The effectiveness of a diet with beef as key protein component versus a plant-based diet to support integrated muscle protein synthesis rates in healthy older individuals

Food intake stimulates muscle protein synthesis rates at rest and following
exercise. Ingestion of animal-derived proteins generally leads to a greater
stimulation of muscle protein synthesis when compared to the ingestion of
plant-derived proteins. What is often neglected is that the anabolic properties
of protein isolates do not necessarily reflect the anabolic response to the
ingestion of the whole-foods from which they are derived. This discrepancy is
due to the presence or absence of other components normally found within
whole-food matrices, which influence protein digestion and amino acid
absorption from animal based and plant based protein sources. A rapid and
robust post-prandial release of food-derived amino acids is of particular
relevance for older individuals, who typically show a blunted muscle protein
synthetic response to feeding. Therefore it is currently unknown how
plant-based diets compare to diets containing animal protein in their capacity
to stimulate muscle protein syntheses.

To compare the effectiveness of a diet with beef as key protein source versus
an isocaloric and isonitrogenous plant-based diet to stimulate integrated
muscle protein synthesis rates over a 10 day period, in healthy older
individuals, with and without exercise.

Randomized, counter-balanced, cross-over design, researchers and participants
are not blinded, analysts are blinded.

Over a 10-d period, participants will consume a controlled omnivorous diet (in
which ~60% of total protein intake will come from meat based products) followed
by a controlled meat-free (i.e. plant-based) diet, for 10 days or vice versa.
Both diets will be matched for protein (1.1 g/kg/day) and energy intake.
Additionally participants will perform 4 single-legged exercise training
sessions, will consume a daily dose of deuterated water and collect saliva
samples.

The risks involved in participating in this experiment are minimal. The blood
sample will be comparable to a normal blood draw and the only risk is a small
local hematoma. Muscle biopsies will be obtained under local anaesthesia by an
experienced physician, but may cause some minor discomfort. The discomfort is
comparable to muscle soreness or the pain one has after bumping into the corner
of a table. The ingestion of deuterated water has been applied in numerous
published studies and is entirely safe and non-toxic in the amounts provided in
the present study. The diet will be composed of familiar food products. There
is no direct benefit for the participants, except from their contribution to
scientific knowledge on the impact of omnivorous versus vegan meals on the
stimulation of muscle protein synthesis.