Sharks are finally getting a warm welcome, thanks to a tough,
rubbery material in their skeletons. Though myriad claims
are made for shark cartilage (most spectacularly that it cures
cancer) its actual effect on disease remains uncertain.
What Is It
Bone forms the framework of the human body. Cartilage does
the same for sharks. This elastic substance, which is softer
than bone but tough and fibrous, is found in people as well:
in the nose, for example, and around the joints. In recent
years, shark cartilage products have become popular worldwide
as a much-hyped remedy for a variety of ills. Harvested from
the head and fins, the cartilage is first cleaned and dried,
and then ground into a fine white powder.
There is considerable debate, however, about whether the supplement
is effective. Solid evidence proving its health benefits lags
significantly behind the glowing testimonials. What’s
more, ecological concern is mounting because shark populations
around the globe appear to be declining rapidly as a result
of overfishing.
What Does It Do
Most researchers greet the claims made for shark cartilage,
from curing cancer and AIDS to healing arthritis and herpes
with skepticism. Some believe that stomach acids digest shark
cartilage, rendering oral supplements ineffective; others
say that even if the body does absorb the cartilage, it has
no demonstrable therapeutic benefits. If shark cartilage does
contain healing ingredients, they are present, at best, only
in very small amounts. Though a few promising studies have
been conducted, additional research is needed to confirm the
effectiveness of this controversial supplement.
Common Uses
• May help fight cancer
• May ease arthritic joint pain, temper the skin lesions
of psoriasis, and help heal cold sores.
Major Benefits
Research dating back to the 1980s sparked interest in this
supplement’s greatest claim to fame: its supposed ability
to battle cancer. Observing that sharks rarely get cancer,
investigators began studying various substances from sharks
and noted that shark cartilage blocks the growth of new blood
vessels. Because blood-vessel growth is essential for tumors
(providing them with an oxygen-rich blood supply that allows
them to survive and grow) the researchers speculated that
the cartilage might fight cancer.
Other theories have been advanced for shark cartilage’s
supposed anticancer effects, and studies in test tubes and
animals suggest that it may have some cancer-fighting benefits.
But what works in the test tube or in animals is often a far
cry from what works in people: Studies have generally failed
to show any significant benefits to people with cancer, even
when shark cartilage was given in very high doses. In fact,
a leading maker of shark cartilage supplements recently admitted
that the substance is “probably not effective”
for cancer.
Additional Benefits
Shark cartilage may have anti-inflammatory properties, however,
that make it useful for treating diseases such as rheumatoid
arthritis and the skin ailment psoriasis. In one study, animals
given a shark cartilage extract experienced less pain and
inflammation from substances that irritate the skin.
Shark cartilage may also ease symptoms of osteoarthritis by
facilitating the delivery of cartilage-building nutrients
to the joints, thereby stimulating cartilage repair while
reducing cartilage breakdown. (Most doctors, however, believe
there are more effective remedies for this purpose, such as
glucosamine.) Because of its possible immune-boosting effects,
the supplement has also been proposed as a treatment for cold
sores and other herpes infections.
How To Take It
Dosage: For disorders such as arthritis: Dosages
of about 2,000 mg of shark cartilage three times a day are
sometimes recommended. For cancer: Practitioners sometimes
recommend doses as high as 1,000 mg per 2.2 pounds of body
weight, which would mean 68,000 mg for someone weighing 150
pounds, a substantial expense for a supplement with unproven
value.
Guidelines For Use: Some researchers suggest
taking the supplement on an empty stomach to minimize exposure
to stomach acids that could destroy any active ingredients.
Because of the large amounts recommended to treat cancer (in
some cases the equivalent of more than 100 capsules a day),
the powder form may be more convenient and inexpensive. However,
those concerned about the fishy taste of many products may
find tablets or capsules the best options.
Possible Side Effects
Even when taken in large amounts, shark cartilage does not
seem to produce any toxic reactions.
Latest Findings
• According to a recent Canadian study, shark cartilage
helps to treat psorias is, a condition that’s marked
by excessive inflammation and growth of new blood vessels
in the skin. To mimic the disease, investigators applied a
chemical irritant to the arms of nine healthy volunteers.
When spread on the skin prior to the application of the irritant,
an extract of shark cartilage effectively curtailed inflammation.
In a follow-up study, the extract also soothed the rashes
of those with psoriasis.
• Though shark cartilage is promoted for its cancer-fighting
properties, the supplement appeared to have no effect in a
recent study conducted by the Cancer Treatment Research Foundation.
Some 60 patients with breast, colon, lung, prostate, and other
advanced cancers took numerous spoonfuls of shark cartilage
three times a day. Over 10 months, the supplement had no discernible
effect on their tumors.
Caution!
Because it may interfere with new blood vessel growth, shark
cartilage should not be used by women who are pregnant or
breast feeding; by anyone who h as suffered a heart attack
or stroke; or by those who have had recent surgery.
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