| Background:Osteoporosis is an important health problem of population aging.The "acid-base hypothesis" holds that acidic diet has an adverse effect on bone,and alkaline intervention will inhibit it,but this statement has not been determined.The impact of acid-base intervention on bone health is still controversial.Objective:To explore the effect of dietary acid-base load on bone metabolism and related influencing factors.Methods:1.We conducted a dietary survey on the inpatients in Zhujiang Hospital of Southern Medical University,calculated the potential renal acid load(PRAL)according to the dietary questionnaire,and divided the subjects into high PRAL and low PRAL groups.We collected the general clinical data,blood sugar,blood lipid,serum electrolyte,liver and kidney function,bone metabolism index and bone mineral density value of the subjects,and we took the fecal samples of the subjects.we obtained the fecal intestinal flora data through 16S rDNA high-throughput sequencing.Finally,the data were statistically analyzed by SPSS software and R software.2.At the same time,we conducted a systematic search in the databases of Scopus,Pubmed,Embase,wed of science and Cochrane Library and some clinical research registration websites,only included the studies of randomized intervention trials,to conduct a meta-analysis on the impact of acid-base diet intervention on bone health.Depending on heterogeneity across studies.Results:1.According to the inclusion and exclusion criteria,86 subjects were finally included in the diet survey.The results showed that in women,the bone mineral density of the high PRAL group was higher than that of the low PRAL group(P<0.05),but there was no significant difference in the effects of bone metabolic markers(P1NP,β-CTX,25-OH-VitD and PTH);In men,there was no significant difference in bone mineral density and bone metabolism;However,after adjusting for age,sex,renal function,glycosylated hemoglobin and other confounding factors,it was found that there was no significant difference in the effect of dietary acid load between men and women on bone mineral density(P>0.05).In the analysis of intestinal flora,combined with the LEfSe analysis results of the intestinal flora of the two groups and after spearman analysis of the key flora species with significant differences and environmental factors,it was found that the abundance of dead Clostridium was higher in the low PRAL group,and was negatively correlated with the bone mineral density of lumbar spine and femoral neck.2.A meta-analysis of the effects of acid-base diet on bone metabolism included 26 studies.The intervention of acid-base diet increased net acid excretion(P=0.003)and urinary calcium excretion(P<0.00001),but had no significant effect on bone metabolism markers and bone mineral density(femoral neck bone mineral density SMD=-0.14(-0.34,0.07),P=0.18;Hip bone mineral density SMD=0.01(-0.21,0.22),P=0.95).On the other hand,alkaline supplement intervention significantly reduced net acid excretion(P<0.00001),urinary calcium excretion(P=0.007),bone resorption marker NTX(SMD=-0.29(-0.48,-0.10),P=0.003)and bone formation marker OC(SMD=-0.23(-0.42,-0.03),P=0.02),but had no significant effect on other serum bone metabolism markers(PTH,IGF-1,BAP,P1NP,CTX);In terms of bone mineral density,alkali supplementation can increase the bone mineral density of femoral neck,lumbar spine and hip(lumbar bone mineral density SMD=1.66(1.33,1.99),P<0.00001;Hip bone mineral density SMD=0.98(0.13,1.83),P=0.02;and femoral neck density was SMD=1.62(1.50,1.74),P<0.00001).Conclusion:1.The results of dietary investigation showed that the acid load of long-term dietary habits had no effect on bone biomarkers and bone mineral density in type 2 diabetic population.2.The results of meta-analysis showed that acidic diet had no effect on bone metabolism,but alkali salt supplementation may be beneficial to bone metabolism. |
