Omega-3 Fish Oils - Fats That Are Good for Everyone
A Step Toward Optimal Health
even your breasts can benefit from the omega-3s
By Dr. Edward R. Rosick
We are a fat-obsessed society. From the Surgeon General's recently declaring an epidemic of obesity to law firms eyeing multimillion-dollar lawsuits against the sellers of fast (or more accurately, fat) foods, the demonization of fat and fat-rich foods has become a national craze.
The concern about excessive fat in our diet is, of course, justified. Estimates of the proportion of Americans who are overweight or obese range as high as 60%, and that proportion is growing larger (in more ways than one) every year. Obesity contributes to a variety of dangerous conditions, including hypertension (high blood pressure) and diabetes. Even if you don't become obese, daily consumption of too much fat can lead to such deadly problems as cancer and coronary heart disease (CHD); the latter alone causes over 500,000 deaths annually in the United States.
Omega-3 Fatty Acids Are Good for You
At first glance, then, it seems that we would all be healthier if we cut back, or even cut out, our consumption of fatty foods. To paraphrase an old saying, however, first glances can be deceiving. Although certain kinds of fats are definitely harmful to our health, others are essential for good health. Not all fats promote conditions such as heart disease; one need only look at the Inuit of Alaska and northern Canada to see that a fat-rich diet is not necessarily a bad thing.
The Inuit at times subsist on little but coldwater fish such as salmon, whose oils are rich in heart-healthy compounds called omega-3 fatty acids.* Yet even with this extremely high-fat diet, the Inuit have a significantly lower incidence of heart disease and sudden cardiac death than we southerners have. It is now believed that an important reason for this is their consumption of omega-3 fatty acids through a diet rich in coldwater fish. (There are, of course, other reasons too, related to the profound differences in lifestyle between the Inuit and us.)
*Fatty acids are not fats, but they are precursors to fats in our bodies. See the two sidebars for an explanation of fatty acids, good fats, and bad fats.
Researchers have been focusing on the potential health benefits of increasing our consumption of omega-3 fatty acids ("omega-3" refers to a particular structural feature of these molecules, which are polyunsaturated). One of the first large-scale studies on this subject, published in 1997, looked at the effects of fish consumption on coronary heart disease and the incidence of heart attacks in 1822 men.1 It was found that men who consumed diets that were high in coldwater fish, and therefore high in omega-3 fatty acids, had a significantly reduced risk of heart disease or dying from a heart attack.
Omega-3 Fatty Acids Protect Against Heart Disease
Multiple studies have now shown that a diet high in omega-3 fatty acids can significantly decrease triglycerides (the chief constituents of fats and oils), which at high levels have been implicated in CHD.2,3 Besides helping to prevent heart disease, omega-3 fatty acids are also helpful in people who already have it or who have suffered a heart attack. A 1999 study reviewed 11 previous studies that had examined the effects of fish consumption and omega-3 fatty acids on patients with CHD.4 The authors concluded that consumption of fish rich in omega-3 fatty acids was associated with a marked reduction in the progression of CHD.
In our bodies, dietary fatty acids are used as a source of chemical energy for our cells, second only to glucose in importance. Whereas some tissues, such as the brain, depend almost exclusively on glucose as an energy source, other tissues, notably the muscles, use fatty acids in addition to glucose. In fact, the most important muscle of all - the heart - normally gets about 60% of its energy from the metabolism of fatty acids.
Fatty acids that are not immediately used as an energy source are normally converted to fat molecules, which the body stores in its adipose (fatty) tissues. Most fats and oils (oils are just fats in liquid form) consist of molecules called triglycerides. A triglyceride is composed of three fatty acid molecules linked to a molecule of glycerol (which is also a source of chemical energy). When the body needs to tap its fat reserves for energy, the triglycerides are broken down to their constituent fatty acids and glycerol.
Because fatty acids are so intimately related to true fats, they are often loosely referred to as fats. True fats made from omega-3 fatty acids or other beneficial fatty acids are good fats, whereas fats made from potentially harmful fatty acids are bad fats. For more about good fats and bad fats, see the other sidebar on this page.
A study published in 2000 looked at the effects of omega-3 fatty acid supplements on people who had a history of heart attacks and coronary artery bypass surgery.5 In those who had had a heart attack, omega-3 fatty acids appeared to decrease significantly the chances of dying from a second heart attack. Also, there is some evidence that supplementation with omega-3 fatty acids actually decreases the risk of the recurrence of atherosclerotic lesions in people who have had coronary artery bypass surgery.
Finally, a study published this year looked at 11 different studies on omega-3 fatty acids (which are also known as n-3 fatty acids) and concluded that
Omega-3 Fatty Acids Protect Women, Not Just Men
Most of the studies on the effects of omega-3 fatty acids on heart disease have shown a gender bias toward men, presumably because men have traditionally been more susceptible to CHD than women. But women are, alas, catching up with men in this regard, and CHD has replaced cancer as the number one cause of death in American women. Fortunately, a study was conducted recently examining the effects of omega-3 fatty acids on CHD in women.7 Over 80,000 women were monitored over a 16-year period. The results were significant, with the authors concluding that
Omega-3 Fatty Acids Reduce the Risk of Sudden Cardiac Death
It has been estimated that sudden death accounts for at least 50% of all deaths attributed to CHD. The majority of these deaths are thought to be caused by the heart's going into a type of arrhythmia (abnormal heart rhythm) in which the heart beats in an irregular, uncoordinated fashion, with little or no blood being pumped into the arteries.*A heart in this type of life-threatening (and usually fatal) arrhythmia has been likened to a bag of worms - there's a lot of motion, but it's not accomplishing anything.
*Many other cardiac arrhythmias have regular, coordinated, productive heartbeats - typically much slower or faster than normal, however - and some are completely benign, posing no threat to health. Some produce no felt symptoms and thus go unnoticed by the "victim."
Men who consumed diets high in
coldwater fish, and thus high in
omega-3 fatty acids, had a
reduced risk of heart disease or
dying from a heart attack.
Although all cardiac arrhythmias can be treated when they occur, preventing their occurrence can be difficult or even impossible. Some types can be readily prevented through the use of prescription drugs or surgical interventions (such as coronary artery bypass surgery, catheter ablation, or implanted pacemakers), but others are resistant to such treatments.
Fortunately, there is now solid evidence, from three studies, that omega-3 fatty acids may substantially reduce the risk of sudden death from cardiac arrhythmias. The first study critically examined earlier studies of the effects of omega-3 fatty acids on CHD and the risk of sudden cardiac death.8 In the authors' words, "The consensus is that n-3 fatty acids have an important cardioprotective effect in patients with established coronary heart
The authors of the second study stated that the actions of omega-3 fatty acids in preventing sudden cardiac death are clearly related to the way in which they protect the heart from going into arrhythmia, even when a person has severe heart disease.9 In their words, "Two such acids - DHA and EPA - derived largely from marine species, especially fatty fish (such as salmon) are mainly responsible for the protective effects of this group of
As if protecting against sudden
cardiac death and cancer weren't
enough, omega-3 fatty acids
may also help in the
treatment of depression.
The third study, conducted over a 17-year period, examined 278 men who did not have a history of heart disease.10 The authors had hypothesized that omega-3 fatty acids would also provide protection for people without known heart disease. Their conclusion was unequivocal: "The n-3 fatty acids found in fish are strongly associated with a reduced risk of sudden death among men without evidence of prior cardiovascular disease."
Omega-3 Fatty Acids Fight Cancer Too
Besides protecting against the ravages of heart disease, omega-3 fatty acids are helpful in a variety of other debilitating conditions, including cancer and mental illness. Breast cancer in women is thought to be promoted by a diet high in saturated fat, and there have been some intriguing studies showing that omega-3 fatty acids (which are polyunsaturated) may protect against this dread disease.
A 1999 review study looked at the relationship between fat intake and the risk of breast cancer.11 The article concluded that diets high in saturated fats may promote breast cancer, whereas omega-3 fatty acids may protect against it, as well as protecting against colon and prostate cancers. And a study published last year examined over 300 women with and without breast cancer.12 The researchers concluded that omega-3 fatty acids provide dietary protection against the development of this disease.
Omega-3 Fatty Acids Even Fight Depression
As if protecting against sudden cardiac death and cancer weren't enough, omega-3 fatty acids may also help in the treatment of depression. Because populations that consume large amounts of fish containing omega-3 fatty acids are known to have reduced rates of depression, researchers have been looking at the effects of supplementation with these compounds on patients with depression. In 1999, a study showed that people with bipolar disorder (a mental illness in which the patient fluctuates between mania and depression) who were given omega-3 fatty acid supplements improved significantly in terms of both their mania and their depression, compared with patients who were given placebo.13
More recently, another study looked at the effects of giving omega-3 fatty acid supplements to people who were suffering from major depression.14 The results were similar: the patients who received the omega-3 fatty acids had a significant decrease in their depression, compared with those who received placebo.
When people talk about bad and good fats, they're probably referring to saturated fats and unsaturated fats, respectively. Saturated fats, found predominantly in butter, margarine, cheese, and meat (including poultry), are generally solids at room temperature. They are pervasive in our modern diet of processed foods and fast foods and are a major factor in many fat-related health risks, such as atherosclerosis, heart disease, and cancer.
In contrast to saturated fats are monounsaturated and polyunsaturated fats, which are generally liquids (oils) at room temperature. Both of these types - but especially the monounsaturated fats - are thought to be much less harmful to our health then saturated fats, and some are, in fact, essential for good health. Monounsaturated fats are found in high-oleic sunflower oil, olive oil, canola oil, and peanut oil, all of which are considered to be heart-healthy, as cooking oils go. Polyunsaturated fats are major constituents of safflower oil, sunflower oil (except for high-oleic sunflower oil), corn oil, soybean oil, and cottonseed oil; these should be avoided because they are easily oxidized, which is undesirable.
Some polyunsaturated fats, however, are very good indeed, namely, the fish oils known as omega-3 fish oils (to which the omega-3 fatty acids are precursors). The two omega-3 fatty acids of greatest benefit to our health are EPA (eicosapentaenoic acid) and DHA(docosahexaenoic acid). They are essential fatty acids, because they are necessary for many functions of the body, including lipid metabolism, blood pressure regulation, immune system modulation, and brain development. Without the consumption of foods or supplements containing omega-3 fatty acids, optimal health would not be possible.
Omega-3 Fatty Acids Are Good for Everyone
Omega-3 fatty acids are being recognized throughout the medical profession as essential for optimal health. By decreasing the chances of sudden cardiac death, protecting against cancer, and helping to relieve depression, these compounds are proof that some fats are good for you. If you are healthy and want to stay that way, omega-3 fatty acids can help you do it. And if you have coronary heart disease and want to prevent your condition from worsening - or even, perhaps, improve it - omega-3 fatty acids can help. They are good for everyone.
- Daviglus ML, Stamler J, Orencia AJ, et al. Fish consumption and the 30-year risk of fatal myocardial infarction. New Engl J Med 1997;336(15):1046-53.
- Miller M. Current perpectives on the management of hypertriglyceridemia. Am Heart J 2000;140(2):232-40.
- Durrington PN, Bhatnager D, Mackness, MI, et al. Omega-3 fatty acid concentrate decreased triglycerides in coronary heart disease patients treated with simvastatin. Heart 2001;85:544-8.
- Marckmann P, Gronbaek M. Fish consumption and coronary heart disease mortality: a systemic review of prospective cohort studies. Eur J Clin Nutr1999;53(8):585-90.
- von Schacky C. n-3 Fatty acids and the prevention of coronary atherosclerosis. Am J Clin Nutr 2000;71(1):224-7.
- Bucher H, Hengstler P, Schindler C, Meir G. n-3 Polyunsaturated fatty acids in coronary heart disease: a meta-analysis of randomized controlled trials. Am J Med 2002;112:298-304.
- Hu F, Bronner L, Willett W, et al. Fish and omega-3 fatty acid intake and risk of coronary heart disease in women. J Am Med Assoc 2002;287(14):1815-21.
- Lorgeril M, Salen P. Fish and n-3 fatty acids for the prevention and treatment of coronary heart disease: nutrition is not pharmacology. Am J Med 2002;112:316-9.
- Rosenberg I. Fish-food to calm the heart. New Engl J Med 2002;346(15):1102-3.
- Albert C, Campos H, Stampfer M, et al. Blood levels of long-chain n-3 fatty acids and the risk of sudden death. New Engl J Med 2002;346(15): 1113-8.
- Bartsch H, Nair J, Owen RW. Dietary polyunsaturated fatty acids and cancers of the breast and colorectum: emerging evidence for their risk modifiers. Carcinogenesis 1999:20(12): 2209-18.
- Maillard V, Bougnoux P, Ferrari P, et al. n-3 and n-6 Fatty acids in breast cancer adipose tissue and relative risk of breast cancer in a case-control study in Tours, France. Int J Cancer 2002;98:78-83.
- Stoll AL, Severus WE, Freeman MP, et al. Omega-3 fatty acids in bipolar disorder: a preliminary double-blind, placebo-controlled trial. Arch Gen Psychiatry 1999;56(5):407-12.
- Nemets B, Stahl Z, Belmaker RH. Addition of omega-3 fatty acids to maintenance medication treatment for recurrent unipolar depressive disorder. Am J Psychiatry 2002;159(3):477-9.
Dr. Rosick is an attending physician and clinical assistant professor of medicine at Pennsylvania State University, where he specializes in preventive and alternative medicine. He also holds a master’s degree in healthcare administration.