PCB in my fish oil?
Are fish oil supplements safe? The Mateel
Environmental Justice Foundation doesn't think we know enough to
tell. In March, the Foundation filed a lawsuit against
fish oil supplement manufacturers, distributors and retailers,
claiming that they fail to give clear warnings, required by
California law, that some of these products expose consumers to
high levels of polychlorinated biphenyls (PCBs).
The fundamental issue is that PCB levels in fish oil vary a lot;
many are clearly safe, but others are not. And consumers can't
know which is which.
Background - Proposition
65
California's Safe Drinking Water and Toxic
Enforcement Act of 1986, still often known as Proposition 65,
requires the state to publish a list of chemicals known to cause
cancer or reproductive toxicity. There are nearly 900 chemicals
on the list.
Companies must give warnings (e.g., via labelling) when
significant concentrations of these listed chemicals are present
in consumer products they buy or are released to the
environment. Companies are excused from giving such warnings
only if the chemicals are below "safe harbor" concentrations.
These "no significant risk" levels have been published for PCBs
and nearly 300 other chemicals. The Proposition 65 "safe harbor"
concentration for PCBs is 90 nanograms (ng) [0.09 mcg] per day.
Mateel test results
Mateel tested 10 fish oil brands and reported too
much PCB in 3 of them. That is, if taken according to the
recommended labelled dose, three of the ten brands would expose
consumers to more than 90 ng/day. None of the three bore
Proposition 65 warnings.
(It's hard to know what this means for the brand in your
cupboard. Tests of different fish oil brands by other
organizations did not find significant levels of PCB's.)
Mateel's lawsuit asks the Court to compel fish oil vendors to
give Proposition 65 warnings to all current and future
customers, and even to past customers (by tracking them down
individually). Mateel also seeks civil penalties (up to $2500
for each day's exposure of a person to PCB without proper
warnings).
What about Canada?
We have nothing comparable to Proposition 65, and
both the US Food and Drug Administration and Health Canada are
much more tolerant of PCBs in food than California. The FDA's
tolerance limit for PCB in fish is 2 parts per million (2 mcg/g
or 2 mg/kg); Meanwhile, Canada is re-evaluating its tolerance
limit for PCB in foods, including fish (there currently is no
limit).
Compared with California's "safe harbor" level of 90 ng, Health
Canada's tolerance limit for fish oils is 0.10 mcg/kg of human
body weight per day, i.e., 7 mcg/day for the average 70 kg
person. As for the US, it is not within the FDA's
jurisdiction to monitor PCB concentration in fish oil
supplements. Just to keep the units straight, 7
mcg/day equals 7,000 ng, or 78 times more than California's 90
ng. On the other hand, the California "safe harbor" level only
determines what warnings must be given. Health Canada requires
that fish oil supplements be tested for PCBs, and will not
permit the sale in Canada of fish oil supplements that exceed
its tolerance limit. Fish oil supplements bearing a
Natural Product Number (NPN) on the label, should have met
Health Canada's regulatory requirements.
Because Health Canada tolerates levels of PCBs that are so much
higher than in California, it would not be surprising for most
supplements to meet Canadian rules. But this isn't always true.
A recent study examined PCB concentrations in thirty fish and
seal oil supplements from pharmacies, health food stores and
supermarkets in Vancouver, and Internet distributors.
All thirty contained PCBs; median PCB concentrations ranged from
12 ng/g (vegetable and mixed fish oils) to 5260 ng/g (shark
oils). The highest PCB concentrations were found in shark, seal
and menhaden oils; one shark liver oil supplement contained
10,400 ng/g of PCBs. The estimated daily PCB intake (using
the maximum daily dose provided on the label) from these
supplements ranged from 0.896-15,700 ng/day (well above Health
Canada's tolerance limit). Different lots from the same
manufacturer can have wildly different results.
What does it all mean?
Food (and supplements) are our major sources of
exposure to PCBs. PCBs are highly fat soluble and
bioaccumulate, with highest concentrations found at the top of
the food chain. Most people consume less than 0.5 mcg/day of
PCBs; those who eat a lot of fish, wildlife or sea mammals may
get more.
Long-term exposure to high levels of PCBs has been linked to
liver and kidney cancer. Long-term, low level PCB exposure may
affect reproduction and can cause developmental impairment in
newborns and young children.
These data make us very cautious about fish oil supplements. For
one thing, we each weigh less than 70 kg, so 7000 ng/day of PCBs
would have a greater impact on us than on Health Canada's
"average" person. For another thing, because results are so
variable, we can't put much faith in Health Canada's insistence
that fish oil supplements have been tested for PCBs. Maybe one
batch was tested, and passed, but there is probably a different
lot for sale today. PCB concentrations in fish oils depend on
many factors, including fish species, season they were caught,
and geographic location, none of which a consumer is told.
For us, the higher levels of PCBs in shark, seal and menhaden
oils provide an excellent reason not to take them. We are
also very concerned about the environmental impact of fishing
out the oceans, and especially about the environmental harm of
killing sharks. Sharks are a keystone species, the top predator
needed to keep all ocean ecosystems in balance, and we have
wiped most of them out in a generation.
Bottom line
All things considered, we think our mothers were
right: it is better to eat fish than to take supplements: it's
high in protein, low in saturated fat, and contains vitamins,
minerals, and other fats and substances that may promote heart
and overall health. And we need to do much more to protect
the oceans - everything is connected.
Health Canada will eventually let us know whether it is
tightening its tolerance for PCBs in food, but meanwhile we are
going to do what we can to avoid it. As to Mateel's lawsuit,
it's a long shot, based on a small sample size. But if it
provokes better testing of contaminants in supplements, it will
have done some good.
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