Nothing Fishy About Omega Oils

Omega-group fatty acids, especially EPA and DHA, play essential roles in human health and nutrition.

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Photo courtesy of the
National Fisheries Institute






By John K. Ashby, Contributing Editor

Our bodies require fat to survive. It is especially vital our diet include the omega fatty acids linoleic acid and alpha-linolenic acid.

These are called essential fatty acids, because the body needs them but cannot make them on its own (some omega-3 fatty acids can be made from alpha-linolenic acid, but not very efficiently).

Any other fatty acids our metabolism requires can be made in our bodies provided we have the above two in sufficient quantities. (For a more complete explanation of fat chemistry, see “The Skinny on Fats," Food Processing, July 2002.) Two specific fatty acids in the omega class are proving increasingly critical to human health: eicosapentanoic acid (EPA) and docosahexanoic acid (DHA).

Fish Oil Makes Waves

In the 1970s, Danish researchers discovered Greenland natives had very low heart disease and other inflammatory-related diseases despite a very high fat diet. The source of that fat was cold water fish, rich in DHA and EPA. The oil in cold water fish is high in DHA and EPA fatty acids.

Omega fats perform a number of important functions, such as protecting against heart disease and aiding in immune function. Other functional aspects of eicosanoids are their ability to act as hormones and as a controller of other hormones. Some eicosanoids control other hormones and cellular activities directly. Unlike many hormones, however, they are synthesized in every cell and not limited to a specific gland.

One area where omegas are receiving significant attention in our aging population is how they affect nerve and brain function. The sheathing that surrounds nerve fibers requires fat for its structure and function, and the eicosanoid omegas are known to specifically help provide fluidity for neural cell walls. The nerves in our brains need DHA omegas to conduct impulses.

The evidence of omega fatty acids’ positive impact on human nutrition and health is so persuasive the FDA just allowed a new health claim for EPA and DHA (see "News"). These health benefits are, for the most part, a function of the ratio of omega-6 to omega-3 fatty acids in the diet, the quantity of omega-3 fats in the diet and the quantity in the diet of the specific omega-3s.

Fatty cold water fish such as this silver king salmon are a good source of omega-3 oils.
Structure and Function


DHA makes up about 15 percent of the cerebral cortex and nearly 40 percent of the retina. It is a crucial component in neural functioning. We know the fat content of nerve cells determines the way the nerve cell functions. This led to research on omega-3’s beneficial influence on cognition, memory, depression and Alzheimer Disease.

Many researchers are convinced, as evidence mounts, that fish oil may be the most beneficial food compound for nerve development and mental health. So much so, in fact, that DHA recently has been approved as generally recognized as safe for use in baby formula. Meanwhile, positive evidence of fish oil’s ability to protect against cardiovascular disease, cancer, osteoarthritis and other inflammation diseases continues to grow.

Availability of the necessary precursors in the cell (the available concentrations of omega-3 and omega-6 fatty acids) plays a huge roll in determining the quantity and type of eicosanoids that will be produced. We must eat omega-3 fats in order to produce the omega-3 dependent eicosanoids, and eat omega-6 fats to produce omega-6 dependent eicosanoids. The two are not the same and do not act the same way in the body.

But dietary availability is without scientific question a huge limiter/enabler of eicosanoids production. A wealth of clinical evidence indicates altering the availability of omega-3 and omega-6 fats has dramatic and predictable effects on human health.

Clash of the Eicosanoids

Omega-6 eicosanoids are related to stress, immune system reduction, clotting, bone thinning and inflammation. The omega-3 eicosanoids balance this out. This primitive system of a set of opposing hormonal controllers usually works in balance. But omega-6/omega-3 fatty acid consumption pattern determines to a large extent what eicosanoids are produced. Starve off either side unreasonably and significant imbalance results – with severe health implications. Balance consumption and your body has a fighting chance to take care of itself.

Omega-3 fatty acids correlate with diets higher in fish (especially fatty fish, such as salmon and tuna), vegetables, walnuts, flaxseed and canola oil. These are also fat sources lower in omega-6 and higher in omega-3 fatty acids.

Omega-6 fatty acids correlate with diets higher in meats and fried foods and low in plant-based foods.

The ratio of omega-6/omega-3 fatty acids in the human diet up until even a century or two ago was close to 1:1. The ratio in the U.S. right now is closer to 20:1, with predictable results: Heart disease, cancer, and immune system disorders are rampant.

Luckily, as nutrition researchers and manufacturers learn more and more about the value of healthful omega fatty acids they can apply the knowledge to creating messages and products consumers are receptive to. This means that including good food sources and supplements of omega fats in the American diet and achieving a healthful balance of omega 3s to omega 6s may soon become the norm again.


TABLE: ESSENTIAL FATTY ACIDS
Essential Fatty Acids Alpha-Linolenic Acid
(18:3n-3)
Linoleic Acid
(18:2n-6)
Number of Carbons 18 18
Number of Double Bonds 3 2
Omega Designation Omega-3 Omega-6
Category Long Chain Polyunsaturated
Fatty Acid
Long Chain Polyunsaturated
Fatty Acid
Significant Related Fatty Acids EPA (20:5n-3)
Eicosapentanoic Acid
DHA (22:6n-3)
Docosahexanoic Acid
GLA (18:3n-6)
Gamma Linolenic Acid
CLA (18:2n-6)
Conjugated Linoleic Acid
Dietary Sources Flaxseed
Rapeseed
Walnuts
Microalgae
Fatty Cold Water Fish
Meat
Peanuts
Corn
Soy
Farmed Salmon
Relative Prevalence in U.S. Diet Low High


About the Author
John K. Ashby is General Manager - Ingredients, for California Natural Products, a manufacturer of rice ingredients for the food industry, and focuses on the nutritional, nutraceutical, functional and organic food markets.
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