Omega-3 Fats: Your Inner Defibrillator

More than half of all sudden cardiac deaths occur in people without any history of heart disease. One of the main causes of sudden death is a sustained abnormal heartbeat called ventricular arrhythmia. (That’s why defibrillators save lives: they jolt the heart into normal rhythm.)

Alexander Leaf of Harvard University led the landmark study demonstrating omega-3 fats’ ability to prevent sudden death. His lab gave arrhythmia-prone dogs fish oil just before they performed a treadmill stress test. The results showed that fi sh oil prevented sudden death in the dogs.

These remarkable results prompted studies to see if similar benefits could be achieved in people. Hints already existed, as eating fish one to two times weekly was associated with a nearly 50 percent
reduction in sudden death.

Fish or Fish Oil Decreases Sudden Death

A study called the Diet and Reinfarction Trial told heart attack patients to eat two fi sh servings per week. The study’s results indicated a 29 percent reduction in death. Another study, the GISSIPrevenzione Trial, involved over 11,000 heart attack patients. In that study, men given 850 milligrams of long-chain omega-3 fats had a 45 percent reduction in sudden cardiac death compared with the unsupplemented group. The U.S. Physician’s Health Study added a vital piece of evidence: omega-3 fats reduce the risk of sudden death even among men without a history of heart disease.

Omega-3 Fats Prevent Arrhythmia in Heart Surgery Patients

A dangerous heart rhythm, atrial fibrillation, is one of the main complications after open-heart surgery. Italian researchers randomly gave fish oil supplements to 80 of 160 patients scheduled for heart surgery. The supplemented group had a marked reduction in atrial fibrillation and spent fewer days in the hospital. The fi sh oil’s effectiveness was comparable to that of the heart-stabilizing medications sotalol and amiodarone—but without their serious side effects, including assorted problems in the liver, lungs, and heart.

Omega-3 Fats May Prevent Arrhythmia in High-Risk Patients

Researchers are hopeful that omega-3 fats will provide an alternative to anti-arrhythmia drugs for patients with implanted defibrillators. But studies on these patients show conflicting results, so the jury is still out.

Omega-6 Increases the Odds of Developing Heart Disease

Excess omega-6 fats trigger blood clotting, clustering of blood cells, and tightening of blood vessels—a compelling bit of information. When you consider the role of omega-6 fats as a contributor to heart disease, the information is chilling.

In the 1970s, there were clues that excess omega-6 fat hurts the heart. Scientists infused animals with the omega-6 fat arachidonic acid, and it caused sudden death within minutes. The cause of death was thrombosis (blood clots).  This lethal effect did not occur after using the same amount of other fats.

Furthermore, all the eicosanoids made from arachidonic acid, except for one, have been found to be potent arrhythmogenic agents (causes of arrhythmia), according to Alexander Leaf’s research. Based on these and other findings, Leaf in a 2001 scientific editorial urged a lowering of dietary omega-6 fats in order to promote heart health.

Notably, the higher the level of arachidonic acid in your body, the greater your risk of death from heart disease. Let’s take a closer look.

Phospholipids

Oil and water don’t mix, so fats need a shuttle to move throughout your blood, which is mainly water. One of these “shuttles” is a phospholipid, which holds one pair of fatty acids. Phospholipids are a major component of all cells, including heart cells, blood cells, and brain cells.

Each phospholipid is like a hanger in which there are two clamps to hold a long pair of pants (but instead of pants, they are fatty acids). One of the clamps, called position 2, is reserved for long-chain fats. Typically, the coveted position goes to one of three fats: the omega-6 fat arachidonic acid or the omega-3 fats EPA or DHA. Which gets in? Whichever fat is in most abundant supply. The supply is based on the proportion of omega-6 to omega-3 fats in the diet. In the case of the American diet, omega-6 fat wins a great majority of the space in the phospholipids, which is why about 75 percent of the long-chain fats in the American body are omega-6 fats.

A new blood test, called the Omega-3 Index, measures the phospholipid content of omega-3 fats. The higher your omega-3 index, the more protection your heart will have. Researchers believe this test might be one of the best indicators for risk of death from heart disease.

LDL Cholesterol: Special-Delivery Taxi for Omega-6 Fat.

The last L inLDL stands for lipoprotein, which is a protein that serves as a taxi for fat. In its center region is the fat payload, including cholesterol and phospholipids, which it delivers into the artery wall.

LDL carries an enzyme that serves as the release pin for the arachidonic acid tethered to the phospholipid. Once freed, the arachidonic acid can make potent omega-6 eicosanoids that trigger blood clotting, inflammation, and arrhythmias—obviously not good for the heart. An elevated blood level of this enzyme is an independent risk factor for heart disease and indicates the extent of artery damage.

Diets High in Omega-6 Fats Promote Atherosclerosis

Diets that are high in omega-6 fats may be especially harmful to people with a genetic disposition to heart disease (who are just being identified, thanks to robust research from the human genome project). The potent omega-6 eicosanoid made from the LOX enzyme (a known trigger of asthma) is powerfully linked to atherosclerosis, especially in people who are genetically wired to make higher levels of this enzyme.

A profound study published in the New England Journal of Medicine found that eating a diet high in omega-6 fat (typical levels in a Western diet) caused an increase in the production of the damaging LOX-based compounds, leading to atherosclerosis. Both omega-6 fats, linoleic acid and arachidonic acid, were significantly associated with increased severity of artery damage.

In another study, Tufts University researchers reported in the May 2006 issue of Circulation that people who have a variation of a gene called apolipoprotein A5 have a higher risk for heart disease,
especially if they eat a diet high in omega-6 fats.

Diets Low in Omega-6 Fats Reduce Death from Heart Disease

The Lyon Diet Heart Trial was a large study designed to see if eating a Mediterranean-style diet would protect against the recurrence of a heart attack, compared with the standard diet recommended by the American Heart Association. The omega-6 fats in the diet were limited to seven grams a day, about what you fi nd in just one tablespoon of corn or soybean oil. The results surprised even the researchers. After four years on this diet, participants experienced a reduction in all causes of death, including heart disease. The impact of this diet was also refl ected in blood phospholipids, with a lower ratio of omega-6 to omega-3 fats.

In spite of the compelling evidence of omega-3 fat’s detriment to heart health, there is not much “buy-in” from the medical community. Since the late 1980s, respected scientists from around the world have brought attention to the omega-6 fat problem in eloquent editorials and studies, only to seemingly fall on deaf ears.

Instead, many health organizations indiscriminately promote the use of polyunsaturated fats to replace artery-clogging saturated fat. Since omega-6 fats are the dominant fat found in polyunsaturated oils (soybean oil, cottonseed oil, sunflower oil, safflower oil, corn oil)—if you seek them out, you will overwhelmingly increase your dietary load of omega-6 fats, which is counterproductive to health.

Fortunately there are ripples of change. In 2005, Joint British Societies issued guidelines to prevent cardiovascular diseases, which not only recommended regular fish consumption, they urged replacing saturated fat with monounsaturated fats (like olive oil). This is significant, because this is the first health association that does not indiscriminately recommend increasing polyunsaturated fats for saturated fats.

To keep your heart healthy, it’s a great start to eat more omega-3 fats, whether from fish or supplements. But it is not enough. Dietary omega-6 fats need to be lowered to a healthier balance. This balance is also important for the developing brain, which you can find more detail about on this website.

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