Alkaline diets favor lean tissue mass in older adults

Am J Clin Nutr. 2008 Mar;87(3):662-5. doi: 10.1093/ajcn/87.3.662.


Background: Maintaining muscle mass while aging is important to prevent falls and fractures. Metabolic acidosis promotes muscle wasting, and the net acid load from diets that are rich in net acid-producing protein and cereal grains relative to their content of net alkali-producing fruit and vegetables may therefore contribute to a reduction in lean tissue mass in older adults.

Objective: We aimed to determine whether there was an association of 24-h urinary potassium and an index of fruit and vegetable content of the diet with the percentage lean body mass (%LBM) or change in %LBM in older subjects.

Design: Subjects were 384 men and women > or =65 y old who participated in a 3-y trial comparing calcium and vitamin D with placebo. Potassium was measured in 24-h urine collections at baseline. The %LBM, defined as total body nonfat, nonbone tissue weight/weight x 100, was measured by using dual-energy X-ray absorptiometry at baseline and at 3 y. Physical activity, height, and weight were assessed at baseline and at 3 y.

Results: At baseline, the mean urinary potassium excretion was 67.0 +/- 21.1 mmol/d. Urinary potassium (mmol/d) was significantly positively associated with %LBM at baseline (beta = 0.033, P = 0.006; adjusted for sex, weight, and nitrogen excretion) but not with 3-y change in %LBM. Over the 3-y study, %LBM increased by 2.6 +/- 3.6%.

Conclusion: Higher intake of foods rich in potassium, such as fruit and vegetables, may favor the preservation of muscle mass in older men and women.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Absorptiometry, Photon
  • Acid-Base Equilibrium
  • Aged
  • Aging / physiology*
  • Aging / urine
  • Body Composition / physiology*
  • Creatinine / urine
  • Cross-Sectional Studies
  • Female
  • Fruit* / chemistry
  • Humans
  • Longitudinal Studies
  • Male
  • Muscle, Skeletal / drug effects
  • Muscle, Skeletal / physiology*
  • Muscular Atrophy / prevention & control
  • Nitrogen / urine
  • Potassium / urine*
  • Potassium, Dietary / administration & dosage*
  • Potassium, Dietary / metabolism
  • Surveys and Questionnaires
  • Vegetables* / chemistry


  • Potassium, Dietary
  • Creatinine
  • Nitrogen
  • Potassium