Amino Acid Solution to Muscle Loss
Elderly women who take a combination of hydroxymethylbutyrate (HMB), arginine, and lysine may increase protein formation in the body, leading to greater muscle mass, improved strength, and better physical functioning, according to a study in Nutrition (2004;20:445–51).
Muscle mass decreases with advancing age; by age 70, the rate of muscle loss in the human body is about 15% per decade. As a result, elderly people may lose mobility and be at increased risk for falls and diseases such as osteoporosis. Women tend to lose more muscle mass than men do. Age-related muscle loss may be caused by decreased levels of certain hormones, changes in the structure of the muscle itself, or certain disease processes.
Current treatment strategies for muscle loss include hormone therapy, nutritional intervention, and exercise. Hormone therapy yields inconsistent results and carries a significant risk of side effects. Nutritional intervention is not always effective in restoring muscle mass. Weight training can build and maintain muscle mass; unfortunately, few elderly people engage in this kind of exercise.
HMB, a metabolic byproduct of the amino acid leucine, can slow the rate of protein breakdown in muscle tissue and minimize muscle damage during periods of intensive exercise training. HMB can be found in foods such as catfish and alfalfa. Arginine, an amino acid needed to increase protein synthesis in the body, is found in foods such as dairy products, meat, fish, nuts, and chocolate. Lysine is an essential amino acid, meaning that it cannot be made by the body, so it must be consumed in the diet from sources such as legumes (beans, peas), brewer’s yeast, dairy products, fish, and meat. The body incorporates lysine into many proteins, and it may stimulate muscle protein synthesis. Many elderly women have much lower levels of lysine than do younger people.
The new study examined the role of HMB, arginine, and lysine supplementation on measures of strength, muscle mass, and protein status in elderly women. Fifty women aged 62 to 90 years took part in the study. The participants were randomly assigned to receive either (1) 2 grams of HMB, 5 grams of arginine, 1.5 grams of lysine, and 500 mg of vitamin C (amino acid mixture) in 8 ounces of water, or (2) nontreatment (placebo) in 8 ounces of water, each morning with breakfast for 12 weeks. To assess the effectiveness of the treatment, the following parameters were measured at the beginning of the study and again after 12 weeks: get-up-and-go functionality (how quickly the participants could stand from a seated position, walk three meters, turn around, walk back, and return to a seated position); leg strength; handgrip strength; circumference of the dominant thigh, arm, and forearm; hip and abdomen circumference; percentage of body fat and lean body mass; rates of protein synthesis and loss; and hormones affecting protein synthesis in the body.
The group treated with the amino acid mixture had significantly greater get-up-and-go functionality, leg strength, and handgrip strength than the placebo group. In addition, the average limb circumference increased significantly in the treatment group compared with the placebo group, suggesting an increase in muscle mass. The hip and abdomen circumferences tended to decrease and the lean body mass tended to increase in the treatment group, again suggesting an increase in muscle mass. Protein synthesis was 20% greater in the treatment group than in the placebo group. No differences in hormone levels were noted between the groups.
The mixture used in this study is very well tolerated and relatively inexpensive, making it a logical first-line treatment for the widespread and difficult-to-treat problem of muscle loss in the elderly.
Kimberly Beauchamp, ND, received her bachelor’s degree from the University of Rhode Island and her Doctorate of Naturopathic Medicine from Bastyr University in Kenmore, WA. She is a co-founder and practicing physician at South County Naturopaths, Inc., in Wakefield, RI. Dr. Beauchamp teaches holistic medicine classes and provides consultations focusing on detoxification and whole-foods nutrition.
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