Fish oil prevents atrial fibrillation
KUOPIO, FINLAND. The three most important components of fish oil are eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and docosapentaenoic acid (DPA). Extensive research has established that EPA and DHA play a vital role in the prevention of Alzheimer’s disease, atherosclerosis, heart attack, angina, stroke, congestive heart failure, depression and cancer. Clinical trials have also shown that fish oil supplementation is effective in the treatment of many disorders including high blood pressure, rheumatoid arthritis, diabetes, ulcerative colitis and Raynaud’s disease.

Now Finnish researchers report that high serum levels of EPA, DHA and DPA are associated with a significantly reduced risk of developing atrial fibrillation (AF). Their study included 2174 men enrolled in the Kuopio Ischemic Heart Disease Risk Factor Study begun in 1984-1989. The men were 42, 48, 54 or 60 years of age at the baseline examination. During 17.7 years of follow-up, 11% of the participants were found to have AF upon admission to hospital (for arrhythmia or other reasons). This corresponds to an incidence rate of 0.6% a year. NOTE: Considering that the study only included men admitted to hospital, it is clear that the population-wide incidence would be significantly higher than 0.6% a year.

At baseline, the mean percentages of EPA, DPA and DHA in serum fatty acids were 1.67%, 0.55% and 2.46% respectively. After adjustment for age and other possible confounders the researchers observed that men in the highest quartile of EPA+DPA+DHA concentration (5.3 – 15.6%) had a 35% reduced risk of developing AF when compared to men in the lowest quartile (1.7 – 3.6%). The absolute risk in the lowest quartile group was 13.4% vs 8.7% in the highest quartile group. Further analysis revealed that DHA accounted for the entire risk reduction and that EPA and DPA levels were not associated with risk of developing AF.

Considering only lone afibbers (no heart disease prior to diagnosis of AF) strengthened the association between serum fatty acid concentration of DHA and AF risk. Men in the lowest quartile had a risk of 10.9%, while those in the highest quartile had a risk of only 5.6% – a relative risk reduction of 49%.

The mean serum fatty acid concentration of alpha-linolenic acid (found in flaxseed and other vegetable oils) was 0.74% and was not related to the risk of developing AF. A hair analysis revealed no correlation between methylmercury level (methylmercury is an increasingly common contaminant of fish) and risk of AF, nor did a high methylmercury level attenuate the beneficial effects of DHA. There was also no evidence that age, hypertension, systolic blood pressure or a history of ischemic heart disease modified the association between DHA level and AF risk.
Virtanen, JK, et al. Serum long-chain n-3 polyunsaturated fatty acids and risk of hospital diagnosis of atrial fibrillation in men. Circulation, Vol. 120, December 8, 2009, pp. 2315-21

Fish oils prevent AF recurrence following PVI
AUSTIN, TEXAS. Atrial fibrillation is a common sequel to coronary artery bypass grafting (CABG). In 2005 a team of Italian researchers reported that supplementation with 2 grams/day of fish oil (EPA + DHA) for 5 days prior to CABG reduced the incidence of postoperative AF from 33.3% (control group) to 15.2% (fish oil group). Now a team of researchers from St. David’s Medical Center in Austin, TX, Northeastern College of Medicine in Canton, OH, IKEM in the Czech Republic, and McMaster University in Hamilton, Canada reports that fish oil supplementation before and after a pulmonary vein isolation (PVI) procedure reduces the risk of AF recurrence.

Their retrospective study included 1500 afibbers who underwent a pulmonary vein antrum isolation (PVAI) procedure at St. David’s between 2004 and 2007. Two hundred and eighty-five patients (19%) had supplemented with a minimum of 655 mg of fish oil (in capsules) for at least a month prior to their PVAI and continued to do so during the entire follow-up period. It was possible to closely match 129 of these patients (70% paroxysmal and 30% persistent or permanent) with 129 patients (control group) from the remaining 1215 patients who had not taken fish oil. The two groups were matched for type of afib, age, gender, left atrial size, ejection fraction and the presence of type 2 diabetes, hypertension, coronary artery disease and stroke. The two groups, fish oil group and control group, were scheduled for follow-up (including 48-hr Holter monitoring) 3, 6, 9 and 12 months after the procedure and were equipped with a cardiac event monitor during the first 5 months following their PVAI.

During the blanking period (8 weeks following the procedure) 27% of patients in the fish oil group and 44% in the control group experienced afib recurrence; in other words, fish oil supplementation reduced the risk of early recurrence by 39%. Procedural failure (afib recurring more than 8 weeks from the PVAI) was 23% in the fish oil group and 32% in the control group, or a risk reduction of 28%. The research team also noted that the fish oil group had a significantly lower pre-procedure level of C-reactive protein (CRP) than did the control group (2.1 mg/L vs. 3.0 mg/L). CRP, an important marker of inflammation, measured 48 hours after the procedure was also lower in the fish oil group (14.3 mg/L vs. 18.0 mg/L). Complication rates were similar in the two study groups.

The research team concludes that patients treated with long-chain omega-3 polyunsaturated fatty acids (fish oils) prior to and following a PVAI experienced a lower incidence of early recurrence and procedural failure compared to untreated patients.
Shaheen, PD, et al. Omega-3 polyunsaturated fatty acid supplementation reduced atrial fibrillation recurrence after pulmonary vein antrum isolation. Indian Pacing and Electrophysiology Journal, Vol. 9, No. 6, November 1, 2009, pp. 292-98

Fish oils and PVCs
DURHAM, NORTH CAROLINA. Ventricular ectopy (premature ventricular complexes or PVCs) affects many heart attack victims, but is also a problem for atrial fibrillation patients. Ventricular ectopy, if sustained, can lead to ventricular fibrillation in patients with heart disease and ventricular fibrillation, in turn, can result in sudden cardiac death (SCD). There is substantial evidence that EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), the main components of fish oil, protect against the development of coronary heart disease (CHD) and help prevent SCD in patients who have suffered a heart attack (myocardial infarction or MI). There is also evidence that the plant-based omega-3 fatty acid alpha-linolenic acid (ALA) may be cardioprotective. Researchers at Duke University now report that omega-3 fatty acids may be helpful in reducing ventricular ectopy in recovering MI patients.

Their study involved 260 MI patients who were enrolled in the study within 72 hours of their heart attack. Most of the study participants were male (62.9%) with an age ranging between 27 and 86 years, and an average left ventricular ejection fraction of 52%. Most of the patients (88.5%) were taking beta-blockers at the time of their assessment and, not surprisingly, most had one or more comorbid conditions. Thus, 59% had hypertension, 41% diabetes, 12% chronic obstructive pulmonary disorder (COPD), and 7% congestive heart failure. Seventy-three percent had a history of smoking and 57% were current smokers.

All participants completed the Harvard food-frequency questionnaire to determine their average dietary intake of omega-3 fatty acids during the year preceding their MI. They also underwent 24-hour Holter monitoring either during or immediately following their hospital stay. Evaluation of the data collected showed a clear inverse relationship between the intake of omega-3 fatty acids and the number of daily PVCs (including couplets, triplets, bigeminy, etc). Based on a daily energy intake of 1000 kcal, the researchers observed that an average daily intake of 0.6 gram of n-3 fatty acids was associated with 450 PVCs/day, while an intake of 0.9 gram/day was associated with only 235 PVCs/day. They estimate that a 1-gram/day increase in the intake of EPA + DHA could reduce the number of PVCs by as much as 800/day. ALA reduced PVCs in a similar fashion, but although it has been shown to help prevent CHD, there is no evidence that it reduces SCD. The researchers conclude that future randomized, controlled trials are needed to investigate whether fish oil supplementation during hospitalization for MI will reduce the number of sudden cardiac deaths.
Smith, PJ, et al. Association between n-3 fatty acid consumption and ventricular ectopy after myocardial infarction. American Journal of Clinical Nutrition, Vol. 89, May 2009, pp. 1315-20

Net benefit of fish consumption
HARTFORD, CONNECTICUT. An adequate daily intake of fish oils, particularly EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), is associated with a wealth of health benefits including decreased risk of heart disease, lower blood pressure, improvement in rheumatoid arthritis, prevention of macular degeneration, and reduced risk of type 2 diabetes. There is also evidence that fish oil consumption is beneficial for patients with depression, schizophrenia, and Parkinson's disease. Finally, several studies have confirmed that fish oils, especially DHA, are essential for optimum development of an infant's brain and visual acuity.

Thus, it is not surprising that health authorities promote the frequent consumption of fish with the American Heart Association (AHA) specifically recommending that healthy people eat fish at least twice a week. The AHA also recommends that patients with heart disease consume at least 1000 mg of EPA + DHA every day.

Unfortunately, it is becoming more and more apparent that fish consumption is not always beneficial. Gary Ginsberg and Brian Toal from the Connecticut Department of Public Health point out that many fish are now heavily contaminated with methylmercury, a highly toxic compound with profound deleterious effects on both the cardiovascular and nervous system. Many researchers have studied these adverse effects and a consensus has been arrived at as to just what amounts of methylmercury are likely to produce serious consequences. Similarly, many studies have been done to determine the minimum daily intakes of EPA + DHA needed to obtain significant benefits. The two Connecticut researchers have combined these findings into two models aimed at predicting the net health benefits of consuming particular fish and seafood. One model is concerned with determining the net benefit for adult men and women (in regard to heart disease), the other with determining the net benefits for pregnant women and infants.

The researchers looked at 13 fish and seafood specimens available fresh in Connecticut and 3 varieties of canned tuna. They found that it was safe for adults to consume unlimited amounts of tilapia, pollack, flounder, cod, shrimp, trout, herring, canned light tuna, and Atlantic salmon, although they warn that farmed salmon may not be desirable due to concerns about its possible content of carcinogens. Swordfish and shark should be totally avoided and tuna steak should be eaten no more than once a week. Canned white tuna (Albacore), halibut, sea bass, and lobster can safely be eaten twice a week. Their recommendations for pregnant women and infants are somewhat more restrictive in that consumption of canned light tuna and cod should be limited to twice a week and consumption of canned white tuna, tuna steak, halibut, sea bass and lobster should be limited to once a week.
Ginsberg, GL and Toal, BF. Quantitative approach for incorporating methylmercury risks and omega-3 fatty acid benefits in developing species-specific fish consumption advice. Environmental Health Perspectives, Vol. 117, February 2009, pp. 267- 75

Fish oil deficiency in older people
WATERLOO, CANADA. There is ample evidence that an adequate intake of EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), the main components of fish oil, helps protect against cardiovascular disease, cognitive decline, rheumatoid arthritis, and macular degeneration. It is generally accepted that a minimum daily intake of about 500 mg of EPA + DHA is required to achieve meaningful benefits. A recent study involving Canadian children between the ages of 4 and 8 years found that 78% of them did not meet the recommended intake for children[1]. Now researchers from the University of Waterloo report that residents of retirement homes are also likely to be deficient in EPA + DHA.

Their study involved 15 residents (7 male and 8 female) aged between 79 and 98 years. The EPA and DHA content of their meals, snacks, and supplements was determined by actual measurement in duplicate food and supplement samples. Their blood level of fatty acids was determined from fingertip prick blood samples. The average (mean) daily intake of EPA + DHA was only 121 mg (median of 53 mg/day). Also of interest was that the average ratio of omega-6 to omega-3 fatty acids was 6.8 to 1. Analysis of blood samples showed that EPA concentration amounted to only 0.7% of total fatty acids, while DHA concentration was 1.8% of total fatty acids, both well below desirable levels. Interestingly enough, only one study participant consumed more than 400 mg/day of EPA + DHA and this person was taking a fish oil supplement.

The researchers conclude that this particular group of retirement home residents did not receive anywhere near the daily recommended amount of EPA + DHA through their habitual (government mandated) diet. They suggest that fish oil supplementation be considered for residents of long-term care facilities since it would likely be impractical and cost-prohibitive to provide the required amount through the regular serving of fish. It is also of interest, and considerable concern, that the average intake of vitamin D (mean 190 IU/day), vitamin E (mean 7.5 IU/day), and magnesium (mean 270 mg/day) were all below recommended dietary allowances (600 IU/day, 15 IU/day, and 400 mg/day respectively).
[1] Madden, SM, et al. Direct diet quantification indicates low intakes of n-3 fatty acids in children 4 to 8 years old. Journal of Nutrition, Vol. 139, March 2009, pp. 528-32
Fratesi, JA, et al. Direct quantitation of omega-3 fatty acid intake of Canadian residents of a long-term care facility. Appl Physiol Nutr Metab, Vol. 34, 2009, pp. 1-9

DHA + lutein prevents cognitive decline
BOSTON, MASSACHUSETTS. Cognitive decline and dementia are common among the elderly. It is estimated that 10% of people aged 65 years and 33% of individuals aged 85 years suffer from cognitive impairment, more specifically, a reduced ability to learn and remember. There is considerable evidence that both DHA (docosahexaenoic acid), a major component of fish oils, and lutein, a common dietary carotenoid, are essential for brain health. There is also evidence that lutein tends to accumulate in the macula (a small area of the retina essential for clear, detailed vision) and thereby helps prevent the initiation and progression of age-related macular degeneration. Now researchers at the Center on Aging at Tufts University report that supplementing with DHA + lutein is effective in preventing cognitive decline.

Their double-blind clinical trial involved 49 women (aged 60 to 80 years) who were randomized to receive DHA (800 mg/day), lutein (12 mg/day), DHA + lutein, or placebo. The study participants had blood samples drawn at enrolment and were subjected to a battery of cognitive tests (verbal fluency, memory, processing speed, and accuracy) at enrolment and after 4 months of supplementation. Diet was monitored with food frequency questionnaires at enrolment and at 2 and 4 months to ensure that there were no confounding changes in dietary intake. All cognitive outcomes were also adjusted for age and level of education.

At the end of the study, the researchers observed that participants who had taken DHA + lutein scored significantly higher on tests involving different aspects of memory. Thus, the DHA + lutein group improved in efficiency, learning shopping lists or lists of words with fewer trials, on average, after supplementation. All three supplement groups improved significantly on the verbal fluency test. It was also noted that DHA supplementation resulted in an increased uptake of lutein by the macula. The researchers conclude that supplementation with DHA and lutein significantly improves cognitive function in the elderly.
Johnson, EJ, et al. Cognitive findings of an exploratory trial of docosahexaenoic acid and lutein supplementation in older women. Nutritional Neuroscience, Vol. 11, No. 2, 2008, pp. 75-83