Mycoprotein as the Basis of a Sustainable Diet to Support Muscle Mass Maintenance and Reconditioning in Older Adults.
Condition: Aging; Sarcopenia
MeSH terms: Sarcopenia
Study type: Interventional

Summary: 
      A hallmark of ageing is loss of skeletal muscle mass and strength (sarcopenia). Sarcopenia is
      explained, partially, by reduced responsiveness of muscle to dietary protein. This 'anabolic
      resistance' can be overcome by consuming protein in close proximity to exercise and/or
      adequate amounts across the day. Consequently, there is momentum for a greater protein RDA
      for older individuals. Concurrently, there is a need to establish an evidence base for the
      efficacy of non-animal proteins.

      Mycoprotein is a sustainable non-animal derived protein that imposes a significantly lower
      environmental burden than animal sources. Our previous work suggests that mycoprotein has the
      potential to support muscle tissue remodelling to a similar extent as animal derived protein
      sources. The study will employ a deuterium oxide tracer to quantify muscle protein synthesis
      over a period of three days in response to a vegan diet or animal based diet, alongside daily
      unilateral resistance exercise in older adults.
    

Detailed description: 
      Dietary protein plays a critical role in the daily regulation of muscle mass by virtue of its
      ability to regularly stimulate muscle protein synthesis rates. Sarcopenia is mechanistically
      explained, at least in part, by the reduced responsiveness of older adult's muscle tissue to
      these anabolic properties of dietary protein. However, this 'anabolic resistance' can be
      overcome by paying attention to the synergy that exists between the anabolic effects of
      dietary protein and physical activity. Specifically, consuming dietary protein in close
      temporal proximity to physical activity and/or adequate amounts of dietary protein per meal
      is an effective strategy to optimise muscle protein metabolism in older adults. These
      mechanistic, physiological findings are supported by longitudinal studies showing that older
      individuals who consume modestly greater amounts of dietary protein than the current RDA,
      and/or maintain/adopt an active lifestyle, experience reduced rates of sarcopenia and
      typically live healthier lives.

      With the importance of dietary protein to support active, healthy ageing evident, and a
      consequent scientific momentum moving towards a considerable (≥50%) rise in recommended
      protein intake for older individuals, the inevitable question arises: 'where should this
      dietary protein to support healthy ageing come from?' Current and future generations are
      required to view developments in human nutrition through the lens of mounting challenges
      associated with the sustainability of increased production of animal proteins, a concern also
      of primary importance to Quorn Foods. However, research into the nutritional physiology of
      alternative, sustainable, non-animal derived protein sources is in its infancy, particularly
      so in older adults. Therefore, there is considerable scientific interest, public health value
      and commercial opportunity in establishing a robust evidence base for the efficacy of
      non-animal, sustainably produced dietary protein sources to support active, healthy ageing.

      Mycoprotein, a food source produced by continuous fermentation of the filamentous fungus
      Fusarium venenatum, imposes a significantly lower environmental burden during its production
      compared with animal sources. In collaboration with Quorn Foods, we recently reported that
      acute consumption of mycoprotein in young adults results in equivalent amino acid
      bioavailability to that of milk protein, and therefore shows promise as a protein source to
      support muscle anabolism and metabolic health in numerous populations. In the present
      proposal, we wish to translate and extend these findings into the older adult population. We
      will exploit a stable isotope tracer approach (oral administration of deuterium oxide ['heavy
      water']) to make in vivo measurements of cumulative, free living muscle protein synthesis
      rates in response to a highly sustainable, non-animal derived, mycoprotein based diet with or
      without physical activity, compared with a more traditional diet reliant on animal derived
      protein sources (matched for total protein). The study will increase our knowledge of how
      effective non-animal derived proteins are at supporting muscle tissue remodelling in the
      elderly.
    

Intervention name(s): Protein, calorie and macronutrient controlled diet, derived from either omnivorous or non-animal sources, alongside unilateral resistance exercise, over a three-day period.
Intervention type(s): Other
Intervention description(s): Participants received a control diet either derived from omnivorous or non-animal food sources, providing 1.8g.kg.day of protein, for a three-day period. Calories were calculated and set to place participants in a state of energy balance. Participants completed three bouts of unilateral resistance exercise, 5 sets of 30 maximal concentric knee extension contractions, on each morning that they received the control diet. During this three-day period participants also consumed a deuterium oxide tracer allowing for the measurement of muscle protein synthesis, in rested and exercised tissue, with incremental biopsies.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: Ageing; Muscle protein synthesis; Resistance exercise; Sarcopenia; Sustainable protein