Association between dietary acid load and grip strength in adults 50 years and older: a cross-sectional study

Authors: KONIECZYNSKI, ELSA - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; CEGLIA, LISA - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; REITSHAMER, ELISE - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; DAWSON-HUGHES, BESS - Jean Mayer Human Nutrition Research Center On Aging At Tufts University

Submitted to: Calcified Tissue International
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/15/2024
Publication Date: 7/24/2024
Citation: Konieczynski, E., Ceglia, L., Reitshamer, E., Dawson-Hughes, B. 2024. Association between dietary acid load and grip strength in adults 50 years and older: a cross-sectional study. Calcified Tissue International. https://doi.org/10.1007/s00223-024-01258-5.
DOI: https://doi.org/10.1007/s00223-024-01258-5

Interpretive Summary: Dietary acid load reflects the balance of intake of acid-producing foods, grains and protein, and alkali-producing foods, such as fruits and vegetables. An elevated dietary acid load is a risk factor for reduced muscle mass; however, the relationship between dietary acid load and muscle strength is unknown. We examined the association between the dietary acid load and grip strength in a nationally representative sample of 4,059 U.S adults, aged 50 years of age and older. Consistent with our hypothesis, grip strength was significantly lower in women consuming higher dietary acid loads. In contrast, we identified no association between grip strength and dietary acid load in the men. This study highlights a gender-specific association between dietary acid load and grip strength in older adults, emphasizing the potential benefits of higher fruit and vegetable intake for maintaining muscle strength, particularly in women.

Technical Abstract: Background: Dietary acid load - the balance of acidogenic byproducts from the metabolism of grains and proteins and alkalinogenic byproducts from the metabolism of fruits and vegetables - may affect muscle strength in middle- and older-aged adults with age-related losses in kidney acid handling. Aim: To determine if dietary acid load is associated with grip strength in a nationally representative sample of adults 50 years of age and older. Methods: We examined the cross-sectional association of grip strength with dietary acid load quantified through potential renal acid load (PRAL) and net endogenous acid production (NEAP) in 4,059 adults aged 50 years and older in the 2011-2014 NHANES survey cycles. PRAL and NEAP were estimated from two 24-hour recalls and categorized into sex-specific quartiles. Grip strength was measured on a handheld dynamometer. Multiple linear regression models were used to determine the associations of PRAL and NEAP (as quartiles) with grip strength for men and women separately, adjusting for total energy, age, race/ethnicity, weight, physical activity, smoking, serum 25-hydroxyvitamin D, and estimated glomerular filtration rate. Results: Grip strength was inversely associated with quartiles of PRAL (ptrend=0.049) and NEAP (ptrend=0.034) in women and not associated with quartiles of PRAL or NEAP in men in the fully adjusted models.