Understanding Omega-3s

by Zrinka Peters

MANY PEOPLE HAVE HEARD of the mysterious ‘omegas’—part of the family of ‘good fats’ that are now making headlines as many nutritionists (and dissatisfied dieters) discover that popular low-fat or non-fat diets have done little to slim America down. In fact, weight gain and obesity has grown to be a problem of near-epidemic proportions in the US, particularly in the past 10 years as the non-fat craze really began to take off. Ironically, many overweight people are actually suffering from a fat deficiency—a deficiency of the essential fats which are necessary for good health. Now, instead of just promoting low-fat diets, health authorities are drawing clear lines between ‘bad’ and ‘good’ fats and encouraging Americans to consume more of the good ones.

Among the ‘good’ are the two essential fatty acids (EFAs) Alpha-linolenic acid (ALA) and Linoleic acid (LA), which are part of the omega-3 and omega-6 families, respectively. These are ‘essential’ because our bodies can’t manufacture them like we can many other fatty acids. In other words, we have to get them from the foods we eat. When omega-3s and 6s are found in a right balance in the body, they work together to promote good health. An imbalance, on the other hand, can cause serious problems. The University of Maryland Medical Center reports that “omega-3 fatty acids help reduce inflammation and most omega-6 fatty acids tend to promote inflammation. A healthy diet should consist of roughly two to four times more omega-6 fatty acids than omega-3 fatty acids. The typical American diet tends to contain 14-25 times more omega-6 fatty acids than omega-3 fatty acids and many researchers believe this imbalance is a significant factor in the rising rate of inflammatory disorders in the United States.”

The importance of these EFAs, combined with the fact that most Americans are deficient in omega-3s, has led to an explosion of research. Omega-3s are now known to be vital in helping to stave off a whole host of illnesses, including heart disease, high blood pressure, arthritis, asthma, breast cancer, depression, reproductive problems and allergies, among many other physical and mental ailments—even behavioral disorders such as attention deficit/hyperactivity disorder (ADHD).

There are 3 major types of fatty acids which are collectively classified as omega-3s — Alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Strictly speaking, ALA is the only one which is really “essential” since, in a healthy body, ALA is later converted into EPA and then into DHA.

EFAs are highly concentrated in the brain and in cell membranes in the retina, indicating that they are also vital during pregnancy and in infancy for proper cognitive and visual development. This is why DHA is now being promoted as an important addition to many infant formulas.

There are several easily attainable sources of omega-3s. Most people who are serious about getting more omega-3s in their diet turn to either flax seeds and their oil, or cod liver or other fish oil to meet these requirements. Is one better than the other? The answer is controversial, and there are plenty of health authorities who swear by one or the other. What we can do is to point out some of the differences.

EPA and DHA are found primarily in fatty cold water fish and their oils. Cod liver oil is the most potent source, but other fish, such as salmon, sardines, mackerel, herring and trout are also good sources. This is why health officials are urging us to eat more fish. The American Heart Association recommends eating fish at least twice per week in order to consume more of these fatty acids.

Cod liver oil is prized because it contains the highest known concentrations of EPA and DHA. Taking a small amount of the oil on a regular basis is the best known way of easily meeting the need for these nutrients, and cod liver oil has been used with impressive results in numerous disease-fighting therapies. It also contains significant amounts of vitamins A and D. The vitamins can be either naturally occurring in the oil, or in some cases they are removed and replaced with synthetic vitamins. Oil sold under the ‘Cod Liver Oil’ label can actually be made up of many different types of fish oil all in the same bottle. If you want 100% pure cod liver oil, make sure that is what is stated on the label. In choosing a supplement, it is important to choose a high-quality brand which guarantees its product to be free of contaminants, and also to make sure that, particularly if you take any other vitamins or supplements, that the combined levels of vitamins A and D do not exceed a safe amount.

The downside of getting these good fats solely from regular consumption of fish is that most fish on the market today is contaminated to one degree or another by heavy metals such as mercury as well as PCBs (polycarbonated biphenyls) and dioxins. Unfortunately, while fish has always been one of the most nutritious foods available, now we are advised to limit the quantity and type of fish eaten so as not to consume too many toxic byproducts.

The highest concentration of ALA is found in flax seeds and flax seed oil, but it can also be obtained in smaller amounts from other plant sources like walnuts and walnut oil, pumpkin seeds and their oil, and canola oil.

The ALA in flax seed oil is later converted, in healthy bodies, to EPA and DHA. However, for this conversion to take place requires the presence and activity of an enzyme that has been found to be deficient in some people. For this reason some believe getting the EPA and DHA directly from fish oils is more beneficial.

On the other hand, organic flax seed and oil can be easily found, allowing us to avoid the pollutants which affect virtually all marine life, and whole flax seeds can be ground, offering the added benefits of fiber, protein, vitamins, minerals. Flax seeds are also the best known source of lignans (plant compounds which have strong antioxidant properties).

The Oregon State University Micronutrient Information Center reports that, “In healthy young women, approximately 21% of dietary ALA is converted to EPA and 9% is converted to DHA. The better conversion efficiency of young women compared to men appears to be related to the effects of estrogen.” These results suggest that flax and other plant sources of ALA may be more useful for women’s health, while marine sources may be better for men.

Whether cod liver or flax oil is “better” for providing omega-3 fatty acids is a point of dispute among nutritionists; however, the fact that we need omega-3s for optimum health, regardless from where we get them, is not. •

from the July-August 2008 issue

Many overweight people are actually suffering from a deficiency of the essential fats which ar enecessary for good health.