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Background/Objectives: The purpose of this study was to evaluate the independent and combined associations of moderate-to-vigorous physical activity (MVPA), leisure time sedentary behavior and daily protein consumption on lower extremity muscular strength and lean mass. Subjects/Methods: Data from the 1999-2002 NHANES were utilized (N=1080 adults 50-85 y). Leg lean mass was estimated from dual-energy x-ray absorptiometry scans. Knee extensor strength was assessed objectively using the Kin Com MP dynamometer. MVPA and leisure time sedentary behavior were assessed via questionnaire, with the number of meals per day of [greater-than or slanted equal to]30 g of protein per meal assessed via a 'multiple pass' 24-h dietary interview. Results: Meeting MVPA guidelines ([beta]=16.3, P=0.02) and consuming at least two meals per day of [greater-than or slanted equal to]30 g of protein per meal ([beta]=28.8, P=0.02) were independently associated with greater lower extremity strength, whereas sedentary behavior was not ([beta]=11.6, P=0.23). Finally, there was no evidence of a three-way interaction of these behaviors on lower extremity strength ([beta]=-8.7; P=0.70) or lower extremity lean mass ([beta]=144.5; P=0.75). Conclusions: Although MVPA and frequency of protein consumption of [greater-than or slanted equal to]30 g of protein per meal were independently associated with lower extremity lean mass and strength, the results of the present study do not provide evidence to suggest that there is a three-way interplay between MVPA, sedentary behavior and frequency of protein consumption [greater-than or slanted equal to]30 g of protein per meal on lower extremity lean mass and strength., Author(s): P D Loprinzi [sup.1] , J P Loenneke [sup.2] , D L Hamilton [sup.3] Author Affiliations: (1) Department of Health, Exercise Science, and Recreation Management, Physical Activity Epidemiology Laboratory, [...]

Background/Objectives: To investigate whether intake of whey protein and butter naturally enriched in medium-chain fatty acids (MC-SFAs) (C6-C12) affected body composition, insulin sensitivity, blood pressure (BP) and plasma cholesterol concentrations. Subjects/Methods: A 12-week randomised, double-blinded, intervention study was completed in 52 abdominally obese adults. Subjects were assigned to one of four dietary supplementations: 63 g per day of milk fat with either high- (8.5 g per day) or low-MC-SFA (6.9 g per day) content combined with 60 g per day of whey or casein. We examined changes in the body composition by dual-energy X-ray absorption scan, insulin sensitivity using homoeostatic model assessment of insulin resistance (HOMA-IR) and Matsuda index, and diurnal BP and plasma cholesterol concentrations. Two-factor analysis of variance was used to examine the impact of MC-SFA content and protein type. Results: We observed that lean body mass increased by 981 g (95% confidence interval (CI): 248-1713; P=0.010) after high-MC-SFA compared with low-MC-SFA supplementation. Concomitantly, total body-fat percentage increased by 0.70 percentage points (95% CI: 0.10-1.31; P=0.024) after intake of low-MC-SFA butter compared with intake of high-MC-SFA butter. Both changes were independent of protein type (P=0.96 and P=0.99, respectively). We found no difference in HOMA-IR, Matsuda index, diurnal BP or plasma cholesterol concentrations related to MC-SFA content or protein type. Conclusions: Enhanced intake of MC-SFA increased the lean body mass and caused a significantly lower total body-fat percentage compared with lower intake of MC-SFA. Consequently, the composition of dairy fat should be considered when evaluating the impact of dairy products on body composition., Author(s): M Bohl [sup.1] , A Bjørnshave [sup.1] [sup.2] , M K Larsen [sup.3] , S Gregersen [sup.1] , K Hermansen [sup.1] Author Affiliations: (1) Department of Endocrinology and Internal [...]

BACKGROUND/OBJECTIVE: A distinct suppressive effect of a whey protein (including glycomacropeptide)-enriched preload drink on subsequent food intake in comparison with a maltodextrin carbohydrate-enriched preload was demonstrated in an earlier companion study with the same female subjects; however, the potential mediators underlying the effect are unclear. The objective of this study was to investigate how the ingestion of a whey protein-enriched preload beverage affected postprandial plasma concentrations of several satiety-related gastrointestinal hormones and metabolites in comparison with a maltodextrin carbohydrate-enriched preload. SUBJECTS/METHODS: Eighteen normal-weight women were studied in a single-blind, randomized block design. Blood samples were collected at various time intervals for 120 min after consumption of a test drink (300 ml, ~ 1300 kJ) enriched (45 g) with either maltodextrin carbohydrate or whey protein containing naturally present glycomacropeptide. RESULTS: Plasma-active ghrelin concentrations decreased after both maltodextrin carbohydrate- and whey protein-enriched test drinks (P < 0.05). The whey protein-enriched beverage led to increased plasma concentrations of cholecystokinin (CCK) at 60 and 75 min (P < 0.05), glucagon-like peptide-1 (GLP-1) at 90 min (P < 0.001), peptide tyrosine-tyrosine (PYY) at 90 and 120 min (P < 0.01) and pancreatic polypeptide (PP) from 15 to 120 min (P < 0.05) compared with maltodextrin carbohydrate. Total amino acid, urea and ammonia plasma concentrations were also higher after whey protein compared with maltodextrin carbohydrate ingestion (P < 0.01). CONCLUSIONS: Increased plasma concentrations of some gastrointestinal hormones related to satiety, particularly PP, and of amino acids and their metabolites, may have acted either singly or together to mediate the observed satiety response to whey protein. European Journal of Clinical Nutrition (2015) 69, 179-186; doi:10.1038/ejcn.2014.266; published online 7 January 2015, INTRODUCTION The rapid worldwide rise in the prevalence of obesity has led to growing interest in dietary modifications that can enhance satiety and reduce dietary energy intake. (1) Several scientific [...]

Dietary proteins have an insulinotropic effect and thus promote insulin secretion, which indeed leads to enhanced glucose clearance from the blood. In the long term, however, a high dietary protein intake is associated with an increased risk of type 2 diabetes. Moreover, branched-chain amino acids (BCAA), a prominent group of amino acids, were recently identified to be associated with diabetes. Observational data and intervention studies do not point in the same direction regarding the effect of protein intake on insulin sensitivity and diabetes risk. Therefore, the first aim of this review will be to discuss human studies addressing high dietary protein intake and insulin action, with special attention for BCAA. In the second part, we will highlight the (patho) physiological consequences of high-protein diets regarding insulin action, in particular the role of the mechanistic target of the rapamycin pathway. European Journal of Clinical Nutrition (2014) 68, 973-979; doi: 10.1038/ejcn.2014.123; published online 2 July 2014, INTRODUCTION Insulin resistance is defined as tissues no longer being sensitive to the physiological actions of insulin, in particular glucose uptake. The insulin-mediated uptake of glucose can decrease when tissues [...]

The importance of fish in meeting the nutritional requirements of the body for good health and a better standard of living cannot be overemphasized. The average consumption of protein in Nigeria is below 62 gm per day and a larger proportion of this is of plant origin. This has been found to be below the 70 gm minimum recommended by the World Health Organization (WHO) and hence adequate consumption of fish would go a long way in correcting the protein intake shortfall. This research looked into the consumption pattern of fish among households in Ibadan North Local government Area of Oyo State, Nigeria. This is with a view to examining the various factors of social and economic importance affecting the level of consumption of fish and other protein foods in the study area. Stratified sampling technique was used to group the 12 wards in the study area into three. Structured questionnaires were used to collect information from the heads of the 40 randomly selected households in each of the three groups. Data collected from 100 fully completed questionnaires were analyzed using descriptive statistics, multiple regression and Chi-Square tests. The descriptive statistics result shows that majority of the consumers were male (67%), with a mean age of 35.5 years. The mean amount of money spent on fish per month by the households was N3, 672.60 ($24.48). The regression result reveals that the total monthly expenditure on fish was positively affected by monthly expenditure on food and total monthly expenditure on animal protein. The coefficient of determination ([R.sup.2]) of 0.682 implies that 68.2% of the variation in the household monthly expenditure on fish was explained by the variables in the regression model while the Chi-Square ([X.sup.2]) calculated value of 77.7234 establishes the significant relationship between the respondents' income and their expenditure on fish. It is expected that with the potentials of wide acceptability of consumption of catfish, fish farmers should take advantage of the market, explore better means of increasing its production and add value to their product. There is also the need for survey on the current level of fish consumption at the states and national levels. This could assist in enhancing policy formulation to increase production, sustain and improve on the current level of consumption in order to reduce the incidence of nutrition-induced health problems particularly among the low income consumers in the society. Key words: Consumption, Fish, Household, Expenditure, Nutrition-induced, INTRODUCTION Nigeria is faced with an acute nutrition problem, which is mostly due to inadequate food supply, poor income and lack of proper education on food selection. This problem leads [...]

BACKGROUND/OBJECTIVES: We examined the associations between carbohydrate substitutions (total; low-, medium-, high-glycemic index (GI) carbohydrates) for fat or protein and risk of type 2 diabetes. SUBJECTS/METHODS: The cohort comprised 25 943 male smokers among whom 1098 diabetes cases were identified from a national register during a 12-year follow-up. Diet was assessed by a validated food frequency questionnaire. The relative risks (RR) and confidence intervals (CI) for diabetes were analyzed using Cox proportional hazard modeling, and multivariate nutrient density models were applied to examine the associations between substitutions of macronutrients and diabetes risk. RESULTS: The risk of diabetes was lower when fat or protein was replaced with an isoenergetic amount (2% of energy intake) of carbohydrates, the multivariate RRs were 0.96 (95% CI: 0.94, 0.99) and 0.85 (95% CI: 0.80, 0.90), respectively. The lower risks were due to replacing saturated plus trans fatty acids, and meat, milk or plant protein with carbohydrates, respectively. Low-, medium- or high-GI carbohydrates did not associate with lower diabetes risk when replacing fat or fatty acids, except when total fat was replaced with medium-GI carbohydrates. Low-, medium- and high-GI carbohydrates had similar inverse associations with diabetes risk when they replaced total, meat or milk protein. CONCLUSION: Higher carbohydrate intake at the expense of fat, attributable to trans and saturated fatty acids, or protein was associated with decreased diabetes risk. Replacing fat or protein with lower-GI carbohydrates was not more beneficial than replacing it with higher-GI carbohydrates. European Journal of Clinical Nutrition (2012) 66, 716-721; doi:10.1038/ejcn.2012.24; published online 29 February 2012 Keywords: carbohydrates; fats; glycemic index; proteins; type 2 diabetes, INTRODUCTION Several large prospective cohort studies have assessed the association of carbohydrate intake and risk of type 2 diabetes. Many of the studies reported no association (1-6) and some recent [...]

A double-blind randomized controlled trial is conducted to analyze the impact of the early intervention of dietary proteins on the risk of beta-cell autoimmunity in children. Such intervention is shown to highly impact the markers of autoimmunity, which are later shown to lead to type 1 diabetes.

Epidemiological studies have revealed a relationship between poor early growth and development of type 2 diabetes and other features of metabolic syndrome. The mechanistic basis of this relationship is not known. However, compelling evidence suggests that early environmental factors, including nutrition, play an important role. Studies of individuals in utero during a period of famine showed a direct relationship between maternal nutrition and glucose tolerance. Further evidence has come from studies of monozygotic twins who were discordant for type 2 diabetes. Nutrition during the early postnatal period has also been shown to have long-term consequences on metabolic health. Excess nutrition and accelerated growth during the neonatal period has been suggested to be particularly detrimental. Animal models, including maternal protein restriction, have been developed to elucidate mechanisms linking the early environment and future disease susceptibility. Maternal protein restriction in rats leads to a low birth weight and development of type 2 diabetes in the offspring. This is associated with [beta] cell dysfunction and insulin resistance. The latter is associated with changes in expression of key components of the insulin-signaling cascade in muscle and adipocytes similar to that observed in tissue from young men with a low birth weight. These differences occur prior to development of disease and thus may represent molecular markers of early growth restriction and disease risk. The fundamental mechanisms by which these programmed changes occur remain to be fully defined but are thought to involve epigenetic mechanisms. doi: 10.3945/jn.109.111237.

Early puberty onset is associated with hormone-related cancers, but whether diet in childhood influences pubertal timing is controversial. We examined the association of protein intake in early and mid-childhood with the ages at take-off of the pubertal growth spurt (ATO), peak height velocity (APHV), and menarche in girls and voice break in boys using data from the longitudinal Dortmund Nutritional and Anthropometric Longitudinally Designed Study. Among participants who provided 3-d weighed dietary records at 12 mo, 18-24 mo, 3-4 y, and 5-6 y, 112 had sufficient anthropometric measurements between 6 and 13 y to allow estimation of ATO. Life-course plots were used to identify critical periods of total, animal, and vegetable protein intake (percentage of total energy intake) for pubertal timing. At these ages, the association between tertiles of protein intake (T1-T3) and the outcomes was investigated using multiple linear regression analysis. A higher total and animal protein intake at 5-6 y was related to an earlier ATO. In the highest tertile of animal protein intake at 5-6 y, ATO occurred 0.6 y earlier than in the lowest [(mean, 95% CI) T1: 9.6, 9.4-9.9 vs. T2: 9.4, 9.1-9.7 vs. T3: 9.0, 8.7-9.3 y; P-trend = 0.003, adjusted for sex, total energy, breast-feeding, birth year, and paternal university degree]. Similar findings were seen for APHV (P-trend = 0.001) and the timing of menarche/voice break (P-trend = 0.02). Conversely, a higher vegetable protein intake at 3-4 and 5-6 y was related to later ATO, APHV, and menarche/voice break (P-trend = 0.02-0.04). These results suggest that animal and vegetable protein intake in mid-childhood might be differentially related to pubertal timing. doi: 10.3945/jn.109.114934.

The influence of supplemental protein during gestation on maternal hormones and fetal growth was determined in composite beef heifers. At AI, 118 heifers were stratified by BW within each composite genotype (BeefX = 1/2 Senepol, 1/4 Brahman, 1/8 Charolais, 1/8 Red Angus and CBX = 1/2 Senepol, 1/4 Brahman, 1/4 Charolais) into 4 treatment groups: high high (HH = 1.4 kg CP/d for first and second trimesters of gestation), high low (HL = 1.4 kg of CP/d for first trimester and 0.4 kg of CP/d for second trimester), low high (lowH = 0.4 kg CP/d for first trimester and 1.4 kg of CP/d and for second trimester), or low low (LL = 0.4 kg CP/d for first and second trimesters). Maternal plasma IGF-I and -II, total IGFBP, and leptin concentrations were determined at 14 d before AI and at d 28, 82, 179, and 271 post-AI (mean gestation length 286 d), and leptin concentrations were also determined at calving. Increased dietary protein increased maternal plasma IGF-I (P < 0.001 on d 28, 82, and 179), IGF-II (P = 0.01 on d 82; P = 0.04 on d 271), and total IGFBP (P = 0.002 on d 82; P = 0.005 on d 179; P = 0.03 on d 271). Maternal plasma IGF-I at d 271 was negatively associated with calf crown-rump length at birth (P = 0.003). BeefX had greater birth weight calves (P = 0.01), greater IGF-II (P < 0.001), increased ratios of IGF-I:total IGFBP (P = 0.008) and IGF-II:total IGFBP (P < 0.001), and reduced total IGFBP compared with CBX (P = 0.02). Increased dietary protein during second trimester increased maternal plasma leptin at calving (P = 0.005). Maternal plasma leptin near term was positively associated with heifer BCS (P = 0.02) and with calf birth weight (P = 0.04), and at calving was positively associated with heifer age at AI (P = 0.02). These findings suggest that maternal dietary protein, age, and genotype influence plasma concentrations of metabolic hormones and fetal growth in Bos indicus-influenced heifers. Key words: cattle, crude protein, fetal growth, gestation, insulin-like growth factor, leptin

The present study aimed to evaluate the effects of rearing system and level of dietary protein supplementation on growth performance, metabolic profile, plasma leptin, and carcass composition of young Podolian bulls. At the beginning of the finishing period (about 14 mo of age), animals were divided into 3 groups according to rearing system and dietary protein level: indoor receiving a diet with 15% CP of DM (IND); and outdoor, at pasture, receiving a supplementation with 12% CP of DM (OUT12) or with 15% CP of DM (OUT15). Plasma leptin concentration increased (P < 0.05) with age, whereas it was unaffected by rearing system and protein level. Positive correlations between plasma leptin concentration, ADG (r = 0.861, P < 0.001), and blood glucose concentration (r = 0.977, P < 0.001) were observed, whereas NEFA and triglycerides were not correlated with leptin concentration. At the end of the finishing period (about 20 mo of age), young bulls in the OUT12 group showed greater (P < 0.05) cholesterol concentrations in blood than the OUT15 group, whereas the OUT15 group showed greater urea concentrations compared with IND (P < 0.01) and OUT12 groups (P < 0.001). Average daily gains, feed conversion ratio, and final BW were similar between groups. Intramuscular lipid content of LM, semitendinosus, and semimembranosus muscles was correlated with plasma leptin before slaughtering (r = 0.77, P < 0.01; r = 0.67, P < 0.01, r = 0.79, respectively). Correlations between plasma leptin and intramuscular fat were found starting from 18 mo of age for LM (r = 0.44; P < 0.05) and from 19 mo for semimembranosus (r = 0.56; P < 0.05) and semitendinosus (r = 0.58; P < 0.05). Mean value of intramuscular fat and intramuscular fat of LM was greater in OUT15 than OUT12 (P < 0.05). No differences were found between 12 and 15% CP supplementations for growth and carcass data. Therefore, we conclude that the extensive rearing system supplemented with 12% CP may be adequate to sustain good growth performance and carcass quality from the Podolian breed. These data also provide confirmation that leptin, in cattle, is directly related to nutritional status and may represent a suitable predictor for body fat starting from 1 mo before slaughtering. Key words: carcass composition, leptin, metabolic profile, Podolian cattle, protein level, rearing system

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jada.2009.06.369 Byline: T. Brock Symons, Melinda Sheffield-Moore, Robert R. Wolfe, Douglas Paddon-Jones Abstract: Ingestion of sufficient dietary protein is a fundamental prerequisite for muscle protein synthesis and maintenance of muscle mass and function. Elderly people are often at increased risk for protein-energy malnutrition, sarcopenia, and a diminished quality of life. This study sought to compare changes in muscle protein synthesis and anabolic efficiency in response to a single moderate serving (113 g; 220 kcal; 30 g protein) or large serving (340 g; 660 kcal; 90 g protein) of 90% lean beef. Venous blood and vastus lateralis muscle biopsy samples were obtained during a primed, constant infusion (0.08 [mu]mol/kg/min) of L-[ring-.sup.13C.sub.6] phenylalanine in healthy young (n=17; 34[+ or -]3 years) and elderly (n=17; 68[+ or -]2 years) individuals. Mixed muscle fractional synthesis rate was calculated during a 3-hour postabsorptive period and for 5 hours after meal ingestion. Data were analyzed using a two-way repeated measures analysis of variance with Tukey's pairwise comparisons. A 113-g serving of lean beef increased muscle protein synthesis by approximately 50% in both young and older volunteers. Despite a threefold increase in protein and energy content, there was no further increase in protein synthesis after ingestion of 340 g lean beef in either age group. Ingestion of more than 30 g protein in a single meal does not further enhance the stimulation of muscle protein synthesis in young and elderly. Article History: Accepted 30 January 2009

Proteins are likely to organize into complexes that assemble and disassemble depending on cellular needs. When [approximately equal to] 800 yeast strains expressing GFP-tagged proteins were grown to stationary phase, a surprising number of proteins involved in intermediary metabolism and stress response were observed to form punctate cytoplasmic foci. The formation of these discrete physical structures was confirmed by immunofluorescence and mass spectrometry of untagged proteins. The purine biosynthetic enzyme Ade4-GFP formed foci in the absence of adenine, and cycling between punctate and diffuse phenotypes could be controlled by adenine subtraction and addition. Similarly, glutamine synthetase (Gln1GFP) foci cycled reversibly in the absence and presence of glucose. The structures were neither targeted for vacuolar or autophagosome degradation nor colocalized with P bodies or major organelles. Thus, upon nutrient depletion we observe widespread protein assemblies displaying nutrient-specific formation and dissolution. aggregation | metabolism | microscopy | proteomics | quiescence

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jada.2009.03.003 Byline: Nicholas P. Hays, Helen Kim, Amanda M. Wells, Oumitana Kajkenova, William J. Evans Abstract: Many elderly people have a low intake of dietary protein, yet their protein requirement may be higher than the current Recommended Dietary Allowance. High-quality protein supplements may be useful to enhance nitrogen retention and increase the availability of essential amino acids in elderly people. We compared the nitrogen balance of two protein supplements (Resource Beneprotein Instant Protein Powder, Nestle HealthCare Nutrition, Minnetonka, MN, a whey protein concentrate; or Pro-Stat 101, Medical Nutrition USA, Englewood, NJ, a concentrated, fortified, collagen protein hydrolysate) varying in type but not amount of protein content using a crossover study design. The study consisted of two 15-day diet trials separated by a [greater than or equal to]1-week washout period. Nine healthy elderly women (age 71[+ or -]1 years) were provided a eucaloric diet containing approximately the protein Recommended Dietary Allowance of 0.8 g/kg body weight/day. The supplements constituted about half of the total protein provided to each subject. Nitrogen balance responses were assessed over days 6 to 10 and days 11 to 14 of each trial. Measured nitrogen content of the foods indicated that subjects consumed 0.81[+ or -]0.02 g protein/kg/day and 0.85[+ or -]0.05 g/kg/day for the whey and fortified collagen protein trials, respectively. Body weight decreased (P=0.02) after consumption of the whey supplement, with no significant changes in body weight or composition resulting from the consumption of the collagen supplement. Nitrogen excretion was higher during the whey supplement trial than during the collagen trial (P=0.047). Therefore, a concentrated, fortified, hydrolyzed collagen protein supplement maintained nitrogen balance and preserved lean body mass during 15 days of consumption of a relatively low-protein diet. Article History: Accepted 3 October 2008

BACKGROUND: In Bangladesh, millions of people are exposed to arsenic in drinking water; arsenic is associated with increased risk of cancer. Once ingested, arsenic is metabolized via methylation and excreted [...]

Ruminally cannulated Rambouillet wether lambs were used in three 6 x 6 Latin square experiments (n = 6/experiment) to determine which essential AA limit N retention. Lambs (BW = 36.9 [+ or -] 1.9 kg for Exp. 1, 35.1 [+ or -] 1.4 kg for Exp. 2, and 46.0 [+ or -] 1.3 kg for Exp. 3) were housed in metabolism crates and limit-fed (DMI = approx. 1.8% of BW daily) twice daily a soybean hull-based diet low in ruminally undegradable protein. Treatments for Exp. 1 were continuous abomasal infusions of a solution (500 mL/d) containing 1) no AA (CON), 2) a mixture of 10 essential AA and 2 nonessential AA (10EAA), 3) 10EAA with Met removed, 4) 10EAA with Lys removed, 5) 10EAA with His removed, and 6) 10EAA with Thr removed. Treatments for Exp. 2 were abomasal infusions of 1) CON, 2) 10EAA, 3) 10EAA with Leu, Ile, and Val removed (-BCAA), 4) 10EAA with Arg removed, 5) 10EAA with Phe removed, and 6) 10EAA with Trp removed. Treatments for Exp. 3 were abomasal infusions of 1) CON, 2) 10EAA, 3) -BCAA, 4) 10EAA with Leu removed, 5) 10EAA with Ile removed, and 6) 10EAA with Val removed. All lambs received continuous infusions of acetate and propionate into the rumen and dextrose into the abomasum to supply additional energy. Periods were 7 d: 3 d for adaptation to abomasally infused treatments and 4 d for fecal and urinary collections. Blood samples were collected 3 h after feeding on d 7. In all 3 experiments, N retention was greater (P < 0.10) for lambs receiving 10EAA vs. CON, demonstrating that the basal AA supply from CON was limiting. Removal of each of the essential AA from 10EAA decreased (P < 0.10) their concentrations in plasma (except for Trp), indicating that 10EAA supplied these AA in excess of the animal's requirement. In Exp. 1, N retention (g/d) decreased (P < 0.10) in response to the removal of Met and Thr, but was not affected by removal of Lys and His from 10EAA. In Exp. 2, N retention decreased (P < 0.10) in response to removal of all 3 branched-chain AA, Arg, and Trp, whereas the removal of Phe from 10EAA did not affect N retention. In Exp. 3, N retention decreased (P < 0.10) in response to removal of branched-chain AA and Val, but was not affected by the omission of Leu and Ile from 10EAA. The results of this research demonstrated that Met, Thr, Arg, Trp, and Val limited N retention of lambs fed a diet low in ruminally undegradable protein. Key words: lamb, limiting amino acid, nitrogen retention

The health and quality-of-life implications of overweight and obesity span all ages in the United States. We investigated the association between dietary protein intake and loss of lean mass during weight loss in postmenopausal women through a retrospective analysis of a 20-week randomized, controlled diet and exercise intervention in women aged 50 to 70 years. Weight loss was achieved by differing levels of caloric restriction and exercise. The diet-only group reduced caloric intake by 2,800 kcal/week, and the exercise groups reduced caloric intake by 2,400 kcal/week and expended ~400 kcal/week through aerobic exercise. Total and appendicular lean mass was measured using dual energy x-ray absorptiometry. Linear regression analysis was used to examine the association between changes in lean mass and appendicular lean mass and dietary protein intake. Average weight loss was 10.8 [+ or -] 4.0 kg, with an average of 32% of total weight lost as lean mass. Protein intake averaged 0.62 g/kg body weight/day (range=0.47 to 0.8 g/kg body weight/day). Participants who consumed higher amounts of dietary protein lost less lean mass and appendicular lean mass (r=0.3, P=0.01 and r=0.41, P<0.001, respectively). These associations remained significant after adjusting for intervention group and body size. Therefore, inadequate protein intake during caloric restriction may be associated with adverse body-composition changes in postmenopausal women.

Sickle cell disease is associated with hypermetabolism and a consequent shortage of substrates for normal growth and healthy immune response. The protein:energy ratio is a major determinant of dietary adequacy; the requirement for optimal growth of control mice is 20% of energy from dietary protein. This study investigated the efficacy of increased dietary protein for improving weight gain and reducing inflammation in the Berkeley sickle cell mouse model (S). The study examined the effect of diet on weight gain and circulating levels of 2 inflammatory proteins, C-reactive protein (CRP), and cytokine interleukin-6 (IL-6). Male C57BL/6 (C) control (n = 8) and S mice (n = 8) were randomized at weaning to 40 d of isoenergetic diets containing 20% (normal) and 35% (high) of energy from protein (C20, C35, S20, S35), replacing dextrin. Rate of weight gain was calculated and plasma CRP and IL-6 concentrations determined by ELISA. Liver mRNA expression of these proteins was measured by real-time PCR and L-arginase by colorimetric assay. S35 mice tended to gain weight more rapidly than S20 mice (P = 0.06) and more rapidly than C35 mice (P < 0.01). Circulating CRP and IL-6 levels were also lower in S35 mice than in S20 mice (P < 0.05), as was liver CRP mRNA expression (P < 0.01). These results demonstrate that introducing a high protein diet at weaning attenuates the steady-state inflammation in this S mouse model. Dietary L-arginine availability was investigated as a possible mechanism for increased nitric oxide production and consequent reduced inflammation.

Cats require more dietary protein than noncarnivorous species. Earlier work showed that cats lack the ability to regulate hepatic urea cycle enzymes in response to dietary protein concentration. We thus hypothesized that cats are unable to fully adapt protein oxidation to protein intake, particularly at low-protein concentrations. We used indirect respiration calorimetry to assess cats' ability to adapt substrate oxidation to diets containing different concentrations of protein, including 1 below their protein requirement. Nine cats (5 males and 4 females; 2.7 [+ or -] 0.5 y; 4.49 [+ or -] 0.19 kg) consumed each of 4 semipurified diets containing 7.5% [low protein (L[P.sup.3])], 14.2% [adequate protein (AP)], 27.1% [moderate protein (MP)], and 49.6% [high protein (HP)] of metabolizable energy from protein in a modified crossover design, beginning with the MP diet and then consuming the remaining diets in random order. After adaptation to each diet, cats completed a 5-d nitrogen balance trial and at least 2 12-h indirect calorimetry measurements. There was a significant effect of diet on protein oxidation (P< 0.0001), which measured 10.4 [+ or -] 0.5, 14.1 [+ or -] 1.0, 25.0 [+ or -] 1.7, and 53.2 [+ or -] 1.7% of total energy expenditure for the LP, AP, M,P and HP diets, respectively. The ratio of protein oxidation:protein intake was higher with the LP diet (1.39 [+ or -] 0.07) than the other 3 diets (AP, 1.00 [+ or -] 0.07; MP, 0.93 + 0.06; HP, 1.07 [+ or -] 0.03; P < 0.0001), indicating a net loss of protein with the LP diet. Thus, cats are able to adapt protein oxidation to a wide range of dietary protein concentrations, provided their minimum protein requirement is met.

Protein ingestion stimulates muscle protein synthesis and improves net muscle protein balance. Insulin resistance has been suggested to result in a reduced muscle protein synthetic response to food intake. As such, we hypothesized that type 2 diabetes patients have a impaired muscle protein synthetic response to food ingestion. To test this hypothesis, 10 male type 2 diabetes patients using their normal oral glucose-lowering medication (68 [+ or -] 2 y) and 10 matched, normoglycemic men (65 [+ or -] 2 y) were randomly assigned to 2 crossover treatments in which whole body and muscle protein synthesis were measured following the consumption of either carbohydrate (CHO) or carbohydrate with a protein hydrolysate (CHO+PRO). Primed, continuous infusions with L-[[ring-.sup.13][C.sub.6]]phenylalanine and L-[[ring-.sup.2] [H.sub.2]]tyrosine were applied and blood and muscle samples were collected to assess whole-body protein balance and mixed muscle protein fractional synthetic rate over a 6-h period. Whole-body phenylalanine and tyrosine flux were higher after the CHO+PRO treatment compared with the CHO treatment in the diabetes and control group (P < 0.01). Protein balance was negative following CHO but positive following CHO+PRO treatment in both groups. Muscle protein synthesis rates were higher in both groups following the CHO+PRO (0.086 [+ or -] 0.014%/h) treatment than in the CHO treatment (0.040 [+ or -] 0.003%/h; P < 0.01) with no difference between the diabetes patients and normoglycemic controls. We conclude that the muscle protein synthetic response to CHO or CHO+PRO ingestion is not substantially impaired in longstanding, type 2 diabetes patients treated with oral blood glucose-lowering medication.

Crohn's disease is frequently associated with nutritional deficiencies, often a result of disease activity and poor oral intake. This study investigated the adequacy of dietary intake, based on the Canadian Dietary Reference Intake, in ambulatory patients with Crohn's disease and a normal body mass index (BMI; calculated as kg/[m.sup.2]). This was a cross-sectional study of 74 patients with mean age of 35.7 [+ or -]1.4 years and BMI of 23.05[+ or -]0.45. All patients completed a 7-day food record and a diary for the Crohn's Disease Activity Index. Mean Crohn's Disease Activity Index was 138.99[+ or -]11.38. Energy and protein intakes were within the recommended levels of intake, but total carbohydrates, fat, and saturated fat intake exceeded the recommended levels of <55%, <35%, and <10% in 39.2%, 27%, and 59.5% of the patients, respectively. Micronutrient intakes were suboptimal most notably for folate, vitamins C, E, and calcium. There were no substantial differences between patients with active and inactive disease in terms of failure to meet the Dietary Reference Intake. In conclusion, in this population sample, a large number of ambulatory patients with Crohn's disease have suboptimal dietary patterns despite a normal BMI and inactive disease. Dietary counseling and supplementation may be warranted in this patient population.