Acute effects of soft drink intake on calcium and phosphate metabolism in immature and adult rats.
OBJECTIVE
To test the acute effects of the intake of a phosphoric acid containing soft drink on acid-base balance and on calcium and phosphate metabolism.


METHODS
We studied 14 young adult male Sprague-Dawley rats aged 90 days, and 14 immature animals aged 30 days. Half of the animals in each group were randomly assigned to receive either tap water (controls), or Coca-Cola ad libitum for seven days. After this period, the rats were individually placed in metabolic cages to collect 24 hours urine, and they were exsanguinated by aortic puncture. Immediately, pH and ionized calcium were measured in whole blood. Creatinine, phosphate and total calcium were determined in the urine and plasma. Plasma levels of PTH, 1 alpha, 25 (OH)2 D3 and 25 OH D3 were measured by IRMA and RIA commercial kits.


RESULTS
The animals receiving the soft drink, both adults and immature, developed significant hypercalciuria and hyperphosphaturia. In immature animals, the plasma pH dropped from 7.45 +/- 0.04 to 7.33 +/- 0.02 (p < 0.05) but did not change in adult animals. Ionized calcium dropped significantly from 1.06 +/- 0.04 to 0.80 +/- 0.06 meq/L (p < 0.05) in immature animals but not in the adult animals. Only immature rats developed significant reduction of 1 alpha, 25 (OH)2 D3 and 25 OH D3, whereas only the adult rats developed significant hyperparathyroidism. Immature animals showed more severe derangement of calcium and phosphate metabolism related to soft drink intake.
Amato
D
D
Unidad de Investigación Médica en Enfermedades Nefrológicas, Hospital de Especialidades, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, México, D.F.
Maravilla
A
A
Montoya
C
C
Gaja
O
O
Revilla
C
C
Guerra
R
R
Paniagua
R
R
D000136:Acid-Base Equilibrium / Q000187:drug effects; D000375:Aging / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002253:Carbonated Beverages / Q000009:adverse effects*; D004326:Drinking / Q000187:drug effects; D008297:Male; D010755:Organophosphates / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
D010755:Organophosphates; D002118:Calcium