- Masaaki Nagano (Department of Basic Medical Sciences, National Institute for Minamata Disease / MASAAKI_NAGANO@env.go.jp)
Department of Basic Medical Sciences, National Institute for Minamata Disease
Methylmercury (MeHg) exposure during pregnancy is a concern because of its potential health risks to the fetus. Wheat bran (bran), which is the outer layer of wheat kernel, is used as a functional substance in food for specified health uses in Japan. In the present study, we examined the effect of bran on the accumulation and excretion of Hg in mice to evaluate its potential use for reducing the health risk of MeHg. Female BALB/cByJ mice were administered MeHg chloride (4 mg Hg/kg, p.o.). Immediately after administration, the mice were fed a basal diet supplemented with 0%, 5%, or 15% bran, and urine and feces were collected for 14 days. The bran groups had lower total Hg levels in all tissues including the brain compared with the control group, but the effects were significant only in the blood and brain of mice on the 15% bran diet. Urinary Hg excretion in the bran groups was markedly higher than in the control group, although there was no difference in the excretion between the bran groups. Moreover, fecal Hg excretion in the bran groups was substantially higher than in the control group and was dose-dependent. These results suggest that bran intake after MeHg exposure may enhance Hg excretion both in urine and feces and decrease tissue Hg levels. In conclusion, dietary bran might be useful for reducing Hg burden in humans ingested MeHg in food.