Warning! 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 DeficitDisorder (ADD), these
products should not be given to children. Some species of
blue-green algae naturally produce toxins known as microcystins.
As aresult, 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
This preliminary 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
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, vomiting, 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
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
What are blue-green algae???
What are blue-green algae and why do they contain
naturally-occurring toxins? Blue-green algae, scientifically
known as cyanobacteria, are organisms that form in shallow, warm,
slow moving or still water. Historically, large scale harvesting
of blue-green algae masses was done for research purposes, to
study their properties, and their possible use as
therapeutic and antibiotic agents, as well as their potential as
agricultural commodities. They can also be harvested from outdoor
ponds or natural lakes.
At present, blue-green algae are manufactured and sold in some
pharmacies and health food stores as food supplements, often in
tablet or caplet form. While in the water, some species of
cyanobacteria naturally produce toxins, as a by-product of their
metabolism. The toxins are then stored in the algae
cell-like structure. Toxin concentration levels are affected by
environmental factors such as exposure to sun, depth of the water
and the type of minerals in the water. Levels of the toxins will
fluctuate with environmental changes, and are not predictable.
Without scientific testing, there is no way to detect the
presence or level of toxins in the algae.
Why is Health Canada concerned about blue-green algae tablets and
capsules? The algae that are harvested to manufacture
blue-green algae tablets and capsules may be contaminated with
toxins. Although Health Canada has asked manufacturers to conduct
screening for the toxins, the screening may not be
Recently, a researcher at the University of Alberta conducted an
independent sampling, to test the level of one of the toxins,
Microcystin-LR of natural health products containing blue-green
algae. Of the nine randomly selected samples that were tested,
all showed levels of Microcystin-LR which exceeded the levels
considered safe for daily consumption by both Health Canada and
the World Health Organization.
The findings have been validated by Health Canada, where an
additional six products were also tested and found to contain
varying levels of microcystin, including one significantly high
A more common variety of blue-green algae, Spirulina, has not
been found to contain toxins at harmful levels.
However, more thorough analysis is required, since growing
conditions are generally unknown.
How harmful are the toxins???
As mentioned, the levels of toxins produced and
stored by the algae are unpredictable. The degree of
contamination, and by extension the degree of risk, depends on
when the algae were harvested, what types of algae were present,
and how strong the presence of the toxins were at the time of
harvest. Each batch will have a different level of contamination.
It is therefore difficult to measure the degree of risk in
each product, or even in each batch of the same product. Each
batch would need to be screened. The degree of risk is also
dependent on how much and how long a person is exposed to the
Microcystins are toxins which accumulate in the liver, and can
cause damage over the long term. Because of their comparatively
lower body weight, children are particularly at risk
of liver damage, as well as gastro-intestinal effects, if they
are exposed to the toxin in large amounts over an extended period
of time. At low to moderate levels of exposure, the effects may
be reversible. High levels of exposure to the toxins can have
How are these products regulated???
The majority of products containing blue-green algae are sold as
nutritional supplements, which would be classified as a food. As
a food, they are subject to supervision by Health Canada and the
Canadian Food Inspection Agency, without any specific regulation,
so long as there are no medical claims made, and the products
themselves are safe. If medical claims are made, the products are
then considered to be drugs, subject to the requirements and
regulations on safety, quality and effectiveness that all drugs
undergo in order to be approved for sale in Canada.
What is Health Canada doing about the situation?
As a precautionary measure, consumers have been advised by Health
Canada to discontinue the use of of the products, until evidence
of their safety can be firmly established. At present, Health
Canada is investigating the situation and conducting a
market survey of the Canadian market to determine the exact
nature of the blue-green algae products, as well as how the
products are being used, in order to establish the potential for
exposure to the toxins. Further testing would then be conducted
to analyze the levels present in the products. Depending
on the outcome, follow-up steps will be taken, including possible
Because of the fluctuation of toxin levels in the algae, it would
be important to determine how manufacturers address the potential
hazard by quality control mechanisms or manufacturing processes
and whether these are done consistently.
What about the use of blue green algae as a treatment for
Attention Deficit Disorder in children? Health Canada has not
received any evidence which supports use of blue-green algae as
an effective treatment for Attention Deficit Disorder in
children. Meanwhile, there is a potential risk of children being
exposed to harmful levels of toxins, if they ingest
blue-green algae products, particularly if they ingest the
products for an extended period of time. As a precaution, until
such time as they can be proven safe for use in children, the use
of blue-green algae products should be discontinued in children.
What involvement does the new Office of Natural Health Products
have in this situation? The Office of Natural Health Products was
created specifically to deal with issues like this one, where
questions of safety and quality are raised over products of
natural origin. Once functional, the new Office will
be distinctly capable of navigating the complicated territory of
natural health products, ensuring that the products are
consistently safe, of high quality, and properly labeled.
Although the Office is in the midst of
formation, it will be monitoring the situation closely.
DISCUSSION DOCUMENT: FUNCTIONAL FOODS AND NUTRACEUTICALS
Beginning April 1999, the Nutrition Labelling Policy Review is
entering a nation-wide consultation phase. This Nutrition
Labelling Consultation Kit is designed to help you add your
comments and ultimately, influence the
development of nutrition labelling policy for Canada.
Office of Natural Health Products seeks members for transition
team (3 May 1999)
In a letter to individuals and associations in the Canadian
natural health products sector, Health Canada has issued a call
for experts to serve on a transition team that will help the
Office of Natural Health Products implement the recommendations
of a report of the Standing Committee on Health, Natural Health
Products: A New Vision.