Warning
1999-69
May 5, 1999
Toxins may be present in blue-green algae products
OTTAWA - As a precaution, Health Canada is advising consumers that products containing blue-green algae may contain toxins harmful to the liver and, despite recent, unfounded reports that they can be used as a treatment for Attention Deficit Disorder(ADD), these products should not be given to children. Some species of blue-green algae naturally produce toxins known as microcystins. As a result, these toxins may potentially be present as contaminants in products made from blue-green algae. With lower body weights, children are at greater risk of developing serious liver damage should the blue-green algae product be contaminated with microcystins.
In order to determine the extent of this potential problem, Health Canada, through the Office of Natural Health Products, Therapeutic Products Program, and the Food Directorate of the Health Protection Branch, is undertaking a survey of products containing blue-green algae to determine how many are on the market, in what forms they are sold, and the levels of microcystins they contain. This survey is expected to take several months to complete and will provide the additional information required to do a complete risk assessment for blue-green algae products.
There are many products containing blue-green algae sold in Canada, through both retail outlets and direct-sellers. Some of these products are sold in tablet, capsule, or powder forms as food supplements, often as a natural source of minerals. The blue-green algae used in these products may come from natural sources (lakes) or may be cultivated (controlled ponds). A recent, independent sampling done by a researcher at the University of Alberta found several products containing natural-sourced blue-green algae with microcystin levels which exceed those considered safe for daily consumption by both Health Canada and the World Health Organization. Preliminary data from the Department's first round of testing to date has confirmed elevated microcystin levels in some natural-sourced products.
This prelimary work indicates that the potential for contamination may be greater for products made from blue green algae from natural lakes. More analysis is required to determine the full extent of the problem and what manufacturing processes could potentially reduce or eliminate the presence of microcystins.
Microcystins accumulate in the liver and can cause liver damage. Adverse symptoms from long-term use of these products (weeks to months) may not be obvious, but could range from a feeling of general malaise or gastro-intestinal discomfort, to jaundice. Children appear to be more sensitive to these toxic effects, which are more likely to present as acute gastro-intestinal symptoms (nausea, vomitting, diarrhea, etc.).
Due to the potential health risk, consumers who choose to use products containing blue-green algae, especially those from natural lakes, should do so only for short periods of time, as required, and discontinue their use in children. Those with concerns should contact their health care professional for advice.
Health Canada will continue to survey and analyze products made from blue-green algae and, based on the results of its analysis, may take further measures to protect the health of Canadians. Health Canada will also investigate those products which make medicinal claims. The Department has not received any evidence to support the use of blue-green algae as an effective treatment for ADD in children and has not granted authorization for marketing of any blue green algae products for any therapeutic purpose.
Media inquiries:
Bonnie Fox-McIntyre/JoAnne Ford
Health Canada
(613) 957-1588
Public Inquiries:
(613) 957-2991
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