Effect of Calcium Deficiency on Vitamin B₁₂ Absorption in Rats

Abstract

The influence of calcium on vitamin B₁₂ absorption was investigated in two experiments. In the first we investigated whether B₁₂ malabsorption in rats with biliary diversion through choledochocolic fistula is caused by deficiency of calcium in the small intestine. Calcium concentrations were measured in 10 fistula-and 10 shamoperated rats. Fistula rats had steatorrhea, but the concentration of calcium in the intestinal lumen was increased. In the second experiment we studied the effect of calcium deficiency on B₁₂ absorption. Ten young rats were fed a low-calcium diet and 10 rats a control diet for 4 weeks. Rats on the low-calcium diet had moderately reduced calcium concentration in the blood and in the intestinal juice but unaltered calcium concentration in the cytosol fraction of intestinal mucosal scrapings. The absorption of ⁵⁷CoB₁₂ was unimpaired. This suggests that moderate calcium deficiency does not influence the intestinal absorption of vitamin B₁₂ in the rat.

Key words:

• Bile fistula
• calcium
• rats
• vitamin B₁₂