engleski

Sodium and potassium effects on bone mass in rats

High sodium intake may reduce calcium retention by increasing urinary calcium loss while alkaline potassium salts have opposite effects. Therefore, theoretically, increased potassium intake may protect bone mass in individuals with high sodium intake. We evaluated effects of both high sodium and high potassium intake on bone mass in growing rats. Six-week-old female Wistar rats were randomly assigned into four groups according to the drinking solution (compounds were dissolved in deionized water): control (deionized water only), 1.2% sodium chloride, 1.2% potassium citrate, and 1.2% sodium chloride plus 1.2% potassium citrate. All rats were fed on marginal (0.33%) calcium in diet. After 10-week exposure, we evaluated bone mineral density (BMD) and content (BMC) of the whole body and 24-h urinary calcium, potassium, sodium, magnesium, and phosphorus excretion. Subsequently, we killed all animals and removed right femurs to assess bone weights and bone calcium. Body weight gain did not differ among groups. Sodium-loaded rats drank more and had greater urine volume. High sodium chloride intake increased urinary calcium, sodium, potassium, phosphorus, and magnesium excretion. Potassium supplementation increased urinary potassium excretion and decreased urinary excretion of calcium, phosphorus, and magnesium. Neither sodium nor potassium intake affected total body BMD and BMC or femur weights. However, both femoral calcium content and concentration were lower in sodium-loaded rats and potassium supplementation diminished these sodium effects. Potassium supplementation itself had no effect on bone calcium compared to controls. In conclusion, under our experimental conditions, we found that increased potassium intake protects bone mass in sodium-loaded growing rats. Therefore, increased potassium intake may have beneficial effects on bones during growth and development in children consuming higher sodium in diet.

sodium; potassium; bone mass; rats

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