Four Plasma Glucose and Insulin Responses to a 75 g OGTT in Healthy Young Japanese Women.

The incidence of diabetes has been gradually increasing, not only in middle-aged individuals but also in young individuals. However, insulin and glucose patterns have not been investigated in apparently healthy young individuals, as they are typically grouped as controls. In this study, we investigated and classified glucose and insulin patterns in healthy young women. Sixty-two nonobese women without metabolic disease were recruited. The subjects underwent a 75 g oral glucose tolerance test (OGTT), physical measurements, and a biochemical examination. Two subjects displayed impaired glucose tolerance. The 62 subjects were categorized into four patterns by plasma glucose and insulin peak time during OGTT: normal type (n = 39), insulin-late type (n = 11), insulin- and glucose-late type (n = 7), and insulin-very late type (n = 5). OGTT glucose and insulin levels at all time points, insulinogenic index, HOMA-IR, and glucose area under the curve (AUC) significantly differed among the four groups. However, insulin AUC did not significantly differ. We did not detect significant differences in body condition or biochemical measurements. Our study demonstrated that some healthy young individuals might have delayed insulin secretion by OGTT. Early detection of altered glucose metabolism might be helpful to improve lifestyle choices and prevent progression to diabetes.

Intake and urinary amounts of biotin in Japanese elementary school children, college students, and elderly persons.

Biotin enzymes such as pyruvate carboxylase and acetyl-CoA carboxylase are involved with the most basic metabolism. Thus, it is very important to monitor the biotin nutritional status for maintaining good health. We examined urinary excretion and the intake of biotin in a Japanese sample population of 60 boys and 36 girls (10-12 y), 37 male and 135 female college students (18-27 y), and 35 female elderly persons (70-84 y) living freely. All food consumed, and the corresponding weighing, for 4 consecutive days were recorded. A 24-hour urine sample was collected on the fourth day, and the urine biotin was measured. The urine biotin at the fourth day was 57.8, 50.9, 81.0, 66.2, and 82.3 nmol/day in boys, girls, male students, female students, and elderly persons, respectively. The average intake of biotin for 4 consecutive days was 35, 31, 28, 26, and 32 µg/day in boys, girls, male students, female students, and elderly persons, respectively.

Association between 24 hour urinary α-tocopherol catabolite, 2,5,7,8-tetramethyl-2(2'-carboxyethyl)-6-hydroxychroman (α-CEHC) and α-tocopherol intake in intervention and cross-sectional studies.

The objective is to determine the association between the 24 hour urinary α-tocopherol catabolite, 2,5,7,8-tetramethyl-2(2'-carboxyethyl)-6-hydroxychroman (α-CEHC) and α-tocopherol intake in an intervention and a cross-sectional studies. In the 4-weeks intervention study, Japanese men (n = 10) consumed the test diet in week 1, and the test diet plus varying amounts of α-tocopherol in the three subsequent weeks: 21 µmol/d α-tocopherol in week 2, 63 µmol/d in week 3, and 125 µmol/d in week 4. A significant association between α-tocopherol intake and urinary α-CEHC was observed in this strictly controlled experiment (r = 0.99, p<0.001). In the cross-sectional study, all foods consumed over 4 consecutive days were recorded in 76 free-living young subjects (18-33 years). The association was weak, but a significant relationship was observed (r = 0.29, p<0.05) even in the cross-sectional study. In the cross-sectional study adults, mean estimated α-tocopherol intake calculated by urinary α-CEHC and the excretory ratio was 91% of their mean intake over the 4 days. The results show that urinary α-CEHC level reflected recent α-tocopherol intake in free-living young Japanese adults, and could be used as a measure of intake during the previous few days, both for group means and for individual rankings within a group.

Twenty-four-hour urinary water-soluble vitamin levels correlate with their intakes in free-living Japanese schoolchildren.

OBJECTIVE: To examine the association between 24 h urinary water-soluble vitamin levels and their intakes in free-living Japanese schoolchildren. DESIGN: All foods consumed for four consecutive days were recorded accurately by a weighed food record. A single 24 h urine sample was collected on the fourth day, and the urinary levels of water-soluble vitamins were measured. SETTING: An elementary school in Inazawa City, Japan. SUBJECTS: A total of 114 healthy, free-living, Japanese elementary-school children aged 10-12 years. RESULTS: The urinary level of each water-soluble vitamin was correlated positively to its mean intake in the past 2-4 d (vitamin B1: r = 0·42, P < 0·001; vitamin B2: r = 0·43, P < 0·001; vitamin B6: r = 0·49, P < 0·001; niacin: r = 0·32, P < 0·001; niacin equivalents: r = 0·32, P < 0·001; pantothenic acid: r = 0·32, P < 0·001; folic acid: r = 0·27, P < 0·01; vitamin C: r = 0·39, P < 0.001), except for vitamin B12 (r = 0·10, P = NS). Estimated mean intakes of water-soluble vitamins calculated using urinary levels and recovery rates were 97-102 % of their 3 d mean intake, except for vitamin B12 (79 %). CONCLUSIONS: The results show that urinary levels of water-soluble vitamins, except for vitamin B12, reflected their recent intakes in free-living Japanese schoolchildren and could be used as a potential biomarker to estimate mean vitamin intake.

Urinary excretion of vitamin B1, B2, B6, niacin, pantothenic acid, folate, and vitamin C correlates with dietary intakes of free-living elderly, female Japanese.

We hypothesized that 24-hour urinary excretion of water-soluble vitamins might correlate with their intake in free-living Japanese elderly females aged 70 to 84 years. We performed a cross-sectional study composed of 37 healthy, elderly, Japanese females living freely. All foods and the corresponding weights consumed for 4 consecutive days were recorded accurately. A 24-hour urine sample was collected on the fourth day, and the urinary content of water-soluble vitamins was measured. The urinary levels of all vitamins, except for B(12) (r = 0.01; P = .936), were correlated positively with the mean intake over the recent 4 days (vitamin B1: r = 0.62; P < .001; vitamin B2: r = 0.57; P < .001; vitamin B6: r = 0.37; P < .005; niacin: r = 0.54; P < .001; niacin equivalents: r = 0.54; P < .001; pantothenic acid: r = 0.59; P < .001; folate: r = 0.55; P = .001; and vitamin C: r = 0.53; P < .001). Mean estimated intakes of water-soluble vitamins calculated using urinary concentrations and recovery rates showed 96% to 107% of their 3-day mean intake, except for vitamin B12 (65%). We conclude that urinary levels of water-soluble vitamins, except for B12, reflected their recent intake in free-living Japanese elderly females and could be used as a measure of their intake during the previous few days both for group means and for individual rankings within a group.

Urinary excretion of vitamin B12 depends on urine volume in Japanese female university students and elderly.

Recent studies have shown that urinary excretion of water-soluble vitamins reflects their intake in humans. However, some have reported that physical characteristics and urine volume may affect the amount of vitamin compounds found in urine. We hypothesized that physical characteristics and urine volume could affect urinary excretion of B-group vitamins. Twenty-four-hour urine samples were collected from 186 free-living Japanese women aged 19 to 21 years and 104 free-living Japanese subjects aged 70 to 84 years. Correlations between urinary output of each B-group vitamin and body height, body weight, body mass index, body surface area, urine volume, and urinary creatinine were determined. Only urinary vitamin B(12) was strongly correlated to urine volume in young (r = 0.683, P < .001) and elderly (r = 0.523, P < .001) subjects. To confirm this finding, 20 Japanese adults were orally administered 1.5 mg of cyanocobalamin (500-fold higher daily intake); and correlations between urinary vitamin B(12) and urine volume were determined. The load of cyanocobalamin increased vitamin B(12) content in the urine by only 1.3-fold. Urinary vitamin B(12) was strongly correlated with urine volume on the day before taking, the day of taking, and the day after taking cyanocobalamin (r = 0.745, P < .001; r = 0.897, P < .0001; and r = 0.855, P < .0001, respectively). We conclude that urinary excretion of vitamin B(12) is dependent upon urine volume, but not on intake of vitamin B(12). Physical characteristics and urine volume are less important for B-group vitamins except for vitamin B(12) as biomarker.