Alkaline diets favor lean tissue mass in older adults

Authors: Dawson-Hughes, Bess; HARRIS, SUSAN - TUFTS/HNRCA; CEGLIA, LISA - TUFTS/HNRCA

Submitted to: The American Journal of Clinical Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/26/2007
Publication Date: 1/1/2008
Citation: Dawson-Hughes, B., Harris, S.S., Ceglia, L. 2008. Alkaline diets favor lean tissue mass in older adults. American Journal of Clinical Nutrition. 87(3):662-665.

Interpretive Summary: Maintaining muscle mass is important to prevent falls and fractures, particularly in aging populations. More acidic diets containing protein and cereal grains that lack sufficient fruits and vegetables may contribute to reduced lean tissue mass in older adults. This 3-year calcium and vitamin D versus placebo trial followed the diets of 384 men and women age 65+. Lean Body Mass, defined as total body non-fat, non-bone tissue mass, was measured at the beginning and end of the study. Physical activity, height, and weight were also assessed at both times. Study results indicated that higher intake of fruits and vegetables, foods rich in potassium, was associated with more favorable changes in lean body mass. Thus fruits and vegetables may help preserve muscle mass in older men and women.

Technical Abstract: Maintaining muscle mass in aging is important to prevent falls and fractures. The net acid load from diets that are rich in acidogenic protein and cereal grains relative to their content of alkalinogenic fruits and vegetables may contribute to reduced lean tissue mass in older adults. This analysis was conducted to determine whether there was an association of 24-hr urinary potassium (K), an index of fruit and vegetable content of the diet, with lean body mass (LBM) or change in LBM in older subjects. Subjects were 384 men and women age 65+ who participated in a 3-yr calcium and vitamin D versus placebo trial. 24-Hr urinary K was measured at baseline. LBM, defined as total body non-fat, non-bone tissue mass, was measured by DXA at baseline and 3 years. Physical activity, height, and weight were assessed at baseline and 3 years. Results at baseline showed the mean urinary K excretion was 67.0 +/- 21.1 mmol/d. Urinary K was positively associated with LBM at baseline (B= 0.026, P = 0.003, adjusted for sex, age, weight, physical activity score, and nitrogen excretion) and with 3-yr change in LBM (B= 0.008, P = 0.046, adjusted for sex, age, weight, physical activity score, treatment group and baseline LBM). Higher intake of fruits and vegetables, foods rich in potassium, may help preserve muscle mass in older men and women.