Induction of spermidine/spermine N1-acetyltransferase in human cancer cells in response to increased production of reactive oxygen species

Hemostatic factors play an important role in the complications of ischemic heart and vessel disease. Dietary fats such as n-3 fatty acids have been shown to possibly influence hemostatic factors. However, most studies reporting an inverse association between cardiovascular disease and fish and n-3 fatty acid consumption used supplemental doses of fish oil or intakes exceeding the typical amount consumed by the US population. This report examined the associations of usual intakes of fish, linolenic acid, eicosapentaenoic acid, and docosahexaenoic acid with fibrinogen, factor VII, factor VIII, and von Willebrand factor in the Coronary Artery Risk Development in Young Adults (CARDIA) Study. The analyses reported here included 1672 black and white men and women aged 24 to 42 years in 1992 to 1993. After adjustment for age, body mass index, diabetes, number of cigarettes smoked per day, race, and energy and alcohol consumption, no significant associations were observed between those who consumed no fish versus those who consumed the highest level of dietary fish with respect to fibrinogen, factor VIII, or von Willebrand factor for any race-sex group. Comparisons of tertile 1 versus tertile 3 for dietary linolenic acid, eicosapentaenoic acid, and docosahexaenoic acid were also not significantly associated with fibrinogen, factor VII, factor VIII, or von Willebrand factor for any race-sex group. These data suggest that customary intakes of fish and n-3 fatty acids in populations that generally do not consume large amounts of these food items are not associated with these hemostatic factors.     

Intake of very-long-chain n-3 fatty acids related to social status and lifestyle

OBJECTIVES: Little information is available about the intake of very-long-chain n-3 fatty acids in random samples of populations. We examined if the intake of these fatty acids was associated with gender, social status and lifestyle in a similar way as other indicators for a healthy diet in a nationwide survey. DESIGN AND SUBJECTS: Data were obtained from self-administered quantitative food frequency questionnaires filled in by a representative sample of Norwegian men and women, aged 16-79 y. 3144 (63%) of the invited subjects responded with acceptable questionnaires. RESULTS: Daily intake of very-long-chain n-3 fatty acids was on average 0.9 g/d and 0.4% of total energy was derived from these fatty acids. Energy derived from very-long-chain n-3 fatty acids was slightly higher among men than women, and two-fold higher among subjects aged 60-79 vs 16-29 y. White collar workers had higher intake of very-long-chain n-3 fatty acids than blue collar workers. Men and women in the highest quartile of intake of very-long-chain n-3 fatty acids had 2-3 E% higher fat intake (mostly mono- and polyunsaturated fatty acids), as compared to individuals in the lowest quartile. They also had 3-4 fold higher daily intake of retinol and vitamin D, as well as 20-50% higher intake of fruits and vegetables, dietary fibre and vitamin C. CONCLUSIONS: Intake of very-long-chain n-3 fatty acids was correlated to indicators for healthy dietary habits. However, contrary to many other indicators of a healthy diet, energy derived from very-long-chain n-3 fatty acids was not significantly associated with female gender or non-smoking.     

Dietary intakes of middle-aged European, Maori and Pacific Islands people living in New Zealand

AIM: To compare dietary intakes of Maori, Pacific Islands and European men and women in New Zealand. METHODS: A food frequency questionnaire was used to calculate nutrient intakes of 5523 New Zealand workers aged 40 years and over (3997 men, 1524 women) from a cross-sectional survey carried out between 1988 to 1990. RESULTS: Compared with European men and women, Maori women and Pacific Islands men and women consumed larger amounts of total energy per day. Age-adjusted nutrients expressed as percentage contribution to total energy intakes showed that Maori and Pacific Islands men and women consumed less carbohydrate, fibre and calcium, and more protein, fat, saturated fat and cholesterol than European men and women, respectively. These results were consistent with fewer servings of cereal and cheese per month, and more servings of red meats, fish and eggs in Maori and Pacific Islands participants compared with Europeans, after adjusting for age and total energy intakes. Pacific Islands men and women also consumed more servings of chicken, fewer cups of milk and fewer servings of fruit per month compared to Europeans. Maori men and women consumed more slices of bread and fewer servings of vegetables per month compared to European men and women. CONCLUSIONS: There were striking differences in dietary habits, food selections and cooking practices between European, Maori and Pacific Islands participants. Dietary intakes of Maori workers were closer to those of Europeans than those of Pacific Islands participants. Ethnic differences were due to larger portion sizes and increased frequency of most foods in Maori and Pacific Islands participants.     

Intake of fatty acids and risk of coronary heart disease in a cohort of Finnish men. The Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study

The relation of intakes of specific fatty acids and the risk of coronary heart disease was examined in a cohort of 21,930 smoking men aged 50-69 years who were initially free of diagnosed cardiovascular disease. All men participated in the Finnish Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study and completed a detailed and validated dietary questionnaire at baseline. After 6.1 years of follow-up from 1985-1988, the authors documented 1,399 major coronary events and 635 coronary deaths. After controlling for age, supplement group, several coronary risk factors, total energy, and fiber intake, the authors observed a significant positive association between the intake of trans-fatty acids and the risk of coronary death. For men in the top quintile of trans-fatty acid intake (median = 6.2 g/day), the multivariate relative risk of coronary death was 1.39 (95% confidence interval (CI) 1.09-1.78) (p for trend = 0.004) as compared with men in the lowest quintile of intake (median = 1.3 g/day). The intake of omega-3 fatty acids from fish was also directly related to the risk of coronary death in the multivariate model adjusting also for trans-saturated and cis-monounsaturated fatty acids (relative risk (RR) = 1.30, 95% CI 1.01-1.67) (p for trend = 0.06 for men in the highest quintile of intake compared with the lowest). There was no association between intakes of saturated or cis-monounsaturated fatty acids, linoleic or linolenic acid, or dietary cholesterol and the risk of coronary deaths. All the associations were similar but somewhat weaker for all major coronary events.     

Folate, vitamin D, and iron intakes are low among pregnant Finnish women

OBJECTIVE: To evaluate dietary habits and nutrient intake of Finnish pregnant women, to relate these to the use of dietary supplements, and to explore possible dietary variations according to age and education. DESIGN: A random dietary survey using two five day estimated food records. SETTING: Pregnant women from 13 maternity clinics in the city of Oulu, Finland. SUBJECTS: One hundred and eighteen pregnant women in their third trimester. MAIN RESULTS: The main sources of energy were cereal products and milk products. The consumption of fish and poultry was low. Women with a higher educational level consumed more vegetables, fruit, fruit juices, and tea and less sausages, inner organs and coffee than women with a lower educational level. Younger women (< 25 y) consumed more sugar and pork and less berries, butter and inner organs than older women. On average 15% of the total energy was supplied by protein, 33% by fats, 52% by carbohydrates, and 12% by sucrose. Compared to the Nordic nutrition recommendations, the proportion of polyunsaturated fatty acids and the intake of dietary fibre were low and the intake of sugar high. The intakes of vitamins and minerals met or exceeded the recommended allowances, except for vitamin D, folate, and iron. Of the subjects 70% used dietary supplements. With the exception of vitamin D, folate, and iron, both the supplement users and non-users had an adequate nutrient intake from their diet. CONCLUSIONS: A balanced diet covers the increased nutrient requirements during pregnancy, with the exception for vitamin D, folate, and iron. The use of dietary supplements during pregnancy is excessive and partly focused on the wrong nutrients. Young and less educated, and smoking pregnant women need more nutritional guidance.     

Intake of trans fatty acids and risk of coronary heart disease among women

Trans isomers of fatty acids, formed by the partial hydrogenation of vegetable oils to produce margarine and vegetable shortening, increase the ratio of plasma low-density-lipoprotein to high-density-lipoprotein cholesterol, so it is possible that they adversely influence risk of coronary heart disease (CHD). To investigate this possibility, we studied dietary data from participants in the Nurses' Health Study. We calculated intake of trans fatty acids from dietary questionnaires completed by 85,095 women without diagnosed CHD, stroke, diabetes, or hypercholesterolaemia in 1980. During 8 years of follow-up, there were 431 cases of new CHD (non-fatal myocardial infarction or death from CHD). After adjustment for age and total energy intake, intake of trans isomers was directly related to risk of CHD (relative risk for highest vs lowest quintile 1.50 [95% Cl 1.12-2.00], p for trend = 0.001). Additional control for established CHD risk factors, multivitamin use, and intakes of saturated fat, monounsaturated fat, and linoleic acid, dietary cholesterol, vitamins E or C, carotene, or fibre did not change the relative risk substantially. The association was stronger for the 69,181 women whose margarine consumption over the previous 10 years had been stable (1.67 [1.05-2.66], p for trend = 0.002). Intakes of foods that are major sources of trans isomers (margarine, cookies [biscuits], cake, and white bread) were each significantly associated with higher risks of CHD. These findings support the hypothesis that consumption of partially hydrogenated vegetable oils may contribute to occurrence of CHD.     

Diet and breast cancer risk in a cohort of Finnish women

The associations between dietary antioxidant vitamins, dietary fiber, and selected foods and risk of breast cancer were studied in 4697 initially cancer-free women, aged 15 years or older. At baseline (1967-1972) the women were interviewed for total habitual diet over the preceding year. During a 25-year follow-up period 88 breast cancer cases were diagnosed. There was a significant inverse gradient between milk consumption and occurrence of breast cancer, whereas higher consumption of fried meat was associated with increased risk of breast cancer. No significant relationships were found between the intakes of vitamin E, vitamin C, beta-carotene, lycopene, lutein or dietary fiber and the occurrence of breast cancer.     

Stress analysis of the human temporomandibular joint

OBJECTIVE: To examine how dietary intake varies with age in a nation-wide sample of adult Norwegian women, and to evaluate the impact of lifestyle and socio-economic status on important dietary aspects. DESIGN: Cross-section study. SETTING AND SUBJECTS: A food frequency questionnaire was mailed to a random, nation-wide sample of 20 000 women aged 45-69y, and 9885 questionnaires were accepted for nutritional analyses. RESULTS: Dietary habits differed moderately with age. The oldest women reported a higher consumption of potatoes and fish, whereas the youngest reported more coffee, meat, and alcohol. The reported intake of fruit, vegetables, and potatoes was lower than recommended in all age groups. Older women had a slightly better distribution of energy yielding nutrients than younger women, although the median percentage of energy from fat was too high in all age groups. The median dietary fibre density of the diet was close to the recommended level in all age groups, yet lowest among the youngest women. Practising a healthy lifestyle and having a higher socio-economic status were associated with reporting a healthier diet. However, adjusting for lifestyle and socio-economic factors did not substantially alter the associations between diet and age. CONCLUSIONS: Older women tend to have a healthier diet than younger women. The relationship does not seem to be strongly confounded by lifestyle and socio-economic status, although these factors are also related to dietary habits.     

Adipose tissue trans fatty acids and breast cancer in the European Community Multicenter Study on Antioxidants, Myocardial Infarction, and Breast Cancer

To investigate the relationship between trans fatty acids and postmenopausal breast cancer in European populations differing greatly in their dietary fat intakes, a case control study using adipose tissue stores of trans fatty acids as a biomarker of exposure was conducted. Subjects included 698 postmenopausal incident cases of primary breast cancer and controls randomly drawn from local population and patient registries, ages 50-74 Concentrations of individual trans fatty acids in gluteal fat biopsies were measured in these women. The adipose concentration of trans fatty acids showed a positive association with breast cancer. The covariate-adjusted association with breast cancer. The covariate-adjusted OR was 1.40 (95% confidence interval: 1.02, 1.93) for the difference between the 75th and 25th percentiles of total adipose trans. The adjusted OR for trans in the lowest tertile of polyunsaturated fatty acid reached 3.6 (2.2, 6.1). These associations were not attributable to differences in age, body mass index, exogenous hormone use, or socioeconomic status. These findings suggest an association of adipose stores of trans fatty acids with postmenopausal breast cancer in European women. They require confirmation in other populations, with concomitant consideration of the potential roles of dietary saturated and monounsaturated fats.     

Flavonoid intake and coronary mortality in Finland: a cohort study

OBJECTIVE: To study the association between dietary intake of flavonoids and subsequent coronary mortality. DESIGN: A cohort study based on data collected at the Finnish mobile clinic health examination survey from 1967-72 and followed up until 1992. SETTINGS: 30 communities from different parts of Finland. SUBJECTS: 5133 Finnish men and women aged 30-69 years and free from heart disease at baseline. MAIN OUTCOME MEASURE: Dietary intake of flavonoids, total mortality, and coronary mortality. RESULTS: In women a significant inverse gradient was observed between dietary intake of flavonoids and total and coronary mortality. The relative risks between highest and lowest quarters of flavonoid intake adjusted for age, smoking, serum cholesterol concentration, blood pressure, and body mass index were 0.69 (95% confidence interval 0.53 to 0.90) and 0.54 (0.33 to 0.87) for total and coronary mortality, respectively. The corresponding values for men were 0.76 (0.63 to 0.93) and 0.78 (0.56 to 1.08), respectively. Adjustment for intake of antioxidant vitamins and fatty acids weakened the associations for women; the relative risks for coronary heart disease were 0.73 (0.41 to 1.32) and 0.67 (0.44 to 1.00) in women and men, respectively. Intakes of onions and apples, the main dietary sources of flavonoids, presented similar associations. The relative risks for coronary mortality between highest and lowest quarters of apple intake were 0.57 (0.36 to 0.91) and 0.81 (0.61 to 1.09) for women and men, respectively. The corresponding values for onions were 0.50 (0.30 to 0.82) and 0.74 (0.53 to 1.02), respectively. CONCLUSIONS: The results suggest that people with very low intakes of flavonoids have higher risks of coronary disease.     

Assessment of trans-fatty acid intake with a food frequency questionnaire and validation with adipose tissue levels of trans-fatty acids

Past studies of the association of trans-fatty acid intake with coronary heart disease have been hindered by the lack of a database on the trans-fatty acid content of various foods. The authors used new data from the US Department of Agriculture to estimate trans-fatty acid intake using a self-administered food frequency questionnaire (FFQ), and they assessed the validity of the FFQ by comparing the dietary estimates with trans-fatty acid concentrations in adipose tissue. The 1996 study included 27 women and 24 men aged 51-78 years. The mean consumption of total trans-fatty acids estimated from the FFQ was 2.24 g per day and 5% of total dietary fat. The mean concentration of total trans-fatty acids in buttock adipose tissue was 4.7% of total fatty acids. Pearson correlations between total dietary intake of trans-fatty acids and total trans-fatty acid levels in adipose tissue were 0.67 (95% confidence interval (CI) 0.36-0.84) among men and 0.58 (95% CI 0.26-0.79) among women. After adjustment for energy intake, age, and body mass index, the correlation coefficients were 0.76 (95% CI 0.51-0.89) among men and 0.52 (95% CI 0.17-0.75) among women. The FFQ validated in this study is an important new tool for assessing usual intake of trans-fatty acids.     

Uveitis and central nervous system vasculitis

The purpose of this double-blind study was to investigate the influence of adding a quercetin-containing supplement to the diet on plasma quercetin status, serum/platelet fatty acid levels and risk factors for heart disease. Healthy men and women with cholesterol levels of 4.0-7.2 mmol/L, consumed four capsules daily of either a quercetin-containing supplement (1.0 g quercetin/d) or rice flour placebo for 28 d. Quercetin intakes were approximately 50-fold greater than the dietary intakes associated with lower coronary heart disease mortality on the basis of epidemiologic studies. Subjects consuming quercetin-containing capsules had plasma quercetin concentrations approximately 23-fold higher than those of subjects consuming the control capsules. Quercetin supplementation did not modify serum total, LDL or HDL cholesterol or triglyceride levels. There were also no alterations of other cardiovascular disease or thrombogenic risk factors, including platelet aggregation, platelet thromboxane B2 production, blood pressure or resting heart rate. Furthermore, there was no effect on the levels of (n-6) or (n-3) polyunsaturated fatty acids in serum or platelet phospholipids. In conclusion, supplementation with quercetin-containing capsules markedly enhanced the plasma quercetin concentration but had no effect on other cardiovascular or thrombogenic risk factors.     

Dietary practices and lipid intake in relation to plasma lipid profile in Hong Kong Chinese

OBJECTIVE: To study dietary lipid intake and plasma lipid profile of the Hong Kong Chinese population as part of a territory wide survey on cardiovascular risk factors. DESIGN: Randomised age and sex stratified survey. SUBJECTS: 1010 subjects aged 25-74 y (500 men, 510 women). MEASUREMENTS: A food frequency method with food tables compiled for Hong Kong was used for nutrient quantitation, while a separate questionnaire was used to examine dietary practices. Plasma lipid profile was estimated using standard laboratory methods. RESULTS: Total calorie, fat, saturated fatty acid (SFA), poly- and mono-unsaturated fatty acid (PUFA and MUFA), and cholesterol intake were higher in men; however when adjusted for caloric intake no difference was observed. Men had lower intake of PUFA as percentage of total energy had a higher Hegsted Score compared with women. Subjects consuming beans twice or more per week had lower total cholesterol and LDL-cholesterol concentrations. Overall, the population dietary intake was close to the ideal for cardiovascular health: percentage fat not greater than 30% of the total calorie intake, saturated fat intake not greater than 10% of calories, and cholesterol less than 180 mg/1000 Kcal. CONCLUSION: The dietary pattern for Hong Kong Chinese appear to be satisfactory with respect to cardiovascular health.     

Effects of carbontetrachloride and chenodeoxycholic acid on hepatic monooxygenase system, lipid peroxidation and some immunologic parameters in rats

BACKGROUND: Nutritional characteristics of the mediterranean diet, with a high intake of complex carbohydrates, fibre, monounsatured fatty acids and vegetables, are related to a lower prevalence of some nutritional associated diseases. The aim of our study was to perform a longitudinal analysis of the evolution of food intake in a mediterranean population in order to observe its influence on the energy and nutritional intake and their balance. The latter could have some effects on health status. METHODS: Dietary intake was evaluated using the 24 hours recall method in a representative sample (n = 941, age range = 10-69) of a Reus population. This longitudinal study consisted of 70% of the samples studied in 1983 using identical methodology. RESULTS: During this decade (1983-1993), energy intake decreased significantly 180 kcal/day for men and 158 kcal/day for women, carbohydrates being the main cause for this drop (132 and 84 kcal/day less for men and women, respectively). Protein intake decreased significantly in both sexes, 5.6% for men and 8.0% for women. However, the evolution of fat intake was different for men (no changes) and for women (a significant decrease of 5.7%). Saturated and monounsatured fatty acids did not show significant changes in this decade. Cholesterol intake decreased significantly in both sexes. Energy percents obtained from lipids, saturated and monounsaturated fatty acids significantly increased. However, in absolute values very little changes in fat intake in both sexes were observed. CONCLUSIONS: The dietary pattern evolved to a lower energy intake with an increment of the percentage of dietary lipids, but this feature was did not reflect a greater fat intake in absolute values. Moreover, the main characteristics of the typical mediterranean diet (which is basically different to the usual diet of other non mediterranean european countries mainly due to its richness in monounsaturated fatty acids) did not change in the period analyzed.     

Current zinc intake and risk of diabetes and coronary artery disease and factors associated with insulin resistance in rural and urban populations of North India

OBJECTIVE: To determine the association between current zinc intake and prevalence of coronary artery disease (CAD) and diabetes as well as factors associated with insulin resistance. DESIGN, SUBJECTS AND METHODS: In this cross sectional survey, 3575 subjects, aged 25 to 64 years, including 1769 rural (894 men. 875 women) and 1806 urban (904 men, 902 women) subjects were studied. The survey methods included questionnaires for 7-day food intake record, physical examination, and electrocardiography using World Health Organization criteria. RESULTS: The prevalence of CAD, diabetes and glucose intolerance was significantly higher among subjects consuming lower intakes of dietary zinc. There was a higher prevalence of hypertension, hypertriglyceridemia and low high-density lipoprotein cholesterol levels which showed significant upward trend with lower zinc intakes. Serum lipoprotein (a) and 2-hour plasma insulin levels also were associated with low zinc intake. Multivariate logistic regression analysis after adjustment for age showed that zinc intake and CAD were inversely associated. Serum zinc (odds ratio:men 0.77, women 0.57), serum triglycerides (men 0.86, women 0.81), blood pressure (0.83 men, women 0.76), diabetes mellitus (men 0.90, women 0.85), central obesity (men 0.88, women 0.87), glucose intolerance (men 0.66, women 0.57) and low high-density lipoprotein cholesterol (men 0.72, women 0.70) were significant risk factors for CAD (explained by tertiles of zinc status) in urban subjects. These associations were not observed in rural subjects. CONCLUSION: Lower consumption of dietary zinc and low serum zinc levels were associated with an increased prevalence of CAD and diabetes and several of their associated risk factors including hypertension, hypertriglyceridemia and other factors suggestive of mild insulin resistance in urban subjects.     

Dietary cholesterol affects serum lipids, lipoproteins and LDL metabolism in cynomolgus monkeys in a dose-dependent manner

To examine the mechanism(s) underlying the cholesterolemic response to dietary cholesterol and saturated fatty acids, low density lipoprotein (LDL) metabolism was studied in two groups of cynomolgus monkeys fed diets containing 30 or 36% of total energy as fat. At each dietary fat level, the same group of monkeys was sequentially fed three dietary cholesterol concentrations as egg yolk in the following sequence: low (0.01 mg/kJ), medium (0.03 mg/kJ) and high (0.05 mg/kJ) for 30, 32 and 24 wk, respectively. Dietary polyunsaturated and monounsaturated fatty acids were the same in the two groups; the 6% difference in fat was due to the saturated fatty acids, 12:0 and 14:0. Serum total cholesterol, LDL cholesterol and LDL apolipoprotein B concentrations increased (P < 0.05) with dietary cholesterol in a dose-dependent manner in both fat groups. These elevations were the result of generally increasing LDL apolipoprotein B production rates, concomitant with reduced LDL apolipoprotein B fractional clearance at the high cholesterol intake. Serum HDL cholesterol and HDL apolipoprotein A-I concentrations were not affected in a consistent manner. These results demonstrate that cynomolgus monkeys are hyperresponsive to dietary cholesterol compared with humans, suggesting that this model may be useful in identifying metabolic and genetic predictors for hyperresponsiveness to dietary cholesterol in humans as well as assessing the metabolic heterogeneity of responses to dietary cholesterol.     

Dietary linoleic acid increases and palmitic acid decreases hepatic LDL receptor protein and mRNA abundance in young pigs

The present study was conducted to determine the effects of dietary fatty acids on hepatic LDL receptor (LDLr) protein abundance and mRNA levels. Sixty pigs were randomized into 10 groups and fed corn-soybean meal diets containing three cholesterol levels (0.25%, 0.5%, and 1.0%, w/w) with no added fat, or fats rich (30% of calories) in palmitic acid or linoleic acid. A control group was fed the base diet with no added fat. After 30 days, plasma LDL-cholesterol (LDL-C) levels increased as the dietary cholesterol increased (P < 0.05); however, there was no significant effect of either fatty acid. Dietary fatty acids, however, had distinctly different effects on hepatic LDLr protein (analyzed by ELISA) and mRNA (analyzed by Northern blot) abundance. When pigs consumed diets containing 0.25% cholesterol, linoleic acid increased hepatic LDLr protein 40% whereas palmitic acid reduced it 40% (P < 0.05). These changes in LDLr protein abundance were accompanied by parallel changes in hepatic LDLr mRNA; linoleic acid increased LDLr mRNA 2-fold (P < 0.01), whereas palmitic acid decreased it 60% (P < 0.01). The differential effects of fatty acids on LDLr expression were only observed at 0.25% cholesterol, suggesting that higher intakes of cholesterol have a dominant and repressive effect on regulation of LDLr expression. Cholesterol intake increased hepatic total cholesterol levels (P < 0.01) while dietary fatty acids had no effect on hepatic sterols. In summary, our results indicate that dietary linoleic acid and palmitic acid have markedly different effects on hepatic LDLr protein abundance that are mediated by differential effects on LDLr mRNA and protein levels. Further studies are needed to fully elucidate the molecular mechanisms by which fatty acids regulate LDLr mRNA and protein levels.     

Comparison of food frequency questionnaires: the reduced Block and Willett questionnaires differ in ranking on nutrient intakes

Food frequency questionnaires, major tools in epidemiologic studies, are often criticized for biased and imprecise intake estimates. The aim of this study was to compare the performance of two widely used food frequency questionnaires, a reduced 60-item Block questionnaire and a 153-item Willett food frequency questionnaire, relative to three 24-hour recalls administered by telephone. The dietary data were collected in 1991 from a group of healthy women age 25-49 years (n=101) during the baseline period of a weight-loss intervention study in Minneapolis, Minnesota. Total energy and macro- and micronutrient intakes were compared across methods by using four analytic approaches: comparison of means and correlation coefficients, regression analysis, and estimation of percent agreement between each questionnaire and recalls. The Block instrument showed an overall underestimation bias, but was more successful in categorizing individuals on percent energy from fat and carbohydrate intakes than was the Willett instrument. The Willett instrument showed no overall underestimation bias and was more successful in classifying individuals on vitamin A and calcium intakes. Diverging performance characteristics of diet assessment methods have an implication for the design of studies, interpretation of results, and comparison of findings across studies.     

Inverse relation of dietary protein markers with blood pressure. Findings for 10,020 men and women in the INTERSALT Study. INTERSALT Cooperative Research Group. INTERnational study of SALT and blood pressure

BACKGROUND: The purpose of this study was to assess relations to blood pressure (BP) in individuals of markers of dietary protein in their 24-hour urine collections. METHODS AND RESULTS: INTERSALT (INTERnational study of SALT and blood pressure) was a cross-sectional study of 10020 men and women aged 20 to 59 years in 52 population-based samples in 32 countries worldwide, with quality-controlled standardized procedures and assessment of multiple possible confounders. Three measurements of dietary protein in 24-hour urine of each individual participant were studied: total nitrogen and urea as indexes of total protein intake, and sulfate as an index of sulfur-containing dietary amino acids. Repeat examination was performed in a random 8% of participants to assess reliability and to correct for regression-dilution bias. Significant independent inverse relationships were found between BP (systolic and diastolic) and both 24-hour urinary total nitrogen and urea nitrogen, with adjustment for age, sex, alcohol intake, body mass, and 24-hour urinary sodium, potassium, calcium, and magnesium. With adjustment for regression-dilution bias, it was estimated that systolic and diastolic BP were on average 3.0 and 2.5 mm Hg lower, respectively, for persons with dietary total protein intake 30% above the overall mean than for those whose dietary protein intake was 30% below the overall mean (12.94 versus 6.96 g/d urinary total nitrogen, equivalent to 81 versus 44 g/d dietary protein, respectively). For the association of these markers with diastolic BP, results were similar for younger (20- to 39-year-old) and older (40- to 59-year-old) persons and for women and men. For their relation to systolic BP, regression coefficients were larger both for those aged 40 to 59 years than for those aged 20 to 39 years and for women than for men. Nonsignificant inverse relations were recorded for urinary sulfate and BP. CONCLUSIONS: These INTERSALT findings lend support to the hypothesis that higher dietary protein intake has favorable influences on BP.     

Nutritional influences on bone mineral density: a cross-sectional study in premenopausal women

The association between current and past dietary intake and bone mineral density (BMD) was investigated in 994 healthy premenopausal women aged 45-49 y. BMD was measured with dual-energy X-ray absorptiometry (DXA). Dietary intake was assessed with a food-frequency questionnaire (FFQ). Energy-adjusted nutrient intakes were grouped into quartiles and mean BMD at the lumbar spine (LS), femoral neck (FN), femoral trochanter (FT), and femoral Wards (FW) were calculated. With higher intakes of zinc, magnesium, potassium, and fiber, LS BMD was significantly higher (P < 0.05-0.006), and a significant difference in LS BMD was also found between the lowest and highest quartiles for these nutrients and vitamin C intake (P < 0.05-0.01). These results remained significant after adjustment for important confounding factors. LS BMD and FT BMD were lower in women reporting a low intake of milk and fruit in early adulthood than in women with a medium or high intake (P < 0.01). High, long-term intake of these nutrients may be important to bone health, possibly because of their beneficial effect on acid-base balance.