Efficacy of spirulina extract plus zinc in patients of chronic arsenic poisoning: a randomized placebo-controlled study

Clin Toxicol (Phila). 2006;44(2):135-41. doi: 10.1080/15563650500514400.


Background: Millions of people in Bangladesh, India, Taiwan, and Chile are consuming high concentration of arsenic through drinking water, and thousands of them have already developed chronic arsenic poisoning. There is no specific treatment. Some authors suggest the use of vitamins and minerals for more than 6 months. The present placebo-controlled double-blind study was conducted to evaluate effectiveness of spirulina extract plus zinc in the treatment of chronic arsenic poisoning.

Methods: Forty-one patients of chronic arsenic poisoning were randomly treated orally by either placebo (17 patients) or spirulina extract (250 mg) plus zinc (2 mg) (24 patients) twice daily for 16 weeks. Each patient was supplied with arsenic-safe drinking water by installing a locally made water filter at household level. Effectiveness of spirulina extract plus zinc was evaluated by comparing changes in skin manifestations (clinical scores), arsenic contents in urine and hair, between the placebo- and spirulina extract plus zinc-treated groups.

Results: The concentrations of total arsenic in water (without filtration) of placebo- and spirulina extract plus zinc-treated groups were 150.1 +/- 18.3 and 161.7 +/- 23.9 microg/l, respectively. Intake of these high concentrations of arsenic lead to increased excretion of arsenic in urine (72.1 +/- 14.5 microg/l in placebo-treated group and 78.4 +/- 19.1 microg/l in spirulina plus zinc-treated group). After 2 weeks of using filtered water, there were significant reduction of both arsenic intake through water and urinary arsenic excretion (8.3 +/- 3.6 microg/l and 18.4 +/- 7.3 microg/l in placebo group; 9.7 +/- 5.4 microg/l and 21.6 +/- 5.8 microg/l) in spirulina extract plus zinc-treated group. There was a sharp increase in urinary excretion of arsenic (138 +/- 43.6 microg/l) at 4 weeks following spirulina plus zinc administration and the effect was continued for another 2 weeks. Spirulina extract plus zinc removed 47.1% arsenic from scalp hair. Spirulina extract had no major adverse effect that required physician's attention. The clinical scores (median) for melanosis before and after treatment with placebo was not statistically significant (p > 0.05), whereas in spirulina extract plus zinc-treated group it was statistically significant (p < 0.01). In cases of keratosis, the median clinical scores before and after treatment was not statistically significant (p > 0.05) in placebo-treated group. In spirulina extract plus zinc-treated group, the clinical scores for keratosis before and after treatment was statistically significant (p < 0.05).

Conclusions: Results show that spirulina extract (250 mg) plus zinc (2 mg) twice daily for 16 weeks may be useful for the treatment of chronic arsenic poisoning with melanosis and keratosis.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Arsenic / analysis
  • Arsenic / urine
  • Arsenic Poisoning / complications
  • Arsenic Poisoning / drug therapy*
  • Arsenic Poisoning / urine
  • Bacterial Proteins / administration & dosage
  • Bacterial Proteins / adverse effects
  • Bacterial Proteins / therapeutic use*
  • Bangladesh
  • Catchment Area, Health
  • Chronic Disease
  • Double-Blind Method
  • Drug Compounding
  • Drug Therapy, Combination
  • Female
  • Hair / chemistry
  • Humans
  • Keratosis / drug therapy*
  • Keratosis / etiology
  • Keratosis / urine
  • Male
  • Melanosis / drug therapy*
  • Melanosis / etiology
  • Melanosis / urine
  • Middle Aged
  • Spirulina
  • Zinc / administration & dosage
  • Zinc / adverse effects
  • Zinc / therapeutic use*


  • Bacterial Proteins
  • Zinc
  • Arsenic