title: A higher alkaline dietary load is associated with greater indexes of skeletal muscle mass in women.
abstract: Conservation of muscle mass is important for fall and fracture prevention but further understanding of the causes of age-related muscle loss is required. This study found a more alkaline diet was positively associated with muscle mass in women suggesting a role for dietary acid-base load in muscle loss.
  
  
  BACKGROUND
  Conservation of skeletal muscle is important for preventing falls and fractures but age-related loss of muscle mass occurs even in healthy individuals. However, the mild metabolic acidosis associated with an acidogenic dietary acid-base load could influence loss of muscle mass.
  
  
  METHODS
  We investigated the association between fat-free mass (FFM), percentage FFM (FFM%) and fat-free mass index (FFMI, weight/height²), measured using dual-energy X-ray absorptiometry in 2,689 women aged 18-79 years from the TwinsUK Study, and dietary acid-base load. Body composition was calculated according to quartile of potential renal acid load and adjusted for age, physical activity, misreporting and smoking habit (FFM, FFMI also for fat mass) and additionally with percentage protein.
  
  
  RESULTS
  Fat-free mass was positively associated with a more alkalinogenic dietary load (comparing quartile 1 vs 4: FFM 0.79 kg P < 0.001, FFM% 1.06 % <0.001, FFMI 0.24 kg/m² P = 0.002), and with the ratio of fruits and vegetables to potential acidogenic foods.
  
  
  CONCLUSIONS
  We observed a small but significant positive association between a more alkaline diet and muscle mass indexes in healthy women that was independent of age, physical activity and protein intake equating to a scale of effect between a fifth and one half of the observed relationship with 10 years of age. Although protein is important for maintenance of muscle mass, eating fruits and vegetables that supply adequate amounts of potassium and magnesium are also relevant. The results suggest a potential role for diet in the prevention of muscle loss.
authors.affiliation: Department of Nutrition, Norwich Medical School, University of East Anglia, NR4 7TJ Norwich, UK. a.welch@uea.ac.uk
authors.forename: A A
authors.initials: AA
authors.lastname: Welch
authors.forename: A J
authors.initials: AJ
authors.lastname: MacGregor
authors.forename: J
authors.initials: J
authors.lastname: Skinner
authors.forename: T D
authors.initials: TD
authors.lastname: Spector
authors.forename: A
authors.initials: A
authors.lastname: Moayyeri
authors.forename: A
authors.initials: A
authors.lastname: Cassidy
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods; D000136:Acid-Base Equilibrium / Q000502:physiology; D000293:Adolescent; D000328:Adult; D000368:Aged; D000468:Alkalies / Q000008:administration & dosage*; D000886:Anthropometry / Q000379:methods; D001823:Body Composition / Q000502:physiology; D004032:Diet / Q000706:statistics & numerical data*; D004044:Dietary Proteins / Q000008:administration & dosage; D005247:Feeding Behavior; D005260:Female; D005638:Fruit; D006801:Humans; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology*; D012042:Registries; D055948:Sarcopenia / Q000503:physiopathology / Q000517:prevention & control*; D014675:Vegetables; D055815:Young Adult
chemical_list: D000468:Alkalies; D004044:Dietary Proteins