The Expanding Role of Omega-3

in the prevention and treatment of chronic disease.

While the health benefits of poly-unsaturated fatty acids (PUFA) omega-3 have been well established for the past three decades, it is only recently, since its appearance as a pharmaceutical agent, that this remarkable fish oil product has received recognition for its
usefulness as a preventive and therapeutic agent in a wide range of clinical disorders.

espite the growing number of clinical studies which clearly demonstrate its multiple health benefi ts, many physicians continue to withhold fish oil from patients, depriving them of a valuable, cost effective, and safe remedy for several conditions that may pose serious and costly risks to their health.
The striking evidence, from well controlled studies, should serve well to encourage health professionals to prescribe, with confidence, this modern healer of many ills, clearly mindful of its efficacy, safety and well tolerability.

An extensive review of the positive healthy benefits of omega-3 prompted Dr Carl Lavie to say, “Physicians are not as familiar with omega-3 studies …as they are with statins…as they should be”, and as a therapeutic agent, omega-3 should be “promoted to clinicians”.


Dr Lavie and his associates reviewed data from 40,000 participants included in retrospective epidemiological studies and large randomised controlled trials, and found compelling evidence for the positive benefits of omega-3, both in primary and secondary prevention of cardiovascular disease, and also for heart failure. The positive effects of omega-3 were observed on total mortality, sudden death, CHD mortality, and cardiovascular mortality.

The first randomised clinical trial (RCT) which demonstrated the benefits of omega-3 was conducted in 1989 at the University
of Wales, known as the Diet and Reinfarction Trial (DART). In this study 2033 men with a history of a previous heart attack
were given a fish diet twice a week, and after 2 years of dietary intervention experienced a 29% reduction in mortality.

A landmark trial, conducted by Italian researchers in 1999, the GISSI-Prevenzione Trial, enrolled 11000 subjects who had previously suffered a heart attack, and gave them 1000mg daily of fish oil in the form of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), together with vitamin E, and reported a dramatic 30% reduction in cardiovascular mortality and a 45% reduction in sudden death at the conclusion of the 4 year study.

Researchers at Harvard University, in 2002, reported that men who had high levels of EPA and DHA in their blood had an 80% lower risk of sudden cardiac death compared to those with low serum levels of these fi sh oils.

More recently, clinical studies have demonstrated that omega 3 lowers serum triglycerides, thereby reducing a signifi cant cardiac risk factor that accompanies the life threatening metabolic syndrome.

Peer reviewed scientific studies demonstrate that omega-3 may alleviate depression, inhibit cancer, boost bone health and reduce the pain of arthritis


Furthermore, the potential complications of unstable vascular wall plaque have been averted in studies which demonstrate a slowing in the rate of plaque growth,6 and also by altering the unhealthy composition of unstable plaque, thereby reducing its propensity to rupture with tragic consequences.

One of the most dramatic benefi ts of omega-3 is its ability to prevent sudden death by suppressing potentially lethal abnormal cardiac arrhythmias in patients who have a history of heart muscle damage. In contrast to prescription medicines omega-3 reduces mortality in heart disease and arryhthmias without increasing mortality risk, often a consequence of a pharmaceutical

The effects of omega-3 were studied in atrial fibrillation, a common heart arryhthmia, in patients recovering from bypass surgery, and recorded as a 54% reduction benefit.

A novel case reporting the successful termination of sustained vetricular tachycardia with 1 gram of omega-3 was reported by clinicians in the Department of Cardiology, Wythenshawe Hospital, UK.

The potential use of omega-3 supplementation as an aid to conventional anti-arrhythmic drugs has been underscored by recent studies that show a suppression of ventricular tachycardia with intra-venous administration of omega-3, 11 and the prevention of fatal arrhythmias in high risk subjects by omega-3 oral supplementation.

The therapeutic benefi t of omega-3 for heart failure patients was tested in a four year study involving 6975 adult patients who were randomised to receive 1 gram of omega-3 daily. Compared with patients receiving placebo, or rosuvastatin 10mg. daily, those receiving omega-3 had a lower death rate and a lower rate of cardio-vascular related hospitalisation than the placebo or statin group.


The broad range of health benefi ts linked to dietary omega-3 extend beyond the positive outcomes for high risk cardiac patients, as well as asymptomatic persons with no history of cardiac disease.

Peer reviewed scientifi c studies demonstrate that omega-3 may alleviate depression, inhibit cancer, boost bone health and reduce the pain of arthritis.

Many of these common disorders have been attributed to the excessively high levels of omega-6 in the typical Western diet.

Omega-6 is a polyunsaturated fatty acid which has inflammatory characteristics, and is ubiquitous in processed foods and commercially prepared consumer products. It has been shown that excessive omega-6 promotes the inflammatory processes
that underlie many common chronic ailments, and is a likely cause for the galloping trend of obesity, diabetes and wide-ranging chronic inflammatory disorders afflicting modern society today.

Dietary omega-3 can neutralise these unwantedinflammatory effects and shift the physiological balance from a pro-inflammatory state to an anti-inflammatory state. Simopoulos has shown how improvements in the omega-6/omega-3 ratio can exert beneficial suppressive effects, with various ratios correlating with improved mortality benefits in cardiovascular disease, colorectal cancer, breast cancer, rheumatoid arthritis and asthma Lower ratios of omega 6/omega 3 in the range of 4:1, or lower, are able to reduce the risk of several chronic disorders highly prevalent in Western society, as well as in developing countries.

Similarly, reductions in the ratio of omega 6 to omega-3 have resulted in significant improvement in the mental health of patients, suffering from a wide range of affective disorders. The anti-inflammatory effects of omega-3 have been shown to enhance functionality of the cerebral neuronal membranes in treated patients, promoting neurite growth and effectively reversing the clinical
symptoms of several psychiatric disorders of affect, like schizophrenia, depression and suicidal ideation.


The expanded use of omega-3 marine oils in preventing and treating certain common cancers has received much attention in recent years and holds much promise for future cancer treatment.

Countries where high consumption of fish is the norm have reportedly lower cancer rates than elsewhere. The potential role of fish oil in cancer protection was tested by researchers as early as 1995.

More recently, evidence has been uncovered for the role omega-3 plays in reprogramming genetic signals during colon cancer initiation.

These findings have been duplicated in studies and reported by other researchers.

17 The protective role of omega-3 may be attributed to its promotion of a healthy balance between omega-6 and omega-3
which limits the inflammatory mechanisms contributing to elevated cancer risk.

Reducing the potential harm caused by pro-inflammatory vegetable oils containing omega-6 was shown in the Singapore Chinese
Healthy Study to reduce breast cancer.

Omega-3 promotes its cancer protecting properties through inhibition of angiogenesis (tumour blood vessel formation) 21 and inhibition of surface receptors on cancer cells that promote cell proliferation. In experimental studies designed to test the ability of omega-3 to suppress cancer growth, scientists discovered a tumour destructing gene (apoptosis) that was expressed by high levels
of omega-3.

Laboratory application of this discovery in experiments with breast cancer cells demonstrated a 25% inhibition of the cancer cells growth by adding EPA and DHA to the cells.23 The benefits of offering supplemental omega-3 to patients receiving chemotherapy for breast cancer were tested by Menendez et al, who successfully demonstrated the enhanced effectiveness of using omega-3 prior to chemotherapy initiation.

The positive immune responses which derive from omega-3 supplementation may also play a supportive role in post-operative healing following cancer surgery. The anti-inflammatory benefits of supplemental omega-3 during and after surgical

A 2002 study reported that men who had high levels of EPA and DHA in their blood had an 80% lower risk of sudden cardiac death compared to those with low serum levels of these fish oils.

recovery are likely to offer exceptional healing benefits for critically ill patients.

The post-operative benefits in respect of healing, enhanced immunity and shorter hospital stays were documented by Ferraras et al (2005) in respect of surgery for gastric cancer,26 and Nilsen et al (1993) in respect of coronary by-pass surgery.


A plethora of studies have thus clearly identified the therapeutic merits of omega-3 (PUFA), providing strong supportive evidence that supplemental omega-3 confers a distinct survival advantage at all levels of risks to human health.


1. J. Am Coll Cardiol, Aug 11, 2009; 54: 585-594.
2. Lancet, 1989 Sept 30;2 (8666) :757-61 (DART).
3. Lancet, 1999 Aug 7 : 354 (9177):447-55 (GISSIPrevenzione).
4. New Eng J Med 2002 April 11, 346; (5) 113-8.
5. Am J Med Sci 2005 Dec; 330 (6): 295-302
6. Cardiovasc Res. 2001 Dec; 52 (3): 361-71
7. Lancet 2003 Feb 8, 361(9356): 477-85.
8. Lancet 1989 Sept 30, 2 (8666): 757-61
9. J Am Coll Cardiol 2005 May 7, 45 (10) 1723-8
10. Europace 2006, 8(5): 330-332: doi:10. 1093.
11. Lancet 2004; 363:1441-2
12. Circulation 2005: 112; 2762-8.
13. Journal Watch 2008: 7 (10).
14. Biomed. Pharmacother. 2002 Oct; 56(8): 365-79.
15. Nature 2006; 440:813-7
16. Int J. Cancer 2003 Nov 1:107 (2):276-82.
17. Cancer Res 2004 Sept 15:64 (18):6797-804.
18. Nutr Cancer 2002, 42 (2):180-5.
19. Br J Cancer 2006 Mar 27:94(6):842-53
20. Br J Cancer 2003 Nov 3:89 99):1686-92.
21. Nutr Cancer 2000:37 (2):119-23.
22. Neoplasia 2006 Feb:8 (2):112-24.
23. Int J Cancer 2005 Nov 10, 117 (3) 340-8.
24. Euro J Cancer Prev. 2005 June:14 (3):263-70.
25. Lipids 2004 Dec; 39(12):1147-61.
26. Clin Nutr 2005 Feb 24, (1):55-65.

Dr Neville Wilson is a Doctor in Maynooth

1 Comment

  1. clare on March 10, 2014 at 8:49 pm

    Dear Dr Neville
    Thank you for letting read up on your page about fish oils i am so happy that i am
    taking them for the past ten years and will continue to do so. I also see you where i the missions what a wonderful doctor you are it was a pleasure meeting you last Saturday.

    Kind regards
    Clare (Heydemann)

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