OBJECTIVEThe goal of this study was to analyze protein requirements in healthy adults through a meta-analysis of nitrogen balance studies.

METHODSA comprehensive search for nitrogen balance studies of healthy adults published up to October 2012 was performed, each study were reviewed, and data were abstracted. The studies were first evaluated for heterogeneity. The average protein requirements were analyzed by using the individual data of each included studies. Study site climate, age, sex, and dietary protein source were compared.

RESULTSData for 348 subjects were gathered from 28 nitrogen balance studies. The natural logarithm of requirement for 348 individuals had a normal distribution with a mean of 4.66. The estimated average requirement was the exponentiation of the mean of the log requirement, 105.64 mg N/kg•d. No significant differences between adult age, source of dietary protein were observed. But there was significant difference between sex and the climate of the study site (P<0.05).

CONCLUSIONThe estimated average requirement and recommended nutrient intake of the healthy adult population was 105.64 mg N/kg•d (0.66 g high quality protein/kg•d) and 132.05 mg N/kg•d (0.83 g high quality protein/kg•d), respectively.

Adult ; Dietary Proteins ; Female ; Humans ; Male ; Nitrogen ; metabolism ; Nutritional Requirements

The effect of alloxan-diabetic rat fed with normal, high fat, low protein and high protein diets on the rate of urea production and the activities of enzymes associated with the urea cycle (ornithine transcarbamoylase, E.C. 2.1.3.3, OTC; arginase, E.C. 3.5.5.1) have been studied in intact and isolated perfused liver. The amount of urea excretion was the highest in the high protein diet group. When each diet group was treated with alloxan, total urea excretion showed little differences between each diet group and its corresponding control group with the exception being in the normal diet group. However, the enzyme activity of OTC was increased significantly by alloxan treatment in low and high protein diet groups as compared to corresponding control groups. Similar results were obtained in arginase activity, although the magnitude of the change was less marked. In liver perfusion experiments on rats treated with alloxan, the amount of urea production and changes in OTC and arginase activity were very similar with those in the intact liver. These results suggest that alloxan treatment in normal diet group causes an increase in urea excretion both in intact and perfused liver regardless of changes in enzyme activities and total urea excretion, and enzyme activities are affected by changes in dietary components but the changes of enzyme activities may not correlate with total urea excretion.
Alloxan ; Animal ; Diabetes Mellitus, Experimental/metabolism* ; Dietary Fats/pharmacology* ; Dietary Proteins/pharmacology* ; In Vitro ; Liver/metabolism* ; Male ; Perfusion ; Rats ; Urea/metabolism* ; Urea/urine

Effects of high protein diet on water metabolism and on various renal functions were studied in 4 medical students. The daily water intake during the high protein intake was averaged to 3,000ml of which 39% was from liquids, 49% from the water contained in food and 12% from the water of oxidation. Of the daily water output, 53% was by urine, 3% by feces and 44% by the evaporation. As compared to the occidental, this average daily water intake of 3,000ml on high protein diet was greater in the Korean. Moreover, the daily water intake for a given caloric intake or body weight was still significantly greater in the Korean. Moreover, the quantitative pattern of daily water exchange was not modified by the protein content in the diet. On the other hand, the urine osmolarity as well as the urea concentration increased when the protein intake was augmented. However, the urinary concentrations of Na+, Cl- and K+ were not affected by the amount of protein intake. When high protein diet was given, the values of CIN and CPAH showed only a slight increase but renal concentrating ability as judged by the magnitude of maximal negative free water clearance (T H20) showed a significant increase. From these results, it is evident that the lower renal concetrating ability of the normal Korean is most likely due to low protein intake. However, greater water intake in the Korean is independent of the changes in the renal concentrating ability. On the basis of these facts, it is again suggested that greater water intake in the Korean is attributable to greater salt intake.
Adult ; Asian Continental Ancestry Group ; Dietary Proteins/*metabolism ; Diuresis ; Human ; Kidney/*physiology ; Korea ; Male ; *Water

Pakistani wheat varieties are grown over a wide agro-climatic range and as such are anticipated to exhibit yield and quality differences. It is therefore necessary to investigate the nutritional status of wheat varieties in terms of biochemical and physiochemical characteristics available for food and nutritional purposes in Pakistan. The result shows that wheat grains of different varieties contain a net protein level of 9.15%-10.27%, 2.15%-2.55% total fats, 1.72%-1.85% dietary fibers, 77.65x10(-6)-84.25x10(-6) of potassium and 7.70x10(-6)-35.90x10(-6) of sodium ions concentration, 0.24x10(-6)-0.84x10(-6) of phosphorus, 1.44%-2.10% ash, 31.108-43.602 g of thousand grain mass (TGM) and 8.38%-9.67% moisture contents. This study is significant in providing an opportunity to explore the available wheat varieties and to further improve their nutritional excellence and also essential for setting nutritional regulations for domestic and export purposes.
Chemical Phenomena ; Chemistry, Physical ; Dietary Fiber ; metabolism ; Fats ; metabolism ; Minerals ; metabolism ; Nutritive Value ; Pakistan ; Plant Proteins ; metabolism ; Triticum ; chemistry ; classification ; metabolism

This study was aimed to investigate the changes of orexin-A (OXA) and neuropeptide Y (NPY) expression in the hypothalamus of the fasted and high-fat diet fed rats. For the experiments, the male Sprague-Dawley (SD) rats were used as the model of high-fat diet-induced obesity. The mean loss of body weight (MLBW) did not show the linear pattern during the fasting; from 24 h to 84 h of fastings, the MLBW was not significantly changed. The numbers of OXA-immunoreactive (IR) neurons were decreased at 84 h of fasting compared with those in other five fasting subgroups. The NPY immunoreactivities in the arcuate nucleus (ARC) and the suprachiasmatic nucleus (SCN) observed at 84 h of fasting were higher than that observed at 24 h of fasting. The number of OXA-IR neurons of the LHA (lateral hypothalamic area) in the high-fat (HF) diet fed group was more increased than that of the same area in the normal-fat (NF) diet fed group. The NPY immunoreactivities of the ARC and the SCN were higher in HF group than those observed in the same areas of NF group. Based on these results, it is noteworthy that the decrease of the body weight during the fast was not proportionate to the time-course, implicating a possible adaptation of the body for survival against starvation. The HF diet might activate the OXA and the NPY in the LHA to enhance food intake.
Adaptation, Physiological/physiology ; Animals ; Arcuate Nucleus/metabolism ; Dietary Fats ; Eating ; Fasting/*physiology ; Hypothalamic Area, Lateral/metabolism ; Hypothalamus/*metabolism ; Immunohistochemistry/veterinary ; Intracellular Signaling Peptides and Proteins/*metabolism ; Male ; Neuropeptide Y/*metabolism ; Neuropeptides/*metabolism ; Obesity ; Rats ; Rats, Sprague-Dawley/physiology ; Suprachiasmatic Nucleus/metabolism

Prevalence of non-alcoholic fatty liver disease (NAFLD) is about 20-25% in Korean adults population. Obesity is strongly associated with NAFLD and the prevention of obesity is a major public issue. Unfortunately, pharmacological treatment of obesity and NAFLD remains uncertain. Only weight loss by dietary changes been shown to lead to histological improvement in fatty liver. So the nutrition therapy is a cornerstone of treatment for NAFLD. Epidemiologic studies show that saturated fat, trans-fatty acid, carbohydrate, and simple sugar have strong correlation with intrahepatic fat accumulation. But, true associations with specific nutrients still remain unclear. Recently, fructose consumption has been rising in many countries and several epidemiologic studies show that fructose consumption has strong correlation with metabolic diseases. The consumption of excessively added sugar in the pathogenesis of steatohepatitis has received attention. Most clinicians agree with lifestyle modification are effective in histologic improvement. Total energy intake restriction is the most important action to reduce intrahepatic fat accumulation. Macronutrient composition may also have correlation with the development of NAFLD. To reduce the incidence of NAFLD, public statements on optimal dietary education program have been issused. Various specific dietary programs are suggested. Among them low fat diet and low carbohydrate diet are suggested in patients with NAFLD. However, there is no ideal diet to obtain the histological improvement in NAFLD. Further randomised controlled studies about specific diet are needed to determine the long-term benefit and histological improvement by ideal diet. Tailoring diet therapy to a patient's lifestyle is more important than universal specific dietary program.
*Diet ; Diet, Carbohydrate-Restricted ; Diet, Fat-Restricted ; Dietary Proteins/metabolism ; Energy Intake ; Fatty Acids, Monounsaturated/metabolism ; Fatty Liver/diet therapy/epidemiology/*etiology ; Humans

OBJECTIVETo investigate the effects of maternal nutritional manipulation on fetal mRNA abundance of uncoupling protein UCP2, UCP3 and carnitine palmityl transferase 1 (CPT1), and find out an optimal maternal diet and targets for pharmacological prevention and treatment of obesity.

METHODSWistar pregnant rats were assigned to two groups which received a standard diet (SD) and a high protein diet (HPD) during pregnancy, respectively. After delivery, the male offspring were assigned to control group (CON) and high protein group (HP) according to their maternal diet, which were suckled by dams that received SD during pregnancy. Offspring were fed with SD from weaning (week 3) to week 8. Then CON were allocated to two groups: CON (SD during the whole experiment); HFCON (high fat control). HFCON and HP group rats were fed with high-fat diet (HFD) for 6 wk to induce obesity. At 0, 3, 8 and 14 wk of age, blood and tissue were collected for analyzing blood fat and abundance of UCP2, 3 and CPT1 mRNA.

RESULTSIn HP body weight and TG were decreased after weaning (F = 4.589, P = 0.039; F = 27.001, P = 0.000) and HFD (F = 16.076, P = 0.00; F = 71.518, P = 0.000). Obesity rates were significantly decreased in HP after HFD (chi2 = 8.076, P = 0.004). The abundance of UCP3 and CPT1 mRNA was persistently higher in HP than in CON or HFCON, and the abundance of UCP2 mRNA was also persistently higher than in CON or HFCON after weaning. Moreover the abundance of CPT1 mRNA was significantly increased after weaning and HFD compared with that after SD, the abundance of UCP2, UCP3 mRNA was also increased after HFD compared with that after SD.

CONCLUSIONSIncreasing protein intake during pregnancy might prevent offspring from HFD-induced obesity in adult, moreover might increase offspring the expression of UCP2, UCP3 and CPT1 mRNA. UCP2, UCP3 and CPT1 might participate in prevention and treatment of obesity by mediating fatty acid oxidation.

Animal Feed ; Animals ; Animals, Newborn ; Carnitine O-Palmitoyltransferase ; metabolism ; Dietary Proteins ; Female ; Fertile Period ; Ion Channels ; metabolism ; Male ; Mitochondrial Proteins ; metabolism ; Obesity ; metabolism ; Pregnancy ; RNA, Messenger ; genetics ; Rats ; Rats, Wistar ; Uncoupling Protein 2 ; Uncoupling Protein 3

OBJECTIVE: To investigate the effect of diet-induced hyperlipidemia on TGF-beta/Smad signaling pathway in the kidney of diabetic rats, and to explore the mechanism by which hyperlipidemia leads to renal injury in diabetes. METHODS: Diabetic rats and non-diabetic rats were fed with normal fat diet and high fat diet for 16 weeks, respectively. The expressions of TGF-beta1, TbetaRII, and Col-IV mRNA in the renal cortex were examined by reverse transcriptase-PCR,TbetaRII and p-Smad staining in glomerular cells were detected by immunohistochemical staining, and the expression of TGF-beta1 and Col-IV protein was determined by Western blot. RESULTS: Diet-induced hyperlipidemia up-regulated the levels of TGF-beta1, TbetaRII, p-Smad, and Col-IV protein and mRNA in the renal cortex of diabetic rats compared with those of non-diabetic rats. However, feeding high fat diet to non-diabetic rats had no influence on the expression of TGF-beta1, TbetaRII, p-Smad2, and Col-IV in the renal cortex. CONCLUSION Hyperlipidemia induced by high fat diet ingestion leads to renal injury in diabetic rats through activating TGF-beta1 /Smad signaling pathway.
Animals ; Diabetes Mellitus, Experimental ; complications ; metabolism ; Diabetic Nephropathies ; metabolism ; Dietary Fats ; administration & dosage ; Female ; Hyperlipidemias ; complications ; metabolism ; Kidney ; metabolism ; Rats ; Rats, Sprague-Dawley ; Signal Transduction ; Smad Proteins ; metabolism ; Transforming Growth Factor beta1 ; metabolism

3-Hydroxybutyric Acid ; blood ; Animals ; Dietary Carbohydrates ; administration & dosage ; Dietary Fats ; administration & dosage ; Dietary Proteins ; administration & dosage ; Disease Models, Animal ; Epilepsy ; diet therapy ; metabolism ; pathology ; Hippocampus ; metabolism ; Kainic Acid ; Ketone Bodies ; metabolism ; Male ; Mossy Fibers, Hippocampal ; pathology ; RNA, Messenger ; analysis ; Rats ; Rats, Sprague-Dawley ; Receptors, Kainic Acid ; analysis ; genetics

Whey protein concentrate (WPC 80) and sodium caseinate were hydrolyzed by Protamex to 5%, 10%, 15%, and 20% degree of hydrolysis (DH). WPC 80, sodium caseinate and their hydrolysates were then analyzed, compared and evaluated for their nutritional qualities. Their chemical composition, protein solubility, amino acid composition, essential amino acid index (EAA index), biological value (BV), nutritional index (NI), chemical score, enzymic protein efficiency ratio (E-PER) and in vitro protein digestibility (IVPD) were determined. The results indicated that the enzymatic hydrolysis of WPC 80 and sodium caseinate by Protamex improved the solubility and IVPD of their hydrolysates. WPC 80, sodium caseinate and their hydrolysates were high-quality proteins and had a surplus of essential amino acids compared with the FAO/WHO/UNU (1985) reference standard. The nutritive value of WPC 80 and its hydrolysates was superior to that of sodium caseinate and its hydrolysates as indicated by some nutritional parameters such as the amino acid composition, chemical score, EAA index and predicted BV. However, the E-PER was lower for the WPC hydrolysates as compared to unhydrolyzed WPC 80 but sodium caseinate and its hydrolysates did not differ significantly. The nutritional qualities of WPC 80, sodium caseinate and their hydrolysates were good and make them appropriate for food formulations or as nutritional supplements.
Amino Acids ; chemistry ; Caseins ; chemistry ; metabolism ; Dietary Proteins ; analysis ; Evaluation Studies as Topic ; Hydrolysis ; Milk Proteins ; chemistry ; metabolism ; Models, Statistical ; Nutritive Value ; Protein Hydrolysates ; chemistry ; Solubility ; Temperature ; Time Factors ; Tryptophan ; chemistry ; Whey Proteins