Postprandial amino acid availability after intake of intact or hydrolyzed meat protein in a mixed meal in healthy elderly subjects: a randomized, single blind crossover trial.

The absorption of dietary proteins affects the anabolic response, among others protein synthesis. For elderly, optimal amino acid absorption is warranted to preserve the amino acid pool of the body, especially skeletal muscle proteins. Therefore, the aim of this study was to characterize if hydrolyzing meat protein (HMP) would improve the amino acid absorption after ingestion of meat compared to equal amounts of the same meat proteins but present in a different structure; steak or minced meat. With a crossover study design on 12 healthy older adults (> 65 years of age, BMI 18.5-30), the amino acid absorption kinetics were explored by ingesting 0.55 g protein/kg LBM as a mixed meal together with intrinsically [2H5]phenylalanine labeled meat proteins prepared as a STEAK, MINCED meat, or HMP. Plasma [2H5]phenylalanine enrichment as well as AA concentrations were measured by mass spectrometry from blood samples drawn during a 5-h postprandial period. After HMP ingestion, [2H5]phenylalanine was faster absorbed in the initial 2 h compared to STEAK and MINCED. The peak time in AA concentrations was faster in HMP compared to STEAK and MINCED. However, the peak AA concentrations were not different between STEAK, MINCED, and HMP. Although HMP showed to have the fastest initial amino acid appearance in older adults, the peak EAA concentrations were similar after ingesting meal with either STEAK, MINCED, or HMP in the 5-h postprandial period.

Very-Low-Calorie Ketogenic Diets With Whey, Vegetable, or Animal Protein in Patients With Obesity: A Randomized Pilot Study.

CONTEXT: We compared the efficacy, safety, and effect of 45-day isocaloric very-low-calorie ketogenic diets (VLCKDs) incorporating whey, vegetable, or animal protein on the microbiota in patients with obesity and insulin resistance to test the hypothesis that protein source may modulate the response to VLCKD interventions. SUBJECTS AND METHODS: Forty-eight patients with obesity (19 males and 29 females, homeostatic model assessment (HOMA) index ≥ 2.5, aged 56.2 ± 6.1 years, body mass index [BMI] 35.9 ± 4.1 kg/m2) were randomly assigned to three 45-day isocaloric VLCKD regimens (≤800 kcal/day) containing whey, plant, or animal protein. Anthropometric indexes; blood and urine chemistry, including parameters of kidney, liver, glucose, and lipid metabolism; body composition; muscle strength; and taxonomic composition of the gut microbiome were assessed. Adverse events were also recorded. RESULTS: Body weight, BMI, blood pressure, waist circumference, HOMA index, insulin, and total and low-density lipoprotein cholesterol decreased in all patients. Patients who consumed whey protein had a more pronounced improvement in muscle strength. The markers of renal function worsened slightly in the animal protein group. A decrease in the relative abundance of Firmicutes and an increase in Bacteroidetes were observed after the consumption of VLCKDs. This pattern was less pronounced in patients consuming animal protein. CONCLUSIONS: VLCKDs led to significant weight loss and a striking improvement in metabolic parameters over a 45-day period. VLCKDs based on whey or vegetable protein have a safer profile and result in a healthier microbiota composition than those containing animal proteins. VLCKDs incorporating whey protein are more effective in maintaining muscle performance.

High fat diet incorporated with meat proteins changes biomarkers of lipid metabolism, antioxidant activities, and the serum metabolomic profile in Glrx1-/- mice.

Red and processed meat consumption has been associated with oxidative stress, diabetes and non-alcoholic fatty liver disease (NAFLD). This study was aimed at exploring the effects of high-fat meat protein diets on potential metabolite biomarkers in Glrx1-/- mice, a well-documented mouse model to study NAFLD. Male Glrx1-/- mice were fed a control diet with 12% energy (kcal) from fat, a high-fat diet supplemented with casein (HFC) with 60% energy (kcal) from fat, and a high-fat diet supplemented with fish (HFF) or mutton proteins (HFM) for 12 weeks. The results of biochemical and histological analyses indicated that the intake of HFM increased hepatic total cholesterol, triglycerides, serum alanine transaminase and aspartate transaminase, and macro- and micro-vesicular lipid droplet accumulation, which were accompanied by altered gene expression associated with the lipid and cholesterol metabolism. HFF diet fed Glrx1-/- mice significantly ameliorated diet-induced NAFLD biomarkers compared to HFC and HFM diets. In addition, serum metabolome profiling identified metabolites specifically associated with lipid metabolism bile acid metabolism, sphingolipid and amino acid metabolism pathways. A HFM diet increased the abundance of LysoPC(15:0), LysoPC(16:0), LysoPC(20:1), LysoPE(18:2), LysoPE(22:0), LysoPE(20:6), O-arachidonoylglycidol, 12-ketodeoxycholic acid and sphinganine that are associated with NAFLD. The KEGG metabolic pathway of identified metabolites of high fat diets showed that the differential metabolites were associated with lipid metabolism, linoleic acid metabolism, amino acid metabolism, bile acid metabolism, sphingolipid metabolism, and glutathione metabolism pathways whereas HFF diet ameliorated NAFLD by modifying these pathways. These results provide potential metabolite biomarkers for NAFLD induced by HFM diet.

Substitution of dietary protein sources in relation to colorectal cancer risk in the NIH-AARP cohort study.

PURPOSE: To evaluate the substitution effect of plant for animal protein with risk of CRC in the large prospective National Institutes of Health-AARP cohort study. METHODS: Protein intake was assessed at baseline using a food frequency questionnaire. HRs and 95% CIs were estimated using multivariable adjusted hazard ratios from Cox proportional hazards models. We used a substitution model with total protein intake held constant, so that an increase in plant protein was offset by an equal decrease in animal protein. RESULTS: Among 489,625 individuals, we identified 8,995 incident CRCs after a median follow-up of 15.5 years. Substituting plant protein for animal protein was associated with a reduced risk of CRC (HR for highest vs. lowest fifth 0.91; 95% CI 0.83-0.99). This reduction in CRC risk appeared to be primarily due to substituting plant protein for red meat protein (HR 0.89; 95% CI 0.81-0.97), not white meat protein (HR 0.96; 95% CI 0.88-1.05) or other animal protein (HR 0.94; 95% CI 0.86-1.03). When further evaluated by source, reduction in CRC risk was limited to the substitution of protein from bread, cereal, and pasta for red meat protein (HR 0.86; 95% CI 0.80-0.93); this association was stronger for distal colon (HR 0.78; 95% CI 0.67-0.90) and rectal cancer (HR 0.79; 95% CI 0.68-0.91) but null for proximal colon (HR 0.99; 95% CI 0.88-1.11). CONCLUSIONS: This study shows that substituting plant protein for animal protein, especially red meat protein, is associated with a reduced risk of CRC, and suggests that protein source impacts CRC risk.

Does Beef Protein Supplementation Improve Body Composition and Exercise Performance? A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Protein supplementation might improve body composition and exercise performance. Supplements containing whey protein (WP) have received the most attention, but other protein sources such as beef protein (BP) are gaining popularity. We conducted a systematic review and meta-analysis of randomized controlled trials that compared the effects of exercise training combined with BP, WP or no protein supplementation (NP), on body composition or exercise performance. Secondary endpoints included intervention effects on total protein intake and hematological parameters. Seven studies (n = 270 participants) were included. No differences were found between BP and WP for total protein intake (standardized mean difference (SMD) = 0.04, p = 0.892), lean body mass (LBM) (SMD = -0.01, p = 0.970) or fat mass (SMD = 0.07, p = 0.760). BP significantly increased total daily protein intake (SMD = 0.68, p < 0.001), LBM (SMD = 0.34, p = 0.049) and lower-limb muscle strength (SMD = 0.40, p = 0.014) compared to NP, but no significant differences were found between both conditions for fat mass (SMD = 0.15, p = 0.256), upper-limb muscle strength (SMD = 0.16, p = 0.536) or total iron intake (SMD = 0.29, p = 0.089). In summary, BP provides similar effects to WP on protein intake and body composition and, compared to NP, might be an effective intervention to increase total daily protein intake, LBM and lower-limb muscle strength.

Westernized Diet is the Most Ubiquitous Environmental Factor in Inflammatory Bowel Disease.

Inflammatory bowel disease (IBD), a collective term for Crohn disease and ulcerative colitis, is a polygenic disease thought to be triggered by environmental factors. A Western or westernized lifestyle may be a major driver of the growing incidence of IBD. IBD may represent dysregulated mucosal inflammation to gut microbiota. Despite many review articles on environmental factors in IBD, no consensus exists regarding which factor contributes most to trigger the onset of IBD. Identification and recognition of major environmental factors are prerequisite for effective disease treatment and prevention. Representative environmental factors such as smoking, breastfeeding, nonsteroidal anti-inflammatory drugs, antibiotic use in childhood, oral contraceptives, and appendectomy do not correlate with disease onset in most patients with IBD. In contrast, diet appears to be important in most cases of IBD. Diets rich in animal protein (risk factor) and deficient in dietary fiber (preventive factor) are characteristic of westernized diets in affluent societies. Recent research shows that westernized diets are associated with a reduced gut microbial diversity (dysbiosis), which may result in increased susceptibility to IBD and other common chronic diseases. Plant-based diets rich in dietary fiber are associated with increased microbial diversity. Recent reports on IBD therapy that replaced westernized diets with plant-based diets achieved far better outcomes than those previously reported in the literature. We believe that westernized diet-associated gut dysbiosis is the most ubiquitous environmental factor in IBD. Adoption of this concept may have the potential to provide a better quality of life for patients with IBD.

Daily and per-meal animal and plant protein intake in relation to muscle mass in healthy older adults without functional limitations: an enable study.

OBJECTIVE: Animal protein sources are considered to be of higher quality than plant protein sources in terms of stimulating muscle metabolism. Our objective was to investigate whether protein intake from animal and plant sources on a daily and per-meal basis differs between healthy older adults with normal and with low muscle mass. METHODS: In this cross-sectional study including 100 healthy, community-dwelling adults (51 women) aged 75-85 years without functional limitations dietary intake was assessed using 7-day food records. Protein intake was classified by six animal and six plant protein sources. Skeletal muscle index (SMI) was determined based on bioelectrical impedance analysis and categorized into 'normal' or 'low' (men ≤ 8.50, women ≤ 5.75 kg/m2). The absolute animal and plant protein intake and their proportion of total protein intake were compared between these groups using Mann-Whitney U test. RESULTS: Daily protein intake was 0.96 ± 0.27 g/kg body weight (BW), 61 ± 10% hereof were from animal origin with no difference between men and women. SMI was low in 39% of men and 35% of women. No differences in absolute daily animal and plant protein intake between participants with normal vs. low SMI were observed. The proportion of animal protein was not different on neither a daily nor a per-meal basis between those with normal and those with low SMI. Women with low SMI consumed less animal protein (in g) for breakfast (4.8 ± 4.1 g vs. 8.5 ± 6.9 g, p = 0.031) and fewer meals per day with at least 50% animal protein (2.2 ± 0.9 vs. 2.7 ± 1.0, p = 0.046) compared to those with normal SMI. CONCLUSION: On a daily basis, the absolute and relative animal protein intake does not differ between healthy older adults without functional limitations with normal vs. low SMI. However, our results indicate that in women animal protein intake on a per-meal basis might be of relevance for the maintenance of muscle mass.

Breastfeeding and complementary feeding in relation to body mass index and overweight at ages 7 and 11 y: a path analysis within the Danish National Birth Cohort.

Background: Infant feeding may play an important role in the development of childhood overweight and obesity. Objective: The objective of this study was to examine whether duration of breastfeeding (BF), timing of introduction of complementary food, and protein intake at age 18 mo are associated with body mass index [BMI (measured in kg/m2)] and overweight at ages 7 and 11 y, independent of BMI during infancy. Design: Children participating in the Danish National Birth Cohort were followed up at ages 7 and 11 y. Information on infant feeding, protein intake at age 18 mo, Ponderal Index at birth, child BMI (at ages 5 mo, 12 mo, 7 y, and 11 y), and several parental factors was available. Path analysis was used to assess the direct and indirect effects of infant feeding on BMI z scores (BMIz) at ages 7 (n = 36,481) and 11 y (n = 22,047). Logistic regression analyses were used to examine associations with overweight. Results: Duration of BF was not associated with childhood BMIz at ages 7 and 11 y. Earlier introduction of complementary food (<4 mo old) was not associated with BMIz at age 7 y, but with a 0.069 (95% CI: 0.021, 0.117, P = 0.005) higher BMIz at age 11 y and increased risk of overweight at age 11 y (OR 1.44; 95% CI: 1.04, 2.00; P = 0.03). Protein intake from dairy products (per 5 g/d) was associated with higher BMIz only at age 7 y (OR: 0.012; 95% CI: 0.003, 0.021; P = 0.007). Protein intake from meat and fish (per 2 g/d) was associated with a 0.010 (95% CI: 0.004, 0.017; P = 0.003) higher BMIz at age 7 y, a 0.013 (95% CI: 0.005, 0.020; P = 0.002) higher BMIz at age 11 y and increased odds of overweight at age 7 y (OR: 1.07; 95% CI: 1.03, 1.10; P < 0.001), but not at age 11 y. Conclusions: Intake of protein from meat and fish at age 18 mo was associated with higher BMIz and risk of overweight in childhood. However, the effect sizes were small. Early introduction of complementary food may be associated with child BMIz and child overweight. This study was registered at www.clinicaltrials.gov as NCT03334760.