Nutrients excreted in ileostomy effluents after consumption of mixed diets with beans or potatoes. I. Minerals, protein, fat and energy.

The small intestinal excretion of protein, fat, energy, magnesium, calcium, iron and zinc from two isocaloric diets including either instant bean flakes (174 g/d) or potato flakes (102 g/d) was studied in seven ileostomy subjects. Out of the variable part of the diet all starch and dietary fibre, and about half of the energy was provided from bean flakes or potato flakes, respectively. The small variation in ileostomy excretion between two consecutive days, after one adaptation day, suggests that ileostomy studies can be performed with reasonable precision in 2 days. During the 2-day potato period average daily excretions of gross energy and protein were 236 kcal (988 kJ; 11 per cent of intake) and 13 g (12 per cent), respectively. The excretions were significantly (P less than 0.001) higher during the bean period, 378 kcal (1582 kJ; 16 per cent) and 17 g (15 per cent). Fat intake and excretion were not different. After making allowance for dietary fibre, the apparent nutrient energy digestibilities were over 90 per cent, with only 43 kcal (180 kJ; 2 per cent) difference between the two periods. Apparent absorption of magnesium was lower during the bean period, 7 per cent compared to 25 per cent (P less than 0.02). The study has thus shown that only slightly less apparent small intestinal absorption occurs from a diet with bean flakes compared to potato flakes, so the nutritional consequences of beans on other nutrients seem to be small.