Consumption of protein-enriched milk has minor effects on inflammation in older adults?A 12-week double-blind randomized controlled trial

Introduction: Aging is associated with increased levels of circulating inflammatory markers and reduced muscle mass and strength. Objective: We investigated whether intake of protein-enriched milk for 12 weeks would influence markers of inflammation among adults ≥ 70 years of age with reduced physical strength. Methods: In a double-blind randomized controlled intervention study, subjects were randomly allocated into two groups, receiving a protein-enriched milk (2 x 20 g protein/d, n=14, mean (±SD) age 76.9 ± 4.9 yrs) or an isocaloric carbohydrate drink (n=17, age 77.7 ± 4.8 yrs) for 12 weeks. We measured serum and mRNA expression levels of inflammatory markers in PBMCs. Results: Significant differences in the mRNA expression of nuclear receptor subfamily, group H, member 3 (NR1H3, encoding the LXRα transcription factor) and interferon gamma (INFG) were observed between groups. The mRNA level of TNFRSF1A was significantly reduced, while the mRNA level of dipeptidyl-peptidase 4 (DPP4) was significantly increased, in the control group. The serum level of TNFα increased significantly in the control group, while sTNFRSF1A increased significantly in both groups, but with no significant differences between groups. Conclusion: Consumption of a low-fat, protein-enriched milk for 12 weeks had minor effects on inflammatory related markers in older adults compared to an isocaloric carbohydrate drink

Meals with Similar Fat Content from Different Dairy Products Induce Different Postprandial Triglyceride Responses in Healthy Adults: A Randomized Controlled Cross-Over Trial

Postprandial lipemia is a risk factor for cardiovascular disease. Dairy products differ in nutrient content and food matrix, and little is known about how different dairy products affect postprandial triglyceride (TG) concentrations. We investigated the effect of meals with similar amounts of fat from different dairy products on postprandial TG concentrations over 6 h in healthy adults. A randomized controlled cross-over study was performed on 47 subjects (30% men), with median (25th–75th percentile) age of 32 (25–46) y and body mass index of 23.6 (21.0–25.8) kg/m2. Meals included 1 of butter, cheese, whipped cream, or sour cream, corresponding to 45 g of fat (approximately 60 energy%). Serum concentrations of TGs (primary outcome), and total cholesterol (TC), low density lipoprotein cholesterol (LDL cholesterol), high density lipoprotein cholesterol (HDL cholesterol), insulin, glucose, non-esterified fatty acids, and plasma glucose-dependent insulinotropic polypeptide (secondary outcomes) were measured before the meal and 2, 4, and 6 h postprandially. Incremental AUC (iAUC) was calculated for the responses, and data were analyzed using a linear mixed model. Sour cream induced a 61% larger TG-iAUC0–6 h compared to whipped cream (P < 0.001), a 53% larger TG-iAUC0–6 h compared to butter (P < 0.001), and a 23% larger TG-iAUC0–6 h compared to cheese (P = 0.05). No differences in TG-iAUC0–6 h between the other meals were observed. Intake of sour cream induced a larger HDL cholesterol-iAUC0–6 h compared to cheese (P = 0.01). Intake of cheese induced a 124% larger insulin iAUC0–6 h compared to butter (P = 0.006). No other meal effects were observed. High-fat meals containing similar amount of fat from different dairy products induce different postprandial effects on serum TGs, HDL cholesterol, and insulin in healthy adults. The potential mechanisms and clinical impact of our findings remain to be further elucidated. The study was registered at www.clinicaltrials.gov as NCT02836106

Reduced plasma concentration of branched-chain amino acids in sarcopenic older subjects: a cross-sectional study

Branched-chain amino acids (BCAA) are essential amino acids that are necessary for muscle mass maintenance. Little is known about the plasma concentrations of BCAA and the protein intake in relation to sarcopenia. We aimed to compare the non-fasting plasma concentrations of the BCAA and the dietary protein intake between sarcopenic and non-sarcopenic older adults. Norwegian older home-dwelling adults (≥70 years) were invited to a cross-sectional study with no other exclusion criteria than age. Sarcopenic subjects were defined by the diagnostic criteria by the European Working Group on Sarcopenia in Older People. Non-fasting plasma concentrations of eight amino acids were quantified using NMR spectroscopy. Protein intake was assessed using 2×24-h dietary recalls. In this study, ninety out of 417 subjects (22 %) were sarcopenic, and more women (32 %) than men (11 %) were sarcopenic (P<0·0001). Sex-adjusted non-fasting plasma concentrations of leucine and isoleucine, and the absolute intake of protein (g/d), were significantly lower among the sarcopenic subjects, when compared with non-sarcopenic subjects (P=0·003, P=0·026 and P=0·003, respectively). A similar protein intake was observed in the two groups when adjusted for body weight (BW) and sex (1·1 g protein/kg BW per d; P=0·50). We show that sarcopenia is associated with reduced non-fasting plasma concentration of the BCAA leucine and isoleucine, and lower absolute intake of protein. More studies are needed to clarify the clinical relevance of these findings, related to maintenance of muscle mass and prevention of sarcopenia