Grant: Project Grant

As we age we lose muscle and strength. This phenomenon is known as sarcopenia and it, like osteopenia is to osteoporosis, is a precursor to significant health problems. In the case of osteopenia and osteoporosis we know that one's risk for fracture increases. However, with sarcopenia there is no corresponding sarcoporosis, but instead we begin to lose strength and muscle function. Eventually the loss of muscle function can become so bad that we lose the ability to conduct activities of daily living and tasks such as getting into and out of chair are significantly compromised. People with more advanced muscle and strength loss are at high risk for the development of full disability, which oftentimes leads to full time institutionalized care. Nonetheless, we know that eating an appropriate amount of protein, containing the right amount of amino acids (the building blocks of protein), can help in preserving muscle mass. We also know, based on previous work from our group that the protein needs of older persons are higher, likely by 50% or more, than those of young persons. Regrettably, this evidence is not incorporated into professional practice. In fact, advice to consume less protein, particularly from high quality animal proteins may be, if followed, unwittingly resulting in accelerating muscle loss in older persons. Thus, the aim of this project is to combine two highly innovative methodologies using what are know as stable isotopes (non-radioactive isotopes) to determine just how much protein older men and women need to maintain their muscles. We are studying men and women separately since there are important sex-based differences. Importantly, we will focus on how much protein their muscles need to slow muscle loss as they age. We will also study older men and women who have sarcopenia to see what has happened in their muscle that led to them developing sarcopenia.