Bioavailability of magnesium contained in purple laver (Asakusa-Nori) by rats with scarce magnesium, being evaluated from serum magnesium, kidney calcification, and bone magnesium contents.

An experiment was designed to evaluate the bioavailability of purple laver (Asakusa-Nori, Porphyra tenera Kjellman) magnesium (Mg) in Mg-scarcity Fischer 344 male rats from serum Mg level, kidney calcification and bone Mg contents. Male rats of 4 weeks of age were divided into four groups of six rats. The four groups were control (20SC), Mg-restricted (-Mg20SC), -Mg20SC plus purple laver (-Mg20SCP), and 20SC plus purple laver (20SCP) group respectively. To -Mg20SC, 1/10 Mg of the 20SC diet was added. -Mg20SCP diet purple laver as a Mg source. 20SCP diet was designed to contain double amount of Mg. After a 3-week experimental period, rats were decapitated. Blood serum, right kidney, and right femur were collected and Mg, calcium (Ca), phosphorus (P) were determined. Serum Mg concentration of the -Mg20SC was 1/3 of the 20SC, indicating apparent hypomagnesemia. Serum P also showed lowered concentration. On the other hand, the serum Ca indicated higher value than the other groups, indicating hypercalcemia. Addition of purple laver to -Mg20SC diet resulted in a normal serum Mg, Ca, and P level. The Mg-scarcity (-Mg20SC) rats accumulated much amount of kidney Ca. Whereas, there was no significant difference in kidney Ca between control (20SC) group and purple laver-supplemented (-Mg20SCP) rat group. The -Mg20SC rats showed lowered ash content and reduced Mg and P concentrations in the femur. Purple laver supplementation increased the ash, Mg, and P. All of the results indicated that the purple laver Mg was used as a Mg source.(ABSTRACT TRUNCATED AT 250 WORDS)