Physical Activity Performed in the Evening Increases the Overnight Muscle Protein Synthetic Response to Presleep Protein Ingestion in Older Men.

BACKGROUND: The age-related decline in skeletal muscle mass is partly attributed to anabolic resistance to food intake. Dietary protein ingestion before sleep could be used as a nutritional strategy to compensate for anabolic resistance. OBJECTIVE: The present study assessed whether physical activity performed in the evening can augment the overnight muscle protein synthetic response to presleep protein ingestion in older men. METHODS: In a parallel group design, 23 healthy older men (mean ± SEM age: 71 ± 1 y) were randomly assigned to ingest 40 g protein intrinsically labeled with l-[1-(13)C]-phenylalanine and l-[1-(13)C]-leucine before going to sleep with (PRO+EX) or without (PRO) performing physical activity earlier in the evening. Overnight protein digestion and absorption kinetics and myofibrillar protein synthesis rates were assessed by combining primed, continuous infusions of l-[ring-(2)H5]-phenylalanine, l-[1-(13)C]-leucine, and l-[ring-(2)H2]-tyrosine with the ingestion of intrinsically labeled casein protein. Muscle and blood samples were collected throughout overnight sleep. RESULTS: Protein ingested before sleep was normally digested and absorbed, with 54% ± 2% of the protein-derived amino acids appearing in the circulation throughout overnight sleep. Overnight myofibrillar protein synthesis rates were 31% (0.058% ± 0.002%/h compared with 0.044% ± 0.003%/h; P < 0.01; based on l-[ring-(2)H5]-phenylalanine) and 27% (0.074% ± 0.004%/h compared with 0.058% ± 0.003%/h; P < 0.01; based on l-[1-(13)C]-leucine) higher in the PRO+EX than in the PRO treatment. More dietary protein-derived amino acids were incorporated into de novo myofibrillar protein during overnight sleep in PRO+EX than in PRO treatment (0.042 ± 0.002 compared with 0.033 ± 0.002 mole percent excess; P < 0.05). CONCLUSIONS: Physical activity performed in the evening augments the overnight muscle protein synthetic response to presleep protein ingestion and allows more of the ingested protein-derived amino acids to be used for de novo muscle protein synthesis during overnight sleep in older men. This trial was registered at Nederlands Trial Register as NTR3885.

Nitrate-Rich Vegetables Increase Plasma Nitrate and Nitrite Concentrations and Lower Blood Pressure in Healthy Adults.

BACKGROUND: Dietary nitrate is receiving increased attention due to its reported ergogenic and cardioprotective properties. The extent to which ingestion of various nitrate-rich vegetables increases postprandial plasma nitrate and nitrite concentrations and lowers blood pressure is currently unknown. OBJECTIVE: We aimed to assess the impact of ingesting different nitrate-rich vegetables on subsequent plasma nitrate and nitrite concentrations and resting blood pressure in healthy normotensive individuals. METHODS: With the use of a semirandomized crossover design, 11 men and 7 women [mean ± SEM age: 28 ± 1 y; mean ± SEM body mass index (BMI, in kg/m(2)): 23 ± 1; exercise: 1-10 h/wk] ingested 4 different beverages, each containing 800 mg (∼12.9 mmol) nitrate: sodium nitrate (NaNO3), concentrated beetroot juice, a rocket salad beverage, and a spinach beverage. Plasma nitrate and nitrite concentrations and blood pressure were determined before and up to 300 min after beverage ingestion. Data were analyzed using repeated-measures ANOVA. RESULTS: Plasma nitrate and nitrite concentrations increased after ingestion of all 4 beverages (P < 0.001). Peak plasma nitrate concentrations were similar for all treatments (all values presented as means ± SEMs: NaNO3: 583 ± 29 µmol/L; beetroot juice: 597 ± 23 µmol/L; rocket salad beverage: 584 ± 24 µmol/L; spinach beverage: 584 ± 23 µmol/L). Peak plasma nitrite concentrations were different between treatments (NaNO3: 580 ± 58 nmol/L; beetroot juice: 557 ± 57 nmol/L; rocket salad beverage: 643 ± 63 nmol/L; spinach beverage: 980 ± 160 nmol/L; P = 0.016). When compared with baseline, systolic blood pressure declined 150 min after ingestion of beetroot juice (from 118 ± 2 to 113 ± 2 mm Hg; P < 0.001) and rocket salad beverage (from 122 ± 3 to 116 ± 2 mm Hg; P = 0.007) and 300 min after ingestion of spinach beverage (from 118 ± 2 to 111 ± 3 mm Hg; P < 0.001), but did not change with NaNO3 Diastolic blood pressure declined 150 min after ingestion of all beverages (P < 0.05) and remained lower at 300 min after ingestion of rocket salad (P = 0.045) and spinach (P = 0.001) beverages. CONCLUSIONS: Ingestion of nitrate-rich beetroot juice, rocket salad beverage, and spinach beverage effectively increases plasma nitrate and nitrite concentrations and lowers blood pressure to a greater extent than sodium nitrate. These findings show that nitrate-rich vegetables can be used as dietary nitrate supplements. This trial was registered at clinicaltrials.gov as NCT02271633.