Scientists noticed a curiously low incidence of heart disease
among Greenland Eskimos despite their high-fat diet. The reason?
They were eating fish rich in omega-3 fatty acids. Later studies
confirmed the cardioprotective effect of fish oils while uncovering
other benefits as well.
What Is It
The fat in fish has a form of polyunsaturated fatty acids
called omega-3s. These differ from the polyunsaturated fatty
acids found in vegetable oils (called omega-os), and they
have different effects on the body. (Fish don’t manufacture
such fats but get them from the plankton they eat; the colder
the water, the more omega-3s the plankton contains.) The two
most potent forms of omega-3s, eicosapentaenoic acid (EPA)
and docosahexanoic acid (DHA), are found in abundance in cold-water
fish such as salmon, trout, mackerel, and tuna (including
the canned variety). The sources of a third type of omega-3,
alpha-linolenic acid (ALA), are certain vegetable oils (such
as flaxseed oil) and leafy greens (such as purslane). However,
ALA doesn’t affect the body in the same way that EPA
and DHA do.
What Does It Do
Omega-3s play a key role in a range of vital body processes,
from blood pressure and blood clotting to inflammation and
immunity. They may be useful for preventing or treating many
diseases and disorders.
Common Uses
• Help prevent cardiovascular disease; useful for other
circulatory conditions as well.
• Block disease-related inflammatory responses in the
body.
• May lower blood pressure.
Prevention
Fish oils appear to reduce the risk of heart disease. They
do this in several ways. Most importantly, the presence of
omega-3s makes platelets in the blood less likely to clump
together and form the clots that lead to heart attacks. Next,
omega-3s can reduce triglycerides (blood fats related to cholesterol)
and may lower blood pressure. In addition, recent research
has shown that omega-3s strengthen the heart’s electrical
system, preventing heart-rhythm abnormalities. However, the
strongest evidence for the cardiovascular benefits of fish
oils comes from studies in which the participants ate fish
rather than taking fish oil supplements.
Within the artery walls, omega-3s inhibit inflammation, which
is a factor in plaque buildup As a result, therapeutic doses
of fish oils are one of the few successful ways to prevent
the reblockage of arteries that commonly occurs after angioplasty,
a procedure in which a small balloon is guided through an
artery to a blockage and then is inflated to compress plaque,
widen the vessel, and improve blood flow to the heart. This
effect on blood vessels makes fish oils helpful for Raynaud’s
disease as well.
Additional Benefits
Omega-3s are also effective general anti-inflammatories, useful
for joint problems, lupus, and psoriasis. Studies indicate
that people with rheumatoid arthritis experience less joint
swelling and stiffness, and may even be able to manage on
lower doses of anti-inflammatory drugs, when they take fish
oil supplements. In a yearlong study of people with Crohn’s
disease (a painful type of inflammatory bowel disease), 69%
of those taking enteric-coated fish oil supplements (about
3 grams of fish oils a day) stayed symptom-free, compared
with just 28% of those receiving a placebo. Fish oils may
also help ease menstrual cramps. In addition, omega-3s may
play a role in mental health. Some experts believe there’s
a correlation between the increasing incidence of depression
in the United States and the declining consumption of fish.
And a preliminary study suggested that omega-3 fatty acids
may reduce the severity of schizophrenia by about 25%.
How To Take It
Dosage: For heart disease, Raynaud’s disease,
lupus, and psoriasis:
Take 3,000 mg of fish oils a day. For rheumatoid arthritis:
Take 6,000 mg a day. For inflammatory bowel disease: Take
5,000 mg a day.
Guidelines For Use: Fish oil supplements
are not necessary for heart disease prevention or treatment
if you eat fish at least twice a week. However, supplements
are recommended for rheumatoid arthritis and other inflammatory
conditions. Take capsules with meals. Supplements may be easier
to tolerate if you take them in divided doses; for example,
1,000 mg three times a day, instead of 3,000 mg in one sitting.
Possible Side Effects
Fish oil capsules may cause belching, flatulence, bloating,
nausea, and diarrhea. Very high doses may result in a slightly
fishy body odor. There’s some concern high doses can
lead to internal bleeding. But a study of people with heart
disease who took 8,000 mg of fish oil supplements in addition
to aspirin (an anticoagulant) found no increase in internal
bleeding.
Some studies found high doses of fish oils worsen blood sugar
control in people with diabetes; others have shown no effect.
To be safe, people with diabetes should not take more than
2,000 mg of fish oil supplements a day without the advice
of their doctor.
Individuals with high fasting triglycerides should be careful
if they also have high LDL (“bad”) cholesterol:
Therapeutic doses of fish oils can increase LDL. Garlic supplements,
however, may be the remedy. One study found garlic reversed
the fish oils’ LDL-raising effect. For rheumatoid arthritis
and other inflammatory conditions, eating fish is probably
not sufficient, and fish oil supplements are recommended.
Caution!
• Because omega-3 fatty acids inhibit blood clotting,
consult a doctor before using fish oil supplements if you
have a blood disorder or if you are taking anticoagulant medications.
• Don’t take fish oil supplements two days before
or after surgery.
Shopping Hints
• If you find you can’t tolerate one brand of
fish oil supplements, try another. Side effects vary from
brand to brand.
• Don’t try to save money by buying fish oil supplements
in bulk because they can go rancid very quickly. Always store
fish oil pills in the refrigerator.
• Don’t buy cod liver oil to get your omega-3s.
It contains high amounts of vitamin A and vitamin D, both
of which can be toxic in large doses.
Latest Findings
• According to a preliminary study from the University
of California, Los Angeles, omega-3s may help tight breast
cancer and maintain healthy breast tissue. Animal studies
also indicate that fewer breast tumors develop when fish oils
are part of a healthy diet.
• Fish oils may help prevent colon cancer. Participants
in a recent study who took 4,400 mg of fish oils a day produced
much less of one potent carcinogen associated with colon cancer
than those on a placebo.
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