This mouse study screened food materials for reducing absorption of strontium and speeding excretion of cesium. Calcium alginate, laminaran and kelp given with an oral strontium chloride dose lowered strontium in the femur after 24 hours. Coffee and theophylline increased urinary cesium excretion.
Key numbers
- Femur strontium after calcium alginate, laminaran and kelp was reported as 75.4, 80.2 and 92.1 percent of the strontium-only control, each significant at p below 0.05 (Results, p. 2; Fig. 1).
- Strontium chloride dose: 20 mg per 10 mL per kg body weight, given once with each test material (Methods, p. 2).
- ICP-MS limit of quantification for strontium was 0.05 ppb (Methods, p. 2).
- Sodium alginate given as a single dose did not reduce femur strontium, unlike longer dietary feeding in earlier rat work (Results, p. 3).
Methods (brief)
Mice received test materials (alginates, chondroitin sulfate, methyl cellulose, carboxymethyl cellulose, laminaran, freeze-dried kelp) together with strontium chloride; after 24 hours both femurs were digested in nitric acid and strontium measured by ICP-MS with yttrium internal standard. A separate arm measured cesium in 72-hour urine.
Evidence fitness
Supports animal evidence that kelp and its polysaccharide laminaran reduce short-term uptake of stable strontium into bone. It does not establish human efficacy or doses, and the authors note that native bone strontium makes absorbed and pre-existing strontium hard to separate.
Limitations
Single high dose of stable strontium; n = 5 per group; results expressed relative to control without absolute femur concentrations in the text. The phrasing of the percentages leaves some ambiguity, but the figure axis is the femur strontium content rate relative to control. The alginates were bought from the same manufacturer as in the rat alginate study.
Related evidence
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