What are omega-6 fatty acids?

Omega-6 fatty acids are a class of essential polyunsaturated fatty acids with the initial double bond in the sixth carbon position from the methyl group (hence the "6"). Examples of foods rich in omega-6 fatty acids include corn, safflower, sunflower, soybean, and cottonseed oil.

What are the n-3 and n-6 fatty acids?

These are synonyms for omega-3 and omega-6 fatty acids, respectively.

What are trans fatty acids?

Trans fatty acids (trans fats) are made through hydrogenation to solidify liquid oils. Heating omega-6 oils such as corn oil to high temperatures creates trans fats. Trans fats increase the shelf life of oils and are found in vegetable shortenings and in some margarines, commercial pastries, fried foods, crackers, cookies, and snack foods. Intake of trans fatty acids increases blood LDL-cholesterol ("bad" cholesterol), decreases HDL cholesterol ("good cholesterol"), and raises the risk of coronary heart disease.

What are the benefits of omega-3-fatty acids?

Scientific evidence is mounting that fish oil (predominantly omega-3-fatty acids) can reduce the risk of sudden cardiac death. Some scientists also believe that omega-3 fatty acids can improve one's blood lipid (cholesterol and triglyceride) levels and decrease the risk of coronary heart disease.

What is coronary heart disease?

Coronary heart diseases are heart conditions caused by atherosclerosis (hardening and narrowing) of the coronary arteries, arteries that supply blood and oxygen to the heart muscle. Coronary arthrosclerosis is typically silent; people can have coronary atherosclerosis for years to decades without any symptoms or signs of heart disease. Symptoms and signs of coronary heart disease develop when the diseased arteries become critically narrow or completely blocked so that they can no longer deliver adequate blood and oxygen to the heart muscle. Obesity, high blood cholesterol, high blood pressure, cigarette smoking, and diabetes mellitus can accelerate the arthrosclerosis process, and increase the risks of developing coronary heart disease. Coronary heart diseases include heart attacks, sudden cardiac death, angina, heart failure and heart rhythm disturbances.

What is sudden cardiac death?

Coronary heart disease is an important cause of death in the United States. Death from coronary heart diseases can be due to heart failure, arrhythmias (abnormally fast or slow heart rhythm) or sudden cardiac death. Each year more than five hundred thousand Americans die of heart attack, and approximately 250,000 die of sudden cardiac death.

Most sudden cardiac death is due to ventricular fibrillation. Ventricular fibrillation is a chaotic electrical disturbance that causes the heart to stop beating. Ventricular fibrillation typically occurs at the onset of a heart attack, usually before the victim can reach the hospital. Ventricular fibrillation will lead to brain death within minutes unless effective CPR can be delivered and/or the normal heart rhythm is restored by electric shocks (called defibrillation). More than 50% of people who die of sudden cardiac death have no signs or symptoms of coronary heart disease.

What is the scientific evidence behind omega-3-fatty acids?

There are several types of evidence suggesting that omega-3-fatty acids prevent death from heart disease; epidemiological evidence, archeological evidence, evidence from animal studies, observation studies, and interventional studies.

Epidemiological evidence

Epidemiology is the study of populations in order to determine the frequency and distribution of disease and measure risks. Scientists have observed that populations with high fish intake (Alaskan natives, Greenland Eskimos, and Japanese living in fishing villages) have low rates of cardiovascular disease and low rates of sudden cardiac death.

Archeological evidence

There is archeological evidence that the early ancestors in the Paleolithic period were lean, fit and free of coronary heart disease. Their physical fitness was in part due to their active hunter-gatherer life style (they exerted themselves daily for food, water, and physical security) and in part due to their diet.

The diet of the Paleolithic ancestors consisted mainly of natural and unprocessed food. Compared to the modern American diet, it contained more fruits, vegetables, nuts, lean protein, polyunsaturated and monounsaturated fats, and omega-3-fatty acids. Their diet also contained little saturated fats, no trans fats, and no refined grains and sugars.

The animal meats in the Paleolithic period were different from the meats of today's domesticated animals. The animal meats then were rich in omega-3-fatty acids because the algae, plants, and grass (foods of the grazing animals and fish in those days) were rich in omega-3-fatty acids. Today's domesticated animals are corn and grain fed. Consequently meat from these domesticated animals is high in saturated fat but low in omega-3 fatty acids. Today's farm fish meat is often lower in omega-3-fatty acids than non-farmed fish.

Americans today lead generally sedentary lives, not the active hunter-gatherer lifestyle our genetics were designed for. The average American diet today is high in saturated foods, trans fats, and foods rich in grains and refined sugars. Our modern diet is also poor in omega-3 fatty acids. The combination of sedentary life and our modern diet is the prime cause for our epidemic of obesity, high blood pressure, diabetes, and coronary heart disease.

Animal studies

In studies involving animals (dogs, rats, and marmosets), omega-3-fatty acids were found to prevent ventricular fibrillation (thus preventing sudden death) when given to animals just prior to experimentally induced heart attacks. Omega-3-fatty acids were found also to terminate ventricular fibrillation in animals suffering experimentally induced heart attacks. Therefore scientists suspect that omega-3-fatty acids may prevent ventricular fibrillation of the heart in event of a heart attack in humans.