Postprandial muscle protein synthesis following wheat protein ingestion in vivo in humans

The progressive loss of skeletal muscle mass with aging, or sarcopenia, has a
major impact on our health care system due to increased morbidity and greater
need for hospitalization and/or institutionalization. One way to prevent
skeletal muscle loss is to improve dietary intake of the elderly. Both whey and
casein seem to offer an anabolic advantage over soy protein for promoting
muscle hypertrophy. As a consequence it is assumed that (all) plant based
proteins have less potent anabolic properties when compared with animal based
proteins. However, there is little theoretical background for such assumptions.

Primary Objective: To provide evidence for the efficacy of wheat protein and
wheat protein hydrolysate when compared with milk proteins as a dietary protein
to stimulate postprandial muscle protein synthesis in vivo in healthy older
humans. Secondary objective: To test whether ingesting a higher quantity (60 g)
of wheat protein hydrolysate results in a muscle protein synthetic response
similar to a meal-like amount (30 g) of whey protein.

double-blind, placebo-controlled intervention study

A protein beverage (350 mL) containing 30 g of whey, casein, wheat protein, or
wheat protein hydrolysate or 60 g of wheat protein hydrolysate will be consumed
(n=12 per group).

The burden and risks associated with participation are small. Insertion of the
catheters is comparable to a blood draw and could result in a small hematoma.
Muscle biopsies will be taken under local anesthesia by an experienced
physician, but may cause some minor discomfort for maximally up to 24 h after
completion. The discomfort is comparable to muscle soreness or the pain one has
after bumping into a table. We will take 5 and 18 blood samples (8 mL) during
the screening and experimental trial respectively. The total amount of blood we
draw is less than half the amount of a blood donation and will be completely
restored in approximately 1 month. Participants come to the university twice: 1
screening (4 hours) and 1 experimental trial (entire day). For both the
screening and the experimental trial, participants have to be fasted, so they
are not allowed to eat and drink (except for water) from 22h00 the evening
before. Also, 3 days prior to the experimental trial participants should keep
their diet as constant as possible, do not perform any type of intense physical
exercise, and do not consume alcohol. During the screening we will perform a
DEXA and an OGTT. Furthermore, we will ask the participants to fill out a
medical questionnaire and record their food intake and activity for 2 days
prior to the experimental trial. During the experimental trial, we will collect
muscle and blood samples, and participants have to consume a protein beverage
(commercially available food product). There is no direct benefit for the
participants, only their contribution to scientific knowledge and nutritional
strategies that prevent muscle loss in the elderly, which will be obtained from
this study and used in the future.