Dietary total antioxidant capacity from different assays in relation to serum C-reactive protein among young Japanese women.

BACKGROUND: The association between dietary total antioxidant capacity (TAC) from different assays and serum C-reactive protein (CRP) has not been assessed in non-Western populations. We examined the association between dietary TAC and serum CRP concentration in young Japanese women using different four TAC assays. METHODS: The subjects were 443 young Japanese women aged 18-22 years. Dietary TAC was assessed with a self-administered diet history questionnaire and the TAC value of each food using the following four assays: ferric reducing ability of plasma (FRAP); oxygen radical absorbance capacity (ORAC); Trolox equivalent antioxidant capacity (TEAC); and total radical-trapping antioxidant parameter (TRAP). Serum CRP concentrations were measured by highly sensitive nephelometry. RESULTS: The major contributor to dietary TAC was green, barley, and oolong tea (FRAP: 53%, ORAC: 45%, TEAC: 36%, and TRAP: 44%). The prevalence of elevated CRP concentrations (≥ 1 mg/L) was 5.6%. TAC from FRAP was inversely associated with serum CRP concentrations (adjusted odds ratio [OR] for elevated CRP concentration in high [compared with low] dietary TAC group: 0.39 [95% confidence interval (CI): 0.16-0.98]; P = 0.04). TAC from ORAC was inversely associated with CRP, although the association was not significant (OR: 0.48 [95% CI: 0.20-1.14]; P = 0.10). TAC from TEAC was inversely associated with CRP (OR: 0.32 [95% CI: 0.12-0.82]; P = 0.02), as was TAC from TRAP (OR: 0.31 [95% CI: 0.12-0.81]; P = 0.02). CONCLUSIONS: Dietary TAC was inversely associated with serum CRP concentration in young Japanese women regardless of assay. Further studies are needed in other populations to confirm these results.

Sensitivity and specificity of published strategies using urinary creatinine to identify incomplete 24-h urine collection.

OBJECTIVE: Although urinary creatinine has been used to identify incomplete 24-h urine in numerous epidemiologic studies, information on its utility is limited. We examined the sensitivity and specificity of several strategies that use creatinine to identify incomplete urine using the p-aminobenzoic acid (PABA) check method as reference. METHODS: Subjects were 654 female Japanese dietetic students 18-22 y of age. A single 24-h urine sample was collected, with recording of the time of the start and end of the collection period and missing urine volume. Simultaneous administration of PABA was done to assess completeness. The sensitivity and specificity of five strategies derived from the literature that used creatinine to identify incomplete urine were calculated as the proportion of incomplete and complete urine correctly identified, respectively. RESULTS: A total of 7.6% of subjects was identified as having incomplete urine by PABA (PABA recovery <85%). This proportion significantly (P < 0.0001) decreased (to 5.5%) after considering self-reported collection time and missing urine volume in the calculation of total urine volume. The sensitivity and specificity of the strategy of Knuimann et al. (incomplete urine = <0.7 of [mmol urinary creatinine x 113]/[21 x kilograms of body weight]) were 0.47 and 0.99, respectively. The corresponding values of other strategies were 0.11-0.22 and 0.57-1.00, respectively. CONCLUSION: At least in well-motivated populations in which the proportion of incomplete urine is presumed to be small, the strategy of Knuimann et al. and consideration of the self-reported collection time and missing urine volume in the estimation of total volume may be useful.

Dietary glycemic index is associated with decreased premenstrual symptoms in young Japanese women.

OBJECTIVES: High glycemic index (GI) carbohydrates may increase brain serotonin, which in turn acts to alleviate premenstrual symptoms, because, although the main determinant of brain serotonin concentration is a high plasma ratio of tryptophan to other large neutral amino acids, a high-GI diet has been shown to increase this ratio. In this observational cross-sectional study, we investigated associations between dietary GI and other dietary carbohydrates and premenstrual symptoms. METHODS: Subjects were 640 female Japanese dietetic students 18-22 y of age. Dietary carbohydrates were assessed using a validated, self-administered, comprehensive diet history questionnaire. Menstrual cycle symptoms were assessed using the retrospective version of the Moos Menstrual Distress Questionnaire (MDQ). Independent associations of dietary GI and glycemic load and intake of available carbohydrate and dietary fiber with the MDQ total score and subscale scores (pain, concentration, behavioral change, autonomic reactions, water retention, and negative affect) in the premenstrual phase (expressed as percentages relative to those in the intermenstrual phase) were examined. RESULTS: Dietary GI was independently inversely associated with total MDQ score in the premenstrual phase (P for trend = 0.02). Dietary GI also showed independent and inverse associations with several MDQ subscale scores in the premenstrual phase, including concentration, autonomic reactions, and water retention (P for trend < 0.05). Conversely, dietary glycemic load and intake of available carbohydrate and dietary fiber were not associated with any of the MDQ scores in the premenstrual phase. CONCLUSION: Dietary GI was independently associated with decreased premenstrual symptoms in a group of young Japanese women.

Hardness (difficulty of chewing) of the habitual diet in relation to body mass index and waist circumference in free-living Japanese women aged 18-22 y.

BACKGROUND: Animal studies suggest the beneficial effect of hardness of diet on body weight and adiposity. No human studies have examined hardness of diet in relation to obesity. OBJECTIVE: We examined cross-sectional associations of hardness of the habitual diet with body mass index (BMI; in kg/m(2)) and waist circumference in free-living humans. DESIGN: Subjects were 454 female Japanese dietetic students aged 18-22 y. Dietary hardness was assessed as an estimate of masticatory muscle activity for the habitual diet (ie, the difficulty of chewing the food). The consumption of a total of 107 foods was estimated by means of a self-administered, comprehensive diet history questionnaire, and masticatory muscle activity during the ingestion of these foods was estimated according to published equations. Waist circumference was measured at the level of the umbilicus. RESULTS: Mean BMI was 21.4 (95% CI: 21.1, 21.6), and mean waist circumference was 73.6 (72.9, 74.3) cm. Mean dietary hardness was 178 (175, 181) mV x s/1000 kcal. Dietary hardness was not significantly associated with BMI. However, it was negatively associated with waist circumference (P for trend = 0.005). This association remained after adjustment not only for potential confounding factors (P for trend = 0.028) but also for BMI (P for trend = 0.002). CONCLUSIONS: Whereas no association between dietary hardness and BMI was seen, increasing dietary hardness was associated with lower waist circumference even after adjustment for BMI in free-living young Japanese women. This finding could make innovative contributions to the literature and raise issues for future studies regarding diet and obesity.

Nutrient and food intake in relation to serum leptin concentration among young Japanese women.

OBJECTIVE: Little is known about the relation of modifiable dietary factors to circulating leptin concentrations, particularly in young adults and non-Western populations. We examined cross-sectional associations between nutrient and food intake and serum leptin concentration in young Japanese women. METHODS: Subjects were 424 female Japanese dietetic students 18-22 y of age. Intake of macronutrients (protein, total fat; saturated, monounsaturated, and polyunsaturated fatty acids; and carbohydrate), dietary fiber, and 12 food groups was assessed with a validated, self-administered, comprehensive, diet history questionnaire. Fasting blood samples were collected, and serum leptin concentrations were measured by radioimmunoassay. RESULTS: For nutrients, only dietary fiber was a significant determinant of serum leptin concentration. Increasing dietary fiber intake was associated with lower serum leptin concentration independent of potential confounding factors, including body mass index (mean serum leptin concentrations in the lowest and highest quintiles of dietary fiber intake were 8.6 and 7.5 ng/mL, respectively; P for trend = 0.026). Vegetables and pulses were the only foods significantly associated with serum leptin concentration, with higher intakes independently associated with lower concentrations (mean serum leptin concentrations in the lowest and highest quintiles of intake were 8.1 and 7.0 ng/mL, P for trend = 0.007, for vegetables and 8.8 and 7.6 ng/mL, P for trend = 0.019, for pulses, respectively). CONCLUSION: Intake of dietary fiber, vegetables, and pulses showed an independent inverse association with serum leptin concentration in a group of young Japanese women.

Moisture and mineral content of human feces--high fecal moisture is associated with increased sodium and decreased potassium content--.

BACKGROUND: The origin of moisture in diarrhea feces is unknown but may represent the unabsorbed part of intestinal contents or alternatively, body fluid excreted into the digestive canal. If the latter mechanism contributes to moisture in the feces, active transport of water (H2O) associated with ion exchange channels may be involved. OBJECTIVE: To investigate this possibility we measured the content of moisture and minerals (sodium [Na], potassium [K], calcium [Ca], magnesium [Mg], phosphorus [P], zinc [Zn], iron [Fe], copper [Cu] and manganese [Mn]) in feces collected during a 12-d metabolic study on 11 young Japanese female students. DESIGN: The study was carried out as part of a human mineral balance study. The same quantity of food was supplied to each of the subjects throughout the study without consideration of body weight. Fecal specimens were collected throughout the study and were separated into those originating from the diet during the balance period based on the appearance of the ingested colored marker in the feces. RESULTS: The moisture content of the feces ranged between 53 and 92%. Na content in the feces was low and stable when the moisture content was below 80%, whereas it increased up to serum levels when the moisture content increased above 80%. On the other hand, K content increased when compared to dry matter base. However, when comparing concentration/g moisture, K content increased when moisture was below 70%, but decreased when this rose above 70%.

Association between Hardness (Difficulty of Chewing) of the Habitual Diet and Premenstrual Symptoms in Young Japanese Women.

Recent evidence suggests that voluntary rhythmic movements such as chewing may increase blood serotonin and subsequently brain serotonin, which in turn acts to alleviate premenstrual symptoms. In this observational cross-sectional study, we tested the hypothesis that hardness (difficulty of chewing) of the habitual diet (i.e. dietary hardness) is associated with decreased premenstrual symptoms. Subjects were 640 female Japanese dietetic students aged 18-22 years. Dietary hardness was assessed as an estimate of masticatory muscle activity for the habitual diet (i.e. the difficulty of chewing the food). The consumption of a total of 107 foods was estimated by means of a self-administered, comprehensive diet history questionnaire, and masticatory muscle activity during the ingestion of these foods was estimated according to published equations. Menstrual cycle symptoms were assessed using the retrospective version of the Moos Menstrual Distress Questionnaire, from which total score and subscale scores (i.e. pain, concentration, behavioral change, autonomic reactions, water retention, and negative affect) in the premenstrual phase were calculated and expressed as percentages relative to those in the intermenstrual phase. Dietary hardness was not associated with total score in the premenstrual phase (P for trend = 0.48). Further, no association was seen for any subscale score in the premenstrual phase (P for trend = 0.18-0.91). In conclusion, this preliminary study failed to substantiate a hypothesized inverse relationship between hardness of the habitual diet and premenstrual symptoms. Considering the plausibility of the putative mechanism, however, further investigation using more relevant measures of chewing and premenstrual symptoms is warranted.

Total n-3 polyunsaturated fatty acid intake is inversely associated with serum C-reactive protein in young Japanese women.

Little is known about the relation of dietary factors to circulating C-reactive protein (CRP) concentrations in young adults and non-Western populations. We cross-sectionally examined associations between dietary intake and serum CRP concentrations in young Japanese women. The subjects were 443 female Japanese dietetic students aged 18 to 22 years. Dietary intake was assessed with a validated, self-administered, comprehensive, diet history questionnaire. Serum CRP concentrations were measured by highly sensitive nephelometry. The prevalence of elevated CRP (> or = 1 mg/L) was 5.6%. After adjustment for possible confounding factors including body mass index, a significant inverse association was seen between total n-3 polyunsaturated fatty acid intake and elevated CRP. The multivariate adjusted odds ratios of elevated CRP for women with intake below and above the median (1.1% of energy) were 1.00 and 0.33 (95% confidence interval, 0.13-0.82; P = .02), respectively. Intake of eicosapentaenoic acid + docosahexaenoic acid and alpha-linolenic acid was not associated with elevated CRP concentrations (P = .62 and P = .27, respectively). Vitamin C intake was independently inversely associated with elevated CRP, although the association was nonsignificant (P = .10). No clear associations were observed for other dietary factors examined including total fat, saturated fatty acids, monounsaturated fatty acids, polyunsaturated fatty acids, total dietary fiber, soluble dietary fiber, insoluble dietary fiber, and magnesium; fruits, vegetables, and fish and shellfish; and dietary glycemic load (P = .27 to P = .99). In conclusion, total n-3 polyunsaturated fatty acid intake showed an independent inverse association with elevated serum CRP concentration in a group of young Japanese women.

Lower estimates of delta-5 desaturase and elongase activity are related to adverse profiles for several metabolic risk factors in young Japanese women.

Little is known about the relation between the activities of certain enzymes involved in endogenous fatty acid synthesis and metabolic risk factors, particularly in young adults and non-Western populations. In this cross-sectional study, we examined the associations between estimated desaturase and elongase activities and metabolic risk factors in young Japanese women. The subjects were 640 female Japanese dietetic students aged 18 to 22 years. Body height and weight, from which body mass index (BMI) was derived, waist circumference, and blood pressure were measured. Fasting blood samples were collected for biochemical and fatty acid measurements. Desaturase and elongase enzyme activities were estimated as the ratio of product to precursor of individual fatty acids in serum lipids. delta-9 desaturase activity was positively associated with BMI, diastolic blood pressure, total and low-density lipoprotein cholesterol, and triacylglycerol and was negatively associated with high-density lipoprotein cholesterol (P