The effect of soaking in domestic processing, on the nutritive value of the common bean (Phaseolus vulgaris, L.) cv IAC-Carioca, was studied. Five treatments were carried out with experimental diets, and offered to male, recently weaned Wistar rats. The protein sources were, respectively, control diet (casein) (CC), casein plus the soluble solids found in the soaking water (CSS), freeze dried bean cooked without soaking (BNS), freeze dried bean cooked with the non-absorbed soaking water (BSW), freeze dried bean cooked without the non-absorbed soaking water (BSNW), and an aproteic diet (AP) for corrective purposes. The anti-nutritional factors (phytates and tannins), were determined in the differently processed beans and in the soaking water. The following values for the reduction of phytates were obtained: BNS (20.9%), BSNW (60.8%) and BSW (53.0%), and the tannins were reduced by: BNS (86.6%), BSNW (88.7%) and BSW (89.0%). No significant differences were observed between the various treatments using the common bean as protein source, with respect to the net protein ratio (NPR). With respect to the digestibility corrected by non-protein diet, values varying between 94.1% and 94.6% for casein, and between 57.5% and 61.4% for the common bean, were observed, the treatment BNS being more digestible. It was concluded that soaking did not interfere with the NPR of the experimental diets containing the common bean as protein source, nor did it reduce the tannin content. However soaking was capable of reducing the phytate levels in the common bean. On the other hand, soaking was unable to increase the protein digestibility of the common bean, since the treatment BNS showed the highest value for digestibility.
Of four fractions (CH2Cl2, EtOAc, BuOH and H2O) from mustard leaf (Brassica juncea), the EtOAc fraction showed the strongest inhibitory effects, which were concentration-dependent, on the formation of advanced glycation end products and free radical-medi-ated protein damage in an in vitro system, indicating that this fraction has a potential protective role against diabetes and/or its complications. Based on these results, we carried out an in vivo study to determine whether the EtOAc fraction protected against diabetic oxidative stress induced by streptozotocin. Oral administration of the EtOAc fraction at doses of 50 and 200mg/kg body weight/d for 10 d reduced the serum levels of glucose and glycosy-lated protein, implying that the impaired glucose metabolism due to diabetes had been ame-liorated. In addition, the EtOAc fraction significantly reduced the thiobarbituric acid-reac-tive substance levels of serum and hepatic and renal mitochondria. Furthermore, the elevated levels of superoxide and nitrite/nitrate were reduced in a dose-dependent manner by oral administration of the EtOAc fraction. These findings suggest that the EtOAc fraction from mustard leaf might be beneficial in attenuating the damage caused by oxidative stress involved in diabetes and its complications.
Free radical-mediated oxidative stress has been implicated in the pathogenesis of numerous chronic diseases. Vitamin E is known to play an important role in the free-radical quenching process. However, clinical trials with vitamin E have yielded contrasting results in the prevention of several diseases related to oxidative stress. This study was undertaken to investigate the antioxidative and humoral immunologic effects of vitamin E supplementation in three different age groups: young (mean age 32.7±5.7 y), middle-aged (mean age 47.0±5.0 y) and elderly (67.6±4.7 y) women. Volunteer subjects were given a supplement of 400 IU dl-α-tocopherol acetate for 6 wk. Thiobarbituric acid reacting substances (TBARS) in the plasma significantly decreased with vitamin E supplementation. In addition, the radical scavenger activities (RSA) of red blood cells significantly increased with vitamin E supplementation in all age groups. However, humoral immune response modulation was not observed following vitamin E supplementation. Even though there is no clear indication that vitamin E supplementation is necessary to improve the humoral immune functions, vitamin E supplementation may be beneficial to all adult age groups as a preventive measure for complications related to oxidative damage.
The effects of feeding dietary and defatted oyster meat on lipid metabolism were investigated in rats by comparing measurements with those of casein and soybean pro-tein. In the first experiment, male rats were fed 0.1% and 1% cholesterol-supplemented diets containing casein, oyster or soybean protein under the same dietary level of protein (20%). The concentrations of serum and liver cholesterol in the oyster group were significantly lower than those in the casein group for both the 0.1% and 1% cholesterol-supplemented diets. The cholesterol-lowering effect of oyster meat was more predominant than that of soybean protein, Feeding oyster meat significantly decreased the serum triglyceride concen-tration as compared to feeding casein for the 0.1% cholesterol-supplemented diets, and it reduced hepatic triglyceride concentration in both groups fed the 0.1% and 1% cholesterol-supplemented diets. The excretion of fecal total steroids was higher in the rats fed oyster meat than those fed casein or soybean protein for both the 0.1% and 1% cholesterol-supple-mented diets. In the second experiment, the effects of defatted oyster on lipid metabolism were compared with casein and soybean protein in diets supplemented with cholesterol. The serum cholesterol concentration in the defatted oyster group was comparable to that in the other two groups, but the ratio of high-density lipoprotein-cholesterol to total choles-terol was higher in the defatted oyster group. The feeding of defatted oyster induced a lower liver cholesterol concentration as compared to casein and soybean protein. Serum and liver triglyceride levels were lower in the defatted oyster group than in the casein group. Defatted oyster accelerated the fecal excretion of both neutral and acidic steroids as compared to casein. Our results suggest that the feeding of oysters exerts a more potent hypolipidemic activity than soybean protein, and the effect may be ascribed to both lipid and non-lipid frac-tions in oyster.
The influences of various doses of capsaicin on endurance capacity remain to be clarified. The purpose of this study was to determine whether or not capsaicin delays stored tissue glycogen depletion. Rats were orally given either a vehicle or a dose of cap-saicin, 6, 10, or 1.5mg/kg of body weight, 2 h before exercise. The rats in each group were divided into three subgroups for resting and swimming exercise (30 min, exhaustion). Swimming exercises were performed with a weight corresponding to 3% body weight at-tached to the tail, and the endurance capacity was evaluated by the swimming time until exhaustion. The 15 mg/kg dose of capsaicin significantly (p<0.05) enhanced the en-durance performance time and plasma concentration of epinephrine, norepinephrine, free fatty acid and glucose rose to significantly higher levels within 30 min; swimming exercise compared to rest (p<0.05). At the 15mg/kg capsaicin dosage, the plasma insulin level de-creased to significantly lower levels in group subjected to 30-min swimming as compared to the resting group (p<0.05), while plasma glucagon rose to a significantly higher level (p<0.05). Liver and gastrocnemius muscle glycogen in the group subjected to 30-min swimming was maintained at significantly higher concentrations in the rats fed 15mg/kg of capsaicin as compared to the vehicle counterparts (p<0.05). These results suggest that the improvement in swimming endurance with the high capsaicin dosage is caused by an increase in fatty acid utilization as the energy source, resulting in the sparing of glycogen.
Oral tolerance is a potential strategy for preventing or minimizing aberrant immune responses. Although, oral tolerance has been extensively studied, to date the effects of dietary protein on the induction of oral tolerance are poorly understood. We have previously shown that restricted dietary protein induces oral tolerance to ovalbumin. This study was designed to investigate whether or not such tolerance occurs with beta-lactoglobulin (BLG) instead of ovalbumin (OVA) and if the tolerance resulting from this feeding regimen involves Thl-mediated immune response. Female BALB/c mice fed either 20% or 5% dietary protein were given 5 mg BLG or water orally for four consecutive days and then immunized intraperitoneally (ip) twice with BLG at 3-wk intervals. Oral tolerance induction was compared in BLG-fed and water-fed mice by measuring total IgE, BLG-specific antibodies, footpad reactions, splenocyte proliferation, and cytokine production. When mice were given BLG orally before ip immunization, the Thl-mediated immune responses (production of IL-2, IFN-y, and IgG2a) were significantly reduced, whereas the Th2-mediated immune responses (production of IL-4 and IgGl) were unchanged. The Thl-mediated immune responses were markedly down-regulated in mice fed 5% protein as compared to those in mice fed 20% protein. Moreover, the production of total IgE, BLG-specific IgE, splenocyte proliferation, and footpad reactions were more reduced in mice fed 5% protein than those in mice fed 20% protein. The present study provides evidence that dietary protein plays an important role in the induction of oral tolerance against BLG as the result of, clear down-regulation of Thl helper activity accompanied by a reduction in IgE.
This study was designed to examine 1) the role of exercise physical activity (EPA), and then 2) physical fitness and body composition upon variation of the total energy expenditure (TEE) in healthy Japanese men aged 30 to 69 y (n=40). EPA and TEE Were as-sessed over 14 d using an accelerometer and a doubly labeled water (DLW) method, respectively. Basal metabolic rate (BMR) was measured after 10 h fasting on the morning of the day of DLW dosing. Physical activity-induced energy expenditure (PAEE) was calculated by subtracting BMR and diet-induced thermogenesis (DIT=10% TEE) from TEE. EPA was subdivided into three intensities: low, moderate and high and the accumulated duration (time expressed in minutes) of each of these was calculated. Body composition and physical fitness (VO2max) were determined using an underwater weighing method and a treadmill exercise test, respectively. BMR (mean±SD: 1, 459±181 kcal/d) declined significantly with age (r=-0.37, p<0.05), but PAEE (946±320 kcal/d) and TEE (2, 672±369 kcal/d) did not. A multiple stepwise regression analysis was used to develop an empirical model that relates energy expenditure measured by the DLW (TEE) to age, height, body mass index, FM, FFM, percentage body fat, VO2max, and accumulated duration spent for low-, moderate-, and high-intensity EPA. The results revealed that FFM and high-intensity EPA were identified as important determinants of TEE and accounted for 51%. We may therefore conclude that 1) high-intensity EPA appears to be relevant in determining TEE, especially among active individuals, and 2) body composition was more important than physical fitness in determining TEE in this population.
To investigate the comprehensive effects of polyunsaturated fatty acids (PUFA) on gene expression, we analyzed changes of mRNA expression in PUFA-treated HepG2 cells using a DNA micro array. We incubated HepG2 cells for 24h with or without 0.25mM oleic acid (OA), arachidonic acid (AA), eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA), and then compared the expression profiles of thousands of genes using a GeneChip. PUPA influenced the expression of various genes related to cell proliferation, growth and adhesion, as well as for many transcription factors including sterol regulatory element binding proteins (SREBP). Treatments with AA, EPA, and DHA repressed the expression of genes related to cholesterol and lipid metabolism. Moreover, data from gene chip analysis proved that PUFA reduced the expression of prostasin, which is a serine protease. By measuring the mRNA levels of SREBPs, mevalonate pyrophosphatase and prostasin using quantitative RT PCR, we confirmed the effect of PUFA revealed by gene chip analysis. These data might provide useful clues with which to explore novel functions of PUFA.
We have previously reported that centenarians (persons≥100 y old) in Tokyo prefer dairy products. Dietary preferences may be associated with longevity. The aim of the present study was to investigate the relationship between dietary patterns and further survival in centenarians. During 1992-1999, we examined the dietary practices of 104 centenarians (29 men and 75 women; mean age, 100.3±0.9 y) who lived in the Tokyo metropolitan area. Dietary patterns were classified by k-means cluster analysis. As clinical co-variables, we considered activities of daily living, cognitive function, nutritional status, presence of important disease, gender, and age at the time of the initial survey. Survival data were recorded yearly until 2001, and then tested with Kaplan-Meier analysis and the log rank statistic. Four dietary patterns were identified a pattern preferring vegetables (n=33), a pattern preferring dairy products (n=26), a pattern preferring beverages (n=10), and a pattern preferring cereals (n=35). No clinical variables differed between the four dietary patterns. In 2001, 28 centenarians were still alive. The survival rate for those preferring dairy products was the highest of the four dietary patterns; in particular, being significantly higher than the pattern preferring beverages (p=0.048). A dietary pattern preferring dairy products was associated with increased survival in Tokyo-area centenarians.
The effects of dietary 1, 3-diacylglycerol-rich oil (DG oil) on glucose and lipid metabolism were investigated in comparison with triacylglycerol (TG) oil in female genetically obese Wistar fatty rats. The obese rats and their lean littermates (8 wk old) were fed a synthetic diet containing 10% (w/w) DG or TG oil for 5wk, The body weights, abdominal fat weights, and the plasma and liver TG concentrations were not significantly different due to dietary fat type in the obese and lean rats. The plasma glucose concentrations were significantly elevated by dietary DG oil as compared to TG oil in the portal vein and inferior vena cava of obese and lean rats. The plasma free fatty acid concentrations were markedly elevated by dietary DG oil as compared to TG oil in the portal vein and inferior vena cava of both genotype rats, particularly in the obese rats. In the glucose tolerance test, the obese rats fed DG oil showed glucose intolerance, possibly due to the markedly elevated plasma free fatty acids. Thus, the effects of dietary DG oil on lipid-lowering effects and anti-obesity were not observed in either genotype in the present study. Moreover, it is remarkable that glucose intolerance was induced by dietary DG oil in the genetically obese rats.
The subcutaneous administration of monosodium glutamate to normal adult male mice at dose levels of 4 and 8mg/g body weight caused a significant increase in lipid peroxidation level in the arterial tissue. The levels of total sulfhydryl and protein-bound sulfhydryl groups were found to be significantly increased, whereas non-protein-bound sulfhydryl, representing the glutathione level, was significantly decreased. It was also ob-served that the administration of monosodium glutamate at a dose level of 4mg/g body weight and above induced oxidative stress by significantly lowering the activities of antioxidant enzymes like superoxide dismutases, catalase, and glutathione metabolizing enzymes like glutathione reductase and glutathione peroxidase in the arterial tissue.