We’ve written several articles on the apparent benefits of a higher protein diet for the older athlete. Loss of muscle mass starts fairly early and loss of strength is often apparent by middle age. We do not know how much protein intake is ideal for humans. High protein diets for older people have been geared towards controlling sarcopenia. Sarcopenia is the term used to describe the muscle loss that happens as people age. Sarcopenia is a major cause of frailty. Osteoporosis, where loss of calcium from bones leads to brittleness and fractures, is the other big problem. Sarcopenia and osteoporosis can be worse for women who have less bone mass and less muscle mass to start with. A number of studies have shown that older people preserve more muscle if their protein intake is increased. If older people can preserve more muscle that should mean fewer people needing assisted-living. Exercise, including resistance exercise also helps preserve muscle. Exercise also strengthens bone and protects against osteoporosis. As for the older athlete, preservation of muscle mass may provide a competitive edge. For more easy-going people, preservation of muscle mass may mean:
- less of the sinking feeling you get when you realize you know exactly where your body should have been when you took that flying leap for a frisbee.
- fewer pained expressions on the faces of children when you fail a back flip
- less aggravation opening jars
A new study by a team of researchers from the US and Italy examined protein intake in adults over age 50 compared with rates of Cancer, Diabetes, Mortality in general and IGF-1 (a growth hormone) levels. Study subjects were divided into two groups: ages 50 to 65 and those over 65. For people ages 50 to 65 a high protein diet increased risk of cancer, diabetes and death in general. IGF-1 levels were also higher in these adults. IGF-1is a growth hormone that may preserve muscle mass, but may also increase risk of cancer. Middle-age users of deer antler velvet, which contains IGF-1, beware. Researchers also found that people who ate more plant protein had lower death rates than people who ate more animal protein. In bullet points:
High protein diet for people age 50 to 65
- High animal protein diet increased risk of cancer by 400% in adults 50-65
- High animal protein diet Increased risk of death by 75%
- High animal protein diet increased risk of death from diabetes-related causes by 500%
- High plant-based protein diet showed little to no increase in death or cancer risk
High protein diet for people over age 65
- high protein diet reduced risk of cancer and death in people over age 65
- Risk of death from diabetes-related causes was the same as it was for adults 50-65
Conclusions for dietary protein intake:
The researchers in this case also compared epidemiological findings with data derived from mice, which is unusual. One of their conclusions was that a low protein intake diet during middle age followed by a high protein intake in later age may “optimize healthspan and longevity.” I would add some considerations to that:
- It didn’t seem to be protein in itself thatwas the main culprit in the study, although there was some interesting data on ifg-1 levels and protein intake. One of the problems with some forms of animal protein (meat) is that carcinogents (cancer causers) may form during high heat cooking.
- Animal fat will contain more lipophilic chemicals than vegetable fats. Some lipophilic chemicals build up in humans over time.
- It seems likely that something besides protein is causing the problem.
- There may be other considerations for post-menopausal women, who seem to weather aging (functionally) better when protein intake is higher.
- People age 50-65 are different than people 65 and older. The 65 and older group may already have weeded out people who were vulnerable to heart disease. (This would probably not hold for cancer).
High protein diets have been popular for a number of years now. High protein diets, especially meat based high protein diets, have been especially popular in the Crossfit Community. Unless you are a middle aged adult, a high animal protein diet may be bad for your long-term health. It would be nice to know what the results would be if high-fat/high protein/poor lifestyle/obesity was separated from high protein/healthy lifestyle/healthy weight. Hopefully the researchers will continue this line of inquiry.
Levine, M., Suarez, J., Brandhorst, S., Balasubramanian, P., Cheng, C., Madia, F., Fontana, L., Mirisola, M., Guevara-Aguirre, J., Wan, J., Passarino, G., Kennedy, B., Wei, M., Cohen, P., Crimmins, E., & Longo, V. (2014). Low Protein Intake Is Associated with a Major Reduction in IGF-1, Cancer, and Overall Mortality in the 65 and Younger but Not Older Population Cell Metabolism, 19 (3), 407-417 DOI: 10.1016/j.cmet.2014.02.006
Gregorio L, Brindisi J, Kleppinger A, Sullivan R, Mangano KM, Bihuniak JD, Kenny AM, Kerstetter JE, & Insogna KL (2014). Adequate Dietary Protein is Associated with Better Physical Performance among Post-Menopausal Women 60-90 Years. The journal of nutrition, health & aging, 18 (2), 155-60 PMID: 24522467
Beasley JM, Wertheim BC, LaCroix AZ, Prentice RL, Neuhouser ML, Tinker LF, Kritchevsky S, Shikany JM, Eaton C, Chen Z, & Thomson CA (2013). Biomarker-calibrated protein intake and physical function in the Women’s Health Initiative. Journal of the American Geriatrics Society, 61 (11), 1863-71 PMID: 24219187