| Calcium,magnesium and other mineral elements in water are mainly existing in the form of ions and easily to be absorbed by the body.Drinking water is an important way to supplement the body of minerals.Studies have shown that PRAL(potential renal acid load)of the water with different mineral content is different,will affect the body's acid-base balance,thereby affecting the bone health.Our previous studies have also shown that the decline of mineral content in drinking water may bring bones dysplasia and other health risks.The comparative study of new drinking water(purified water,mineral water,etc.)and bone health has increased in recent years,but less attention has been paid to children and adolescents.The study of osteoporosis has made it clear that it has a direct relationship with the bone growth of children and adolescents.At present,young people tend to eat Western food(high protein,high energy,low intake of fruits and vegetables),long-term will cause acid-base imbalance in the body,leading to chronic metabolic acidosis.In order to explore the relationship between drinking water with acid-base status and bone development in children and adolescents,the following studies were carried out.Firstly,we collected commercially bottled natural mineral water from different regions in China,tested the main mineral contents,and assessed the contribution rate of drinking mineral water to the dietary reference intakes(DRIs)of the population at all ages.Secondly,we investigated the effect of five kinds of drinking water with different mineral content and PRAL value on the acid-base status and bone growth of rats by animal experiment.Thirdly,we constructed a chronic metabolic acidosis rat model,and observed the effect of the five kinds of drinking water on acid-base status and bone growth in chronic metabolic acidosis rats.Research methods:1.Contribution rate of commercial bottled natural mineral water to the residents' Dietary Reference Intakes of calcium and magnesiumDomestic commercially bottled natural mineral water were collected,and the content of soluble total solid(TDS),calcium(Ca),magnesium(Mg)were measured.According to the TDS content,the mineral water can be divided into high(TDS>1500mg/L),medium(TDS,500~1500 mg/L),low salinity(TDS<500mg/L)groups.In accordance with the Chinese residents dietary reference intakes(DRIs),we assessed the contribution to the DRIs of Ca and Mg while consumping the mineral water.2.Effect of five kinds of drinking water on acid-base status and bone growth in developmental ratsOne hundred 3-week-old weaning SD rats were randomly divided into 5 groups after one week of adaptive feeding,given with tap water(TP),natural water(NW),purified water(PW),natural mineral water 1(NMW1)and natural mineral water 2(NMW2),respectively.After the end of the experiment,the levels of bone metabolic markers in serum separated from the abdominal aorta were determined by ELISA.The femurs were collected for micro-CT scanning,three-dimensional reconstruction and biomechanical test.We observed the effects of five kinds of drinking water on the status of acid-base,bone metabolism,bone microstructure and biomechanical properties of rats.3.Effect of five kinds of drinking water and chronic metabolic acidosis on acid-base status and bone growth in ratsAmmonium chloride(0.28 mol/L)was added to the drinking water of the remaining rats in the second part of the subject,and chronic metabolic acidosis rats were constructed.After 3 weeks of feeding,the rats were treated to observe the effects of five kinds of drinking water on acid-base state,bone metabolism,bone microstructure and biomechanical properties of rats.4.Statistical analysis of dataThe data were analyzed by SPSS 20 and Office 2007.According to the characteristics of data distribution,the measured data were expressed as mean ± standard deviation.The correlation between the groups was analyzed by one-way ANOVA.The correlation analysis between the indexes was analyzed by Sperman correlation analysis,and the difference was statistically significant by P <0.05.Results:1.A total of 56 species of bottled natural mineral water were collected.The proportion of high,medium and low salinity was 14%,16% and 70%,respectively.The mineral content in the water varied widely.1 L high salinity mineral water could provide residents of all ages more than an average of 20% of the magnesium requirement.Its contribution to children and adolescent magnesium DRIs was higher,meeting the children under the age of 11 more than 30% of the average magnesium requirements,up to more than 100%.1 L medium salinity mineral water on the population of magnesium DRIs contribution rate was low,the average to meet the requirements of not more than 5%.1 L low salinity mineral water on the population of magnesium DRIs contribution rate was even lower.2.There were no significant differences in dietary,drinking water and acid-base status between the five groups after three months of feeding.The serum osteocalcin content in purified water group was significantly lower than that in tap water group and two natural mineral grous(P<0.05),and there was a trend lower than that of natural water group.The surface area density of bone trabecula in natural and purified water groups was significantly higher than that in two kinds of natural mineral water groups(P<0.05).There was no significant difference in the biomechanical index of the femur between the groups.Correlation analysis showed that osteocalcin and bone surface area density were correlated with most minerals in water,and were strongly correlated with the total dissolved solids,calcium and magnesium.3.After the model of chronic metabolic acidosis was established,the weight of rats decreased with the degree of acidosis.There was no difference between the five kinds of drinking water on diet,drinking water and acid-base status.The levels of deoxypyridinoline in purified water group were significantly lower than those in the other four groups(P<0.05).Bone mineral density and bone volume fraction of natural mineral water 1 group were significantly higher than those of tap water,natural water and purified water(P<0.05).The maximum load,maximum stress of natural water group and purified water group were significantly higher than those of tap water group and natural mineral water 2 group(P<0.05).Conclusions:1.Mineral content varied greatly in commercial bottled natural mineral water.1 L high salinity mineral water could provide calcium and magnesium DRIs over 20% of the average contribution rate,the contribution rate of children and young people was greater(calcium can be as high as 88.33%,magnesium can be more than 100%).Medium salinity mineral water was also an important source of calcium,to meet the average age of about 20% of the residents of the age requirements.Low salinity mineral water on the residents of calcium and magnesium requirements of the contribution rate was low.2.After drinking five kinds of water,the balance of acid and alkali in rats could be maintained.Osteocalcin and trabecular bone strength were sensitive indicators to water quality.The activity and bone turnover of osteoblasts in purified water group were lower than those in tap water group and mineral water groups.The bone microstructures of natural and purified water groups were weaker than those of natural mineral water groups.3.There were no significant differences in the indexes of acid-base status between the groups under the treatment of five drinking water and chronic metabolic acidosis.The bone resorption level of purified water group was significantly lower than that of the other four groups,and the bone formation level was lower than that of the other four groups,which indicated that the bone transformation level was low.The microstructure of the femur in the group of natural mineral water group1 was better than that of the tap water group,the natural water group and the purified water group.The femur of the natural water group and the purified water group were less prone to elastic deformation than the tap water group and the natural mineral water group2.Overall conclusion:The mineral content of commercially available bottled natural mineral water is very different.The high salinity mineral water is an important source of calcium and magnesium for residents,especially children and adolescents.Medium salinity mineral water can also meet the residents about 20 % of the average calcium requirement,while contributing less to magnesium DRIs.Low salinity mineral water on the contribution rate of calcium and magnesium DRIs is low.Animal experiments did not find that the impact of drinking water on acid-base status are different.The natural minerals in the water are closely related to the skeletal developmental indicators.Long-term consumption of purified water was not conducive to the development of rat bone growth,and drinking bicarbonate-rich alkaline natural mineral development of bone was better. |
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