Exploration of food materials and components showing the suppressing effect on absorption of strontium and the promoting effect on excretion of cesium in vivo

In March 2011, enormous radioactive materials, mainly 137Cs, 129I, 90Sr and so on were released from the Fukushima Daiichi nuclear power plant after The Great East Japan Earthquake. Tap water, raw milk, vegetables, mushrooms, fruit, nuts, seaweed, marine invertebrates, fish, beef, wild animal meat, brown rice, wheat, tea leaves and other foodstuffs were contaminated by many radionuclides. In particular, when we eat foods contaminated by radioactive materials, it is thought that internal radiation exposure may cause and increase cancer risk. This study was performed to search food materials and components showing an inhibitory effect of strontium absorption and promotive effect of cesium excretion for the reduction of internal radiation exposure. In mice groups given kelp and laminaran, the concentrations of strontium in femurs of mice administrated with strontium chloride were significantly decreased compared with the control group (the only-strontium-chloride treated group). It was suggested that kelp and laminaran may inhibit the gastrointestinal absorption of Sr in vivo. We examined promoting effects of samples showing diuretics on cesium excretion into urine of mice. The Cs excretion ratio into urine was significantly increased by orally administration of coffee and theophylline compared with the only-cesium-chloride administered group. Our results indicate that these food materials and components can be useful tools to prevent internal radiation exposure by cesium and strontium.