Omega-3 Fatty Acids
June 22 2009     
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Abstract
Omega-3 fatty acids (also known as polyunsaturated fatty acids; PUFAs)
cannot be manufactured in our body; they are considered essential fatty acids.
Omega-3 fatty acids can be found in nut oils and fish such as salmon, tuna and
halibut, they are also available in dietary supplements. Basically, there are three
types of omega 3 fatty acids available in supplements and they are alpha-
linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic
acid (DHA).  ALA is converted to EPA and DHA in our body, once eaten. Studies
suggest that omega-3 fatty acids may offer multiple health benefits, as it reduces
inflammation, and lower the risk of having certain chronic diseases such as heart
disease, cancer and arthritis. Study indicates that omega-3 is important for the
cognitive development of infants. Deficiency of omega-3 fatty acids may lead
to poor memory, dry skin, depression, poor circulation, tiredness and
heart issues. Research studies indicate an proper balance of omega-3 and
omega-6 is important for obtaining the health benefits. A typical American diet
tends to contain 14-25 times more omega-6 fatty acids while a healthy diet
should consist of roughly 2-4 times more omega-6 fatty acid. Excessive amount
of omega-6 fatty acids may lead to higher risk of inflammatory disorders.

The Mediterranean diet contains whole grains, vegetables, fish, olive oil, garlic,
fresh fruits and other food rich in omega-3 fatty acid; it does have a healthier
balance between omega-3 and omega-6 fatty acids.

Health Benefits of Omega-3 Fatty Acids
Research studies suggest that intake of omega-3 fatty acids may benefit people
at risk of various chronic diseases:

Alzheimer’s Disease
The dietary omega-3 fatty acid, docosahexaenoic acid (DHA) has been found
limited amyloid, oxidative damage and synaptic and cognitive deficits in a
transgenic mouse model.  Thus, it may benefit people at risk of Alzheimer’s
disease. [12]

High cholesterol / High blood pressure / Heart disease
High intake of the omega-3 polyunsaturated fatty acids (omega-3PUFA) found in
fish oils (eicosapentaenoic and docosahexaenoic acids) may benefit people at
risk of heart failure. Omega-3 fatty acids have been used as a strategy for
secondary prevention of heart disease in some countries. [4] Fish oil
supplementation lowers plasma triglyceride levels, and omega-3 fatty acid
demonstrate anti-inflammatory effects. [1]

Dietary omega-3 fatty acids decrease the risk of cardiovascular disease. Both
epidemiologic and interventional studies have demonstrated beneficial effects of
omega-3 fatty acids on many cardiovascular disease end points, including all
cardiovascular disease (defined as all coronary artery disease, fatal and
nonfatal myocardial infarction, and stroke combined), all coronary artery
disease, fatal and nonfatal myocardial infarction, stroke, sudden cardiac death,
and all-cause mortality. Much of the evidence comes from studies with fish oil
and fish; to a lesser extent, data relate to plant-derived omega-3 fatty acids. [8]

Flax oil has been used as a vegetative source of omega-3 fatty acid for patients
suffered from ischemic heart disease, hyperlipidemia and high blood pressure
also resulted in positive dynamic of clinical manifestation. [7]

Diabetes
Omega-3 fatty acid may benefit people at risk of Type 2 Diabetes. It has been
observed that the omega-3 fatty acids content was higher and omega-6 fatty
acid content was lower in Icelandic milk when compared with milk from other
Nordic countries. And this may explain the higher supply of omega-3 fatty acids
from milk correlated with low incidence of Type 2 Diabetes and coronary heart
disease mortality in Iceland compared to the other Nordic countries. [13]

In a study of 5103 female nurse diagnosed type 2 diabetes but free of
cardiovascular disease or cancer, higher consumption of fish was also
associated with a significantly lower total mortality. Higher consumption of long-
chain omega-3 fatty acids was associated with a trend toward lower incidence of
coronary heart disease and total mortality among diabetic women. [14]

Weight loss
Cancer cachexia is a distressing weight loss syndrome commonly seen in
advanced cancer patients. It is associated with reduced quality of life and shorter
survival time. In some countries, eicosapentaenoic acid (EPA) has been used to
decrease weight loss, promote weight gain and increase survival times in
patients affected with cancer cachexia. However, Dewey A and co-workers from
University of Portsmouth found no difference of the effect of EPA and placebo on
cachexia syndrome often seen in patients with advanced cancer. [10]

Methotrexate is a common chemotherapy, but it comes with multiple side effects.  
Researchers found soybean/ omega-3 fatty acids -containing diet offered
significant protection against methotrexate toxicity in tumor-bearing rats
compared with the casein-containing diet, completely alleviating methotrexate -
induced anorexia, diarrhea, and weight loss, when ingested as the sole diet and
fed 7 days prior to and 7 days following intraperitoneal methotrexate injection. It
means that omega-3 fatty acid may benefit animals on methotrexate by
alleviating its side effects. [19]

Arthritis
A study of 90 patients suggested that daily supplementation with 2.6 gm of
omega 3 fatty acid may result in significant clinical benefit and may reduce the
need for medication. Of course, the effectiveness is also related to the
conditions of the patients. In the study, dosing of 1.3 g of omega 3 plus 3 g of
olive oil, or 6 g of olive oil did not show the degree of effects. [20]

Osteoporosis
The research on the benefits of omega-3 fatty acid on osteoporosis is very
limited.

Depression
In 2000, Mischoulon D and Fava M. from Massachusetts General Hospital and
Harvard Medical School reported that areas where consumption of omega-3 fatty
acid DHA is high are associated with decreased rates of depression. [6] DHA
deficiency states, such as alcoholism and the postpartum period, also are linked
with depression, on the other hand, individuals with major depression have
marked depletions in omega-3 FAs (especially DHA) in erythrocyte phospholipids
compared with controls. [6]

Eating seafood during pregnancy may have beneficial effects on mental health.
Researchers found lower maternal intake of omega-3 fatty acid from seafood
was associated with high levels of depressive symptoms. [3]

Bipolar disorder
Long-chain omega-3 polyunsaturated fatty acid supplementation of 360 mg per
day eicosapentaenoic acid (EPA) and 1560 mg per day docosahexaenoic acid
(DHA) for 6 weeks was found to improve symptoms of mania and depression in
18 children and adolescents. [5]

Schizophrenia
Decreased omegao-3 fatty acid levels have been reported in patients with
depression, schizophrenia or Alzheimer's disease. Eicosapentaenoic acid (EPA)
has been used to treat several psychiatric and neurodegenerative diseases.
Song C and Zhao S, University of Prince Edward Island, Canada, reported that a
total of six out of seven clinical trials showed EPA significantly improved
depressive symptoms when compared with the placebo-treated populations.
Several investigations also reported that EPA could effectively treat
schizophrenia. [23]

Attention deficit/hyperactivity disorder (ADHD)
A recent study has shown that children with attention-deficit hyperactivity
disorder who used omega-3 fatty acid supplements achieved and maintained
symptom control. The data also supported omega-3 fatty acid safety and
tolerability. [2]

Eating disorders
The research on the benefits of omega-3 fatty acid on osteoporosis is very
limited.

Skin disorders
Dietary omega-3 fatty acids protect against photocarcinogenesis in animals. In a
double-blind randomized study, 42 healthy subjects took 4 g daily of purified
omega-3 fatty acids, eicosapentaenoic acid (EPA), or monounsaturated, oleic
acid (OA), for 3 months. Eicosapentaenoic acid (EPA) was bioavailable; the skin
content at 3 months showing a 8-fold rise from baseline. No consistent pattern of
alteration in basal and UVR-exposed skin content of the antioxidants glutathione,
vitamins E and C or lipid peroxidation, was seen on supplementation. However,
researchers found there was a EPA protection against the acute UVR-induced
genotoxicity. [22]

Inflammatory bowel disease (IBD)
Omega-3 fatty acids have been used to treat joint pain associated with several
inflammatory conditions. Goldberg RJ and Katz J.  from York University, Canada,
conducted trials assessing the pain relieving effects of omega-3 fatty acids in
patients with rheumatoid arthritis or joint pain

secondary to inflammatory bowel disease and dysmenorrhea. Basically, they
found supplementation with omega-3 fatty acids for 3-4 months reduces patient
reported joint pain intensity, minutes of morning stiffness, number of painful
and/or tender joints and NSAID (pain killer) consumption. Omega-3 may benefit
people suffered from joint pain associated with rheumatoid arthritis, inflammatory
bowel disease, and dysmenorrhea. [21]

Asthma
Modification of dietary polyunsaturated fatty acids in early childhood is found to
no benefit in preventing atopy and asthma. [18]

Macular Degeneration
Dietary omega-3 long-chain polyunsaturated fatty acid intake is found to be
associated with a decreased risk of progression from bilateral drusen to central
geographic atrophy (a condition related to age-related macular degeneration).
[17]

Menstrual pain
The research on the benefits of omega-3 fatty acid on menstrual pain is very
limited.

Colon cancer
Human colon carcinoma COLO 205, carrying wild type p53, grown
subcutaneously in athymic mice was inhibited 80% by a diet containing a mixture
of omega-3 fatty acids compared to corn oil diet of omega-6 fatty acids. A study
led by Kato T and Pardini RS, University of Nevada, suggested that DHA is the
primary tumor suppressive omega-3 fatty acid in vivo and in vitro and inhibits
cancer growth by p53 dependent and independent pathways, while the marginal
inhibition by EPA is p53 independent. [11]

Study of 42 patients suffered from colorectal cancer showed postoperative
supplementation of omega-3 fatty acids (a combination of omega-3 fish oil and
soybean oil) may have a favorable effect on the outcomes in colorectal cancer
patients undergoing radical resection by lowering the magnitude of inflammatory
responses and modulating the immune response. [9]

Breast cancer
In a European Community Multicenter Study on Antioxidants, Myocardial
Infarction, and Cancer (EURAMIC), breast cancer ratio of long-chain omega-3
fatty acids to total omega-6 fat was showed an inverse association with breast
cancer in four of five centers. [15]

Prostate cancer
Researchers fed individually caged male severe combined immunodeficiency
mice 20% kcal fat diets with the fat derived either primarily from omega-6 fatty
acids (n-6 group) or with the fat consisting of omega-6 and omega-3 fatty acids
in a ratio of 1:1 (omega-3 group), and injected s.c. with Los Angeles Prostate
Cancer 4 (LAPC-4) cells to the mice.  They found tumor growth rates, final tumor
volumes, and serum prostate-specific antigen levels were reduced in the omega-
3 fatty acid group relative to the omega 6 group. The omega-3 fatty acid group
tumors had decreased proliferation and increased apoptosis. [16]

Dietary Sources
Fish, plant, and nut oils are the primary dietary source of omega-3 fatty acids.
Fish, including salmon, mackerel, halibut, sardines, tuna, and herring are the
major dietary sources of the longer-chain omega-3 fatty acids- eicosapentaenoic
acid (EPA) and docosahexaenoic acid (DHA). Sources of plant-derived omega-3
fatty acids-ALA include flaxseed, flaxseed oil, walnuts, canola oil, and soybean
oil. [8]

Available Forms
Most of the dietary supplements of fish oil are in form of capsules or liquid. The
supplements should be kept refrigerated. Be sure to buy good brands of omega-
3 fatty acid supplements certified with low contents of heavy metals and other
poisonous chemicals.

Serving
The effective doses in most studies for adults are about 2-4 g of fish oil daily.
However, the dosing for fish oil supplements should be based on the amount of
omega-3 fatty acids present in the product, not the total amount of the fish oil.
Read the recommendation on the label and consult with doctor for the dosing.
Side Effects and Warning of Omega-3 Fatty Acid

Omega-3 fatty acids may blood-thinning effects; it may interact with other blood-
thinning agents including herbs, supplements and medications. Omega-3 fatty
acid may also increase fasting blood sugar levels and interact with medications
for diabetes. Diabetic patients must consult with their doctors before taking
omega-3 fatty acid. Common side effects, especially when the users are over-
dosed, include diarrhea, belching, bloating and flatulence.

Supplements of fish oil may come with various impurities or unwanted
ingredients. Fish and fish oil supplements may also contain heavy metals, dioxin
and pesticides. It is wise to use supplements with high purity of the omega-3 fatty
acids.

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