Postprandial muscle protein synthesis is higher after a high whey protein, leucine-enriched supplement than after a dairy-like product in healthy older people: a randomized controlled trial.

What Was Tested

Researchers studied Leucine in this randomized controlled trial publication.

The aim of this study was to evaluate whether a specifically designed nutritional supplement in older adults stimulates muscle protein synthesis acutely to a greater extent than a conventional dairy product.

Why It Was Studied

However, these studies supplied only proteins, and no bolus studies have been done with dairy products or supplements that contained also fat and carbohydrates besides proteins.

This trial is registered in the Dutch Trial Register under number NTR1823.

Who Took Part

The age groups tagged for this paper are middle-aged adults and older adults, both men and women.

How the Study Was Run

In design terms this was a randomized and double-blind study.

Random assignment meant chance, not the researchers, decided who got Leucine and who got the comparison, which limits bias.

Blinding on both sides kept the participants and researchers unaware of who received Leucine.

Postprandial mixed muscle protein fractional synthesis rate (FSR) was measured over 4h using a tracer infusion protocol with L-[ring-¹³C₆]-phenylalanine and regular blood and muscle sampling.

What Was Measured

The subject headings attached to it are Amino Acids, Essential, Carbon Isotopes, Dietary Supplements, Exercise, Leucine, Milk Proteins and Muscle Proteins.

What This Means in Plain Language

The paper is a randomized and double-blind study of Leucine.

The abstract goes on to report its results in about 6 sentences; this page does not restate them, so read the paper for the findings and their limits.

The publication is from 2014 (Nutrition journal), a journal based in England.

More context: all human trials.