What is shark liver oil ?
Oil derived
from the livers of deep-water sharks shows some promise
in fighting cancer and boosting the immune system. Until
a decade ago, when a growing number of supplement manufacturers
began to take an interest in this nutritional aid, most
shark livers were routinely tossed overboard. Today, several
companies harvest and process the oil from sharks caught
off of Greenland, Norway, Sweden, and other coasts. The
oil is available as a by-product of the commercial fishing
industry; endangered sharks are not allowed to be killed
solely for their oil.
In centuries past, Nordic fishermen used shark liver oil
as a folk remedy to heal wounds and fight the flu. Japanese
seamen called it samedawa, or "cure all." Interestingly,
a new use emerged in the 1950s, when a Swedish doctor
noted that children with leukemia who were fed calf bone
marrow showed some protection against the adverse effects
of radiation. Investigation revealed that the calf marrow’s
therapeutic actions were due to natural immune-boosting
compounds called alkylglycerols, also present in notably
high concentrations in shark liver oil.
Alkylglycerols are naturally found in
much lower levels in the bone marrow, liver, spleen,
and breast milk of mature cows as well as in humans.
Much of the medical interest in shark liver oil--as
a potential complement to standard cancer treatments
and as a natural immune booster--has focused on these
promising compounds.
Shark liver oil also contains squalamine,
a substance which in animal studies has shown some ability
to fight cancers of the breast, lung, brain, and skin
(melanoma specifically) by choking off the tumor's blood
supply; studies in people are under way. Shark liver
oil capsules sometimes also contain generous amounts
of squalene, an antioxidant and bacteria-fighter. Also
present are omega-3 fatty acids (the heart-healthy oils
found in other deep-water fish) and vitamin A.
There are several books about the health
benefits of shark liver oil, all of which basically
extol the virtues of the product. Even though these
books are written by M.D.s and Ph.D.s, in actual fact,
most of the information is based on either patients
relating their successes or limited lab animal studies.
This does not mean the product has no value, but rather
that based on clinical trials in humans, there’s little
hard evidence about the effectiveness of shark liver
oil for any condition. As such, there are no formally
established dosages for shark liver oil, and the WholeHealth
MD recommendations below follow guidelines set forth
in these books.
Note: Shark liver oil is distinct
from another popular supplement that comes from the
same fish: shark cartilage. This purported cancer fighter
was popularized several years ago in the best-selling
book Sharks Don't Get Cancer. Results from studies on
shark cartilage and cancer have been mixed and are ongoing.
Shark liver oil, however, contains potentially therapeutic
substances different than those found in the cartilage.
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