Suppression of radioactive strontium absorption by sodium alginate in animals and human subjects

The effect of 23 sodium alginate preparations from different species of algae (Sargassum sp.) and kelp (Laminaria sp.) on reducing the absorption of strontium was studied in detail. A pilot production procedure has been established. Na alginate from S. siliquastrum was proven to be a potent agent for reducing Sr absorption, with high efficiency and virtually no toxicity. It reduced the body burden of strontium 3.3-4.2 fold in rats. Strontium absorption in human subjects was reduced by 78% (+/- 8.9) or completely suppressed the increase of serum Sr at 2 h after ingestion of stable Sr in volunteers and decrease 24 h urine Sr to similar extent. No undesirable effects on gastrointestinal function was observed nor were Ca, Fe, Cu and Zn metabolism changed, both in the animal experiments and in human. It was concluded that alginate preparations derived from Sargassum species are a suitable antidote against radiostrontium absorption on a long-term basis, when added to bread at a 6% level. In cases of emergency, an alginate syrup preparation appears to be more suitable because of its rapid action.