The acute postprandial response of blood amino acids in older adults after consumption of dairy protein, plant protein and their blend

Increasing muscle protein synthesis via protein-based nutrition, with or
without exercise, maintains a strong, healthy muscle mass, which in turn leads
to improved health, independence and functionality in older adults. There is
increased interest in plant-based proteins, but these have in general a lower
anabolic effect than animal proteins. Various strategies have been suggested to
augment the anabolic properties of plant proteins, including using plant-animal
protein blends. However, only little is known yet about the anabolic properties
of such an approach. As the peripheral metabolic availability of proteins is an
important aspect that has to be taken into account when screening the anabolic
properties of protein sources/blends, it is the aim of this study to
investigate the postprandial AA response of milk protein, micellar casein, pea
protein, and a milk protein-pea protein blend in healthy older adults.

The primary objective is to quantify the postprandial area under the curve
(iAUC), the maximal level (Cmax) and the time profile (Tmax) of blood amino
acids after ingestion of milk protein, micellar casein, pea protein, and a milk
protein-pea protein blend in healthy older adults.
Secondary objectives are to quantify the postprandial insulin response, and to
quantify the potential muscular response, using an ex vivo muscle cell assay,
of postprandial blood derived from healthy older adults after ingestion of milk
protein, micellar casein, pea protein, and a milk protein-pea protein blend

The study is designed as a randomized, single-blinded within-subject
(cross-over) trial in which a group of 12 subjects receive 4 different protein
drinks.

Four different protein drinks will be investigated: milk protein, micellar
casein, pea protein, and a milk protein/ pea protein blend. All drinks will
contain a 20 gram protein load. All protein supplements will be mixed with 250
mL water and contain some additional non-caloric flavorings

This study is related to older adults, as maintenance of muscle mass and
function * via protein based nutrition - is important in an ageing population.
Research participants will not directly benefit from their participation. The
risks associated with participation in this study are the development of
bruises due to cannulation and transiently decreased iron status due to
repeated blood sampling. The total amount of blood sampled during the 4 week
period is 480 ml (120 ml per week). Compared to the 500 ml which is collected
at a single occasion during blood donation, this amount is not expected to
result in side effects such as fatigue. The main burden of this study consists
of the time involved (4 days ~ 6 hours), and the blood collection.