- Omega-3
fatty acids are one type of essential fatty acids, special fats that
the body needs as much as it needs vitamins. (The other type is
omega-6 fatty acids). Much of the research into the potential
therapeutic benefits of omega-3 fatty acids began when studies of
the Inuit people found that although their diets contain an enormous
amount of fat from fish, seals and whales, they seldom suffer heart
attacks or develop rheumatoid arthritis. This is presumably because
those sources of fat are very high in omega-3 fatty acids.
Subsequent investigation found that the omega-3 fatty acids found in
fish oil can lower tryglyceride levels, thin the blood, and also
decrease inflammation in various parts of the body. These effects,
as well as others, may explain many of fish oils apparent benefits.
- The diet of modern humans contains
a relative excess of omega-6 fatty acids compared to what was the
case for the bulk of our evolutionary history as a species. Many
people consume essential fatty acid (EFA) supplements rich in
omega-3 fatty acids, such as fish oils, in order to rectify this
imbalance and enjoy a reduced
risk of cardiovascular disease, cognitive decline (e.g. depression,
memory loss), diabetes, immune system function, and more.
- Diets high in omega-3 fatty acids
are associated with a lower
risk of morbidity and mortality from several chronic diseases.
Cold-water fish oil is rich in the omega-3 fatty acids
eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Both
have been found to reduce blood lipid levels in hyperlipidemic
patients and may reduce cardiovascular disease risk (Nestel, 1990;
2000).
- Besides its lipid-lowering effects,
a high intake of omega-3 fatty acids, particularly EPA, is
considered to have favorable effects on platelet aggregation and
bleeding time with respect to risk of coronary heart disease and
thrombotic disease (Dyerberg and Bang 1979, Harris 1989 , Kinsella
et al. 1990 ).
- EPA and DHA seem to reduce
triacylycerol levels by suppressing their formation and stimulating
the oxidation, or 'burning', of fatty acicds in the liver (Madsen et
al., 1999). The latter effect seems to be most strongly associated
with EPA (Madsen et al., 1999).
- Fish oils are known to increase
oxidative stress via stimulation of oxidative processes (e.g.,
peroxismal beta oxidation) (Demoz et al., 1994). Thus, it may be
prudent to consume fish oils in combination with antioxidants, such
as vitamin E and vitamin C. (Demoz et al., 1994).
- Insulin resistance can be produced
by consumption of a diet high in saturated fats. Conversely, feeding
of fats containing EPA and DHA has been found to preserve insulin
sensitivity (Storlien et al., 1987).
- Alpha-Linolenic
acid (abundant in Flax Seed Oil) can be converted into EPA
and EPA can be converted into DHA. This rate of the former is,
however, quite limited and restricted (5-10%)(Indu and Ghafoorunissa,
1992; Emken et al., 1994) possibly due to an overabundance of
linoleic acid in the diet (Emken et al., 1994).
|
- Typical
dosages of fish oil are 3 to 9g (3000 mg. to 9000 mg.) daily, but
this is not the upper limit. In one study, participants ingested 60g
daily.
- The most important omega-3 fatty
acids found in fish oil are called EPA (eicosapentaenoic acid) and
DHA (docosahexaenoic acid). In order to match the dosage used in
several major studies, you should probably take enough fish oil to
supply about 1.8g of EPA (1800mg) and 0.9g of DHA daily (900mg).
- Some manufacturers add vitamin E to
fish oil capsules to keep the oil from becoming rancid. Another
method is to remove all the oxygen from the capsule.
- Flaxseed oil also contains omega-3
fatty acids, although of a different kind. It has been suggested as
a less smelly substitute for fish oil. However, there is no evidence
that it is effective when used for the same therapeutic purposes as
fish oil.
|
- Fish oil
appears to be safe. The most common problem is fishy burps. Because
fish oil has a mild blood-thinning effect, it should not be combined
with powerful blood-thinning medications, such asCoumadin (warfarin)
or heparin, except on a physicians advice. However, contrary to some
reports, fish oil does not seem to cause bleeding problems when it
is taken by itself.
- Also, fish oil does not appear to
raise blood sugar levels in people with diabetes. Nonetheless, if
you have diabetes, you should not take any supplement except on the
advice of a physician.
- Fish oil may temporarily raise the
level of LDL (bad) cholesterol, but this effect seems to be
short-lived, and levels return to normal with continued use.
- If you decide to use cod liver as
your fish oil supplement, make sure you do not exceed the safe
maximum of vitamin A and vitamin D. These vitamins are fat soluble,
which means that excess amounts tend to build up in your body,
possibly reaching toxic levels. Pregnant women should not take more
than 2,667 IU of vitamin A daily because of the risk of birth
defects; 5,000 IU per day is a reasonable upper limit for other
individuals. Look at the bottle label to determine how much vitamin
A you are receiving. (it is less likely that you will get enough
vitamin D to produce toxic effects.)
- These statements have not been
evaluated by the Food and Drug Administration. This product is not
intended to diagnose, treat, cure or prevent any disease.
|