Muscle mass and strength naturally decline with age. In this study, 42 healthy adults, ages 55 to 70, took a placebo, or 1,500 mg of l-carnitine with or without 2,000 mg of l-leucine, 3,000 mg creatine and 400 I.U. of vitamin D3 per day.

After eight weeks, muscle mass, strength and mobility were stable in the l-carnitine group, while declining slightly for the placebo group. Those taking the carnitine-leucine-creatine-vitamin D3 combination saw total lean muscle mass increase by an average of 2.2 pounds, leg lean muscle mass increase by 11.2 ounces and, compared to the placebo group, lower leg strength 2.2 pounds greater.

Discussing the findings, doctors said the supplements likely built lean muscle mass and lower leg strength by increasing the ability of the body to synthesize protein, and that taking these nutrients beyond eight weeks may further enhance physical performance in healthy older adults.

Quick Quiz

1  Muscle mass and strength naturally increase with age.

a. True

b. False

 

2  Adults age 55 to 70 who took l-carnitine, l-leucine and creatine also took which nutrient in an effort to build muscle mass and strength?

a. L.acidophilus

b. L-lysine

c. El Torito

d. Vitamin D

 

3  Doctors said the supplements likely built lean muscle mass and lower leg strength by:

a. Increasing the ability of the body to synthesize protein

b. Metabolizing fat more efficiently

c. Regulating the absorption of carbohydrates

d. All of the above

Answers

1  False

2  d. Vitamin D

3  a. Increasing the ability of the body to synthesize protein