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Exercise Prevents Muscle Loss From Low-Protein Diets
By Rosalie Marion Bliss
April 12, 2002
What do you do when your healthy muscles are compromised by a diet intended to support the health of your kidneys? That’s the conundrum of people with chronic renal insufficiency. Although protein-restricted diets may be prescribed to slow the progression of kidney disease, the same diet is also known to lead to muscle loss.
Scientists funded by the Agricultural Research Service recently completed a study looking into ways to mitigate muscle loss caused by low protein intake. The researchers work in the Nutrition, Physiology and Sarcopenia Laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University in Boston, Mass.
The researchers studied a group of 26 individuals older than 50. The study participants, all of whom have moderate renal insufficiency, were asked to consume a low-protein diet for up to eight weeks. The participants then were split into two groups and were randomly assigned either to continue the low-protein diet, along with resistance training, or continue the low-protein diet without exercise for 12 weeks. The diet provided a daily portion of 0.64 grams of protein per kilogram of body weight. For someone weighing 165 pounds, that translates to 48 grams of protein compared with the recommended 60 grams for the same person.
Measurements taken before and after the study period showed total muscle fiber increased with resistance training by 23 percent on average. In addition, muscle strength increased by 32 percent among the participants who exercised, while the nonexercising group lost about 13 percent. The exercising patients maintained body weight; the nonexercisers lost about 7.7 pounds.
It is unknown if similar results would be seen in patients who do not eat a low-protein diet or in those with end-stage renal disease, according to Carmen Castaneda Sceppa, a physician specializing in nutrition. Castaneda Sceppa is the principal investigator of the study, which was recently reported in the Annals of Internal Medicine. Studies conducted for longer periods of time are needed that include larger groups of participants, in more advanced stages of renal disease, according to Castaneda Sceppa.
ARS is the U.S. Department of Agriculture’s chief scientific research agency.
