The bioavailability of magnesium from Wakame (Undaria pinnatifida) and Hijiki (Hijikia fusiforme) and the effect of alginic acid on magnesium utilization of rats

摘要

The bioavailability of Mg from Wakame and Hijiki, and the effects of alginic acid on absorption of dietary Mg were examined in 5 groups of rats fed a control, Wakame, Hijiki, AW (containing the same amount of alginate as in the Wakame) and AH (containing the same amount of alginate as in the Hijiki) diets, and rats fed a low Mg diet (LMg) (twentieth amount of Mg in the original mineral mixture as the control). Food intake and body weight gain were decreased with the addition of sodium alginate to the diets. A large amount of Ca accumulated only in the kidneys of the rats fed the LMg diet. Serum Mg decreased only in the LMg group. Mg content in the defatted left femurs did not differ between the control and Wakame-fed rats and also among those fedon the Wakame, Hijiki and AW diets. The breaking force of the right femurs did not differ between the groups except in the LMg group. The ratio of apparent Mg absorption (%) of the control, LMg, Wakame, Hijiki, AW and AH groups was 82.2, 72.7, 66.9, 50.8, 69.3 and 54.2 in the first experimental period, and 75.3, 52.1, 57.7, 46.9, 62.6 and 60.5 in the second experimental period, respectively. It was clear that the bioavailability of Mg in the Wakame-fed rats was higher than in those eating the Hijiki. Large amounts of sodium alginate lowered Mg absorption from the diet.