All told, omega-3-containing fish oil remains the biggest bang for your buck …

A new study has made a strong case that the regular use of omega-3 fish oil supplements by women may reduce the risk for breast cancer.¹ In this study, involving more than 35,000 postmenopausal women (ages 50 to 76 years), researchers at the Fred Hutchinson Cancer Research Center in Seattle found that those who said that they habitually used fish oil supplements were significantly less likely to develop invasive ductal breast cancer, the most common form of this cancer. Led by Emily White, Ph.D., the researchers asked women who did not have a history of breast cancer to complete a 24-page questionnaire about their use of nonvitamin, nonmineral “specialty” supplements in the study which was aptly named the Vitamins and Lifestyle (VITAL) cohort study. The woman, who frequently took omega-3 supplements over a span of six years, had a 32% lower incidence of breast cancer.

Despite known and suspected risk factors for breast cancer in some of the women, the lower risk was still seen. These risk factors included older age, obesity, heavy drinking, and sedentary lifestyle. Unfortunately, the study was limited because it was an “observational” study, one in which researchers examine the relationship between “exposure,” such as supplement use, and a disease risk. The problem with studies of this type, according to Dr. White, is that, “It cannot show cause-and-effect.” Nevertheless, Dr. White said that it is too soon to recommend that postmenopausal women start taking fish oil for the sake of lowering breast cancer risk. Haven’t we heard this before?

Should Women Wait?

Dr. White also announced that recommendations may follow new evidence from clinical trials that are forthcoming, and specifically a Harvard University trial, just now underway, that will examine the effects of fish oil and vitamin supplements on the risks for cancer, heart disease, and stroke in older men and women. In that study, researchers aim to enroll 20,000 U.S. adults, who will be randomly assigned to take one or both supplements, or placebo pills to serve as a comparison. This type of random double-blind placebo-controlled study is considered the “gold standard” for demonstrating cause-and-effect. But how long will women need to wait, and what will happen during the wait?

Millions of Preventable Deaths

Fish oil, a rich source of omega-3 fatty acids, has been found to be beneficial for heart health, and much more. A number of clinical trials have shown that fish oil may help lower triglycerides (a type of blood fat), high blood pressure and the risk of heart attack in people with established heart disease. High fish consumption has also been linked to a lower risk of developing heart disease. In addition, fish oil is very safe.

Consequently, some experts recommend that adults should consume fish at least twice a week, preferably fish like salmon, mackerel, and trout that contain high omega-3 levels. However, in the White study, 83% of fish oil users took fish oil ≥ 4 times a week, 60% of whom were daily users. The researchers concluded that the participants who used fish oil supplements probably consumed the equivalent of 33–77% of a serving of high omega-3 containing fish each day that the supplement was used. That’s higher than the general recommendation.

According to another recent study, published by the Harvard School of Public Health, the top six preventable risks in the average American lifestyle alone kill more than one million people each year, with omega-3 deficiency now the sixth most significant factor.² Out of the one million preventable deaths (which may be as high as 1.6 million), nearly 100,000 deaths are attributed to health problems related to this insufficient dietary intake, making it a more significant issue than an excessive consumption of trans-fats. That’s amazing! So if we have to wait until the results of the “gold standard” study come in, perhaps 6–8 years, 600,000 to 800,000 individuals will die of preventable deaths. Is there any evidence that the regular use of fish oil supplements is dangerous? Not really. Fish oil is generally considered safe when taken as directed, although it can have side effects, such as stomach upset, heartburn and, at higher doses, bleeding. But when weighed against the upshot of cancer prevention, these are contextually minor.

Fish Oil Lowers Breast Cancer Risk by One-Third

Back to the White et al study, after gathering baseline data, the researchers followed the women for an average of six years to record any diagnoses of breast cancer. Over that period, 880 women were diagnosed with the disease, and of that number, 5 percent had reported regularly using fish oil when the study began. Among women who remained cancer-free, 8 percent had been current fish oil users at the outset. Thus, fish oil use at the start of the study was related to a one-third lower risk of developing breast cancer compared with non-use. These calculations were deconfounded for age, weight, diet and exercise habits, and family history of breast cancer.

Fish oil is known to have anti-inflammatory effects, and chronic inflammation in the body is thought to play a role in the growth and spread of cancer cells. Thus, it is biologically feasible that fish oil could have had a causal effect. In a written statement, noted researcher, Dr. Edward Giovannucci, of the Harvard School of Public Health in Boston, comments, “It is very rare that a single study should be used to make a broad recommendation. … Over a period of time, as the studies confirm each other, we can start to make recommendations.” I’m willing to bet that Dr. Giovanucci takes omega-3 supplements. In fact, when earlier large-scale studies on vitamin E were first published finding positive correlations, despite the usual cautionary notices to wait until there was complete certainty, several Harvard researchers involved in these studies admitted that they were already taking vitamin E supplements. Amazing!

Omega-3s, the Swiss Army Knife of Nutrients

Let’s examine some of the many benefits attributed to omega-3 fish oil.

All-cause mortality: Researchers from Tufts-New England Medical Center report increased consumption of omega-3s from fish or supplements (EPA & DHA, but not ALA) reduces the rates of all-cause mortality, cardiac and sudden death, and possibly stroke.³

Alzheimer’s disease: More than a dozen studies have reported that reduced levels or intake of omega-3s or fish consumption is associated with increased risk for age-related cognitive decline or dementia such as Alzheimer’s disease, reports the Department of Medicine at the University of California, Los Angeles.⁴ Results also suggest that DHA may be more effective if it is begun early or used in conjunction with antioxidants.

Arthritis: Fish oil has been shown to slow the development of arthritis in an animal model and to reduce disease severity. Clinical trials have demonstrated rheumatoid arthritis patients who take fish oil have less pain, less morning stiffness and require fewer non-steroidal anti-inflammatory drugs.⁵

Arrhythmia prevention: Numerous epidemiological studies, case-control series, and randomized trials have demonstrated the ability of fish oil to reduce major cardiovascular events, particularly sudden cardiac death and all-cause mortality. Any patient with documented coronary heart disease and those with risk factors for sudden cardiac death—such as left ventricular dysfunction, left ventricular hypertrophy, prior myocardial infarction, or high-grade ventricular dysrhythmias—should consider fish oil supplementation.⁶

Atopic eczema: DHA intake has been associated with a reduced prevalence of atopic eczema in pregnant Japanese females.⁷

Blood pressures and resting heart rates: Higher levels of DHA in circulating blood biomarkers have been connected with reduced risks for the progression of coronary atherosclerosis and lowered risk from sudden cardiac death. Controlled clinical trials have also indicated the potential for DHA supplementation to have moderate beneficial effects on other cardiovascular disease risk factors, including blood pressures and resting heart rates.⁸

Breast cancer: In a case controlled study, the National Cancer Center Hospital found that a high intake of fatty fish was associated with a reduced risk for breast cancer in both pre- and postmenopausal women.⁹

Cardiovascular disease: A study from the Institute of Endocrinology and Nutrition, at the University of Valladolid, Spain, suggests that a high dietary intake of omega-3s may offer a protective effect against atherosclerotic disease (hardening of the arteries) and reduce serum triglycerides levels. In this study, omega-3 supplementation improved lipid profile and inflammatory markers in patients with diabetes mellitus type 2 and hypertriglyceridemia.¹⁰

Chronic depressive symptoms: From a recent study in Nutrition, data suggest that a higher dietary intake of long-chain omega-3 polyunsaturated acids may lead to a decreased risk of depressive disorders. Findings suggest that dietary intakes of fish and long-chain omega-3 fatty acids help prevent chronic depressive symptoms in women.¹¹

Cognitive decline slow-down: Fish consumption may be associated with slower cognitive decline with age, reports the Rush Institute for Healthy Aging, Rush University Medical Center in Chicago.¹²

Cognitive function impairment: Researchers from the Netherlands report that fatty fish and marine omega-3 consumption was associated with a reduced risk of impaired cognitive function in a middle-aged population, while an intake of cholesterol and saturated fat was associated with an increased risk of impaired cognitive function.¹³

Depression: Depressive disorders with idiopathic (unexplained) symptoms are the most common form of depression. Deficiency of the omega-3 fatty acid DHA is associated with dysfunctions of neuronal membrane stability and transmission of serotonin, norepinephrine and dopamine, which might connect to mood and cognitive dysfunction in depression.¹⁴

Fatal coronary heart disease and sudden cardiac death: Large observational studies, randomized clinical trials, and experimental studies have evaluated the effects of fish and omega-3 fatty acid consumption on fatal coronary heart disease (CHD) and sudden cardiac death (SCD). The Division of Cardiovascular Medicine, Brigham and Women’s Hospital, Harvard Medical School concludes that because more than one-half of all CHD deaths and two-thirds of SCD occur among individuals without recognized heart disease, modest consumption of fish or fish oil—together with smoking cessation and regular moderate physical activity—should be among the first-line treatments for prevention of CHD death and SCD.¹⁵

General health: The DHA component of omega-3s has been found to protect against heart disease and might be beneficial in rheumatoid arthritis, inflammatory bowel diseases, childhood learning and behavior, and adult psychiatric and neurodegenerative illnesses. DHA has an important structural role in the eye and brain, and its supply early in life is known to be of vital importance. Because of these recognized health improvements brought about by DHA, recommendations have been made to increase its intake, especially because most individuals living in Western countries eat low amounts of foods containing DHA.¹⁶

General health: A comprehensive review of omega-3 finds that omega-3 fatty acids are essential in human health and disease and reduce death and poor health from heart problems. Dietary supplementation may also benefit patients with blood lipid abnormalities, atherosclerosis, hypertension, diabetes mellitus, metabolic syndrome (pre-diabetes), obesity, inflammatory diseases, neurological/neuropsychiatric disorders and eye diseases. Consumption of omega-3s during pregnancy reduces the risk of premature birth and improves intellectual development of the fetus.¹⁷

Heart attack: Higher blood levels of omega-3s were associated with a decreased risk of a heart attack (myocardial infarction.)¹⁸

Heart failure sudden death: UK researchers report that dietary omega-3s reduce the risk of sudden death. These fatty acids also have potent anti-inflammatory effects, and may prevent clots and heart vessel blockage. The use of omega-3s should be considered as part of a comprehensive secondary prevention strategy post-myocardial infarction.¹⁹

Hypertension: Omega-3 polyunsaturated fatty acids from fish and fish oils appear to protect against coronary heart disease; their dietary intake is in fact inversely associated with cardiovascular disease morbidity/mortality in population studies. Recent evidence suggests that at least a part of this protective effect is mediated by a relatively small but significant decrease in blood pressure (BP) level.²⁰

Inflammation: In a report from the University of Oklahoma, researchers described how dietary supplementation of omega-3 fatty acids generates potent mediators that control inflammation that is a key factor leading to colon cancer.²¹

Insulin resistance: Omega-3s have shown clinical significance in the prevention and reversal of insulin resistance reports researchers from University of California, Davis.²²

Joint pain: Omega-3 polyunsaturated fatty acids have been used to treat joint pain associated with several inflammatory conditions. The results, published in the journal Pain suggest that omega-3s are an attractive adjunctive treatment for joint pain associated with rheumatoid arthritis, inflammatory bowel disease, and dysmenorrhea.²³

Kidney disease: A high dietary intake of omega-3s reduces diabetic renal (kidney) disease, according to researchers at the University of Mississippi Medical Center.²⁴

Macular degeneration: A study from the Archives of Ophthalmology reports a diet low in trans-unsaturated fat and rich in omega-3 fatty acids and olive oil may reduce the risk of age-related macular degeneration (AMD).²⁵

Macular degeneration: A study from the Centre for Vision Research in Australia provides evidence of protection against early AMD from regularly eating fish, greater consumption of omega-3 polyunsaturated fatty acids, and low intakes of foods rich in linoleic acid.²⁶

Macular degeneration: A large study from the National Eye Institute reports that dietary lipid intake is a modifiable factor that may influence the likelihood of developing sight-threatening forms of AMD. The findings suggest that dietary omega-3 long-chain polyunsaturated fatty acid intake is associated with a decreased risk of progression of macular degeneration.²⁷

Metabolic syndrome: Omega-3 consumption significantly benefits metabolic syndrome (pre-diabetes) and type 2 diabetes primarily with their impact on blood pressure, glucose control, and inflammation. Omega-3s reduce conversion of metabolic syndrome to type 2 diabetes and reduce death rates due to metabolic syndrome and type 2 diabetes.²⁸

Metastatic cancer: Eating fish more than three times per week was associated with a reduced risk of prostate cancer, and the strongest association was for metastatic cancer, compared with infrequent consumption (less than twice per month). Each additional daily intake of 0.5 g of marine fatty acid from food was associated with a 24% decreased risk of metastatic cancer.²⁹

Neuropsychiatric disorders: Epidemiological research indicates that omega-3s may modify the risk for certain neuropsychiatric disorders. Supporting these, the researhers note that decreased blood levels of omega-3 fatty acids have been associated with several neuropsychiatric conditions, including attention deficit hyperactivity disorder, Alzheimer’s disease, schizophrenia, and depression.³⁰

Prostate protection: Researchers at the University of California, San Francisco found that dietary DHA appears protective against aggressive prostate cancer.³¹

Prostate cancer risk reduction: Omega-3s inhibit prostate tumor growth and higher intakes may reduce the risk of total and advanced prostate cancer, reports the National Cancer Institute, National Institutes of Health.³²

Psoriasis: Psoriasis is an inherited inflammatory skin disease influenced by environmental factors. High intake of omega-3s show beneficial effects, along with fasting, low-calorie and vegetarian diets.³³

Rheumatoid arthritis: A recent report finds that fish oil rich in omega-3 fatty acids, especially EPA and DHA, protects against inflammation-induced bone loss in chronic inflammatory diseases like rheumatoid arthritis, periodontitis, and osteoporosis.³⁴

Stroke: From JAMA, higher consumption of fish and omega-3 polyunsaturated fatty acids is associated with a reduced risk of thrombotic infarction, primarily among women who do not take aspirin regularly, but is not related to risk of hemorrhagic stroke.³⁵

Stroke: In the latest and largest stroke study, the Nurses Health Study, a significant decrease in the risk of thrombotic stroke was observed among women who ate fish at least two times per week compared with women who ate fish less than once per month, after adjustment for age, smoking, and other cardiovascular risk factors.³⁶ These data support the hypothesis that consumption of fish several times per week reduces the risk of thrombotic stroke, but does not increase the risk of hemorrhagic stroke.

Sudden cardiac death: During the past 25 years, the cardiovascular effects of omega-3s have been the subject of increasing investigation. In the late 1970s, epidemiological studies revealed that Greenland Inuits had substantially fewer heart attacks compared with Western control subjects. These observations generated more than 4,500 studies to explore this and other effects of omega-3 fatty acids on human metabolism and health. From epidemiology to cell culture and animal studies to randomized controlled trials, the cardioprotective effects of omega-3 fatty acids are becoming widely recognized. A recent study of 11,324 patients showed a 45% decrease in risk of sudden cardiac death and a 20% reduction in all-cause mortality in the group taking 850 mg/day of omega-3 fatty acids.³⁷

Which is Better: Eating Fish or Taking Fish Oil Supplements?

The American Journal of Cardiology reported that large amounts of fish consumption may result in adverse experiences due to the potential presence of environmental toxins such as mercury, polychlorinated biphenyls, dioxins, and other contaminants. The risks of exposure to environmental toxins and hypervitaminosis with fish consumption are substantially reduced through purification processes used to develop selected concentrated fish oil supplements.³⁸

In another study, the consumption of equal amounts of EPA and DHA from oily fish consumed on a weekly basis or from fish-oil capsules on a daily basis is equally effective at enriching blood lipids with omega-3s, reports Saint Luke’s Mid America Heart Institute, Kansas City, Missouri.³⁹

How Much to Take?

Consolidating dose/benefit relationships has enabled us to conclude that the optimal serving size of omega-3s is about 4 grams/day for most individuals, especially if they are predisposed to any of the above conditions. Once again, while omega-3s are quite safe, it is always wise to work with a nutritionally-conscious physician to insure against the possibility that the recommended levels may not be right for you. By the way, the American public agrees with the importance of taking fish oil supplements. They are now the most popular of all individual supplements taken for general health and specific conditions.

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