The intravenous administration of β-cryptoxanthin (320μg/mouse) into 4-wk-old ddY mice caused a new peak in addition to the peak of β-cryptoxanthin during highperformance liquid chromatography (HPLC) of the lipid fraction of lung homogenate. Different HPLC conditions revealed that the new peak might be attributed to a β-carotenelike compound. The average retention times for the new peak and authentic all-trans-β-carotene were 14.97 and 15.00min, respectively, in a HPLC system using a YMC-Pack ODS-A column and methanol-based mobile phase, and 27.05 and 26.93min, respectively, in a HPLC system using a Waters Nova Pack C18 column and methanol-based mobile phase. In a HPLC system using a Waters Nova Pack C18 column and acetonitrile-based mobile phase, the retention times were 10.73, 10.48 and 10.70min for the new peak, authentic all-trans-β-carotene, and 9-cis-β-carotene, respectively. Spectrophotometry with a photodiode array detector showed maximum absorption of 447 and 475nm for the new peak, and 450 and 475nm for authentic all-trans-β-carotene. This new peak was not observed in the lung tissue of control mice. These findings indicate the possible conversion of β-cryptoxanthin to a β-carotene like-compound in ddY mice.
The amide nitrogen atom of glutamine is incorporated into pyridoxine in four eukaryotes (i.e., Emericella nidulans, Mucor racemosus, Neurospora crassa and Saccharomyces cerevisiae) and two prokaryotes (i.e., Staphylococcus aureus and Bacillus subtilis). However, in the prokaryotes Pseudomonas putida, Enterobacter aerogenes and Escherichia coli, it is the nitrogen atom of glutamate that is incorporated into pyridoxine (J Nutr Sci Vitaminol (2000) 46, 55-57). As these results were from experiments conducted under aerobic conditions, we investigated the biosynthesis of pyridoxine on S. cerevisiae under anaerobic conditions. The results showed that [amide-15N]L-glutamine was not incorporated into pyridoxine, unlike the results for aerobic conditions. The incorporation of [15N]ammonium salts into pyridoxine was not inhibited in the presence of casamino acids and tryptophan. The results showed that the nitrogen atoms of amino acids are not used for the biosynthesis of pyridoxine. The incorporation of 15N into pyridoxine was inhibited in the presence of adenine, but not in that of hypoxanthine. Thus, the nitrogen atom of pyridoxine may be from the amino group attached to the C-6 of adenine.
Vitamin A (VA) and insulin-like growth factors (IGF) are important regulators of a wide range of physiological processes. To investigate the IGF system's involvement in the physiological actions of VA, we examined the effects of VA status on components of the IGF system in rats. Male rats (3-wk-old) fed a VA-deficient diet for 11 wk developed VA deficiency, as confirmed by the depletion of serum retinyl and hepatic retinyl palmitate. Rats fed the VA-deficient diet had significantly lower body weight (p<0.05) and lower serum IGF-I concentrations than the rats fed the control diet. The decreases in serum IGF-I levels were accompanied by approximately 40% lower levels of the IGF-I mRNA in the liver and lungs. With respect to the gene expression of other IGF system components, VA deficiency caused a twofold induction of IGF-I receptor (IGF-IR) mRNA in the heart and a twofold reduction in IGFBP-6 mRNA in the lungs, but did not alter the expression of IGF-II, IGFBP-1, IGFBP-3, IGFBP-4 or IGFBP-5 in all tissues examined. When VA-deficient rats received a single injection of retinoic acid (2mg/rat), tissue IGF-I and IGF-IR gene expression did not change after 4 or S h, while the expression of IGF-II, IGFBP-4, and IGFBP-6 mRNAs in some tissues increased rapidly. These results suggest a possible involvement of the IGF system in mediating the physiological actions of VA, including VA-supported growth, in the rat.
In order to determine the interrelationship between dietary iron and zinc levels, the effects of dietary iron levels (2, 10, 20, and 40μg/g) on changes in iron and zinc status and zinc enzyme activities (aminolevulinic acid dehydratase ALA-D EC 4. 2. 1. 24 and alkaline phosphatase ALK-P EC 3. 1. 3. 1) in male Wistar rats were investigated using adequate and marginally deficient zinc diets (2 5 and 5μg/g). When rats were fed 5μg., Zn/g diets, body weight gain and food intake remained unchanged at a Fe diet intake of 20μg/g or greater. Similar tendencies were obtained for hemoglobin, hematocrit, plasma iron, and transferrin saturation. In contrast, liver, spleen, and femur iron concentrations increased gradually with increased iron intake. Feeding diets containing 25μg Zn/g did not alter these parameters. The percentages of apparent iron absorption in both dietary zinc groups tended to increase with decreasing dietary iron and attained maximum levels at an Fe intake of 10μg/g. However, in the case of rats fed Fe at concentrations of 2μg/g iron absorp-tion decreased. Regardless of the dietary zinc level, rats fed diets with an Fe concentration of 2μg/g had decreased zinc absorption and plasma ALK-P activity. However, ALA-D activity was not influenced by dietary iron.
The validity of a food frequency questionnaire (FFQ) was evaluated against four 7-d diet records among 23 men aged 27-70y. Volunteer women recorded the amounts of all foods and beverages consumed by their husbands or fathers over a period of 7 d in four consecutive seasons in 1997 and 1998, and a self administered FFQ was answered by each man after completion of the fourth diet record. The diet record was kept in accordance with the method used for Japan's National Nutrition Survey. The FFQ ascertained frequencies and amounts of consumption of rice, bread, noodles, green tea, and coffee; consumption frequency of 35 food items; and consumption frequency and amount of five alcoholic beverages. As for most nutrients and foods, mean intakes estimated by the FFQ were lower than those estimated from the diet record. Crude intake of nutrients showed fairly good agreement between the two methods in terms of Pearson's correlation coefficient (r>0.5), except for total energy (r=0.23), fat (r=0.36), and vitamin A (r=0.29). The adjustment for energy intake generally reduced the correlation; the reduction being fairly large for fat intake and vitamin A (r=0.19 for both). There was generally good agreement for the intake of foods and beverages with exceptions for fats/oils (Spearman correlation coefficient, rs=0.30) and other vegetables (r=0.35). The highest correlation was observed for alcoholic beverages (r=0.91), bread (rs=0.80), and fruits (r=0.77). An FFQ covering a limited number of common foods may be useful in assessing the relative position of an individual's habitual consumption of foods and nutrients; however, the instrument generally underestimates absolute intake.
The increased expression of quinone reductase (OR) has been associated with anticarcinogenic processes. The aim of this study was to explore the roles of the cruciferous vegetable-derived indoles, indole-3-carbinol (I3C) and indolo[3, 2-b]carbazole (ICZ), on the regulation of OR in both murine (Hepa-1) and human (HepG2) hepatoma cells. The results indicate that ICZ enhanced OR activity in both Hepa-1 and HepG2 cells, whereas its parent compound, I3C, had no significant effect on the induction of OR. Moreover, the ICZ-induced OR activity showed a higher response and expressed a more-significant dose-response in Hepa-1 cells. OR mRNA expression as analyzed by RT-PCR demonstrated a pattern similar to that of the enzyme activity. In conclusion, I3C did not show an enhancement effect on OR activity, but its acidic derivative, ICZ, increased the expression of OR mRNA, which then caused the augmentation of OR activity in Hepa-1 and HepG2 cells.
The purpose of this study is to investigate the effect of taurine on the plasma cholesterol concentration in genetic type 2 diabetic rats fed cholesterol-free or high-choles-terol diets. Diabetic rats (GIG male rats) and normal rats (Wistar male rats) were fed either a cholesterol-free or cholesterol-enriched (1% cholesterol+ 0.2 5 % sodium cholate) diet sup-plemented with or without 3% taurine for 21 or 14 d. Compared to the normal rats, diabetic rats showed a high glucose concentration in their blood and plasma, but it was not affected by taurine feeding. The plasma insulin concentration was higher in the diabetic rats than in the normal rats. At the start of the experiment, the plasma cholesterol concentration was significantly higher in the diabetic rats than in the normal rats. Taurine did not affect the plasma cholesterol level in rats fed the cholesterol-free diet. However, taurine feeding signifi-cantly increased the plasma HDL-cholesterol concentration in the diabetic rats fed the cho-lesterol-free diet. In both the diabetic and normal rats fed the cholesterol diet, the plasma cholesterol concentration was significantly lower in rats fed the diet supplemented with tau-rive than in the rats fed the control diet. It was concluded that taurine has a hypocholes-terolemic effect in both diabetic and normal rats fed diets containing cholesterol. Moreover, these results suggest that taurine seems to affect the HDL-cholesterol metabolism in diabetic rats fed a cholesterol-free diet.
Four groups of 1-mo-old male senescence-accelerated mice (SAMP8) were fed Polygonum multiflorum Thunb. (PM) extract for 18 wk to determine the effect of PM on memory ability and histopathological changes in mice. The baseline diet consisted of a casein diet group, and the three test diets were supplemented with 50% ethanol, 95% ethanol, or water extracts of PM. It was found that the mice fed with PM extracts had better active shuttle avoidance response, fewer vacuole numbers, less lipofuscin in the hippocampus, and lower MDA concentrations in the brain. Our data showed that the ethanol PM extract groups (both 50% and 9 5% groups) had lower lipofuscin percentages and MDA concentrations, and higher total thiol concentrations than the water PM extract group. The 50% ethanol PM extract group showed significantly lower total cholesterol and triglyceride values than the other groups, but the HDL cholesterol level was the same. These results suggest that dietary supplementation with either ethanol or water extracts can reduce brain pathological changes and promote learning and memory ability. The performance of PM extracts depended on the extraction method, with ethanol extraction tending to obtain better results.
This study was aimed at evaluation of the validity and reliability of an alternative dietary measurement method that assists epidemiologic studies. We validated a handheld personal digital assistant with camera and mobile phone card, called Wellnavi, in which a 1-d weighed diet record was employed as a reference method. Twenty college students majoring in food and nutrition participated in this study. They were asked to keep a diet record and to take digital photos of all these recorded food at the same time, then send them to the dietitians by the mobile phone card. In the reliability study, other twenty students from the same college were asked to take digital photos of the same meal during a day by two same instruments under the same circumstances and to send these photos to the different dietitians electronically. With respect to validity, median nutrient intakes estimated by the Wellnavi method and the diet record method are comparable. Correlation coefficients between the median nutrient intakes estimated from these two methods ranged from 0.46 for monounsaturated fatty acid to 0.93 for vitamin B12 and copper (median r=0.77). With respect to reliability, our data show a good agreement between two Wellnavi instruments for most of the nutrients. Correlation coefficients between the nutrient intakes estimated from 2 instruments ranged from 0.55 for vitamin B, and water-insoluble dietary fiber to 0.92 for vitamin B12 (median r=0.78). In conclusion, the results indicate this dietary assessment instrument can usefully measure individual dietary intakes for a variety of nutrients in an epidemiologic study.
In this study, the effect of varying doses of conjugated linoleic acid (CLA) on the growth of transplanted hepatoma dRLh-84 cells and the relationship between tumor growth and prostaglandin (PG) E2 production or cyclooxygenase (COX)-2 expression were examined. Donryu rats were fed an experimental diet containing 0, 0.1, 0.5, or 2 wt.% CLA for 3 wk, and then dRLh-84 cells were transplanted into the liver. Results show that dietary CLA (0.5 and 2 wt.%) significantly enhanced the growth of the transplanted hepatoma cells compared to the non-CLA diet group at 20 d after cell transplantation. Tumor weight at 10 d after transplantation was also significantly higher in the 2 wt.% CLA group than in non-CLA fed rats. Ten days after transplantation, the PGE2 level in the tumor tissue was shown to be depressed in a CLA dose-dependent manner. Cyclooxygenase-2 (COX-2) mRNA expression in the tumor also tended to be lower in the CLA group than in the non-CLA diet group 10 d after transplantation. Dietary CLA did not affect the tumor phospholipid arachidonic acid level, which is a substrate for PG synthesis. These results indicate that dietary CLA of at least 0.5 wt.% enhances the growth of transplanted dRLh-84 cells in vivo. It is believed that growth promotion of dRLh-84 cells in vivo by CLA cannot be clarified by the PG synthesis dependent mechanism.
The effects of oral acute administration and subchronic (34d) feeding of several levels of D-psicose, a C3-epimer of D-fructose, were studied in rats. In the acute administration test, five groups of eight male Wistar rats (3 wk old) were orally given D-psicose in doses of 8, 11, 14, 17, and 20g/kg. Three rats receiving 14g/kg, three rats receiving 17g/kg and eight rats receiving 20g/kg of D-psicose died within 2d after administration. The calculated LD50 values were 16.3g/kg by the Behrens-Karber method and 15.8g/kg by the Litchfield-Wilcoxon method. In the subcronic feeding test, eight groups of seven male Wistar rats (3 wk old) were fed diets containing O (control), 10, 20, 30, and 40% for 34d. One rat fed 30% D-psicose diet and five rats fed 40% D-psicose diet died during the experimental period. Body weight gain, food intake and food efficiency were more extensively suppressed by the higher D-psicose diets. The weights of heart, spleen and abdominal adipose tissue were smaller in the order of dietary D-psicose concentration. Cecal weight increased with increasing D-psicose concentration in the diets. Cecal hypertrophy was observed in rats fed 10-40% D-psicose diets. These results suggest that D-psicose differs in nutritional characteristics from D-glucose or D-fructose. The feeding of diets extremely high in D-psicose seems to be harmful to the intestinal tract.
In a previous study using young Japanese men as subjects, Ebine et al, found that accelerometer (AC) represents a promising technique for measuring free-living total energy expenditure (TEE) when compared to activity records (AR) and heart rate monitoring (HR). Thus, the present study was designed to validate the use of an AC and to determine whether or not the previous findings regarding the three alternative field methods (AC, AR, and HR) could be extended to older Japanese men (n=24; mean±SD age 48±10y, body mass index 23.1±2.7kg/m2 and body fat 18.7±4.8%). TEE values obtained over a 3d period by AR, HR, and AC (3dAC), and AC over a 14d period (14dAC) were simultaneously validated against TEE measured by the doubly labeled water (DLW) method applied within a 14 d period. TEE values obtained by AR, HR, 3dAC, and 14dAC ranged from 1, 750 to 3, 447 kcal/d, 1, 691 to 5, 286 kcal/d, 1, 716 to 2, 765 kcal/d, and 1, 700 to 2, 855 kcal/d, respectively. Expenditures obtained by HR were similar to those obtained using the DLW method, with a mean difference of 57±603 kcal/d (2%), but those obtained using AR, 3dAC, and 14dAC differed substantially from the DLW method, with mean differences of -335±289 kcal/d (12%), -542±249 kcal/d (-19%), and -566±223 kcal/d (-20%), respectively. AR, HR, 3dAC, and 14dAC were significantly correlated with the DLW method, with r values of 0.76 (p<0.0001), 0.67 (p<0.001), 0.78 (p<0.0001), and 0.83 (p<0.0001), respectively. Intra-individual variation indicated by the coefficient of variation (CV) was significantly higher for HR (15±11%, p<0.001) than for AR (7±4%), 3dAC (7±5%), and 14dAC (8±3%). The same findings were obtained using Bland and Altman plots at the population level. Interestingly, 3dAC and 14dAC were significantly correlated with r=0.97 (p<0.0001), with a lower mean difference of 24 kcal/d. These results suggest that, same as the previous study, AC is superior to HR in estimating TEE, and seems to be satisfactory for estimation at both group and individual levels, particularly for large-scale studies of older individuals when compared to the DLW method. However, some modifications of the AC method may be needed to compensate for the underestimation of TEE.
It has been previously shown that a diet containing medium-chain triacylglycerols (MCT) leads to less body fat accumulation as compared to a diet containing longchain triacylglycerols (LCT). We investigated the involvement of diet-induced thermogenesis in the accumulation of body fat in rats fed a diet containing MCT. Twelve male Wistar rats were administered 1 g of MCT or LCT by gavage, and their oxygen consumption was measured for 6 h (experiment 1). Forty male Wistar rats were fed a diet containing 10% MCT or LCT for 6 wk, and their body composition was determined (experiment 2). In experiment 1, oxygen consumption increased to a greater extent after MCT administration than after LCT administration. Diet-induced thermogenesis was significantly (0.67±0.14 kcal) larger after the administration of 1 g of MCT. In experiment 2, there were no differences in food intake or carcass protein content between the LCT group and MCT group. However, carcass fat and intra-abdominal fat content were significantly lower in rats fed MCT than in those fed LCT. We calculated that ingestion of 1 g of MCT decreased body fat by 0.94±0.27 kcal relative to the ingestion of LCT. These results suggest that the larger diet-induced thermogenesis observed in rats fed MCT, compared to that of those fed LCT, is one of the main factors involved in the suppression of body fat accumulation in rats fed MCT.
The data accumulated from epidemiological studies suggests that individuals with elevated blood levels of homocysteine have an increased risk of cardiovascular disease. However, little is known of the food factor that may affect the homocysteine status, except for folate and B-vitamins. Here, we tested the effect of dietary phenolics (i.e., anthocyanin of food colorant) administration on plasma homocysteine concentration in a rat study, since a profound effect on the methionine metabolism was speculated from the 3', 4'-catechol skeletal structure of anthocyanin. Female Sprague-Dawley rats (body weight 100g) orally ingested a single dose of anthocyanin mixture (total 100mg) composed of cyanidin-3-glu-coside (50mg), cyanidin-3-sambubioside (48mg), and cyanidin-3, 5-diglucoside (2mg). The total homocysteine in the plasma collected 90-240min after anthocyanin intake was 1.4 to 1.8-fold (5.2-6.7μmol/L) higher than the basal homocysteine level (3.7μmol/L). In the liver and kidney, anthocyanin significantly affects sulfur amino acid (S-adenosylmethio-nine, SAM, and S-adenosylhomocysteine, SAH) levels, both of which are precursors of plasma homocysteine, and the SAH/SAM ratio showed a significant increase in the liver and kidney. Accordingly, these results suggest that dietary anthocyanin stimulates homo-cysteine synthesis from SAH in the liver and kidney, and the homocysteine yielded transfers into the blood stream. The intake of anthocyanin and its structural homologues may have an effect on the metabolic regulation of sulfur amino acids and possibly increase the risk of vascular disease in humans.
The purpose of this study was to investigate the effect of 5-10g of medium- chain triacylglycerols (MCT) on diet-induced thermogenesis in healthy humans. The study compared diet-induced thermogenesis after ingestion of test foods containing MCT and long-chain triacylglycerols (LCT), using a double-blind, crossover design. Eight male and eight female subjects participated in study 1 and study 2, respectively. In both studies, the LCT was a blend of rapeseed oil and soybean oil. In study 1, the liquid meals contained 10g MCT (10M), a mixture of 5g MCT and 5g LCT (5M5L), and 10g LCT (10L). In study 2, the subjects were given a meal (sandwich and clear soup) with the mayonnaise or margarine containing 5g of MCT or LCT. Postprandial energy expenditure was measured by indirect calorimetry before and during the 6 h after ingestion of the test meals. Diet-induced thermogenesis was significantly greater after 5M5L and 10M ingestion as compared to 10L inges- tion. Ingestion of the mayonnaise or margarine containing 5g MCT caused significantly larger diet-induced thermogenesis as compared to that of LCT. These results suggest that, in healthy humans, the intake of 5-10g of MCT causes larger diet-induced thermogenesis than that of LCT, irrespective of the form of meal containing the MCT.