Diet, an independent determinant for plasma total homocysteine. A cross sectional study of Norwegian workers on platforms in the North Sea

A Western Diet Pattern Is Associated with Higher Concentrations of Blood and Bone Lead among Middle-Aged and Elderly Men

Background: Little is known about the effects of overall dietary pattern on lead concentration.Objective: We examined the association of overall dietary patterns, derived from a semiquantitative food frequency questionnaire, with bone and blood lead concentrations.Methods: These longitudinal analyses included mostly non-Hispanic white, middle-aged-to-elderly men from the Veterans Affairs Normative Aging Study. Long-term lead exposures were measured as tibia and patella lead concentrations by using K-shell-X-ray fluorescence. Short-term lead exposures were measured as blood lead concentrations by using graphite furnace atomic absorption spectroscopy. Dietary pattern scores were derived by using factor analysis. Linear mixed-effects models were utilized to predict blood lead concentrations among 983 men, aged 44-92 y at baseline, with a total of 3273 observations (during 1987-2008). We constructed linear regression models to determine the relations between dietary patterns and bone lead concentrations among 649 participants with an age range of 49-93 y.Results: Two major dietary patterns were identified: a prudent dietary pattern, characterized by high intakes of fruit, legumes, vegetables, whole grains, poultry, and seafood; and a Western dietary pattern, characterized by high intakes of processed meat, red meat, refined grains, high-fat dairy products, French fries, butter, and eggs. After adjusting for age, smoking status, body mass index, total energy intake, education, occupation, neighborhood-based education and income level, men in the highest tertile of the Western pattern score (compared with the lowest) had 0.91 μg/dL (95% CI: 0.41, 1.42 μg/dL) higher blood lead, 5.96 μg/g (95% CI: 1.76, 10.16 μg/g) higher patella lead, and 3.83 μg/g (95% CI: 0.97, 6.70 μg/g) higher tibia lead. No significant association was detected with the prudent dietary pattern in the adjusted model.Conclusions: These findings suggest that the Western diet is associated with a greater lead body burden among the middle-aged-to-elderly men. More studies are needed to examine the underlying mechanisms by which dietary patterns are associated with lead concentrations.

Determinants of hyperhomocysteinemia in healthy and hypertensive subjects: A population-based study and systematic review

AIMS

Hyperhomocysteinemia (HHcy) is known to increase the risk of many diseases. Factors influencing HHcy in healthy and hypertensive subjects remain under-researched.

METHODS

A large population-based study was conducted in 60 communities from Shenzhen, China. Responses to standardized questions on lifestyle factors and blood samples were collected from all participants after a 12-h overnight fast. Multiple linear and multivariate logistic regressions were used to explore risk factors for HHcy. Results were then compared to those from a systematic review of English-language articles listed in Pubmed, EBSCOhost, Web of Science, Embase and Cochrane libraries that investigated HHcy risk factors in healthy and hypertensive subjects.

RESULTS

A total of 1586 healthy (Male/Female = 642/944) and 5935 hypertensive subjects (Male/Female = 2928/3007) participated in our population-based study. In logistic regression analyses, age, BMI and creatinine (Cr) were risk factors, while being female, fruit intake and physical activity were protective factors for HHcy in healthy subjects. In hypertensive subjects, seven [age, smoking, salt intake, systolic blood pressure (SBP), uric acid, triglycerides (TG), and Cr] and four [female, fruit intake, total cholesterol (TC), and glucose] factors were associated with higher and lower HHcy respectively. The review of 71 studies revealed that potential risk factors for Hcy included nutritional, physiologic, lifestyle habits, ethnicity, genetics, interactions between gene-environment, gene-gene, gene-nutritional, environment-environment, nutritional-nutritional.

CONCLUSION

Our study indicates the potential importance of increasing folic acid and vitamin B supplementation, daily fruit and vegetable intake, regular exercise and refraining from tobacco smoking and alcohol consumption as preventive strategies for Hcy.

Evaluation of chemiluminescence method for the analysis of plasma homocysteine and comparison with HPLC method in children samples

OBJECTIVE

To compare the results for homocysteine concentration using chemiluminescence and HPLC methods in samples from school-age children. In addition, to determine the reference values for patients of this age group and assess the real prognostic value of homocysteine in healthy children.

METHODS

A prospective observational study was undertaken to determine plasma levels of homocysteine using two different assays, HPLC and chemiluminescence, in 185 samples from school-age children living in Santo Andre, with no chronic or inflammatory diseases, and absence of pubertal development.

RESULTS

The results were presented in percentiles and reference values were determined within this age group (7-9 years old). Homocysteine concentration ranged from 2.0 to 9.9 µmol/l (r = 0.821 and p < 0.001).

CONCLUSIONS

It was verified that chemiluminescence is comparable to HPLC when both techniques are used to detect homocysteine in school-age children. There is an important correlation between both methods, which allows investigation of this amino acid as a risk factor for heart diseases.

Obesity and metabolic syndrome: potential benefit from specific nutritional components

The prevalence of metabolic syndrome (MetS) manifestations is rapidly increasing worldwide, and is becoming an important health problem. Actually, MetS includes a combination of clinical complications such as obesity (central adiposity), insulin resistance, glucose intolerance, dyslipidemia, non-alcoholic fatty liver disease and hypertension. All these alterations predispose individuals to type 2 diabetes and cardiovascular disease inducing earlier mortality rates among people. In general terms, it is difficult for patients to follow a standard long-term diet/exercise regime that would improve or alleviate MetS symptoms. Thus, the investigation of food components that may deal with the MetS features is an important field for ameliorate and facilitate MetS dietary-based therapies. Currently antioxidants are of great interest due to the described association between obesity, cardiovascular alterations and oxidative stress. On the other hand, high MUFA and PUFA diets are being also considered due to their potential benefits on hypertension, insulin resistance and triglyceride levels. Mineral composition of the diet is also relevant since high potassium intake may improve hypertension and high calcium consumption may promote lipid oxidation. Thus, although nutritional supplements are at the peak of dietetic therapies, the consumption of some specific foods (legumes, fatty fish, vegetables and fruits, etc) with bioactive components within an energy-restricted diet is a promising approach to manage MetS manifestations. Therefore, the present review focuses on some of the most important food components currently investigated to improve and make easier the nutritional MetS treatment.

Homocysteine and ghrelin link with polcystic ovary syndrome in relation to obesity

AIM

Elevated levels of plasma homocysteine and depressed ghrelin levels have been found to be associated with insulin resistance in a number of clinical situations, such as polycystic ovary syndrome. This study was designed to determine the relationship of plasma homocysteine and ghrelin levels with obesity in polycystic ovary syndrome.

MATERIAL AND METHODS

Forty-four adolescents and young women (24 lean, 20 obese) 16-21 years old with polycystic ovary syndrome and age matched 20 healthy adolescents and young women were participated the study. Fasting samples were collected for serum vitamin B12, folate, plasma total homocysteine and ghrelin levels. Serum levels of follicle-stimulating hormone, luteinizing hormone, dehydroepiandrosterone sulfate, insulin, 17-hydroxyprogesterone, free testosterone, sex-hormone binding globulin were measured. Also, serum concentrations of total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides were determined. Oral glucose tolerance test was done, and HOMA-IR index was used to define insulin resistance.

RESULTS

Plasma total homocysteine levels were significantly higher in women with polycystic ovary syndrome and their plasma ghrelin levels were depressed compared to control group (P < 0.05). Obese adolescents with polycystic ovary syndrome had more depressed plasma ghrelin levels compared to lean ones (P < 0.05). Homocysteine levels didn't correlate with body mass index, but positively correlated with insulin resistance (P < 0.05).

CONCLUSION

Elevated plasma homocysteine levels in polycystic ovary syndrome was independent from obesity. Adversely ghrelin levels were depressed with polycystic ovary syndrome in relation to obesity.

Association between yogurt, milk, and cheese consumption and common carotid artery intima-media thickness and cardiovascular disease risk factors in elderly women

BACKGROUND

Despite the contribution of dairy foods to total dietary saturated fat intake, available data indicate that dairy consumption may lower the risk of cardiovascular disease.

OBJECTIVE

The objective of this study was to investigate the relation between consumption of milk, cheese, and yogurt and common carotid artery intima-media thickness (CCA-IMT) in a cohort of elderly women.

DESIGN

Dairy consumption was assessed with a validated food-frequency questionnaire in 1080 participants randomly selected from ambulant white women aged >70 y living in Perth, Western Australia. CCA-IMT was assessed by using B-mode carotid ultrasound 3 y later. Cardiovascular disease risk factors, including serum lipids and blood pressure, were assessed at baseline.

RESULTS

Total dairy product, milk, and cheese consumption was not associated with CCA-IMT (P > 0.05), whereas yogurt consumption was negatively associated with CCA-IMT (unadjusted standardized β = -0.081, P = 0.008; baseline risk factor-adjusted standardized β = -0.075, P = 0.015). Participants who consumed >100 g yogurt/d had a significantly lower CCA-IMT than did participants with lower consumption (unadjusted = -0.024 mm, P = 0.002). This relation remained significant after adjustment for baseline, dietary, and lifestyle risk factors (multivariable analysis = -0.023 mm, P = 0.003).

CONCLUSION

Increased consumption of yogurt, but not of other dairy products, is associated with a lower CCA-IMT, independent of other risk factors.

Smoking, alcohol, and dietary choices: evidence from the Portuguese National Health Survey

BACKGROUND

Unhealthy lifestyle choices tend to cluster, but controversy remains regarding relationships between smoking and dietary habits. The aim of this study was to compare dietary intake and alcohol consumption, according to smoking status, in the Portuguese population.

METHODS

The study sample included all participants in the third Portuguese National Health Survey who were older than 19 years (20,302 women and 17,923 men). Participants were selected from households in the five regions of Portugal (NUTS II classification), using a multi-stage random probability design. Trained interviewers conducted face-to-face interviews in each household and obtained information on social and demographic characteristics, lifestyle and health, smoking, and intakes of selected food and beverages. Age-adjusted and education-adjusted binomial and multinomial logistic regression models were fitted separately for males and females, to estimate the magnitude of the association between smoking and the consumption of various food and beverage groups.

RESULTS

When heavy smokers were compared with non-smokers, the odds ratio (OR) favouring soup consumption was 0.60 (95% Confidence Interval [95%CI]: 0.54-0.68) in males and 0.46 (95% CI: 0.33-0.65) in females. Similar ORs were observed for vegetables (males: OR = 0.56, 95%CI: 0.49-0.64; females: OR = 0.47, 95%CI: 0.32-0.69) and fruit (males: OR = 0.36, 95%CI: 0.31-0.41; females: OR = 0.29, 95%CI: 0.19-0.44). Overall, these food items were consumed at significantly lower levels as cigarette consumption increased. Heavy male smokers, compared to non-smokers, presented lower odds favouring milk consumption (OR = 0.89; 95%CI: 0.67-0.89). When heavy smokers were compared with non-smokers, the ORs favouring wine drinking, among heavy drinkers, were 1.47 (95%CI: 1.27-1.70) in men and 3.97 (95%CI: 2.07-7.61) in women. Similar ORs were observed for beer (males: OR = 3.30; 95%CI: 2.87-3.78; females: OR = 23.1; 95%CI: 12.2-43.6), Port wine (males: OR = 2.21 95%CI: 1.65-2.98; females: OR = 2.85; 95%CI: 0.68-12.1), brandy (males: OR = 3.67 95%CI: 2.98-4.52; females: OR = 13.2; 95%CI: 3.72-46.6) and whisky (males: OR = 3.31; 95%CI: 2.71-4.03; females: OR = 41.4; 95%CI: 18.5-92.5).

CONCLUSION

This study showed that smokers have a higher intake of alcoholic beverages and a lower consumption of food items rich in fibre, antioxidants, or phytochemicals, which are suspected to have beneficial roles in the prevention of multiple chronic diseases.

Dietary fat and plasma total homocysteine concentrations in 2 adult age groups: the Hordaland Homocysteine Study

BACKGROUND

The intake of n-3 (formerly called omega-3) fatty acids (FAs) may be inversely associated with plasma total homocysteine (tHcy) concentrations, but the epidemiologic data are sparse.

OBJECTIVE

We examined the association between dietary fat and tHcy in a Norwegian population.

DESIGN

A cross-sectional, population-based study of 5917 subjects in 2 age groups (47-49 and 71-74 y old) was conducted with the use of food-frequency questionnaires and measurement of plasma tHcy concentrations.

RESULTS

The intake of saturated FAs (SFAs) was positively and significantly (P for trend < 0.001) associated with tHcy concentrations; the difference in plasma tHcy concentrations between the highest and lowest quartiles of SFAs was 8.8%. The intake of marine very-long-chain n-3 FAs was inversely associated with tHcy concentrations; the difference in plasma tHcy concentrations between the lowest and the highest quartiles was -5.0% (P for trend < 0.001). Intakes of total and monounsaturated fat also were positively associated with plasma tHcy concentrations (P for trend < 0.001 and < 0.005, respectively), whereas the intake of polyunsaturated fat was positively associated with tHcy concentrations only in the younger subjects (P for trend = 0.03). The associations were weakened by additional adjustment for B vitamin intake but remained significant for SFA intake (P < 0.001). When stratified for total B vitamin intake, the inverse association between tHcy concentrations and very-long-chain n-3 FAs was significant only in the highest quartile of B vitamin intake (P for trend = 0.001), regardless of supplement use.

CONCLUSIONS

High intakes of SFAs are associated with high plasma concentrations of tHcy. The inverse association between dietary intakes of very-long-chain n-3 FAs and plasma tHcy concentrations is apparent only at high B vitamin intakes.

Milk and the metabolic syndrome

The metabolic syndrome is a cluster of metabolic disorders, namely dyslipidaemia, hypertension, obesity and glucose intolerance. Insulin resistance is the core phenomenon. Co-occurrence is associated with increased cardiovascular disease (CVD) risk. Observational studies found no increased CVD risk with increasing consumption of milk and other dairy products. In several studies dairy consumption was inversely associated with the occurrence of one or several facets of the metabolic syndrome. Many dairy components may contribute to the beneficial effects. Milk and particularly whey appeared insulinotropic when given in a single meal, but not in longer-term intervention. Medium chain fatty acids improve insulin sensitivity. Whey proteins, amino acids, medium chain fatty acids and in particular calcium and other minerals may contribute to the beneficial effect of dairy products on body weight and body fat. Peptides, calcium and other minerals reduce blood pressure. Fermented products and probiotic bacteria decrease absorption of cholesterol, sphingomyelin of cholesterol and fat, calcium of cholesterol, bile acids and fat. Proteins, peptides and bacteria may also reduce plasma cholesterol. Lactose, citrate, proteins and peptides improve weight control, blood pressure and plasma lipids indirectly, by improving calcium bioavailability. Furthermore, dairy consumption improves the bioavailability of folate and other secondary plant components.

In pregnant women who smoke, caffeine consumption is associated with an increased level of homocysteine

AIM

To investigate whether maternal caffeine consumption is associated with increased maternal homocysteine (Hcy) levels in uncomplicated pregnancies.

METHODS

Ninety-two pregnant women were randomly selected, and maternal serum levels of folate, vitamin B(12), and Hcy at gestational weeks 17 and 33 were measured. Caffeine consumption was estimated from dietary records collected at the same gestational ages.

RESULTS

In women who smoked, Hcy levels were associated with caffeine consumption both in gestational weeks 17 and 33 and with folate at week 33. Consumption of one cup of coffee was associated with an increase in maternal Hcy of 0.26 micromol/l at week 17 and 0.69 micromol/l at week 33, indicating that one extra cup (150 ml) of coffee per day may increase Hcy by 5--10% in pregnant smokers. In non-smokers, caffeine consumption was not associated with Hcy levels.

CONCLUSIONS

In uncomplicated pregnancies, maternal caffeine consumption early in the second and in the third trimester is associated with increased maternal Hcy levels in women who smoked, but not in non-smokers.

Elevated plasma homocysteine concentrations as a predictor of steatohepatitis in patients with non-alcoholic fatty liver disease

BACKGROUND

Although steatosis is common in patients with severe hyperhomocysteinemia due to deficiency of cystathionine beta-synthase, there are no satisfactory data on homocysteine concentrations in patients with non-alcoholic fatty liver disease. The main aim of the present study was to evaluate the clinical significance of plasma homocysteine concentrations in patients with non-alcoholic fatty liver disease.

METHODS

Seventy-one non-alcoholic fatty liver disease patients, 36 patients with chronic viral hepatitis and 30 healthy persons were enrolled in the study. Homocysteine levels were measured by high-performance liquid chromatography. Insulin, folate, vitamin B(12) and lipoprotein levels were also determined in all groups.

RESULTS

Homocysteine in the non-alcoholic fatty liver disease group was found to be significantly higher than other groups. Homocysteine was found to be significantly higher in the non-alcoholic steatohepatitis group when compared with simple steatosis group. A positive correlation was found between homocysteine and triglyceride, very-low-density-lipoprotein (VLDL) cholesterol, insulin, and index of insulin resistance in the non-alcoholic fatty liver disease group, and a negative correlation was found between homocysteine and folate, or vitamin B(12) in all groups. The homocysteine threshold for the prediction of steatohepatitis was 11.935 ng/mL. Furthermore; plasma homocysteine was a statistically significant predictor for severity of necroinflammatory activity in non-alcoholic steatohepatitis.

CONCLUSIONS

The plasma homocysteine concentrations were significantly higher in patients with non-alcoholic fatty liver disease, while the concentrations were not affected by chronic viral hepatitis. Plasma homocysteine is a parameter for discriminating steatohepatitis from simple steatosis. Determining the plasma homocysteine concentrations may facilitate selection of steatosis patients in whom a liver biopsy should be performed.

The association of plasma homocysteine levels with serum leptin and apolipoprotein B levels in childhood obesity

BACKGROUND

An elevated plasma total homocysteine (tHcy) level has recently been established as an independent risk factor for thrombosis and vascular disease. However, the relationship between hyperhomocysteinemia and cardiovascular disease and obesity remains controversial. The aim of the study was to investigate a possible relationship between plasma tHcy levels and measures of childhood obesity.

SUBJECTS AND METHODS

Forty children and adolescents with exogenous obesity and 20 non-obese subjects in an age-and sex-matched control group were investigated. Fasting samples were collected for plasma tHcy, serum insulin, leptin, vitamin B12, folate, creatinine and lipid parameters. Anthropometric characteristics and body compositions were assessed in both groups.

RESULTS

The obese patients had significantly higher tHcy levels than the non-obese controls (14.3+/-11.8 micromol/L vs 8.7+/-5.9 micromol/L; P=0.017). In both groups, plasma tHcy was positively related to serum leptin, but serum apolipoprotein B (apo B) levels were positively related to plasma tHcy levels only in obese patients.

CONCLUSIONS

Our study demonstrates for the first time that leptin and apo B are main correlates of tHcy in obese children and adolescents and suggests that hyperleptinemia and increased apo B may contribute to impairment of tHcy metabolism in childhood obesity.

Prospective evaluation of folic acid supplementation on plasma homocysteine concentrations during weight reduction: a randomized, double-blinded, placebo-controlled study in obese women

Elevated total homocysteine concentrations and obesity are both associated with an increased risk of cardiovascular disease. However, previous studies of weight reduction on serum homocysteine concentrations have obtained inconsistent reports. We investigated the effect of folic acid supplementation on serum homocysteine concentrations via a randomized, double-blinded, placebo-controlled study. Seventy-four obese women [age (mean +/- SEM) 41 +/- 1 years; body mass index, 29.6 +/- 0.5 kgs/m2] completed a 12 weeks weight reduction program with dietary advice and light exercise. They were also randomized to take either folic acid supplementation (5 mg daily, n = 36) or placebo (n = 38) groups. This program led to a weight reduction of 7.7% and 8.9% of initial weight for folic acid supplementation and placebo groups, respectively. Serum folate concentrations increased for 3 folds (p < 0.001) in the folic acid group. In the folic acid group, there was a trend of lower fasting serum homocysteine concentrations (7.6 +/- 0.2 vs. 7.3 +/- 0.3 micromol/L), but it did not reach statistical significance (p = 0.170). However, we found that serum homocysteine concentrations decreased significantly in those with higher baseline homocysteine concentrations (8.7 +/- 1.3 vs. 7.8 +/- 1.5 micromol/L, p = 0.004), while it did not change in those with lower baseline homocysteine concentrations (6.6 +/- 0.6 vs. 6.8 +/- 1.2 micromol/L, p = 0.334). Reduction of serum homocysteine concentrations did not correlate with elevation of serum folate concentrations (p = 0.646) in obese women with higher baseline homocysteine concentrations. In conclusion, serum homocysteine concentrations can be maintained in obese women during mild to moderate weight loss. Folic acid supplementation decreased serum homocysteine concentrations in those women who had higher serum homocysteine concentrations before participating in the weight reduction program.

Negative association between circulating total homocysteine and proinflammatory chemokines MCP-1 and RANTES in prepubertal lean, but not in obese, children

This study investigated in prepubertal obese children (POC), compared with prepubertal lean children (PLC), a possible relation among plasma total homocysteine (tHcy)-an independent risk factor for future atherosclerosis-and MCP-1 and RANTES, two circulating chemokines inducing leukocyte transendothelial migration (TEM), implicated in the initial stages of the inflammatory part of the atherosclerotic process. Seventy-two POC were evaluated for circulating tHcy, MCP-1, and RANTES, and compared with 42 healthy PLC. The mean adjusted (for age, sex as well as log10total insulin, vitB12, folate, total cholesterol, HDL cholesterol, log10triglycerides, and log10glucose levels) differences in tHcy, MCP-1, and RANTES levels between PLC and POC were all significant [1.16 nmol/mL (P = 0.03), 26.6 pg/mL (P = 0.02), and 52.9 pg/mL (P = 0.03), respectively]. In PLC, but not in POC, tHcy levels were negatively associated with both circulating MCP-1 (B = -1.68, P = 0.007) and RANTES (B = -1.16, P = 0.01) after adjusting for age, sex, BMI, as well as log10total insulin, vitB12, folate, total cholesterol, HDL cholesterol, log10triglycerides, and log10glucose levels. In conclusion, in POC there is a lack, in contrast to PLC, of a possibly autoregulatory, negative association of elevated tHcy levels to increased MCP-1 and RANTES levels. This could contribute to future, homocysteine-induced atherosclerosis.

Milk drinking, ischaemic heart disease and ischaemic stroke II. Evidence from cohort studies

OBJECTIVE

Milk consumption is considered a risk factor for vascular disease on the basis of relevant biological mechanisms and data from ecological studies. The aim was to identify published prospective studies of milk drinking and vascular disease, and conduct an overview.

DESIGN

The literature was searched for cohort studies, in which an estimate of the consumption of milk, or the intake of calcium from dairy sources, has been related to incident vascular disease.

MAIN OUTCOME MEASURES

Ischaemic heart disease and ischaemic stroke.

RESULTS

In total, 10 studies were identified. Their results show a high degree of consistency in the reported risk for heart disease and stroke, all but one study suggesting a relative risk of less than one in subjects with the highest intakes of milk. A pooled estimate of relative odds in these subjects, relative to the risk in subjects with the lowest consumption, is 0.87 (95% CI 0.74-1.03) for ischaemic heart disease and 0.83 (0.77-0.90) for ischaemic stroke. The odds ratio for any vascular event is 0.84 (0.78-0.90).

CONCLUSIONS

Cohort studies provide no convincing evidence that milk is harmful. While there still could be residual confounding from unidentified factors, the studies, taken together, suggest that milk drinking may be associated with a small but worthwhile reduction in heart disease and stroke risk.

SPONSORSHIP

The University of Wales College of Medicine and Bristol University. Current support is from the Food Standards Agency.

Folic acid supplement decreases the homocysteine increasing effect of filtered coffee. A randomised placebo-controlled study

OBJECTIVE

Elevated levels of plasma total homocysteine (tHcy) are identified as independent risk factors for coronary heart disease and for fetal neural tube defects. tHcy levels are negatively associated with folic acid, pyridoxine and cobalamine, and positively associated with coffee consumption and smoking. A total of 600 ml of filtered coffee results in a tHcy increase that 200 mug of folic acid or 40 mg of pyridoxine supplementation might eliminate.

DESIGN

Randomised, blinded study with two consecutive trial periods.

SETTING

Free living population. Volunteers.

SUBJECTS

A total of 121 healthy, nonsmoking men and women (78%) aged 29-65 y.

INTERVENTIONS

(1) A coffee-free period of 3 weeks, (2) 600 ml coffee/day and a supplement of 200 mug folic acid/day or placebo for 4 weeks, (3) 3-week coffee-free period, (4) 600 ml coffee/day and 40 mg pyridoxine/day or placebo for 4 weeks.

MAIN OUTCOME MEASURES

The difference between the change in tHcy in the supplement group and the change in tHcy in the placebo group during the 4-week trial period.

RESULTS

Coffee abstention resulted in a tHcy decrease of 1.04 mumol/l for the whole group. In the subsequent coffee period, a further decrease of 0.17 mumol/l was observed in the folic acid group whereas an increase of 1.26 mumol/l was observed in the placebo group, the difference was 1.43 mumol/l (95% CI: 0.80, 2.07). Pyridoxine supplement had no impact on tHcy levels.

CONCLUSIONS

Supplementation of 200 mug folic acid/day eliminates the tHcy increasing effect of 600 ml filtered coffee in subjects not already on folic acid supplements. A supplement of 40 mg pyridoxine/day does not have the same effect.

Insulin sensitivity and plasma homocysteine concentrations in non-diabetic obese and normal weight subjects

OBJECTIVE

To determine whether plasma homocysteine (tHcy) levels were related to insulin resistance and obesity in subjects without diabetes or vascular disease.

RESEARCH DESIGN AND METHODS

We studied correlates of plasma tHcy in 26 subjects covering a wide spectrum of obesity and insulin sensitivity (S(I)). The measurement of in vivo insulin sensitivity was performed using the minimal model analysis of the frequently sampled intravenous glucose tolerance test (FSIVGTT).

RESULTS

There was no relationship between tHcy and body mass index. There was a significant relationship between plasma tHcy and S(I) (r=0.53, P=0.006), demonstrating that the more insulin sensitive subjects had higher levels of tHcy. On log transformation of the plasma insulin values, log insulin correlated negatively with plasma tHcy (r=-0.47; P=0.02). None of the subjects were deficient in vitamin B(12) and folate. Plasma vitamin B(12) was significantly related to plasma tHcy (r=-0.44, P=0.017), although we found no significant relationship between plasma folate and tHcy (r=-0.21, P=0.27). S(I) correlated significantly with vitamin B(12) (r=0.4, P=0.045) whereas, we found no significant relationship between S(I) and plasma folate (r=0.27, P=0.2). On multiple linear regression using tHcy as the dependent variable, S(I) and vitamin B(12) remained significant predictors of plasma tHcy, whereas, age and plasma folate were not predictors of tHcy.

CONCLUSIONS

We conclude that in vitamin replete lean and obese individuals, insulin sensitivity correlates significantly with plasma tHcy. This relationship may need to be considered when evaluating the role of plasma homocysteine as a risk factor in patients with obesity and type 2 diabetes.

Homocysteine, cardiovascular disease risk factors, and habitual diet in the French Supplementation with Antioxidant Vitamins and Minerals Study

BACKGROUND

An elevated plasma total homocysteine (tHcy) concentration seems to increase the risk of cardiovascular disease.

OBJECTIVE

We evaluated the determinants of tHcy in healthy French adults.

DESIGN

tHcy was measured by HPLC and fluorometric detection in 1139 women and 931 men aged 35-60 y. Subjects were participants of the Supplementation with Antioxidant Vitamins and Minerals Study, which investigates the effects of antioxidant supplementation on chronic diseases. Red blood cell folate (RBCF), plasma vitamins B-6 and B-12, and cardiovascular disease risk factors were also measured. The habitual diet was assessed in 616 subjects. Cross-sectional analyses were adjusted for age, smoking, energy intake, and concentration or intake of folate and vitamin B-6, where appropriate.

RESULTS

The mean (+/-SD) tHcy concentration was 8.74 +/- 2.71 micro mol/L in women and 10.82 +/- 3.49 micro mol/L in men. In women, tHcy was positively related to age (P = 0.001), apolipoprotein B (P < 0.01), serum triacylglycerol (P < 0.01), fasting glucose (P = 0.02), and coffee and alcohol consumption (both P < 0.01) and inversely related to RBCF (P = 0.11) and plasma vitamin B-12 (P = 0.08) and vitamin B-6 (P = 0.01) intakes. In men, tHcy was positively associated with body mass index (P = 0.03), blood pressure (P < 0.02), serum triacylglycerol (P < 0.01), fasting glucose (P = 0.01), and energy intake (P < 0.01) and inversely associated with physical activity (P = 0.04), RCBF (P = 0.02), plasma vitamin B-12 (P = 0.09), and dietary fiber (P < 0.01), folate (P = 0.03), and vitamin B-6 (P = 0.09) intakes.

CONCLUSION

To control tHcy, decreasing coffee and alcohol consumption may be important in women, whereas increasing physical activity, dietary fiber, and folate intake may be important in men.

Contribution of caffeine to the homocysteine-raising effect of coffee: a randomized controlled trial in humans

BACKGROUND

A high plasma total homocysteine concentration is associated with increased risk of cardiovascular disease. Consumption of unfiltered or filtered coffee raises total homocysteine concentrations in healthy volunteers. The responsible compound, however, is unknown.

OBJECTIVE

The objective was to determine whether caffeine explains the homocysteine-raising effect of coffee.

DESIGN

Forty-eight subjects aged 19-65 y completed this randomized crossover study with 3 treatments, each lasting 2 wk. Subjects consumed 6 capsules providing 870 mg caffeine/d (test treatment), 0.9 L paper-filtered coffee providing approximately 870 mg caffeine/d, or 6 placebo capsules. Blood samples were drawn fasting and 4 h after consumption of 0.45 L coffee or 3 capsules.

RESULTS

The mean fasting plasma homocysteine concentration after the placebo treatment was 9.6 +/- 3.1 micro mol/L. The caffeine and coffee treatments increased fasting homocysteine by 0.4 micro mol/L (95% CI: 0.1, 0.7; P = 0.04), or 5%, and by 0.9 micro mol/L (95% CI: 0.6, 1.2; P = 0.0001), or 11%, respectively, compared with placebo. The increase in homocysteine concentrations 4 h after consumption of 0.45 L coffee relative to consumption of 3 placebo capsules was 19% (P = 0.0001). Caffeine treatment had a much weaker acute effect on homocysteine (4%; P = 0.09). Effects of caffeine were stronger in women than in men, but the effects of coffee did not differ significantly between men and women.

CONCLUSIONS

Caffeine is partly responsible for the homocysteine-raising effect of coffee. Coffee, but not caffeine, affects homocysteine metabolism within hours after intake, although the effect is still substantial after an overnight fast.

Consumption of high doses of chlorogenic acid, present in coffee, or of black tea increases plasma total homocysteine concentrations in humans

BACKGROUND

In population studies, high intakes of coffee are associated with raised concentrations of plasma homocysteine, a predictor of risk of cardiovascular disease. Chlorogenic acid is a major polyphenol in coffee; coffee drinkers consume up to 1 g chlorogenic acid/d.

OBJECTIVE

We studied whether chlorogenic acid affects plasma total homocysteine concentrations in humans. For comparison we also studied the effects of black tea rich in polyphenols and of quercetin-3-rutinoside, a major flavonol in tea and apples.

DESIGN

In this crossover study, 20 healthy men and women ingested 2 g (5.5 mmol) chlorogenic acid, 4 g black tea solids containing approximately 4.3 mmol polyphenols and comparable to approximately 2 L strong black tea, 440 mg (0.7 mmol) quercetin-3-rutinoside, or a placebo daily. Each subject received each of the 4 treatments for 7 d, in random order.

RESULTS

Total homocysteine in plasma collected 4-5 h after supplement intake was 12% (1.2 micromol/L; 95% CI: 0.6, 1.7) higher after chlorogenic acid and 11% (1.1 micromol/L; 95% CI: 0.6, 1.5) higher after black tea than after placebo. Total homocysteine in fasting plasma collected 20 h after supplement intake was 4% (0.4 micromol/L; 95% CI: 0.0, 0.8) higher after chlorogenic acid and 5% (0.5 micromol/L; 95% CI: 0.0, 0.9) higher after black tea than after placebo. Quercetin-3-rutinoside did not significantly affect homocysteine concentrations.

CONCLUSIONS

Chlorogenic acid, a compound in coffee, and black tea raise total homocysteine concentrations in plasma. Chlorogenic acid could be partly responsible for the higher homocysteine concentrations observed in coffee drinkers. Whether these effects on homocysteine influence cardiovascular disease risk remains to be established.

Screening of plasma homocysteine in peripheral arterial disease

BACKGROUND

Homocysteine (HCY) was recently established as an independent risk factor for atherosclerosis. The prevalence of an increased homocysteine plasma concentration was reported to be up to 6-fold higher in patients with different locations of arterial occlusive diseases.

AIM

This study evaluated critically whether the total HCY plasma concentration can be used as a screening marker for peripheral arterial disease in the general population.

METHODS

Study subjects were 40 patients (51.8 +/- 7.5 years) with symptomatic lower limb peripheral arterial disease (PAD) (stage II) and 40 healthy volunteers (45.6 +/- 6.8 years, P< 0.05 vs PAD). The percentage of women in both groups was 30%. The plasma HCY concentration was determined by using derivatization techniques and subsequent fluorescence high-performance liquid chromatography.

RESULTS

Total plasma HCY concentration was significantly higher in the PAD group than in controls (14.90 +/- 5.78 microM vs 11.32 +/- 2.95 microM, respectively, P< 0.001). Also, the coefficient of variation of plasma HCY in PAD was significantly higher than that in the control group, 0.38 vs 0.25 (P< 0.001), respectively, reflecting greater interindividual differences. In addition to a PAD-specific effect, the plasma HCY concentration was also dependent on gender and age (both P< 0.05). Sensitivity and specificity of HCY as a marker of PAD were 0.3 and 0.95, respectively. Positive and negative predictive values were 0.85 and 0.42, respectively.

CONCLUSIONS

From these data it is concluded that HCY metabolism may have an influence on the development of PAD in one-third of all patients with PAD, and that total plasma HCY concentration may not be suited as a screening test for PAD in the general population but rather serves as a monitoring marker in certain risk groups.

Bioactive substances in milk with properties decreasing risk of cardiovascular diseases

Milk is often seen as a potential promotor of atherosclerosis and coronary heart disease because it is a source of cholesterol and saturated fatty acids. But there are several studies indicating that milk and milk products may not affect adversely blood lipids as would be predicted from its fat content and fat composition. There are even factors in milk and milk products which may actively protect from this condition by improving several risk factors. Calcium, bioactive peptides and as yet unidentified components in whole milk may protect from hypertension, and folic acid, vitamin B6 (pyridoxine) and B12 (cyanocobalamin) or other unidentified components of skim milk may contribute to low homocysteine levels. Conjugated linoleic acid may have hypolipidaemic and antioxidative and thus antiatherosclerotic properties. Epidemiological studies suggest that milk and milk products fit well into a healthy eating pattern emphasizing cereals and vegetables.

Heavy coffee consumption and plasma homocysteine: a randomized controlled trial in healthy volunteers

BACKGROUND

An elevated plasma concentration of total homocysteine is considered to be a strong risk factor for cardiovascular disease. Heavy coffee drinking has been related to high homocysteine concentrations in epidemiologic studies and in one experiment in which healthy subjects drank unfiltered, boiled coffee.

OBJECTIVE

Our goal was to determine whether daily consumption of paper-filtered coffee raises plasma concentrations of total homocysteine in healthy subjects.

DESIGN

Twenty-six volunteers (18-53 y of age) consumed 1 L/d of paper-filtered coffee brewed with 70 g regular ground beans or no coffee for 4 wk each in a randomized, crossover design.

RESULTS

The mean (+/-SD) plasma concentration of total homocysteine in fasting blood was 8.1 +/- 1.8 micromol/L after abstention from coffee and 9.6 +/- 2.9 micromol/L after 3-4 wk of coffee drinking, a difference of 1.5 micromol/L (95% CI: 0.9, 2.1 micromol/L) or 18% (P: < 0.001). Coffee increased homocysteine concentrations in 24 of 26 individuals. Circulating concentrations of vitamin B-6, vitamin B-12, and folate were unaffected.

CONCLUSION

Drinking large quantities of paper-filtered coffee raises fasting plasma concentrations of total homocysteine in healthy individuals.

Folate intake, lifestyle factors, and homocysteine concentrations in younger and older women

BACKGROUND

An elevated total homocysteine (tHcy) concentration is considered to be an independent risk factor for cardiovascular diseases and has also been associated with an increased risk of neural tube defects.

OBJECTIVE

The objective of this study was to investigate folate intake, folate status, and the association between folate intake, other dietary and lifestyle factors, and tHcy concentrations in young and older women.

DESIGN

tHcy concentrations were measured in 290 young women aged 25-30 y and in 288 older women aged 60-65 y. All participants completed questionnaires about factors including lifestyle, health, and use of vitamin supplements. Red blood cell folate was measured in 204 of the participants. A subgroup of 258 participants completed dietary records.

RESULTS

Median tHcy was 7.6 micromol/L (range: 6.5-8.9) in the younger women and 9.4 micromol/L (7.7-11.1) in the older women. Folate intake from diet was 283 (224-348) and 268 (210-326) microg/d, respectively, in the 2 age groups. Folic acid intake from supplements (P: < 0.001 for the younger women and P: = 0.026 for the older women) and total folate intake (P: = 0.024 and P: = 0.079) were inversely associated with log tHcy in multiple linear regression analyses. Smoking status, coffee consumption, systolic blood pressure, and body mass index were positively associated and estrogen replacement therapy and tea consumption were inversely associated with log tHcy in some of the models.

CONCLUSIONS

According to the criteria used, between 1% and 36% of the women had suboptimal folate intake. Folic acid is a strong predictor of tHcy concentration; however, several dietary and other lifestyle factors seem to be important as well.