Effect of Acid or Base Interventions on Bone Health: A Systematic Review, Meta-Analysis, and Meta-Regression

Abstract

Osteoporosis is a global health issue among the aging population. The effect of the acid or base interventions on bone health remains controversial. This study performed a systematic review and meta-analysis to investigate effects of acidic diets and alkaline supplements on bone health simultaneously. We conducted a comprehensive literature search in 5 available databases and 1 registered clinical trial system to identify randomized controlled trials (RCTs) that assessed effects of the acid-base intervention on bone health. Depending on heterogeneity across studies, the pooled effects were calculated by fixed-effects or random-effects models. The present study included 13 acidic diet intervention studies and 13 alkaline supplement studies for final quantitative assessments. The meta-analysis showed that acidic diets significantly increased net acid excretion [NAE; standardized mean difference (SMD) = 2.99; P = 0.003] and urinary calcium excretion (SMD = 0.47, P < 0.00001) but had no significant effect on bone turnover markers and bone mineral density (BMD). On the other hand, alkaline supplement intervention significantly reduced NAE (SMD = −1.29, P < 0.00001), urinary calcium excretion (SMD = −0.44, P = 0.007), bone resorption marker aminoterminal cross-linking telopeptide (NTX; SMD = −0.29, P = 0.003), and bone formation marker osteocalcin (OC; SMD = −0.23, P = 0.02), but did not affect the other bone turnover markers. Furthermore, alkaline supplements significantly increased BMD in femoral neck [mean difference (MD) = 1.62, P < 0.00001, I2 = 0%], lumbar spine (MD = 1.66, P < 0.00001, I2 = 87%), and total hip (MD = 0.98, P = 0.02, I2 = 99%). Subsequently, meta-regression analyses identified 1 study that substantially contributed to the high heterogeneity of BMD in the latter 2 sites, but sensitivity analysis suggested that this study did not affect the significant pooled effects. Despite that, the results should be interpreted with caution and need to be further validated by a larger RCT. In summary, through integrating evidence from RCTs, the present meta-analysis initially suggests that alkaline supplements may be beneficial to bone metabolism and acidic diets may not be harmful to bone health. This work may be clinically useful for both clinicians and patients with osteoporosis.

Protein intake and bone mineral density: Cross‐sectional relationship and longitudinal effects in older adults

“…Consumption of plant protein sources typically result in a more bone‐sparing alkaline metabolic environment, which may increase BMD. 32 In addition, animal foods have typically a higher sodium chloride (NaCl) content, 33 and a high NaCl intake combined with a low calcium intake causes high calcium excretion, leading to bone resorption. 34 Previous cross‐sectional research in older adults also found positive associations between animal protein 5 , 35 , 36 and plant protein 5 , 35 with total body and spine BMD.…”

“…However, there are also reasons to argue that plant protein would lead to increased BMD. Consumption of plant protein sources typically result in a more bone‐sparing alkaline metabolic environment, which may increase BMD 32 . In addition, animal foods have typically a higher sodium chloride (NaCl) content, 33 and a high NaCl intake combined with a low calcium intake causes high calcium excretion, leading to bone resorption 34 .…”

Dietary Acid Load and Bone Health: A Systematic Review and Meta-Analysis of Observational Studies

“…However, that study did not conduct any further statistical analysis but only applied the Hill standard review to retrospectively describe the relationship between acid load and bone metabolism. In an additional meta-analysis of 13 randomized clinical trials, alkaline supplementation had beneficial effects on bone metabolism and acidic diets were not harmful for bone health (44). Several randomized controlled trials have reported that high-protein diets which are considered acid-producing diets, have no significant effect on bone turnover markers and BMD (45,46).…”

Ossäre Bedeutung von Mineral- und Heilwässern: Physiologie und epidemiologische Evidenz

“…B. um 50 mEq/Tag, so werden rund 70 mg Calcium weniger ausgeschieden [137]. Dieser Zusammenhang zwischen verminderter Säurelast und reduzierter Calciumexkretion wurde auch für alkalische Wässer [136,138] und Basensupplemente auf Basis von Kaliumcitrat oder -bikarbonat beschrieben [139] (siehe ▶Abb. 4).…”