Two polyol, low digestible carbohydrates improve the apparent absorption of magnesium but not of calcium in healthy young men

The effects of nondigestible oligosaccharides including polyols on intestinal mineral absorption have been studied extensively in animal experiments, but their impact on mineral absorption in humans remains to be established. We investigated the effects of feeding two fermentable, low digestible carbohydrates, on the apparent absorption and balance of calcium (Ca) and magnesium (Mg) in humans. Nine healthy young men were given a control diet with dextrose or polyols, low digestible, fermentable carbohydrates (LHBC, HPFL) for 32-d periods according to a 3 x 3 Latin-square design. During the 18-d period of adaptation, the products were administered gradually in liquid form, up to a maximum of 100 g/d, which was then consumed for 14 d. Ca and Mg levels were measured in diets and in fecal and urine collections to assess apparent mineral absorption and balance. The relative apparent absorptions of Ca and Mg from the control diet were (means [+ or -] SEM) 33.3 [+ or -] 4.6 and 39.8 [+ or -] 2.7%, respectively. Ingestion of both low digestible carbohydrates significantly increased the relative apparent absorption of Mg by about 25%. LHBC, but not HPFL, ingestion increased urinary Mg excretion. Apparent absorption, urinary excretion and balance of Ca were not altered by the ingestion of either low digestible carbohydrate. Ingestion of the low digestible, fermentable carbohydrates, with balanced diets, improved apparent Mg absorption without significant effects on apparent absorption or retention of Ca in healthy young men. Further human studies are therefore still needed to confirm the effects of these products in other populations. KEY WORDS: * calcium * magnesium * fermentation * polyol carbohydrates * mineral balance