obese lipids.

Clinical response to statins: mechanism(s) of variable activity and adverse effects

Statins represent a major advance in the treatment of hypercholesterolemia, a significant risk factor for atherosclerosis. There is, however, notable interindividual variation in the cholesterolemic response to statins, and the origin of this variability is poorly understood; pharmacogenetics has attempted to determine the role of genetic factors. Myopathy, further, has been reported in a considerable percentage of patients, but the mechanisms underlying muscle injury have yet to be fully characterized. Most statins are the substrates of several cytochrome P450s (CYP). CYP polymorphisms may be responsible for variations in hypolipidemic activity; inhibitors of CYPs, e.g. of CYP3A4, can significantly raise plasma concentrations of several statins, but consequences in terms of clinical efficacy are not uniform. Pravastatin and rosuvastatin are not susceptible to CYP inhibition but are substrates of the organic anion-transporting polypeptide (OATP) 1B1, encoded by the SLCO1B1 gene. Essentially all statins are, in fact, substrates of membrane transporters: SLCO1B1 polymorphisms can decrease the liver uptake, as well as the therapeutic potential of these agents, and may be linked to their muscular side-effects. A better understanding of the mechanisms of statin handling will help to minimize adverse effects and interactions, as well as to improve their lipid-lowering efficiency.

Green tea extract for periodontal health

Tea, the commonly consumed beverage, is gaining increased attention in promoting overall health. In specific, green tea is considered a healthful beverage due to the biological activity of its polyphenols namely catechins. Among the polyphenols Epigallo catechin 3 gallate and Epicatechin 3 Gallate are the most predominant catechins. The antioxidant, antimicrobial, anticollagenase, antimutagenic, and c hemopreventive properties of these catechins proved to be helpful in the treatment of chronic diseases like periodontal disease. Studies have demonstrated that the type of processing mainly effects the concentration of catechins. Several epidemiological studies have proved that green tea also has some general health benefitting properties like antihypertensive, reduction of cardiovascular risk, antibacterial, antiviral, and antifungal activity. The present review concentrates on the effects of green tea in periodontal and general health.

APOE distribution in world populations with new data from India and the UK

BACKGROUND

The APOE gene and its protein product is associated with a number of plasma proteins like very-low density lipoprotein (VLDL), high density lipoprotein (HDL) chylomicrons, chylomicron remnants, and plays a crucial role in lipid metabolism. The APOE gene is polymorphic and common alleles (*E2, *E3 and *E4) have been associated with a number of common and complex diseases in different populations. Due to their crucial role in metabolism and clinical significance, it is imperative that allelic variation in different populations is analysed to evaluate the usage of APOE in an evolutionary and clinical context.

AIM

We report allelic variation at the APOE locus in three European and four Indian populations and evaluate global patterns of genetic variation at this locus. The large, intricate and unexpected heterogeneity of this locus in its global perspective may have insightful consequences, which we have explored in this paper.

SUBJECT AND METHODS

Apolipoprotein E genotypes were determined in four population groups (Punjabi Sikhs, Punjabi Hindus, Maria Gonds and Koch, total individuals = 497) of India and three regionally sub-divided British populations (Nottinghamshire, East Midlands and West Midlands, total individuals = 621). The extent and distribution of APOE allele frequencies were compared with 292 populations of the world using a variety of multivariate methods.

RESULTS

Three alleles, APOE*E2, APOE*E3 and APOE*E4, were observed with contrasting variation, although *E4 was absent in the tribal population of Koch. Higher heterozygosities (>43%) in British populations reflected their greater genetic diversity at this locus. The overall pattern of allelic diversity among these populations is comparable to many European and Indian populations. At a global level, higher frequencies of the *E2 allele were observed in Africa and Oceania (0.099 +/- 0.083 and 0.111 +/- 0.052, respectively). Similarly, *E4 allele averages were higher in Oceania (0.221 +/- 0.149) and Africa (0.209 +/- 0.090), while Indian and Asian populations showed the highest frequencies of *E3 allele. The coefficient of gene differentiation was found to be highest in South America (9.6%), although the highest genetic diversity was observed in Oceania (48.7%) and Africa (46.3%). APOE*E2 revealed a statistically significant decreasing cline towards the north in Asia (r = -0.407, d.f. = 70, p < 0.05), which is not compatible with the coronary heart disease statistics in this continent. APOE*E4 showed a significant increasing cline in North European populations. Spatial autocorrelation analysis shows that the variation at this locus is influenced by 'isolation by distance' with a strong positive correlation for lower distances up to 1313 km.

CONCLUSION

Overall APOE allelic variation in UK and Indian populations is comparable to previous studies but in tribal populations *E4 allele frequency was very low or absent. At a global level allelic variation shows that geography, isolation by distance, genetic drift and possibly pre-historical selection are responsible for shaping the spectrum of genetic variation at the APOE gene. Overall, APOE is a good anthropogenetic and clinical diagnostic marker.

Lack of association between apolipoprotein E promoters in epsilon4 carriers and worsening on computed tomography in early stage of traumatic brain injury

We investigated the relationship between apolipoprotein E (APOE) promoters (G-219T, C-427T, A-491T) polymorphisms, and worsening CT results in early stage of traumatic brain injury (TBI) in a previously reported cohort of Chinese patients. Radiographic evidence of hemorrhage extension or delayed hemorrhage in acute stage (< 7 days after TBI) was judged by serial CT scanning compared to that on admission. APOE genotyping was performed by means of PCR-RFLP. Chi2 test and logistic regression analyses were done using SPSS software. Of 110 Chinese patients, 19 presented with deteriorated clinical condition in acute stage after hospitalization. Among these 19 patients, serial CT scanning revealed 3 cases with hemorrhage extension and 2 cases with delayed hemorrhage. Chi2 test showed no statistical differences in radiographic worsening/stabilization between the APOE epsilon4(+) and APOE epsilon4(-) groups (p = 0.170 > 0.05). Furthermore, no significant correlation between intracranial bleeding based on CT scanning with genotype or with haplotype frequencies for A-491T, C-427T, or G-219T was found by chi2 test (p > 0.05). In Chinese population, our data do not support the hypothesis that genetic variations within the APOE gene are associated with CT worsening in early stage of TBI.

A 6-month randomized pilot study of black tea and cardiovascular risk factors

BACKGROUND

The effects of black tea consumption on cardiovascular risk factors have been inconsistent in previous randomized trials, all of which have been limited to a few weeks duration.

METHODS

We conducted a pilot parallel-design randomized controlled trial among 31 adults aged 55 years and older with either diabetes or 2 other cardiovascular risk factors but no established clinical cardiovascular disease. Participants were randomized to drink 3 glasses daily of either a standardized black tea preparation or water for 6 months. Cardiovascular risk factors were measured at the beginning and conclusion of the study.

RESULTS

Three participants dropped out of the study, leaving 14 participants assigned to tea and 14 assigned to water eligible for analyses. We found no statistically significant effects of black tea on cardiovascular biomarkers, including lipids, inflammatory markers, hemoglobin, adhesion molecules, prothrombotic and fibrinolytic parameters, and lipoprotein oxidizability. Assignment to tea did not appreciably influence blood pressure, and heart rate among participants assigned to tea was marginally higher than among control participants at 3 months (P = .07) but not 6 months.

CONCLUSIONS

In this randomized trial of black tea intake over 6 months among older adults with known cardiovascular risk factors, black tea did not appreciably influence any traditional or novel biomarkers of cardiovascular risk. Longer randomized trials are needed to verify the inverse association of tea with risk of cardiovascular disease seen in cohort studies and identify potential candidate mechanisms for such an association.

Beneficial effects of green tea--a review

Tea is the most consumed drink in the world after water. Green tea is a 'non-fermented' tea, and contains more catechins, than black tea or oolong tea. Catechins are in vitro and in vivo strong antioxidants. In addition, its content of certain minerals and vitamins increases the antioxidant potential of this type of tea. Since ancient times, green tea has been considered by the traditional Chinese medicine as a healthful beverage. Recent human studies suggest that green tea may contribute to a reduction in the risk of cardiovascular disease and some forms of cancer, as well as to the promotion of oral health and other physiological functions such as anti-hypertensive effect, body weight control, antibacterial and antivirasic activity, solar ultraviolet protection, bone mineral density increase, anti-fibrotic properties, and neuroprotective power. Increasing interest in its health benefits has led to the inclusion of green tea in the group of beverages with functional properties. However, although all the evidence from research on green tea is very promising, future studies are necessary to fully understand its contributions to human health, and advise its regular consumption in Western diets, in which green tea consumption is nowadays limited and sporadic.

Apo E genotype not associated with intravascular coagulation in traumatic brain injury

There is considerable evidence linking both genotype and coagulopathy to vascular complications of traumatic brain injury (TBI) and other cerebral insults. The authors explored a possible connection between the apolipoprotein E (Apo E) genotype, coagulopathy and intravascular microthombosis (IMT) in TBI. The predicted association was not confirmed.

Contemporaneous carrier-state of two or three "proatherosclerotic" variants of APOE, ICAM1, PPARA and PAI-1 genes differentiate CAD patients from healthy individuals

BACKGROUND

Atherosclerosis is the most important cause of coronary artery disease (CAD). Genetic predisposition to CAD is related to polymorphisms of genes encoding products functionally involved in pathogenesis of atherosclerosis. Polymorphisms of genes participating in monocyte adhesion and diapedesis, lipid metabolism and fibrinolysis regulation may be partially responsible for this process. The aim of our study was to assess the polymorphic variants frequencies of ICAM1, APOE, PPARA and PAI-1 genes in CAD patients and healthy blood donors and to find specific arrangement of polymorphic variants which would differentiate both groups.

METHODS

We studied 146 CAD patients and 121 healthy blood donors. Polymorphisms in analyzed genes were examined using PCR-RFLP analysis.

RESULTS

We found significantly higher frequency of 5G allele of PAI-1 gene in patients than in control subjects (p = 0.038, OR = 1.44). We observed also a considerably higher frequency of contemporaneous carriers of two or three "proatherosclerotic" variants: 1) PPARA and PAI-1, 2) APOE and ICAM1 and 3) PPARA, ICAM1 and PAI-1 in CAD group comparing to control subjects. The number of "proatherosclerotic" variants carriers differentiate studied groups also independently of specific genotype arrangement.

CONCLUSION

In conclusion, contemporaneous carrier-state of two or three polymorphic variants within analyzed genes is associated with CAD.

Flavonoids for reduction of atherosclerotic risk

Flavonoids are polyphenolic compounds found in fruits, vegetables, and beverages derived from plants. Foods thought historically by many societies to have healing properties--cocoa, red wine, and tea--are particularly rich in flavonoids. A majority of prospective cohort studies demonstrate a significant inverse association between flavonoid consumption and cardiovascular risk. Short-term studies demonstrate numerous plausible mechanisms by which flavonoids may confer cardiovascular protection: they inhibit low-density lipoprotein oxidation, reduce thrombosis, improve endothelial function, and reduce inflammation. No long-term, randomized, controlled trials of flavonoids with hard clinical endpoints have been conducted. Although there are no recommended daily intake goals for flavonoids, the data presented provide additional rationale to eat a diet containing a variety of flavonoid-rich foods and beverages.

Modest protective effects of isoflavones from a red clover-derived dietary supplement on cardiovascular disease risk factors in perimenopausal women, and evidence of an interaction with ApoE genotype in 49-65 year-old women

Data suggest that soy protein, a source of isoflavones, may have favorable effects on cardiovascular risk factors. Women (n = 205), ages 49-65 y, were randomized into this double blind, placebo-controlled trial of 43.5 mg red clover-derived isoflavones/d. A total of 177 women completed the trial. There were no differences between treatments for changes from baseline to 12 mo in total cholesterol, LDL cholesterol, triglycerides, HDL cholesterol, systolic and diastolic blood pressures, fibrinogen, and plasminogen activator inhibitor type 1 (PAI-1) (P >/= 0.1). Interactions between treatment and menopausal status were significant for changes in triglycerides and PAI-1 (P = 0.02 and P = 0.01), and changes were significant among perimenopausal women. In the isoflavone and placebo groups, changes in triglycerides were -0.2 +/- 0.6 and 0.4 +/- 0.6 mmol/L, P = 0.02, and changes in PAI-1 were -3.06 +/- 5.88 and 4.95 +/- 6.25 IU/L, P = 0.004, respectively. Interactions between apolipoprotein E (apoE) genotype and treatment tended to be significant for changes in total and LDL cholesterol (P = 0.06 and P = 0.05), and differences between treatments were significant in E2/E3 women. In the isoflavone and placebo groups, changes in total cholesterol were -0.61 +/- 0.79 and 0.18 +/- 0.79 mmol/L, P = 0.03, and changes in LDL cholesterol were -0.84 +/- 0.79 and -0.04 +/- 0.69 mmol/L, P = 0.02, respectively. Although there were potentially beneficial changes in triglycerides and PAI-1 among perimenopausal women consuming isoflavones, this study suggests that isoflavones alone are not responsible for the well-documented effects of soy protein on blood lipids. A larger study is required to confirm the effect modification by apoE genotype.

Human Apolipoprotein E concentration in response to diseases and therapeutic treatments

Apolipoprotein (Apo) E is an important circulating and tissular protein involved in cholesterol homeostasis and many other functions. The common polymorphism in the coding region of the gene, four polymorphisms in the promoter region, other additional single nucleotide polymorphisms, as well as several ApoE variants have been identified. Outside genetic polymorphism effects, ApoE concentration is modulated in human plasma and tissue through many processes: 1) transcription regulation through hormone responsive elements; 2) cytokines; 3) compartmentalization in particles or linkage to HSPG; 4) degradation after oxidation, glycation, and proteolysis; and 5) through many specific and nonspecific receptor interactions. Is the level of ApoE in tissue or plasma critical in different pathologies such as cardiovascular diseases (CVD) or Alzheimer's disease (AD)? ApoE is able to bind to Aβ, tau, to be an antioxidant, to respond to inflammation, and is involved in cholesterol delivery, uptake, and accumulation. In experimental situations ApoE injection or positive modulation decreases cholesterol and triglycerides and improves cognitive impairment. ApoE peptides are involved in immune response. It seems more and more clear that low vs. high plasma concentration should be evaluated in large epidemiological studies. Only after such studies can the question be answered: Is a low or high concentration of ApoE beneficial or dangerous? This fascinating apolipoprotein will then be an interesting marker and/or drug target. Drug Dev. Res. 56:95–110, 2002. © 2002 Wiley‐Liss, Inc.

The role of tea in human health: an update

Tea is an important dietary source of flavanols and flavonols. In vitro and animal studies provide strong evidence that tea polyphenols may possess the bioactivity to affect the pathogenesis of several chronic diseases, especially cardiovascular disease and cancer. However, the results from epidemiological and clinical studies of the relationship between tea and health are mixed. International correlations do not support this relationship although several, better controlled case-referent and cohort studies suggest an association with a moderate reduction in the risk of chronic disease. Conflicting results between human studies may arise, in part, from confounding by socioeconomic and lifestyle factors as well as by inadequate methodology to define tea preparation and intake. Clinical trials employing putative intermediary indicators of disease, particularly biomarkers of oxidative stress status, suggest tea polyphenols could play a role in the pathogenesis of cancer and heart disease.

A review of latest research findings on the health promotion properties of tea

Important progress has been made in the past five years concerning the effects of green and black tea on health. Experimentation with new accurate tools provide useful information about the metabolism of tea components in the body, their mode of action as antioxidants at the cellular level and their protective role in the development of cancer, cardiovascular disease and other pathologies. The use of tea components as nutraceuticals and functional foods are also discussed.

Gene-nutrient interactions: dietary behaviour associated with high coronary heart disease risk particularly affects serum LDL cholesterol in apolipoprotein E epsilon4-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 epsilon3/epsilon4 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 epsilon3/epsilon3 or epsilon2/epsilon2 & epsilon2/epsilon3 genotype. A significant positive correlation between alcohol consumption and HDL cholesterol level was present in individuals bearing ApoE epsilon2 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 epsilon4 variant of ApoE.

Apolipoprotein E polymorphisms and concentration in chronic diseases and drug responses

Apolipoprotein (apo) E is an important circulating and tissue protein involved in cholesterol homeostasis and many other functions. The common polymorphism in the coding region of the gene, four polymorphisms in the promoter region, other additional single nucleotide polymorphisms, as well as several apo E variants have been identified. The common coding polymorphism strongly influences the lipid metabolism and the circulating concentration of apo E itself. This polymorphism is at the origin of the implication of apo E in cardiovascular and neurodegenerative diseases, but also of the relation of apo E with longevity. Probably due to its many metabolic and functional consequences, apo E polymorphism has been shown to influence the responses of patients to several drugs (fibrates, statins, hormone replacement therapy, anti-Alzheimer drugs) or environmental interventions (black tea, alcohol, diet). Apo E genotyping may be clinically helpful in defining the risk of patients and their responses to therapeutics. Finally, circulating apo E concentration appears to be altered in diseases and can be modulated by some of the drugs cited above. This parameter can thus also give interesting clinical information and could be a therapeutic target, providing it is validated. At the present time, we cannot exclude that apo E concentration may be the most prominent apo E parameter to be considered in health and disease, while apo E polymorphisms would represent only secondary parameters influencing apo E concentration.

Demographic variation in nutrition knowledge in England

This paper describes a nutrition knowledge survey carried out on a cross-section of the adult population of England (n = 1040), looking at knowledge relating to current dietary recommendations, sources of nutrients, healthy food choices and diet-disease links. Serious gaps in knowledge about even the basic recommendations were discovered, and there was much confusion over the relationship between diet and disease. Significant differences in knowledge between socio-demographic groups were found, with men having poorer knowledge than women, and knowledge declining with lower educational level and socio-economic status. Possible reasons for these differences and implications for public education campaigns and socio-economic inequalities in health are discussed.

The apolipoprotein epsilon4 allele determines prognosis and the effect on prognosis of simvastatin in survivors of myocardial infarction : a substudy of the Scandinavian simvastatin survival study

BACKGROUND

Carriers of the epsilon4 allele of the apolipoprotein E gene are at a higher risk of coronary heart disease than individuals with other genotypes. We examined whether the risk of death or a major coronary event in survivors of myocardial infarction depended on apolipoprotein E genotype and whether the benefits of treatment with simvastatin differed between genotypes.

METHODS AND RESULTS

Cox proportional hazards models were used to analyze 5.5 years of follow-up data from 966 Danish and Finnish myocardial infarction survivors enrolled in the Scandinavian Simvastatin Survival Study. A total of 16% of the 166 epsilon4 carriers in the placebo group died compared with 9% of the 312 patients without the allele, which corresponds to a mortality risk ratio of 1.8 (95% confidence interval, 1.1 to 3.1). The risk ratio was unaffected by considerations of sex, age, concurrent angina, diabetes, smoking, and serum lipids in multivariate analyses. Simvastatin treatment reduced the mortality risk to 0.33 (95% confidence interval, 0.16 to 0.69) in epsilon4 carriers and to 0.66 (95% confidence interval, 0. 35 to 1.24) in other patients (P=0.23 for treatment by genotype interaction). Apolipoprotein E genotype did not predict the risk of a major coronary event. Baseline serum levels of lipoprotein(a) also predicted mortality risk and could be combined with epsilon4-carrier status to define 3 groups of patients with different prognoses and benefits from treatment.

CONCLUSIONS

Myocardial infarction survivors with the epsilon4 allele have a nearly 2-fold increased risk of dying compared with other patients, and the excess mortality can be abolished by treatment with simvastatin.

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 E gene polymorphisms and serum cholesterol in healthy Irish adults: a proposed genetic marker for coronary artery disease risk

BACKGROUND

The apolipoprotein (Apo) E gene, and thus its gene product, plays a central and pervasive role in lipid metabolism by serving as a ligand for lipoprotein receptors. Polymorphisms of this gene have been associated with variation in lipid phenotypes in some Caucasian and Asian populations, but not in others. No such study has been carried out in a resident Irish population.

AIM

A study was designed to examine the relationship between serum cholesterols and Apo E genotype in a cohort of healthy Irish adults.

METHODS

One hundred healthy Irish adults, aged 19-65 years, were recruited from the Cork City area. Two fasting blood samples were collected from each subject. One was assayed for serum cholesterols--total and low-density lipoprotein (LDL), and high-density lipoprotein (HDL)--while the other sample was used for isolation of genomic DNA and determination of Apo E genotype.

RESULTS

While the E2 (12%) was the least prevalent, E3 was the most prevalent Apo E genotype (66%) in this group of healthy Irish adults. A significant Apo E gene-dosage effect was evident, whereby individuals with the Apo E2 genotype had a lower level of total cholesterol, E3 had intermediate levels, and E4 had a higher level. Moreover, those with the Apo E4 genotype had a significantly higher level of LDL cholesterol compared to E2 or E3 genotypes. There was no significant difference in mean serum adjusted HDL-cholesterol levels between the three Apo E genotypes.

CONCLUSION

These findings suggest that healthy Irish adults with the Apo E4 genotype have higher serum total and LDL-cholesterol levels than those with E2 or E3 Apo E genotypes and therefore may have a higher risk of atherosclerotic coronary artery disease and coronary heart disease in later life.

Apolipoprotein E and methylenetetrahydrofolate reductase genetic polymorphisms in relation to other risk factors for cardiovascular disease in UK Caucasians and Black South Africans

Genetic polymorphisms for apolipoprotein E (apo E) and methylenetetrahydrofolate reductase (MTHFR) are believed to modulate risk of coronary heart disease (CHD) acting through regulation of lipid and homocysteine metabolism, respectively. The distributions of apo E and MTHFR alleles in Black South Africans, a population with a low CHD incidence, and UK Caucasians from the Cambridge area, with a higher CHD incidence, were therefore compared. Clinically healthy volunteers (207), including 107 UK Caucasians from the Cambridge area and 100 Black South Africans, participated in the study. Apo E and MTHFR genotypes were determined in all of them. Analyses for serum total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides and plasma fibrinogen were carried out in 65 UK Caucasians and 60 Black South Africans. The apo E epsilon4 allele, which is associated with elevated CHD risk, was present in 48% of Black South Africans compared to 20.8% of Caucasians (P < 0.0001); however, both total and LDL cholesterol levels in Black South Africans were 18-32% lower than in Caucasians with similar apo E genotypes. Hyperhomocysteinemia-causing MTHFR 677T variant was detected in only 20% of Black South Africans (no homozygotes) versus 56% of Caucasians with 12% homozygotes (P<0.0001). Our findings suggest that the potentially unfavourable pattern of apo E allele distribution in Black South Africans does not result in increased CHD incidence due to protection by dietary and/or other life style related factors. The exceptionally low frequency of MTHFR mutant homozygotes in this population suggests that this polymorphism should not be regarded as an important CHD risk factor among Black South Africans.

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.

Genes, variation of cholesterol and fat intake and serum lipids

Several studies have examined gene-diet interactions in the response of plasma lipid concentrations to changes in dietary fat and/or cholesterol. 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 interindividual variability in dietary response. Other loci, including APOA4, APOA1 and APOB have also been found to account for some of the variability in the fasting and fed states.