Dietary sodium intake and prediction of cardiovascular events.

BACKGROUND/OBJECTIVES: The association of dietary sodium and cardiovascular disease (CVD), as well as the reduction of sodium intake in the prevention of CVD, has been under debate. To study whether sodium consumption has a role as a risk factor for fatal and non-fatal CVD. SUBJECTS/METHODS: A well-defined population-based cohort of 1045 subjects collected between 1991 and 1993 (mean age 51.4 years) was used with approximately 19 years' follow-up. At the baseline, 716 subjects filled in a 1-week food follow-up diary, which was used to calculate the daily sodium intake (mg/1000 kcal). RESULTS: The baseline sodium intake correlated significantly with age (rs=0.117, P=0.002), BMI (rs=0.216, P=0.000), waist circumference (rs=0.268, P=0.000), smoking (rs=0.144, P=0.000), alcohol consumption (rs=0.111, P=0.003), systolic blood pressure (rs=0.106, P=0.005) and low-density lipoprotein (LDL) cholesterol (rs=0.081, P=0.033). Those who had cardiovascular events in the follow-up consumed more sodium at the baseline (mean 2010.4 mg/1000 kcal/day, s.d. 435.2, n=101) compared with the subjects without events (mean 1849.9 mg/1000 kcal/day, s.d. 361.2, n=589; t-test; P=0.001). The incidence of cardiovascular events was greater in the highest quartile (22.1%) than in the lower quartiles (first 11.0%, second 9.9% and third 15.6%; X(2); P=0.005). Cox regression analysis showed that sodium intake as a continuous variable predicts CVD events (P=0.031) independently when age, sex, smoking, alcohol consumption, systolic blood pressure, LDL cholesterol and waist circumference were added as covariates. This predictive role is seen especially in the group of subjects on hypertensive medication (P=0.001). CONCLUSIONS: Dietary sodium intake is a significant independent predictor of cardiovascular events in the study population.

Plasma concentrations of the flavonoids hesperetin, naringenin and quercetin in human subjects following their habitual diets, and diets high or low in fruit and vegetables.

OBJECTIVES: To determine the fasting plasma concentrations of quercetin, hesperetin and naringenin in human subjects consuming their habitual diets, and diets either high or low in fruit and vegetables. To investigate whether plasma concentrations of flavanones can serve as biomarkers of their intake. DESIGN: This was a cross-over, strictly controlled dietary intervention consisting of a 2 week baseline period, and two 5 week dietary periods with a 3 week wash-out period in between. The low-vegetable diet contained few fruit and vegetables and no citrus fruit. The high-vegetable diet provided various fruits and vegetables daily including on average one glass of orange juice, one-half orange and one-half mandarin. SUBJECTS: Thirty-seven healthy females. RESULTS: The high-vegetable diet provided 132 mg of hesperetin and 29 mg of naringenin. The low-vegetable diet contained no flavanones. The mean plasma hesperetin concentration increased from 12.2 nmol/l after the low-vegetable diet to 325 nmol/l after the high-vegetable diet. The respective increase for naringenin was from <73.5 nmol/l for all subjects to a mean value of 112.9 nmol/l. The mean plasma quercetin concentration was 52 nmol/l after the baseline period, during which habitual diets were consumed, and it did not change significantly during the intervention. Interindividual variation in the plasma levels of hesperetin and naringenin was marked and, after the baseline and wash-out periods, and the low-vegetable diet, a majority of the samples had plasma flavanone levels below the limit of detection. After the high-vegetable diet, hesperetin and naringenin were detectable in 54 and 22% of all samples. Quercetin was detectable in nearly all samples after all study periods. CONCLUSION: Hesperetin, naringenin and quercetin are bioavailable from the diet, but the plasma concentrations of hesperetin and naringenin are poor biomarkers of intake.

Polymorphisms of key enzymes in homocysteine metabolism affect diet responsiveness of plasma homocysteine in healthy women.

High plasma total homocysteine (tHcy), low dietary intake of folate and other B vitamins, and genetic polymorphisms related to metabolism of homocysteine may interactively contribute to the risk of cardiovascular disease. We investigated whether known mutations in genes regulating homocysteine metabolism affect the responsiveness of serum folate and plasma tHcy to high intake of natural folate from food. Healthy females (n = 37) aged 22-57 y volunteered to participate in a crossover dietary intervention with two 5-wk diet periods (low and high folate diets). Concentrations of serum and RBC folate, serum vitamin B-12 and plasma tHcy were measured at baseline and at the end of each diet period. The prevalences of C677T transition of methylenetetrahydrofolate reductase (MTHFR) gene, 844ins68 of cystathionine beta-synthase (CBS) gene and A2756G mutation of methionine synthase (MS) gene were determined. Compared with the low folate diet, the high folate diet increased the serum folate concentration by 85% (P < 0.001), 77% (P < 0.001) and 55% (P < 0.05) in the subjects with the genotypes C/C (n = 19), C/T (n = 13) and T/T (n = 5), respectively, of the MTHFR gene. Also, the plasma tHcy of the subjects with the genotypes C/C, C/T and T/T was decreased by 11% (P < 0.001), 15% (P < 0.01) and 18% (P < 0.05), respectively, during the high folate diet period. The subjects carrying the G2756 allele of the MS gene (n = 15) had a more extensive reduction (P < 0.05) of plasma tHcy during the high folate diet period than the subjects with the genotype A/A (n = 22). The 844ins68 of CBS gene did not affect plasma tHcy concentrations or diet responsiveness. In conclusion, diet responsiveness of plasma homocysteine may be genetically regulated.

Dietary and other non-pharmacological treatments in patients with drug-treated hypertension and control subjects.

OBJECTIVE: To study the nutrient intakes and other lifestyle patterns of drug-treated hypertensives and control subjects. DESIGN: A cross-sectional population-based epidemiological study. SETTING: The participating study subjects visited the research laboratory of the Department of Internal Medicine of the University of Oulu, Oulu, Finland. PARTICIPANTS: A total of 1045 Finnish men and women aged 40-60 years, of whom 716 (69%) completed 7-day food records. MAIN OUTCOME MEASURES: Intakes of energy, protein, total fat, saturated, monounsaturated and polyunsaturated fatty acids, carbohydrate, alcohol, fibre, calcium, magnesium, potassium and sodium were assessed from 7-day food records. The study also included measurements of blood pressure, blood glucose and plasma lipids, and anthropometric variables. Information about alcohol consumption, smoking habits and physical activity was collected by interviewing. RESULTS: Obesity was common amongst the hypertensive subjects, whose body mass indices were significantly higher than those of the control subjects. Only minor differences existed in the energy intake levels and nutrient intakes of the hypertensive and control cohorts, but the control subjects performed more physical activity than the hypertensive subjects. The dietary recommendations concerning the intakes of total and saturated fats, carbohydrate and fibre were poorly met by both the hypertensive and the control subjects. Alcohol consumption was high amongst the hypertensive men, especially amongst the smokers. CONCLUSIONS: Non-pharmacological treatment, including dietary management, of hypertensive patients at high risk for cardiovascular complications seems still to be inadequate. Additional well-focused efforts are needed to intensify the dietary treatment as well as to reduce alcohol consumption and smoking amongst hypertensives.