Paraoxonase 1 Q192R (PON1-192) polymorphism is associated with reduced lipid peroxidation in healthy young men on a low-carotenoid diet supplemented with tomato juice

The HDL-bound enzyme paraoxonase (PON) protects LDL from oxidation and may therefore attenuate the development of atherosclerosis. We examined the effect of tomato and carrot juice consumption on PON1 activity and lipid peroxidation in healthy young volunteers with different PON1-192 genotypes (Q/R substitution at position 192). In this randomized cross-over study twenty-two healthy, non-smoking men on a low-carotenoid diet received 330 ml/d tomato juice (37.0 mg lycopene, 1.6 mg beta-carotene) or carrot juice (27.1 mg beta-carotene, 13.1 mg alpha-carotene) for 2 weeks. Intervention periods were preceded by 2-week low-carotenoid intake. We determined the PON1-192 genotype by restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR) and measured ex vivo LDL oxidation (lag time), plasma malondialdehyde and PON1 activity at the beginning and end of each intervention period. At baseline, lag time was higher (P<0.05) in QQ (111 (sd 9) min) than in QR/RR subjects (101 (sd 8) min). Neither tomato nor carrot juice consumption had significant effects on PON1 activity. However, tomato juice consumption reduced (P<0.05) plasma malondialdehyde in QR/RR (Delta: -0.073 (sd 0.11) micromol/l) as compared to QQ subjects (Delta:+0.047 (sd 0.13) micromol/l). Carrot juice had no significant effect on malondialdehyde irrespective of the PON1-192 genotype. Male volunteers with the QR/RR genotype showed an increased lipid peroxidation at baseline. Although tomato and carrot juice fail to affect PON1 activity, tomato juice intake reduced lipid peroxidation in healthy volunteers carrying the R-allele of the PON1-192 genotype and could thus contribute to CVD risk reduction in these individuals.     

Plasma concentrations of carotenoids in healthy volunteers after intervention with carotenoid-rich foods

Summary Aim of the study: The present study was conducted to investigate changes in the plasma concentration of carotenoids and carotenoid oxidation products, vitamin A, α- and γ-tocopherol, and ubiquinone-10 during a dietary intervention trial with 23 male healthy volunteers. Method: A two week carotenoid depletion period was followed by a daily consumption of 330 mL tomato juice (40 mg lycopene), then by 330 mL carrot juice (15.7 mg α-carotene and 22.3 mg β-carotene), and then by a 10 g spinach powder preparation (11.3 mg lutein and 3.1 mg β-carotene) served with main meals for two weeks, respectively. Blood samples were collected in the morning after an overnight fasting and carotenoids, vitamin A, tocopherols, and ubichinone were analyzed by reversed-phase HPLC. Results: During the tomato juice intervention, plasma concentrations of trans- and cis-lycopene increased 2-fold compared to the depletion period. Lycopene oxidation products could be demonstrated in plasma and were significantly elevated compared to control (p<0.001). After two weeks of carrot juice consumption, α-carotene and β-carotene concentrations increased 8.6- and 3.2-fold, respectively. Finally, during the spinach consumption period the lutein concentration increased 2-fold, while the β-carotene concentrations were still elevated 2-fold. Conclusions: The moderate change in dietary habits, e.g., the consumption of 330 mL of carotenoid-rich vegetable juices caused significant changes in the plasma carotenoid concentrations, indicating a high bioavailability of carotenoids from the processed vegetable products. The changes in plasma carotenoid concentrations reflected the carotenoid composition of the consumed foods. However, particularly during the tomato juice intervention period the occurrence of lycopene oxidation products and cis-lycopene isomers in plasma was eminent. The formation may be due to antioxidant reactions of lycopene in the organism. Received: 30 September 1998, Accepted: 11 November 1998     

Functionality of endogenous folates from rye and orange juice using human <Emphasis Type="Italic">in vivo</Emphasis> model

Summary. Background: Cereals contribute about a quarter of the daily folate intake from a typical diet in several European countries. However, studies on bioavailability of endogenous folates, in particular of cereal sources, are scarce. Aim of the study: We aimed to study how well natural folates from rye (different rye breads and muesli made of malted rye) and orange juice function in improving folate status of human volunteers compared to a diet containing folic acid fortified wheat bread. Methods: Healthy human volunteers aged 20–66 y took part in a four-week intervention trial in which bread, breakfast cereal and juice were provided. The study had a parallel design with two groups, 1) rye and orange juice group (33 volunteers) and 2) fortified wheat bread and apple juice group (31 volunteers). The test foods provided on average 184 μg and 188 μg folate per day in rye and wheat groups, respectively. Test foods were consumed as part of the subjects' normal diet. Results: In both groups statistically significant increases in serum and red cell folates were observed after the intervention period. The serum folate increased 26 % and 31 %, and red cell folate levels increased 17 % and 15 % in rye and orange juice and wheat and apple juice groups, respectively. The effects did not differ between the rye and wheat groups. Increases in serum and red cell folate were more profound among subjects with low starting folate levels. Decrease in the plasma homocysteine concentrations was observed only in the highest tertile of both groups but not in the group means. Conclusions: Endogenous folates incorporated into a healthy diet, even in moderate amounts, is an efficient way to improve folate status among healthy adults. Folates from different rye products and orange juice showed good bioavailability that was similar to folic acid from fortified white bread. Received: 19 July 2002, Accepted: 6 October 2002 Correspondence to: Dr. Liisa Vahteristo     

Intestinal absorption of lycopene from different matrices and interactions to other carotenoids, the lipid status, and the antioxidant capacity of human plasma

Summary Background: The bioavailability of carotenoids has been investigated in animal studies as well as in human studies, so far mostly for β-carotene. Only few results exist for lycopene. In recent studies, lycopene was significantly better available from processed tomatoes compared to raw tomatoes, when using daily intakes between 16.5 mg and 75 mg lycopene. Aim of the study In a comparative study the availability of a low oral lycopene dosage of 5 mg/d from different food matrices versus soft gel capsules containing tomato oleoresin was assessed. In addition to the plasma carotenoid content, the effect of lycopene ingestion on other plasma carotenoids, the lipid status parameters, and the antioxidant activitys was estimated. Methods Twenty-two female adults (20 – 27 y) were randomized in three groups and were advized to minimize their carotenoid intake for two weeks. After this initial period, two groups received a portion of tomatoes or tomato juice adjusted to a lycopene dose of 5 mg/d, the third group ingested the same dose comprized in soft gel capsules containing tomato oleoresin. During the test period of 6 weeks, the participants continued reducing the intake of carotenoids from food. Fasting blood samples were withdrawn prior to the study, before supplementation started, and then weekly while supplemented. Seven-day dietary records were prepared before the study started and after one week of supplementation. Carotenoids were analyzed by reversed phase HPLC with diode array detection. Dietary records were evaluated using the computer software EBIS 2.1. The plasma total cholesterol, HDL cholesterol, and triglycerides were determined enzymatically. In addition, the antioxidant activity of plasma was estimated by using the TEAC and the TRAP assays. Results The basal levels of lycopene in plasma were comparable for all groups (0.2 – 0.3 μmol/l) and decreased significantly during the two weeks of depletion to approximately 50 % of the basal values. Other plasma carotenoids such as β-carotene and β-cryptoxanthin decreased significantly, too, whereas lutein and zeaxanthin remained unchanged. After supplementation with tomato oleoresin capsules or tomato juice, the plasma lycopene increased significantly, while it remained unchanged during intake of tomatoes. Normal dietary habits were practized of all volunteers before and during the study except vitamin C whose intake was significantly lower during the study period, because the probands were recommended to reduce the intake of fruits and vegetables. Lycopene supplementation did not affect the lipid status parameters of the three groups. After ingestion of lycopene the antioxidant activity of the plasma was not altered. Mean TEAC values were estimated to 0.33 ± 0.05 mmol/l and TRAP values to 1.0 ± 0.1 mmol/l and showed no significant differences in all groups during the whole study period. Conclusions The bioavailability of lycopene varied significantly depending on the administered matrix. Lycopene from tomato oleoresin capsules and tomato juice (processed tomatoes) was better absorbed from the intestine than lycopene from raw tomatoes. The daily intake of 5 mg lycopene, an intake comparable to the usual daily carotenoid intake, did not affect cholesterol and triglycerides in plasma or its antioxidant capacity. Received: 1 March 1999, Accepted: 30 April 1999     

Alcohol, cigarette smoking, dietary factors and the risk of colorectal adenomas and hyperplastic polyps – a case control study

Summary Background & aims Epidemiological studies on the association between lifestyle factors and the risk of colorectal polyps have led to conflicting results. The aim of the present study was to assess the relationship between alcohol consumption, dietary risk factors, cigarette smoking and colorectal adenomas or hyperplastic polyps, respectively. Methods Information on alcohol consumption, a detailed dietary history, cigarette smoking and intake of non-steroidal anti-inflammatory drugs was collected among 502 Caucasian subjects undergoing complete colonoscopy, 207 with colorectal adenomas, 71 with hyperplastic polyps and 224 controls with no polyps. Results Using univariate analysis significant risk factors for adenomas were age above 55 years, male sex, BMI > 24 (OR 1.91 [1.26–2.88]), an intake of ham + sausage > 15 g/day (OR 1.87 [1.12–3.11]) and smoking (OR 1.71 [1.17–2.5]). The association with alcohol intake > 7 g/day was not significant (OR 1.42 [0.97–2.07], p = 0.071). In the multiple logistic regression only age > 55 years (OR 2.97 [1.94–4.52]), male sex (OR 2.12 [1.54–3.6]) and smoking (OR 1.56 [1.01–2.39]) were significant risk factors for adenomas. Unexpectedly the mean consumption of alcohol, wine and beer, was significantly lower in subjects in whom adenomas were localized only in the rectum compared to those having adenomas in the sigmoid or in the proximal colon. Significant risk factors in subjects with hyperplastic polyps on univariate analysis were intake of > 15 g of ham and sausage/day (OR 3.70 [1.49–9.19]), smoking (OR 1.79 [1.04–3.06]) and male sex. In the multiple logistic regression only intake of > 15 g/day of ham + sausage and male sex were significant risk factors (OR 3.24 [1.23–140.8] and 1.83 [1.05–318], respectively). Conclusion When controlling for other potential risk factors, smoking was the only significant lifestyle risk factor for colorectal adenomas and the intake of ham and sausage > 15 g/day for hyperplastic polyps. The intake of alcohol, wine and beer were markedly higher in subjects with adenomas of the colon compared to those with adenomas in the rectum. Received: 16 October 2001, Accepted: 16 January 2002     

Arylesterase activity and antioxidant status depend on PON1-Q192R and PON1-L55M polymorphisms in subjects with increased risk of cardiovascular disease consuming walnut-enriched meat

Human paraoxonase (PON1) exists in 2 major polymorphic forms and has been shown to protect LDL and HDL against oxidation. The aim of this study was to assess the differences between subjects at increased risk of cardiovascular disease (CVD), taking into account the effects of PON1-Q192R and PON1-L55M polymorphisms on 1) basal serum arylesterase activity, lipid peroxidation (LPO), and LDL-cholesterol (LDL-C), HDL-C, total cholesterol (TC), and oxidized-LDL (ox-LDL) concentrations; 2) the relations between arylesterase activity and lipid variables; and 3) the effect of walnut-enriched meat (WM) consumption on arylesterase activity and lipid variables. Twenty-three Caucasians at increased risk of CVD were randomly assigned to diet order groups in a crossover, nonblinded, placebo-controlled trial, consisting of two 5-wk experimental periods [WM and control meat (CM)]. Significant PON1-L55M x PON1-Q192R interactions affected basal serum HDL-C (P = 0.019), LDL-C (P = 0.028) and TC (P = 0.022) and tended to affect arylesterase activity (P = 0.083). Basal arylesterase activity was positively correlated with basal HDL-C (r = 0.53; P < 0.05) and TC (r = 0.43; P < 0.05) and negatively correlated with LPO (r = -0.70; P < 0.01) and the ox-LDL:LDL ratio (r = -0.63; P < 0.01). WM decreased arylesterase activity in PON1-55M carriers (P = 0.012) but not in PON1-L55 individuals, and decreased LPO concentrations in PON1-192R carriers (P = 0.031) but not in PON1-Q192 subjects. To conclude, serum TC, HDL-C, and LDL-C concentrations and arylesterase activity depend on the interaction of PON1-L55M and PON1-Q192R polymorphisms. However, the PON1-Q192R polymorphism is more closely related to antioxidant status. Both polymorphisms modulate the effect of WM consumption on CVD biomarkers.     

The efficacy of dietary intervention alone or combined with hormone replacement therapy in postmenopausal women with hypercholesterolemia in Seoul,Korea

Summary Background Women have an increased incidence of cardiovascular disease (CVD) due to hormone imbalance-induced changes in blood lipid profiles after menopause. Aim of study This study was done to compare the effects of dietary intervention and hormone replacement therapy, alone or in combination, on blood lipids and body weight in Korean postmenopausal women with hypercholesterolemia. Method The subjects were treated by one of three different treatments for 12 weeks: hormone replacement therapy (HRT group, n = 8), dietary intervention (DIET group, n = 8) and hormone replacement therapy combined with dietary intervention (HRT+DIET group, n = 8). Results Serum TC and LDL-C levels decreased by 13–16 % and 24–28 % in the HRT group, by 17–19 % and 21–23 % in the DIET group and by 19–26 % and 32–39 % in the HRT+DIET group, respectively (P < 0.05). Serum HDL-C levels decreased in the DIET group (−6.4 %, P < 0.05) but not in the HRT and HRT+DIET groups. Serum TG levels increased in the HRT group (18 %, P < 0.05) but decreased in the DIET group (−24.4 %, P < 0.05). In the HRT+ DIET group, serum TG levels did not change. Body weight decreased only in the DIET group. Conclusions We can conclude that dietary intervention produces a considerable improvement in blood lipid profiles and body weight, even though our study is limited by the sample size. Thus, the treatment to reduce risk of CVD should be individualized on the basis of the patient's dietary intake status, and at least, HRT should not be substituted for dietary intervention. Received: 16 July 2001, Accepted: 18 February 2002     

Plasma concentration response to drinks containing beta-carotene as carrot juice or formulated as a water dispersible powder

Summary. Background: Bioavailability of β-carotene is highly variable and depends on the source, the formulation and other nutritional factors. Objective: It was the aim of the study to compare β-carotene plasma response to b-carotene dosing with two commercially available drinks, containing β-carotene from carrot juice or as water dispersible β-carotene powder. Design In a randomized, parallel group study design, 4 volunteers per group received daily β-carotene doses of 6–7 or 18–22 mg of either drink over 6 weeks. Blood samples for determination of carotenoid and vitamin A plasma concentrations were collected before supplementation and over the dosing period. Results: Apparent steady-state β-carotene concentrations were attained after 40 days of supplementation. Consumption of the beverage containing β-carotene as a water dispersible powder resulted in a higher response of β-carotene plasma concentrations with increments of 3.84 ± 0.60 μmol/L (p < 0.05, dose: 7.2 mg/d) and 5.04 ± 0.72 μmol/L (p < 0.05, dose: 21.6 mg/d), respectively, in comparison to the carrot juice-based drink with increments of 0.42 ± 0.33 μmol/L (dose: 6 mg/d) and 1.71 ± 0.55 μmol/L (dose: 18 mg/d), respectively. β-carotene was cleared from the plasma with an apparent half-life of 6–11 days. Plasma concentrations of α-carotene, β-cryptoxanthin, lutein, zeaxanthin, and lycopene remained almost unchanged, whereas retinol plasma concentrations increased slightly. By contrast, with the exception of elevated 13-cis-retinoic acid in one group (21.6 mg/d, water dispersible powder), the concentrations of all-trans-retinoic acid, and the oxo-derivatives or retinoic acid were not significantly affected by b-carotene supplementation. Conclusions: The results confirm that the relative bioavailability of β-carotene depends largely on the source of b-carotene and demonstrate the superior bioavailability of β-carotene powder in comparison to that in carrot juice. Received: 7 May 2002, Accepted: 22 August 2002 This work was supported by a grant from F. Hoffmann-La Roche Ltd., Vitamins and Nutrition Research, Basle, Switzerland. Correspondence to: Prof. Dr. med. Petra A. Thürmann     

A phytosterol-enriched spread improves the lipid profile of subjects with type 2 diabetes mellitus

Summary. Background: Phytosterol-enriched margarines are known to significantly lower total and LDL cholesterol, but little is known about the effect of such margarines in subjects with type 2 diabetes. Aim of the study: Investigation of the effect of a phytosterol-enriched spread in subjects with type 2 diabetes mellitus on serum lipids, Hb_A1c, and blood glucose under free-living conditions. Methods: Randomized, placebo-controlled, double-blind clinical trial in two parallel groups over 12 weeks; 85 type 2 diabetic patients with serum LDL cholesterol levels ≥ 3.60 mmol/l and without hypolipidemic medication were included in the study. Participants consumed 2 × 10 g of spread with or without 8 % phytosterol-esters daily. Fasting blood samples were analyzed at 0, 4, 8, and 12 weeks. Results: After 4 weeks, total and LDL cholesterol were significantly reduced in the phytosterol group by 5.2 % and 6.8 %, respectively, compared to baseline (p < 0.05). After 8 and 12 weeks, these reductions became smaller and were not significant any more compared to baseline or between the groups, but a repeated measurement analysis demonstrated a significant difference for both variables between the two groups (each p < 0.05). HDL cholesterol was significantly increased in the phytosterol group compared to the placebo group after 8 and 12 weeks, but there was no overall difference in the repeated measurement analysis between the two groups. In the phytosterol group, there was a small reduction in Hb_A1c compared to the control group which was only significant after 4 weeks. Conclusions: This clinical study shows that a phytosterol-enriched spread is effective in lowering total and LDL cholesterol in subjects with type 2 diabetes but also illustrates the difficult maintenance under free-living conditions over time. Although this effect is modest, it may contribute to decreasing the elevated risk of cardiovascular disease in type 2 diabetes. Received: 20 September 2002, Accepted: 26 November 2002 Correspondence to: H. Hauner     

Spinach and tomato consumption increases lymphocyte DNA resistance to oxidative stress but this is not related to cell carotenoid concentrations

Summary Background The increased consumption of fruit and vegetables has been linked to protection against different chronic diseases, but the dietary constituents responsible for this association have not been clearly identified. Aim of the study We evaluated the effect of spinach and spinach+tomato puree consumption on cell DNA resistance to an oxidative stress. Methods To this aim, in a dietary controlled intervention study, 9 healthy female volunteers consumed a basal diet low in carotenoids (< 600 μg/day) enriched with daily portions (150 g) of spinach (providing about 9 mg lutein, 0.6 mg zeaxanthin, 4 mg β-carotene) for 3 weeks (from day 0 to day 21) followed by a 2 week wash-out period (basal diet) and finally another 3 weeks (from day 35 to day 56) of diet enriched with daily portions of spinach (150 g) + tomato puree (25 g, providing about 7 mg lycopene, 0.3 mg β-carotene). At the beginning and the end of each period of vegetable intake, blood samples were collected for lymphocyte separation. Carotenoid concentrations of lymphocytes were determined by HPLC and DNA damage was evaluated by the comet assay following an ex vivo treatment with H₂O₂. Results During the first period of spinach consumption, lymphocyte lutein concentration did not increase significantly (from 1.6 to 2.2 μmol/10¹² cells) while lycopene and β-carotene concentrations decreased significantly (from 1.0 to 0.1 μmol/10¹² cells, P < 0.001, and from 2.2 to 1.2 μmol/10¹² cells, P < 0.05, respectively). Lutein and lycopene concentrations increased after spinach+tomato puree consumption (from 1.2 to 3.5 μmol/10¹² cells, P < 0.01, and from 0.1 to 0.7 μmol/10¹² cells, P < 0.05, respectively). The increase may be attributed to the addition of tomato puree to spinach; however, the different concentrations of carotenoids in lymphocytes registered at the beginning of the two intervention periods may have affected the results. DNA resistance to H₂O₂ insult increased significantly after both the enriched diets (P < 0.01); however, no “additive effect” was seen after spinach + tomato puree consumption. In the spinach + tomato intervention period an inverse correlation was observed between lymphocyte lycopene concentration and DNA damage, but this seems not able to explain the protection observed. Conclusions The consumption of carotenoid-rich foods even for a short period of time gives protection against oxidative stress. The results obtained seem to suggest that this protective role is not specifically related to carotenoids. However they may contribute together with other substances present in vegetables to lymphocyte resistance to oxidative damage. Received: 20 September 2001, Accepted: 18 February 2002     

Beta(2)-adrenergic receptor mutation and abdominal obesity risk: effect modification by gender and HDL-cholesterol

Summary Objective and design A case-control study was conducted to examine the association between the 27Glu polymorphism of the β₂-adrenergic receptor gene (ADRB2) and the risk of abdominal obesity (defined by a waist/hip ratio: WHR higher than 0.85). Methods The case series encompassed 112 obese subjects with body mass index (BMI) > 30 kg/m² and WHR > 0.85 and no other major disease except for type 2 diabetes, while the controls were 127 healthy subjects, BMI < 25 kg/m² and WHR < 0.85. Results The association between the risk of abdominal obesity and the 27Glu polymorphism was estimated using multivariate logistic regression. A higher crude odds ratio (OR) of 4.08 (95 % confidence interval: 0.98–16.3) for the 27Glu allele was found among men, while no increased risk was apparent among female participants. Moreover, when the model was adjusted for age, male subjects carriers of the 27Glu allele had a significant ten-fold higher risk of abdominal obesity (OR = 10.31; 95 % CI: 1.4–76.8) and the product-term for the interaction (effect modification) between gender and the ADRB2 mutation was near to the limits of statistical significance (Likelihood ratio test p = 0.056). Interestingly, we also found an effect modification with higher OR among individuals with low HDL-cholesterol (< 1.5 mmol/l) after adjustment for age and gender (OR = 2.87 95 % CI 1.09–7.50) and the product-term for interaction between the 27Glu allele and HDL-cholesterol was statistically significant (Likelihood ratio test p = 0.003). Conclusions. Our results showed that the 27Glu allele of the ADRB2 gene appears to be a risk factor for abdominal obesity among male subjects, specially among those with lower HDL-cholesterol levels. Received: 26 November 2001, Accepted: 2 March 2002     

Relationship between diet and blood pressure in a representative Mediterranean population

Summary. Background: Hypertension is strongly associated with cardiovascular and renal disease. However, despite the efforts made to control hypertension via drug treatment, prevalence of controlled hypertension could be considered low. Aim of the study: We performed the present study to investigate dietary habits among groups with different blood pressure status (normotensive, non-medicated hypertensive, medicated hypertensive) and to analyze the association between blood pressure and intakes of selected nutrients in normotensive and non-medicated hypertensive subjects (n = 1357), and furthermore in those undergoing hypertension drug treatment (n = 210; controlled and non-controlled). Methods: The present cross-sectional, population-based survey (Gerona, Spain) included cardiovascular risk measurements and analysis of dietary intake with corresponding questionnaires. Results: Nutrient intake was similar among groups of different blood pressure status after adjusting for sex, age and energy consumption. Multiple linear regression analysis, after adjustment for several confounders, showed that dietary intake of sodium was directly related to blood pressure. The same was seen for the sodium to potassium ratio and both were independent of hypertension drug treatment. In contrast, an inverse association was observed between blood pressure and dietary calcium intake. Moderate sodium (< 2400 mg Na/d) intake reduced the risk of hypertension by 30 % and 52 % (Odds ratio 0.70; 95 % CI 0.52–0.94, respectively) in normotensive and non-medicated hypertensive subjects. Furthermore, moderate sodium in combination with a calcium intake of more than 800 mg/d reduced the risk of inadequate blood pressure control, by 52 % (Odds ratio 0.48; 95 % CI 0.24–0.95) in subjects undergoing hypertension drug treatment. Controlled hypertension subjects have a significantly higher calcium intake than non-controlled. Conclusion: These results emphasize the importance of diet and overall of sodium intake as non-pharmacological approach in the prevention and treatment of hypertension. Received: 19 November 2001, Accepted: 20 June 2002     

The status of plasma homocysteine and related B-vitamins in healthy young vegetarians and nonvegetarians

Summary. Background: Exclusion of animal products and having only plant protein in vegetarian diets may affect the status of certain B-vitamins, and further cause the elevation of plasma homocysteine concentration. Aim: The purpose of this study was to assess the status of homocysteine and related B-vitamins in vegetarians and nonvegetarians. The effects of biochemical parameters of B-vitamins and dietary protein on plasma homocysteine were also examined. Methods: The study was performed at the Chung Shan Medical University, Taichung, in the central part of Taiwan. Thirty-seven vegetarians (28.9 ± 5.5 y) and 32 nonvegetarians (22.9 ± 1.6 y) were recruited. Nutrient intake was recorded using 3-day dietary records. Fasting venous blood samples were obtained. Plasma homocysteine, folate and vitamin B-12 were measured. Vitamin B-6 status was assessed by direct measures [plasma pyridoxal 5'-phosphate (PLP) and urinary 4-pyridoxic acid (4-PA)] and indirect measures [erythrocyte alanine (EALT-AC) and aspartate (EAST-AC) aminotransaminase activity coefficient]. Results: There was no significant difference in vitamin B-6 intake between the two groups, although the vegetarian group had a significantly lower vitamin B-12 intake than the nonvegetarian group. Vegetarian subjects had significantly lower mean plasma PLP and vitamin B-12 concentrations than did nonvegetarian subjects (p < 0.05); however, a significantly higher mean plasma folate concentration was found in the vegetarian group. Vegetarian subjects had a significantly higher mean plasma homocysteine concentration than nonvegetarian subjects (13.2 ± 7.9 vs. 9.8 ± 2.2 μmol/L). Negative correlations were seen between plasma homocysteine and vitamin B-12 concentrations in the vegetarian (p = 0.004), nonvegetarian (p = 0.026), and pooled (p < 0.001) groups. From best subsets regression analyses, the plasma homocysteine concentration could be significantly predicted by total protein intake (p = 0.027) and plasma vitamin B-12 concentration (p = 0.005) in the pooled group. When the intake of protein is not considered, vitamin B-12 concentration is still a strong predictor of plasma homocysteine concentration (p = 0.012). Conclusions: Vitamin B-12 intake and mean plasma vitamin B-12 concentration were lower for vegetarian subjects than for nonvegetarian subjects, leading to an increase in plasma homocysteine concentration. Vitamin B-6 and folate had little effect on plasma homocysteine concentration when individuals had adequate vitamin B-6 and folate status. Received: 15 July 2002, Accepted: 24 October 2002 The study was supported by National Science Council (NSC 89–2320-B-040–046), Taiwan. Correspondence to: Y. C. Huang     

Absorption and DNA protective effects of flavonoid glycosides from an onion meal

Summary Background. It is widely believed that antioxidant micronutrients obtained from fruit and vegetables afford significant protection against cancer and heart disease, as well as ageing. Flavonoids are potential antioxidants found in food such as onions; information on their effectiveness in vivo is so far lacking. Aims. To determine uptake as well as in vivo antioxidant effects of flavonoids from foods. Methods. Six healthy non-obese normocholesterolaemic female volunteers in the age range 20–44 years participated in a randomised two-phase crossover supplementation trial to compare the antioxidant effects associated with (a) a meal of fried onions and (b) a meal of fried onions and fresh cherry tomatoes. Plasma flavonoids, lymphocyte DNA damage, plasma ascorbic acid, tocopherols and carotenoids, urinary malondialdehyde and 8-hydroxy-2’-deoxyguanosine were determined to assess flavonoid absorption and antioxidant efficacy. Results. Flavonoid glucosides (quercetin-3-glucoside and isorhamnetin-4-glucoside) were significantly elevated in plasma following ingestion of the onion meal and the increases were associated with an increased resistance of lymphocyte DNA to DNA strand breakage. A significant decrease in the level of urinary 8-hydroxy-2’-deoxyguanosine was evident at 4 h following ingestion of the onion meal. After the combined tomato and onion meal, only quercetin was detected in plasma. Endogenous base oxidation was decreased but resistance to strand breakage was unchanged. There was no significant change in the excretion of urinary malondialdehyde following either meal. Conclusion. Both meals – onions, and onions together with tomatoes – led to transient decreases in biomarkers of oxidative stress, although the particular biomarkers affected differ. It is possible that the differences in patterns of response reflect the different uptakes of flavonoids but the underlying mechanism is not understood. Received: 1 April 2000, Accepted: 1 August 2000     

Relationship between Paraoxonase 1 (PON1) gene polymorphisms and susceptibility of stroke: a meta-analysis

Genetic variants of paraoxonase 1 (PON1) were implicated in stroke susceptibility in several case–control association studies. However, the studies have reported apparently conflicting results, rendering precise assessment of the disease risk associated with the variants difficult. A meta-analysis was therefore conducted by including the studies that examined the association between two common polymorphisms (L55M and Q192R) in the coding region of PON1 gene and the risk of stroke. Altogether 10 studies on L55M polymorphism and 11 studies on Q192R polymorphism were included in this meta-analysis. The results showed, although there was no significant association of the 55L allele with stroke [random effects OR = 1.09, 95% CI (0.93, 1.27), P = 0.29], the 192R allele conferred significant risk of stroke in the overall study population [random effects OR = 1.25, 95% CI (1.07, 1.46), P = 0.006]. Same pattern of results as both the allele contrasts was obtained for the homozygote contrasts and the dominant, recessive and additive models. Subgroup analyses for stroke type, age of patients and ethnicity revealed no association of the 55L allele with stroke, whereas the association of the 192R allele persisted significantly in the groups comprising ischemic stroke patients, stroke patients with mean age >60 years and Caucasian subjects. But no significant association of this allele with stroke susceptibility was detected in the East Asian population. Therefore, the results of this meta-analysis indicate, the Q192R polymorphism could be an important risk factor for stroke, especially in the Caucasian population.     

Mediterranean diet and reduction in the risk of a first acute myocardial infarction: an operational healthy dietary score

Summary. Background: Although an important secondary prevention trial reported an impressive protection by a Mediterranean dietary pattern on reinfarction and cardiovascular death, scarce direct epidemiologic evidence is currently available regarding the role of the Mediterranean diet in the aetiology of coronary heart disease. Aims: The aim of the study was to quantify the risk reduction of incident myocardial infarction provided by a Mediterranean dietary pattern. Methods: We included 342 subjects (171 patients who suffered their first acute myocardial infarction and 171 matched controls) in a case-control study. A validated semi-quantitative food frequency questionnaire (136 items) was used. We defined an a priori Mediterranean dietary pattern. We assessed six food items that we considered protective: 1) olive oil, 2) fiber, 3) fruits, 4)vegetables, 5) fish and 6) alcohol. For each of these six dietary factors, we calculated the distribution according to quintiles within the study and assigned each participant a score of 1 to 5 corresponding to the quintile of intake, with 1 representing the lowest and 5 representing the highest quintile. We also estimated the quintiles of two other elements assumed to be associated with a higher risk: 7) meat/meat products and 8) some items with high glycaemic load (white bread, pasta and rice). For these two elements we inversely ranked the score, with 1 representing the highest and 5 representing the lowest quintile. Finally, we summed up the eight quintile values for each participant. A second score (post hoc pattern) was built using only a single cut-off point for these eight elements. The cut-off points for each element in this post hoc pattern were decided according to the dose-response relationships between the consumption of each food item and the risk of myocardial infarction observed in the analyses that used quintiles of each food item. Results: For both patterns, we found that the higher the score, the lower the odds ratio of myocardial infarction. A significant linear trend was apparent after adjustment for the main cardiovascular risk factors. For each additional point in the a priori Mediterranean pattern (observed range: 9–38) the odds ratio (95 % confidence intervals) was 0.92 (0.86–0.98). This estimate was 0.55 (0.42–0.73) when we used the post hoc pattern (range: 0–8). Conclusions: Our data support the hypothesis that a Mediterranean diet (that emphasizes olive oil, fiber, fruits, vegetables, fish and alcohol and reduces meat/meat products) can be an effective measure for reducing the risk of myocardial infarction. However, our results support the exclusion of refined cereals with a high glycaemic load as healthy elements of this pattern. Received: 24 January 2002, Accepted: 13 May 2002     

汉族人芳香二烷基磷酸酯酶启动子-162A／G基因多态性与冠心病发病的关系

目的　研究湖北地区汉族人芳香二烷基磷酸酯酶 (paraoxonasc ,PON1)启动子基因 -162位Ala -Gly基因多态性与冠心病 (CHD)发病的关系。方法　应用多聚酶链反应 -限制性片段长度多态性的分析方法 (PCR -RELP)检测湖北汉族地区CHD患者及正常对照组PON1基因启动子 -162位点的多态性 ,血脂用酶法测定。结果　PON1启动子 -162位点存在多态性 ,有AA ,AG ,GG 3种基因型。 12 8例正常人中AA基因型占 4 7% ,AG基因型占 2 0 3 % ,GG基因型占 75 0 % ,而CHD组与对照组 -162Ala-Gly 基因型分布总体构成比差异无显著性。对照组和CHD组PON基因G等位基因频率分别为 0 85 2和0 913 ,差异也无显著性 (P >0 0 5 )。结论　未发现PON1启动子基因 -162位Ala-Gly多态性与中国人CHD有关。     

Cholesterol-lowering effect of spreads enriched with microcrystalline plant sterols in hypercholesterolemic subjects

Summary Background Plant sterols have been shown to reduce serum lipid concentrations. The effectiveness is highly dependent on the physical state of the plant sterols. By means of a new crystallizing method, plant sterols can be added into dietary fats and oils homogeneously. In this fat ingredient, plant sterols are in a microcrystalline form. Aims of the study We investigated the cholesterol-lowering effect and possible side effects of vegetable oil-based spreads fortified with two different doses of microcrystalline plant sterols. Methods: This double-blind randomized, placebo-controlled study consisted of a 6-wk run-in and a 6-month experimental period. During the run-in period, all 155 hypercholesterolemic subjects received rapeseed oil-based control spread. In the beginning of the experimental period subjects were randomly assigned into one of three experimental groups. The control group continued to use control spread, and the two test groups used spreads with added plant sterols of either 1.5 g/d or 3.0 g/d. The subjects consumed test spreads as a part of their normal diet without any restrictions in lifestyle and diet. Results Plasma total- and LDL-cholesterol concentrations were significantly reduced by 7.5–11.6 % (0.46–0.62 mmol/l) in groups consuming margarine enriched with free plant sterols, compared with the control group. The effects were similar between the two groups consuming either 1.5 g or 3.0 g plant sterols per day. No effect on HDL-cholesterol or triacylglycerol concentrations occurred. The test spreads did not induce any adverse effects in blood clinical chemistry, hematology or decreases in serum concentrations of lipid soluble vitamins. Conclusions Microcrystalline plant sterols are effective in lowering serum total- and LDL-cholesterol concentrations without obvious side effects. The daily dose of 1.5 g plant sterols is enough to reach the maximum effect. Received: 5 December 2000 / Accepted: 14 March 2001     

Malvidin-3-glucoside bioavailability in humans after ingestion of red wine, dealcoholized red wine and red grape juice

Summary Background & Aims Dietary polyphenols, including anthocyanins, are suggested to be involved in the protective effects of red wine against cardiovascular diseases. Very little data are available concerning the bioavailability of anthocyanins, major sources of red pigmentation in red wine. The aim of this study was to compare changes in plasma malvidin-3-glucoside (M-3-G), a red wine anthocyanin, and its urinary excretion after ingestion of red wine, dealcoholized red wine and red grape juice. Design Six healthy male subjects were studied in a randomized cross over setting in a human nutrition research unit under controlled conditions. All subject consumed 500 mL of each beverage on separate days providing the following M-3-G quantities: red wine 68 mg, dealcoholized red wine 58 mg, and red grape juice 117 mg. M-3-G was measured by HPLC and photodiode detection. Results M-3-G was found in plasma and urine after ingestion of all the beverages studied. The aglycon, sulfate or glucuronate conjugates of M-3-G were not detected in plasma and urine. Increases in plasma M-3-G concentrations were not significantly different after the consumption of either red wine or dealcoholized red wine and were about two times less than those measured after consumption of red grape juice. This difference may be caused by the about two times higher M-3-G concentration determined in red grape juice. Area under the plasma concentration curves were as follows: 288±127nmol × h/L (red wine), 214±124nmol × h/L (dealcoholized red wine) and 662±210 nmol × h/L (red grape juice) and showed a linear relationship with the amount of anthocyanin consumed (mean±SD). Conclusions M-3-G is poorly absorbed after a single ingestion of red wine, dealcoholized red wine, or red grape juice and seems to be differentially metabolized as compared to other red grape polyphenols. Our results suggest that not anthocyanins such as M-3-G themselves but rather not yet identified anthocyanin metabolites and/or other polyphenols in red wine might be responsible for the observed antioxidant and health effects in vivo in subjects consuming red wine. Received: 28 May 2001, Accepted: 17 July 2001     

Short- and long-term mortality in a prevalent cohort of morbidly obese patients in Italy

Summary. Background: Morbid obesity has been associated with increased mortality. Aim of the study: We evaluated the risk of short- (2 years) and long-term (10 years) mortality in two consecutive series of Italian morbidly obese patients hospitalized in a Metabolic Unit. Methods: The vital status of 569 patients (435 females and 134 males, BMI 44.4 kg/m², age 46.1 years), first admitted for clinical treatment in two separate periods (1988 and 1996), was ascertained in 1999. Results: Twenty-seven deaths were identified and compared with expected deaths according to mortality rates in the Italian population, to estimate the standardized mortality ratio (SMR). In the first two years after admission only 3 deaths were observed and the SMR tended to be reduced (SMR = 0.5, 95 % CI 0.1–1.5). In contrast, the long-term follow-up showed a significantly elevated risk of death (SMR = 1.6, 95 % CI 1.1–2.4). Conclusions: The follow-up of this Italian prevalent cohort confirm that morbid obesity is associated with increased mortality. The observed SMR might have been attenuated by inclusion in our study of subjects with relatively good health conditions, who are possibly more representative of the general obese population than subjects affected by important obesity-related complications, observed in other studies. The excess risk was not evident in the first two years after clinical treatment. Received: 1 March 2002, Accepted: 13 June 2002