Dietary animal protein intake: association with muscle mass index in older women

J Nutr Health Aging. 2007 Sep-Oct;11(5):383-7.


Background: Aging is associated with reductions in muscle mass and strength, so-called sarcopenia, and is generally characterized using muscle mass index (MMI = FFM (kg)/height (m)2). It is believed that adequate nutrition especially regarding protein intake, can delay this progression and enhance the quality of life of elders.

Objectives: We examined whether the predominant source of protein consumed (animal or vegetal) by older women was associated with MMI.

Design: Thirty-eight healthy, normal weight, sedentary women, aged between 57-75 years (mean age: 66 +/- 5 years old), and taking no medication that could influence metabolism were recruited. Body composition was measured by dual-energy X-ray absorptiometry; muscle protein content was measured by the use of creatinine excretion. Physical activity metabolism was obtained by the use of accelerometry, and indirect calorimetry. Finally, protein intake was measured with a 3-day dietary record.

Results: Significant correlations were observed between MMI and body mass index, fat-free mass, muscle protein content, total protein intake, animal protein intake, fat mass, visceral fat and daily energy expenditure. However, a stepwise regression analysis showed animal protein intake to be the only independent predictor of MMI (r2=0.19; p=0.008).

Conclusions: Our results suggest that protein intake, especially from animal sources, may be associated with a better preservation of MMI. However, more research is needed to confirm our results.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Absorptiometry, Photon / methods
  • Aged
  • Aging
  • Biomarkers / urine
  • Body Composition / drug effects*
  • Body Composition / physiology
  • Calorimetry, Indirect
  • Creatinine / urine
  • Diet Records
  • Dietary Proteins / administration & dosage*
  • Energy Metabolism / physiology
  • Female
  • Humans
  • Meat*
  • Middle Aged
  • Muscle, Skeletal / drug effects*
  • Muscle, Skeletal / physiology
  • Muscular Atrophy / prevention & control*
  • Muscular Atrophy / urine


  • Biomarkers
  • Dietary Proteins
  • Creatinine