Researchers at McMaster University in Ontario conducted a trial that sought to mimic the effects of enforced bed rest on muscle loss among elderly patients. The researchers recruited 16 men and 15 women in their late 60s to participate in the study. The double-blind randomized, controlled trial used either whey protein or collagen in a study design meant to simulate enforced inactivity.
Four phase design
The study design had an initial run-in period in which the subjects were in energy balance, with the recommended level of protein intake (0.8 grams of protein per kilogram of body weight). Then they went into a one week period in which they cut their food intake by 500 calories a day but boosted their protein to 1.6 g/kg.
Another week on the same nutrient intake followed in which they also restricted their movement, as measured by a pedometer, by 750 steps a day. Then followed a week of recovery during which the higher protein intake was maintained.
In the protein supplementation phases, the subjects received 30 grams twice a day of whey protein or collagen peptides. This accounted for about 45% of protein intake during the supplementation phases. The researchers measured lean leg mass and rates of integrated muscle protein synthesis in both groups.
The results showed that neither protein intervention helped preserve LLM during the calorie-and-step reduction phase. In the recovery phase, the whey protein group recovered LLM whereas the collagen group did not.
Collagen had shown some sarcopenia benefits
Lead researcher Stuart Phillips, PhD, a professor of kinesiology at McMaster, said collagen was chosen to as a counterpoise against whey because of its significantly lower leucine content. Leucine is the most important amino acid when ti comes to rebuilding muscle, he said. But he also said that collagen had shown some benefits in combating sarcopenia, such as in this recent trial done in Germany, so his team was eager to see how it matched up.
“We thought that if collagen was as potent as it was in that trial it should be very effective in limiting lean mass loss. That collagen was neither effective in mitigating loss of muscle (then again neither was whey) nor in stimulating muscle regrowth following remobilization casts serious doubt on collagen’s touted anti-sarcopenic properties. In short, whey was superior to a lower quality protein but also we failed to come close to replicating the effects seen in [the German trial]. Importantly, collagen is MUCH lower in leucine than whey — the key amino acid for building muscle — so I am perhaps unsurprised that we could not reproduce the effects see in that paper,” Phillips told NutraIngredients-USA.
Quality, not digestibility or time, is the issue
A one week recovery phase is relatively short. Phillips said the collagen peptides were hydrolyzed, meaning that they would be relatively quickly absorbed so that despite whey’s highly touted fast-digesting benefits, he doubted that that’s what was at work in the recovery phase.
“I don’t think that’s why whey restored muscle and collagen didn’t — that’s absolutely a leucine and protein quality issue,” said.
Would the collagen group have caught up, given more time? That too, was unlikely, he said.
“Given the complete lack of response in the collagen group it’s impossible for me to say whether the collagen supplemented group would have caught up and when. Older people are notoriously bad at what we call ‘catch-up’ growth once muscle is lost it can be a permanent loss without a significant rehabilitative protein. Our work shows whey facilitated that whereas collagen did not,” Phillips said.
Phillips said it’s important to note that his study focused on the muscle loss that hospital patients might experience. The results don’t necessarily generalized to protein applied in different ways, such as helping active seniors to maintain strength and muscle.
“I think it’s important to distinguish between what our subjects did — basically behaved like a hospital patient for 2 weeks — versus normally functioning older adults for whom greater protein intakes can help preserve muscle mass,” he said.
Source: American Journal of Clinical Nutrition
2018 Oct 4. doi: 10.1093/ajcn/nqy193. [Epub ahead of print]
“A randomized controlled trial of the impact of protein supplementation on leg lean mass and integrated muscle protein synthesis during inactivity and energy restriction in older persons.”
Authors: Oikawa SY, McGlory C, D'Souza LK, Morgan AK, Saddler NI, Baker SK, Parise G, Phillips SM