Magnesium absorption in the caecum of rats related to volatile fatty acids production.

Rats were fed with a semi-synthetic diet with or without raw potato starch. (The level of minerals was the same in the two diets.) Because of its special structure raw potato starch was not attacked by rat enzymes. The rats fed on the raw potato starch diet showed increase in caecal weight. The increase in caecal volatile fatty acids (VFA) and decrease in pH were evidence of increased microbial fermentation from the presence of substrate in the caecum. There was also an increase in the arteriovenous difference in VFA and Mg in the caecum. Nutritional balance study was performed and confirmed the better Mg absorption in rats fed on the raw potato starch diet. The lower parts of the digestive tract seem to play an important role in Mg absorption and further studies on the relations between caecal volume, pH, VFA, microbial activity and Mg absorption are necessary.