Effects of rice fiber on mineral balance in young Japanese men

We investigated the effects of rice fiber on mineral balance in 5 healthy young Japanese men. The subjects were given 550g of brown rice daily for 2 weeks and 600g of polished rice for the next 2 weeks. Experimental diets including either rice contained 1.2g of protein per kilogram of body weight and adequate minerals. The K, P, and Mg intake was higher in the first 2-week period than in the second 2-week period because of the supply of brown rice. The weight of the wet and dry feces on the brown-rice diet was twice as much as that on the polished-rice diet. The fecal excretion of K, P, and Mg was greater on the brown-rice diet than on the polished-rice diet. The amounts of K, P, and Mg absorbed were the same on both diets. The apparent absorption rate of K and P on the brown-rice diet was significantly less than that on the polished-rice diet. As the result, balance of absorption and excretion of Na, K, P, Ca, and Mg was similar on both diets. The concentrations of Na, K, Cl, P, Ca, and Mg in plasma were within the normal range on both diets.