Dietary Acid Load Is Not Associated with Lower Bone Mineral Density Except in Older Men,

Abstract

High dietary acid load may be detrimental to bone mineral density (BMD), although sufficient calcium intake might neutralize this effect. In observational studies, the association between BMD and dietary acid load, estimated by net endogenous acid production (NEAP) and potential renal acid load (PRAL), has been inconsistent, and the potential modifying effect of calcium intake has not been assessed. We therefore examined the cross-sectional associations of estimated NEAP and PRAL with BMD in the Framingham Osteoporosis Study. We hypothesized that higher estimated NEAP and PRAL would be associated with lower BMD, but only among those with total calcium intake < 800 mg/d. BMD of the femoral neck and lumbar spine was measured, and estimated NEAP and PRAL were calculated via FFQ among 1069 Framingham Original (1988-1989, 1992-1993; 62% women, mean age 76 y) and 2919 Offspring (1996-2001; 56% women, mean age 60 y) cohort participants. Cohort- and sex-specific ANCOVA was used to calculate multivariable-adjusted mean BMD for estimated NEAP and PRAL quartiles. Assuming no uncontrolled confounding, estimated NEAP, but not PRAL, was inversely associated with femoral neck BMD (P-trend = 0.04) in Original cohort men, whereas neither was associated with lumbar spine BMD. Estimated NEAP and PRAL were not associated with BMD at any site among Original cohort women or Offspring cohort men and women. There were no significant interactions between either estimated NEAP or PRAL and total calcium intake. These results suggest that, with a possible exception of older men, dietary acid load does not have a measureable negative effect on bone health, regardless of total calcium intake.

Dietary Acid Load: A Novel Nutritional Target in Chronic Kidney Disease?

“…Several studies suggest that these adverse effects may be mitigated by a reduction in the dietary acid load, although this area remains controversial (98, 99). In interventional studies, markers of bone resorption are reduced by potassium bicarbonate supplementation or consumption of the DASH diet (9, 100, 101).…”

Dietary Approaches for Bone Health: Lessons from the Framingham Osteoporosis Study

“…One RCT showed pharmacologic doses of potassium citrate (alkaline substance) to be beneficial bone health [53]; however, two other RCTs showed no effect on BMD [54, 55]. Among men in the Framingham Original Cohort, dietary acid load estimated by NEAP was inversely related with femoral neck BMD, but no association was observed at the spine; no significant associations were observed in women [56]. No associations between NEAP and BMD were observed among men or women from the younger, Framingham Offspring cohort.…”

Dietary protein is beneficial to bone health under conditions of adequate calcium intake

“…Similarly, other epidemiologic studies do not support the hypothesis that greater dietary acid load (associated with chronic high protein intake) is detrimental to bone health [8,18]. One study found that in men alone, greater dietary acid load may be detrimental to bone only under conditions of very low calcium intake [9▪].…”