This study aims to estimate the tolerable lactose intake which can be utilized in the digestion by lactase and in the fermentation by intestinal microbes in Japanese female adults. The first, the maximum permissive dosage of lactose not to induce transitory diarrhea was estimated based on the oral ingestion of lactose at several dose levels in all the sub-jects, and compared with that of lactitol which is not hydrolyzed by digestive enzymes. A second lactose tolerance test involving 10g and 30g of lactose was carried out in 10 sub-jects showing resistance to diarrhea, and serum glucose and insulin levels and the amount of hydrogen excreted in the breath were measured for comparison with those of glucose and lactitol. Subjects were 43 Japanese female adults (average: age 20.5±2.1 y, weight 51.3±5.1kg) who had not been diagnosed as having either hypolactasia or being lactose intolerant. Serum glucose and insulin levels were scarcely elevated following the ingestion of both 10g and 30g of lactose, while the amount of hydrogen excreted in the breath was greatly increased following the ingestion of 30g of lactose, but these levels were less following the ingestion of 10g of lactose. In contrast, the ingestion of 15g of glucose significantly increased blood glucose and insulin levels, while no hydrogen was detected in the breath. The maximum permissive dosage of lactose not to induce transitory diarrhea was 0.72g/kg of body weight and that of lactitol was 0.36g/kg of body weight in Japanese adults. The digestive capacity of lactase is less than 10g of lactose by single ingestion, while intestinal microfiora are able to ferment approximately 20-30g of lactose. In addition, the ingestion of more than 10g of lactose might be contributed as prebiotics.
In Western countries underestimation of energy intake (EI) is considered a serious problem in dietary surveys, but information on the accuracy of EI among Japanese people is sparse. We compared estimated EI with measured total energy expenditure (TEE) in 21 Japanese women aged 20-22y. Dietary intake was estimated by 7-d weighed dietary records (7dWR) and a self-administered diet history questionnaire (DHQ). TEE was mea-sured for 25±3d (mean±standard deviation, range: 16-27d) by a uniaxial accelerometer. Both El by 7dWR (1, 498±305kcal/d) and El by DHO (1, 599±331kcal/d) were signifi-cantly lower than TEE (1, 865±179kcal/d) (p<0.001 and p<0.01, respectively), but nei-ther estimated EI nor the magnitude of EI underestimation (20±15% for 7dWR and 13±23% for DHQ) was significantly different between two methods (p=0.25 and p=0.22, respectively). The Spearman correlation (r) between TEE and EI was 0.51 (p=0.02) for 7dWR and 0.09 (p=0.71) for DHQ, indicating better ranking of individuals by 7dWR. The accuracy of El (El/TEE) was negatively associated with the percentage of EI from protein in 7dWR (r=-0.44, p=0.049) and positively associated with the percentage of EI from fat in both 7dWR (r=0.45, p=0.04) and DHQ (r=0.62, p<0.01), suggesting selective overestima-tion of protein and selective underestimation of fat. These results indicate not only underes-timation of habitual EI but also selective under- and/or overestimation of macronutrients in both 7dWR and DHQ.
Previously, we reported that males with mental retardation (MR) (MR group) expended more energy than males without MR (control group) at a given work load. The precise physiological mechanisms for this difference remain unclear. Using the same set of subjects (23age-, height-, and weight-matched male pairs, mean age: 36.3y), we examined possible causes for the observed metabolic difference by monitoring physical movements and evaluating the metabolic capability of the skeletal muscles. In the supine position when no body movements were detected for any subjects, oxygen consumption (VO2) and heart rate (HR) were not markedly different between the MR and the control groups. By contrast, in the sitting and standing positions and during walking at 30 and 50m/min, when signif-icantly larger body movements were monitored in the MR group, VO2 and HR were signifi-cantly higher in this group than in the control group. Linear regression analyses, performed separately in the MR and control groups, revealed that the slope of the regression line of HR on relative exercise intensity (%VO2max) during walking, that of VO2 on walking speeds, and that of VO2 on the number of steps in the MR group were almost identical with those in the control group. These results suggest that the capability of skeletal muscles was not so dif-ferent between the two groups. Thus, the high energy expenditure in the MR group was suggested to be a result of excessive body movements rather than an intrinsic incapability of skeletal muscles.
The objective of the present study was to establish whether high-density lipo-protein 3 (HDL3) or high-density lipoprotein 2 (HDL2) might show an anti-oxidative effect on the acceleration of the oxidative modification of low-density lipoprotein(LDL) by ascorbic acid from measurement of the agarose gel electrophoretic mobility of LDL. LDL was incu-bated without adding transitional-metal ions for 48 or 96h in phosphate-buffered saline (PBS) alone, with ascorbic acid (20μg/mL), or with both ascorbic acid (20μg/mL) and HDL3 (200μg protein/mL). The LDL autoxidation occurred in PBS alone. Although ascor-bic acid significantly suppressed oxidative modification of LDL after incubation for 48h, the opposite was true after 96h. However, since the anti-oxidative ability of HDL2 shows a weaker tendency than that of HDL3, both HDL3 and HDL2 significantly inhibited this accel-eration of oxidative modification of LDL by ascorbic acid as assessed by electrophoretic mobility. If there is an augmented oxidative modification of LDL due to ascorbic acid in vivo, HDL3 or HDL2 may thus have an important role in inhibiting this ascorbic acid-accelerated oxidation of LDL.
8-Hydroxydaidzein (8-OHD), which is produced during the processing of fer-mented soybean products, has a potent antioxidant activity in vitro. There is no information regarding the absorption and excretion of this isoflavone, including its antioxidant effect in vivo. In this study, rats were administered a single oral dose of 8-OHD (20mg/kg body weight), and the blood, liver, kidney and urine were collected at specific intervals up to 18h after dosing. Free 8-OHD in each tissue was directly determined by using HPLC with electro-chemical detection, while its conjugates were detected after the treatment with β-glucu-ronidase and sulfatase. The total 8-OHD in liver reached a high level (9.4 nmol/g) at 1h after dosing, and maintained the relatively high concentration up to 10h. Most of the 8-OHD was present in free form in liver, while the majority of 8-OHD in plasma was conju-gated. This suggests that free 8-OHD in liver is successively converted to glucuronide and/or sulfate and the conjugated 8-OHD is released into the blood. The maximum level of total 8-OHD in plasma or kidney was observed within the first 2h after the oral administration. The level of 8-OHD in these tissues gradually decreased within the further experiments. Excre-tion of the 8-OHD in urine began to rise at 1-2h interval. The mean urinary excretion rate of 8-OHD showed a higher level at 2-4h and 4-6h intervals, while the 8-OHD levels at these intervals in plasma or kidney more rapidly decreased. The cumulative recovery of 8-OHD in the urine over the 0-18h interval was about 36% of the dose. In addition, the liver homogenate from rats killed at 1h and 2h after dosing, which contained a higher level of free 8-OHD, showed a significantly lower susceptibility to lipid peroxidation induced by AAPH or Cu2+ than that at Oh (pre-administered rats). These results suggest that 8-OHD was relatively easily absorbed into rats and might exert its biological activities in vivo, including the antioxidant effect.
The purpose of this study was to evaluate the use of grip strength as an index of nutritional status in 6-10y old children. Seven hundred and eighty seven children (364 boys and 423 girls) in the age group of 6 to 10y were selected from private and municipal schools, orphanages and slums in the cities of Mumbai and Pune, India. Grip strength was measured using the dominant hand. Height, weight, mid-arm circumference and triceps skinfold were also measured in all subjects. A significantly high correlation (p<0.01) was observed between grip strength and age for both sexes. Boys had a higher grip strength than girls at all ages. Grip strength was significantly correlated with height, weight, mid arm cir-cumference, triceps skinfold, arm fat and arm muscle areas (p<0.01). Stepwise multiple regression analyses showed height, weight, triceps skinfold and age to be independent vari-ables influencing grip strength. Grip strength was found to be a specific measure of lean body mass (75 to 94%), but sensitivity was quite low (about 25%). The positive predictive value was variable, ranging from 54.6 to 21.5%. The specificity, sensitivity and positive pre-dictive values were very high when compared with arm muscle area. Grip strength may have a potential value as an additional test for nutritional assessment in field situations and clinical settings.
The purpose of this study was to find whether the synthesis and degradation of N-acetylglutamate would affect urea synthesis when the dietary protein quality was manip-ulated. Experiments were done on three groups of rats given diets containing 10g gluten, 10g casein or 10g whole egg protein/100g for 10d. The urinary excretion of urea, the liver concentrations of N-acetylglutamate and free glutamate, the liver activity of N-acetyl-glutamate synthetase increased with the decline in quality of dietary protein. A reverse cor-relation was observed between the liver N-acetylglutamate degradation and liver N-acetylglutamate concentration. N-Acetylglutamate concentration in the liver was closely correlated with the concentration of glutamate and the N-acetylglutamate synthetase activity in the liver, and excretion of urea. These results suggest that the greater synthesis and the lower degradation rate of N-acetylglutamate in the liver of rats given the lower quality of protein increase the liver concentration of N-acetylglutamate and stimulate urea synthesis.
The purpose of this study was to investigate the effect of heavy alcohol con-sumption on peroxidation status in apolipoprotein B-containing lipoproteins (LDL+VLDL) and plasma as well as plasma homocysteine (HC) levels in patients with chronic alcoholism who drank raki, a national Turkish beverage. For this reason, endogenous diene conjugate (DC) and lipid hydroperoxide (LOON) levels and lag phase, maximum DC formation and propagation rate following copper induction were measured in apolipoprotein B-containing lipoproteins (LDL+VLDL) isolated by precipitation with dextrane sulfate and MgCl2 from plasma. In addition, serum malondialdehyde (MDA), DC, HC, folate and vitamin B12 levels as well as paraoxonase activity were determined. Serum MDA and DC levels were higher in heavy raki drinkers compared to control subjects. Significant increases in endogenous DC and LOOH levels in LDL+VLDL together with shortened lag phase were also observed in patients. In addition, HDL-cholesterol, HC and vitamin B12 levels and HDL-associated paraoxonase activity were found to be higher, but folate levels to be lower in serum of heavy raki consumers. In conclusion, our results indicate that increases in LDL+VLDL oxidizabil-ity and plasma HC levels may enhance the susceptibility to vascular diseases in heavy raki drinkers.
To investigate the incorporation of acetate into fatty acids and their turnover, the time courses for the incorporation of labeled acetate into lipids in the liver and epididy-mal adipose tissue (adipose tissue) after the oral administration to rats were examined for 10d. The labeled acetate was abundantly incorporated into lipids, mainly into triacylglycer-ols (TAG) in the liver, reached a maximum at 2h after the administration and then quickly decreased. In the adipose tissue, the incorporation of the acetate reached a maximum after 8h and began to decrease slowly after 2d. The acetate incorporation into the lipids was markedly lower in the liver, plasma and adipose tissue of rats fed the corn oil diet than in those fed the fat-free diet. However, the half-lives of esterified fatty acids were similar in both dietary groups. The half-lives of esterified C16:0 and C18:1 in the decreasing phase were 5.4 and 8.9h, respectively, in the liver, and 4.3 and 5.6d, in the adipose tissue. The time courses for incorporation into plasma lipids were parallel to those in the liver. Thus the fatty acids synthesized in the liver appeared to be transported to adipose tissues and to stay there longer. Moreover, it is remarkable that 30% of the acetate radioactivities administered were found after 2h in the whole liver: 75% of the products from the acetate at the maximum were lipids and 61% of the lipids, TAG. The major products from acetate in the liver were lip-ids.
Postmenopausal women as well as rodents after ovariectomy, which results in a lack of estrogen, can become obese. Ovariectomy-induced obesity in mice is associated with a decrease in oxygen consumption, indicating repressed energy expenditure. In this study, to elucidate the mechanism of weight gain after ovariectomy, we examined the expression patterns of genes related to energy expenditure and lipid metabolism, in mouse tissues including adipose tissue and skeletal muscle. In adipose tissue and skeletal muscle, at 2-4 wk after ovariectomy, levels of nuclear receptors and cofactors involved in energy expenditure such as ERR1, PPARα and PPARδ, and PGC1α and PGC1β were lower than in control mice. mRNA levels of their targets, medium-chain acyl coenzyme A dehydrogenase and acetyl CoA oxidase, enzymes for fatty acid β-oxidation, were lower. In addition, the expression of PPARγ and SREBP1, transcription factors important for lipogenesis, was decreased, as well as that of acetyl CoA carboxylase and fatty acid synthase, enzymes for fatty acid synthesis, and diacyl glycerol acetyl transferase 1 and 2, enzymes for triglyceride synthesis. These changes in gene expression are consistent with the obese phenotype in mice after ovariectomy. Thus a decrease in the expression of energy expenditure-related genes in adipose tissue and skeletal muscle could, in part, be responsible for obesity after ovariectomy.
The effect of fasting on mouse liver methionine adenosyltransferase (MAT I/III) expression and the regulation of methionine metabolism were investigated. The mRNA level, protein level, and activity of MAT I/III were increased by fasting for 10 or 16h. In spite of the increase of MAT I/III activity, S-adenosylmethionine, the product of methionine due to MAT I/III, decreased. S-Adenosylhomocysteine, which is made from S-adenosylmethionine by its coupling to methyltransferase, increased as a result of fasting for 16h. These results suggest that the total methylation reactions using S-adenosylmethionine are stimulated in the fasting mouse liver. However, the DNA methylation level was not changed by fasting for 16h. Glutathione, which is made by the transsulfuration pathway from homocysteine, decreased due to fasting. Regulation of supplementation of S-adenosylmethionine may occur in the fasting mouse because MAT I/III activity increases and the flow to glutathione is decreased.
This study investigated the regulation of acetyl-CoA carboxylase (ACC) promoter activity by hormones and nutrients. Genomic clones including promoter I (PI) of the ACC gene were isolated and sequenced. ACC PI fragments (-l, 049/+100 or -220/+21bp) were subcloned into the pGL3-Basic vector that includes luciferase as a reporter gene. The ACC PI/luciferase chimeric plasmids were transfected into primary rat hepatocytes using lipofectin. Insulin treatment increased the activity of -1, 049/+100 and -220/+21 ACC PI by 3.0- and 3.5-fold, respectively, compared to the control. The activity of both con-structs was also increased by dexamethasone (Dex) and triiodothyronine (T3), with the greatest effects seen with all three hormones present. With -1, 049/+100 or -220/+21 ACC PI, the addition of glucose increased luciferase activity compared to glucose-free con-trol (p<0.05). On the other hand, polyunsaturated fatty acids (PUFA) reduced the activity of the -1, 0491+100 ACC PI construct, with eicosapentaenoic acid and docosahexaenoic acid showing the greatest effect (about 70% of the control). However, the addition of PUFA to the culture media did not affect the activity of -220/+21 ACC PI. Therefore, insulin, Dex, T3, glucose, and PUFA regulate ACC gene expression, at least in part, through the PI promoter.