In the 1980s, researchers first began noticing the native Inuit (Eskimo)
populations of Greenland and Alaska had a very low occurrence of heart disease
despite a very high-fat diet. The researchers discovered the oils in the deepwater
fish these people consumed (and continue to eat to this day) are rich
in omega-3 polyunsaturated fatty acid. 1,2
These early scientific observations
spawned extensive study and led to the current understanding of how important
fish oil is to heart health.
Questions And Answers
[ Q ]
How can a high-fat diet be good for your heart?
[ A ]
While we generally think of fats as harmful,
there are fats that actually have health benefits. The key is to learn the difference
between the "good" fats and the "bad" ones.
All natural fats are mixtures of different
types of fatty acids. Fatty acids are made up
of carbon atoms comprised of short or long
chains. Each carbon atom has four bonding
sites (similar to imaginary arms) where it
can attach to other atoms. If all binding sites
are attached to hydrogen atoms, the fatty
acid chain is saturated. 3,4
If some binding sites on a carbon atom are
attached to a neighboring carbon (made with
a double bond), the fatty acid chain is unsaturated.
If a fatty acid chain has two or more
double bonds, it is called polyunsaturated. 4,5
Polyunsaturated fatty acids are further
classified by where on the carbon chain the
double bond is located. Linoleic acid is a
polyunsaturated fatty acid with the first
double bond located at the sixth carbon atom
from the omega end; thus, it is an omega-6
fatty acid. 4,5
Linolenic acid, an omega-3 fatty acid, has
its first double bond at the third carbon from
the omega end. Both linoleic and linolenic
fatty acids are essential fatty acids. These
polyunsaturated fatty acids are needed to
sustain life. However, while some fatty acids can be made in the body, these cannot. Both
omega-3 and omega-6 fatty acids must be
consumed in the diet. 4,5
The daily requirement for linoleic fatty
acid is two teaspoons, which is easily met
in the American diet. Linoleic acid is found
in commercial baked goods, prepared foods,
vegetable oils, and margarine. These foods
are abundant and are often consumed in
large amounts. 3
[ Q ]
What's different regarding omega-3 fatty acids?
[ A ]
Omega-3 fatty acids are notably absent
from the American diet. Eicosapen taenoic
acid (EPA), which is derived from linolenic
acid, is the main omega-3 fatty acid in fish.
Docosahexaenoic acid (DHA) is yet another
omega-3 fatty acid found in fish. Both EPA
and DHA are responsible for many impressive
health benefits. 4,5
Fatty acids are an important component
in cell membranes. The cell membrane surrounds
the cell and controls what enters
and exits the cell, protecting the cell. When
fatty acids are saturated with hydrogen
atoms, their chains are rigid and straight.
When cell membranes are composed of saturated
fatty acid chains, they are closely
packed together, creating cell membranes
that are rigid and stiff. 4

Polyunsaturated fatty acids have double
bonds between carbon atoms. These double bonds allow for a flexible, curved structure.
When cell membranes are composed
of polyunsaturated fatty acids, they are
flexible and elastic. Cell membranes that
are flexible are healthier than rigid and
stiff cell membranes. 4,5
Human hearts that are made up of cells
with rigid membranes are more susceptible
to disease. The good news is that hearts
comprised of flexible membranes are
healthier and less likely to develop heart
disease. 5
[ Q ]
What kind of heart problems can fish oil help?
[ A ]
There has been a vast number of clinical
trials and scientific study on the
effect of omega-3 fatty acids and heart
disease. Impressive results have been
noted in lowering the risk of heart attacks
and reducing blood pressure.
One recent study examined the blood
levels of men who lived in Finland, where
fish consumption is fairly high. The men
who had the highest levels of DHA and
EPA had a 44% reduced risk of acute heart
attacks compared to men who had the
lowest levels of these omega-3 fatty acids. 6
The effects of dietary fish and weight
reduction also were examined in a study
of overweight people with high blood
pressure (hypertension). The subjects
were divided into four groups. One group
served as the control and did not receive
treatment. The second group ate a daily
meal of fish that contained 3.65 grams of
omega-3 fatty acids. The third group
went on a weight-reduction diet. And,
the fourth group combined the meal of
daily fish and the weight-reduction diet.
Effects on blood pressure were greatest in
the combined group. Their blood pressures
dropped more than 13 points, much
more than the other groups. 7
Another study of blood pressure and
omega-3 fatty acids determined supplementation
with EPA and DHA was effective
in reducing the blood pressure in individuals
with hypertension.
Blood pressures dropped by
six points during
supplementation, but
returned to baseline after
the study was completed. 8
Omega-3 fatty acids also
been shown to reduce risk factors that
can lead to heart attacks. Two groups of
men living in Portugal were compared.
One group lived in a farming village and
had a low fish intake. The other group
was made up of fishermen who normally
ate a diet high in fish. The group in the
fishing village had lower serum triglyceride
levels and total cholesterol levels,
both heart attack risk factors. 9
Women who have gone through menopause
have a higher risk of heart attacks
than other women. It was determined
that fish oil supplements lowered serum
triglyceride levels and increased high-density
cholesterol levels. The study
concluded fish oil supplementation
reduced the risk of heart attacks by 27%
in postmenopausal women. 10
[ Q ]
Are there any other diseases fish oil might help?
[ A ]
Research has shown fish oil may be
beneficial in combatting several diseases.
Studies have shown omega-3 fatty acids
can reduce the risk of strokes 11, improve
asthma in children 12 , relieve depression 13 ,
and increase the survival time of individuals
with cancer. 14-18
In addition, use of
fish oil supplements improved nutritional
status and increased weight in cancer
patients who have lost a significant amount
of weight. 19-20 There have also been some
impressive results in treating patients with
systemic lupus erythematosus 21 , rheumatoid
arthritis 22 , and multiple sclerosis. 23
[ Q ]
Couldn't eating more fish provide the
same benefits?
[ A ]
Not all species of fish have high levels
of DHA and EPA. Anchovies, salmon,
mackerel, tuna, sardines, and herring are
the best sources of these omega-3 fattyacids.
3 To achieve the most benefit from
eating fish, choices should be made from
this list.
Native Inuit, the peoples that were
initially the focus of the studies on fish
oil, often consume four to five grams of
EPAs daily. This equals one and one-half
to three pounds of fish 3 and is much more
than many people would care to eat.
Thankfully, using a fish oil supplement
can provide these beneficial omega-3
fatty acids in an easy-to-take form.
[ Q ]
I have heard that some fish oil supplements
have artificially increased
the amounts of DHA and EPA in their
fish oil. Does this make the supplements
even more beneficial?
[ A ]
Fish oils may naturally contain DHA
and EPA, or they may be modified to
artificially boost the concentration of
DHA and EPA. Recent Norwegian studies
have demonstrated that modified fish
oils are the least stable and most likely
to become rancid. 24,25
An unstable fish oil can actually cause
an increase in free radical formation in the blood and tissues. Free radicals can
contribute to less flexible blood vessels
that may occur with aging or disease.
Additionally, the overprocessing of fish
oil supplements can result in a loss of
key nutrients and thus decrease their
effectiveness. 24-26
[ Q ]
I have heard that toxins in the waters
from which fish are harvested are also
found in these fish. Aren't the oils that
come from these fish also contaminated?
[ A ]
Purity in fish oil supplements is very
important. Fish oil supplement manufacturers
should be able to provide
documentation of contaminant levels in
their products. Supplements should contain
no detectable dioxin (a widely used toxic
preservative), DDT (a toxic insecticide),
PCB (polychlorinated biphenyls), or heavy
metals such as mercury and lead.
[ Q ]
How can I make sure fish oil capsules will remain fresh?
[ A ]
Choose a fish oil that's not artificially
modified to boost the concentration of
DHA and EPA and that has added natural
antioxidants, including vitamin E, to pre-vent
rancidity and provide superior taste
and efficacy. 27 Refrigerating the container
after opening is often recommended.
Conclusion
Fish oil supplements are a rich source of
the polyunsaturated omega-3 fatty acids,
EPA and DHA. These fatty acids lower
blood pressure, and reduce the risk of
heart attacks and strokes. In addition, EPA
and DHA may benefit individuals with
asthma, multiple sclerosis, systemic lupus
erythematosus, and cancer. Fish oil supplements
provide a natural yet powerful
choice in personal health improvement.
References
1. Kromhout D, Bosschieter EB, de Lezenne Coulander C., et al. The inverse relation between fish consumption
and 20-year mortality from coronary heart disease. N Engl J Med. 1985 May 9; 312( 19): 1205-9.
2. Kromann N, Green A. Epidemiological studies in the Upernavik district, Greenland. Incidence of some
chronic diseases 1950-1974. Acta Med Scand. 1980; 208( 5): 401-6.
3. Pleuss J. Fats. In: Porth CM. Pathophysiology: Concepts of Altered Health States. 5th ed. Philadelphia, Pa:
Lippincott; 1998: 1249.
4. Galperin C, German BJ, Gershwin ME. Omega fatty acids. In: Shils ME, Olson JA, Shine M, Ross AC, Eds.
Modern Nutrition in Health and Disease. 9th ed. Baltimore, Md: Lippincott Williams & Wilkins; 1999: 1346-1347.
5. Fats: saturated and unsaturated. In: Grodner M, Anderson SL, DeYoung S. Foundations and Clinical
Applications of Nutrition: A Nursing Approach. St. Louis, Mo: Mosby; 2000: 118-122.
6. Rissanen T, Voutilainen S, Nyyssonen K, Lakka TA, Salonen JT. Fish oil-derived fatty acids, docosa-hexaenoic
acid and decosapentaenoic acid, and the risk of acute coronary events: the Kuopio ischaemic
heart disease risk factor study. Circulation. 2000; 102: 2677-2679.
7. Boa DQ, Mori TA, Burke V, Puddley IB, Beilin LJ. Effects of dietary fish and weight reduction on ambu-latory
blood pressure in overweight hypertensives. Hypertension. 1998; 32: 710-717.
8. Prisco D, Paniccia R, Bandinelli B, et al. Effect of medium-term supplementation with a moderate dose
of n-3 polyunsaturated fatty acids on blood pressure in mild hypertensive patients. Thromb Res.
1998; 91: 105-112.
9. Torres IC, Mira L, Ornelas CP, Melim A. Study of the effects of dietary fish intake on serum lipids and
lipoproteins in two populations with different dietary habits. Br J Nutr. 2000; 83: 371-379.
10. Stark KD, Park EJ, Maines VA, Holub BJ. Effect of a fish-oil concentrate on serum lipids in postmeno-pausal
women receiving and not receiving hormone replacement therapy in a placebo-controlled,
double-blind trial. Am J Clin Nutr. 2000; 72: 389-394.
11. Iso H, Rexrode KM, Stampfer MJ, et al. Intake of fish and omega-3 fatty acids and risk of stroke in
women. JAMA. 2001; 285: 304-312.
12. Nagakura T, Matsuda S, Shichijyo H, Hata K. Dietary supplementation with fish oil rich in omega-3
polyunsaturated fatty acids in children with bronchial asthma. Eur Respir J. 2000; 16: 861-865.
13. Mischoulon D, Fava M. Docosahexanoic acid and omega-3 fatty acids in depression. Psychiatr Clin North
Am. 2000; 23: 785-794.
14. Bondreau MD, Sohn KH, Rhee SH, Hunt JD, Hwang DH. Suppression of tumor cell growth both in nude
mice and in culture by n-3 polyunsaturated fatty acids: mediation through cyclooxygenase-independent
pathways. Cancer Res. 2001; 61: 1386-1391.
15. Chen ZY, Istfan NW. Docosahexaenoic acid is a potent inducer of apoptosis in HT-29 colon cancer cells.
Prostaglandins Leukot Essent Fatty Acids. 2000; 63: 301-308.
16. Kontogiannea M, Gupta A, Ntanios F, Graham T, Jones P, Meterissian S. Omega-3 fatty acids decrease
endothelial adhesion of human colorectal carcinoma cells. J Surg Res. 2000; 92: 201-205.
17. Gramaglia A, Loi GF, Mongioj V, Baranzio GF. Increased survival in brain metastatic patients treated
with stereotactic radiotherapy, omega three fatty acids and bioflavonoids. Anticancer Res. 1999; 19: 5583-5586.
18. Gogos CA, Ginopoulos P, Salsa B, Apostolidou E, Zoumbos NC, Kalfarentzos F. Dietary omega-3 polyun-saturated
fatty acids plus vitamin E restore immunodeficiency and prolong survival for severely ill
patients with generalized malignancy: a randomized control trial. Cancer. 1998; 82: 395-402.
19. Wigmore SJ, Barber MD, Ross JA, Tisdale MJ, Fearon KC. Effect of oral eicosapentaenoic acid on weight
loss in patients with pancreatic cancer. Nutr Cancer. 2000; 36: 177-184.
20. Barber MD, McMillan DC, Preston T, Ross JA, Fearon KC. Metabolic response to feeding in weight-losing
pancreatic cancer patients and its modulation by a fish-oil enriched nutritional supplement. Clin Sci.
2000; 98: 389-399.
21. Das UN. Beneficial effect of eicosapentaenoic and docosahexaenoic acids in the management of systemic
lupus erythematosus and its relationship to the cytokine network. Prostaglandins Leukot Essent Fatty Acids.
1994; 51: 207-213.
22. Volker D, Fitzgerald P, Major G, Garg M. Efficacy of fish oil concentrate in the treatment of rheumatoid
arthritis. J Rheumatol. 2000; 27: 2343-2346.
23. Nordvik I, Myhr KM, Nyland H, Bjerve KS. Effect of dietary advice and n-3 supplementation in newly
diagnosed MS patients. Acta Neurol Scand. 2000; 102: 143-149.
24. Appleton J, Ackerson A. Health Benefits of a Natural Stable fish Oil. Adv Stand. 1998; 1: 1-2.
25. Saldeen T, Wallin R, Marklinder I. Effects of a Small Dose of Stable Fish Oil Substituted for Margarine in
Bread on Plasma Phospholipid Fatty Acids and Serum Triglycerides. Nutr Res. 1998; 18: 1483-1492.
26. Haglund 0, Luostarinen R, Wallin R, SaIdeen T. Effects of fish oil on triglycerides, cholesterol, lipoprotein (a),
atherogenic index and fibrinogen. Influence of degree of purification of the oil. Nutr Res. 1992; 12: 455-468.
27. VanGoethem B. Enzymatic Therapy Quality Assurance Department. Providing Information from Cardinova.
Stability Studies of Cardinova's Fish Oil Products. March 23, 2001.

Recommend this article to a friend by e-mail here!
Visitor Reviews Of This Article!
Read Visitor Reviews - Write Your Own Review
Back To ATDOnline's Main Page
Back To The Articles Main Page.
Related Articles
Protein Handbook For Beginners: Protein Supplements Vs. Protein Food Sources.
Super Protein: Making Sense Of The Mess!
Whey Protein Product Review: Optimum Nutrition 100% Whey Breaks Through!