Ross Hume Hall,
Ever been called a fathead? Take it as a compliment. Your brain consists mostly of fat. Your intelligence, heartbeat, muscular movements, all depend on the fat cushioned inside your head. Interestingly, when nature first figured out how to send electrical messages through living tissue, she made nerve cells and their connectors out of fat.
Not just any fat, certainly not the saturated fat of beefsteak fame. Rather, nature constructs the brain and the radiating nerve fibers that run from scalp to toe, out of polyunsaturated fat.
But a curious twist of nature leaves humans unable to make key polyunsaturated fats, or to be more exact, fatty acids. These fatty acids must come from plant sources. The entire animal kingdom, from fish to birds to mammals, in fact, is hostage to the plant kingdom for the essential fatty acids.
Linoleic and Linolenic Acids
The two key unsaturated fatty acids are linoleic and linolenic. Nutritionists call them essential because they are as essential to the diet as vitamins and minerals. Thus, you must get these dietary essentials either from plant foods or from animals that eat plants. Linolenic acid, by the way, is also classed as an omega-3 fatty acid. More about this particular fatty acid in a moment.
The essential fatty acids not only conduct nerve impulses, they form the membrane envelopes of brain, heart, muscles, and all other organs. If some wicked wizard suddenly removed all the essential fatty acids from your body, youíd collapse into a damp blob.
But in designing membranes and nerve fibers out of essential fatty acids, nature creates a problem for us humans. The fatty acids structures are inherently unstable. The membrane fatty acids constantly fall apart and must be replaced with new essential fatty acids eaten in your daily food.
Thus your cell membranes, brain cells, and nerve fibers face the constant threat of erosion. Long before you get to the blob stage, mental processes and general body efficiency deteriorate.
Here is list of symptoms caused by insufficient linoleic and linolenic acids in the diet.
Should you be concerned about such symptoms? Is essential fatty-acid deficiency an issue with modern foods? The answer is both no and yes. The food industry some years ago made a massive shift away from using animal fats, such as butter and lard, to making products out of vegetable fats. Commercial baked goods use vegetable fats. Salad dressings and cooking oils are all based on plant sources, like soybeans and canola. .
As a result of the shift to plant-based fats, most people probably obtain sufficient linoleic acid. What of the other essential fatty acid, linolenic? You need both. Nerve cells and the membranes of all cells work because of an intricate interlacing of the two essential fatty acids.
The nutritional problem lies in the dearth of linolenic. The foods the average American eats, because of refinery processing of vegetable oils, are woefully short of linolenic acid, that all essential omega-3 fatty acid.
Linolenic acidís disappearing act
Why has linolenic acid disappeared from food products made from vegetable fat? The reason has nothing to do with nutrition. Itís economic. Linolenic acid, more so than linoleic, is susceptible to air oxidation. Oxidation causes breakup of the fatty acid, forming poisons, which also give a characteristic rancid odor and flavor. This is natureís way of telling you not to eat rancid foods.
Makers of baked goods, potato chips and snack foods obviously donít want to use a fat with the least tinge of a rancid odor. So oil refiners remove the offending linolenic acid before it has a chance to go rancid.
Consider soybean oil, which accounts for 60 percent of all commercial vegetable fats used in the United States. Oil in the intact soybean contains a relatively high proportion of linolenic acid (about seven percent). But refining destroys or removes the linolenic acid. Thus when you see soybean oil mentioned on a product label, the product will not likely supply linolenic acid.
Linolenic acid, an omega-3 fatty acid
Letís have a look at a little biochemistry. Linolenic and linoleic acids belong to two broader series of essential fatty acids, omega-3 and omega-6. Each series consists of several members. Plants make one member each of the two series: linolenic acid (omega-3) and linoleic acid (omega-6). Once eaten, linoleic and linolenic acids are converted by your body biochemistry into other members, respectively, of the two series.
For optimum health, you need both the omega-6 and omega-3 fats in the diet. Why? Animals (human included) are unable to convert one series to the other.
The critical omega-3:omega-6 ratio
Evidence that omega-3 fats are critical to health first surfaced in studies of the Inuit (Eskimos) of northern Canada and Greenland. Eating a traditional diet of fish and seal blubber, these peoples obtained up to two thirds of daily calories from fat. Yet heart disease was rare. Investigators believe that the high level of omega-3 fats in the fish protected the Inuit against heart disease.
The absolute amount of omega-3 fats in the diet, however, may be less important. More critical, you need to balance the amount of omega-3 with the amount of omega-6 fats. The ratio of omega 3:omega-6 fats in the traditional Inuit diet was about 1:2.5. The corresponding ratio in the average American diet is about 1:20.
Nutritionists donít know the best ratio for optimum health, except that 1:20 ratio seems unbalanced. Since Americans get sufficient omega-6 fatty acids in their diet, the practical challenge is to eat more of the omega-3 fatty acids.
Boost omega-3 fatty acids in your diet
Fresh fish is an excellent source of omega-3 fatty acids. Because of expense and possible toxic chemical contamination, however, you may not care to eat more than one fish meal a week Meat also provides both omega-3 and omega-6 fats. But meat delivers a large amount of saturated fat that can overwhelm the two essential fats. True even for the leanest cuts.
Plant sources are your best bet. Of the common cooking oils, canola and soybean, contain the highest percentage). There is a catch. As already mentioned, commercial processing destroys linolenic acid.
So what can you do to increase the amount of omega-3 (linolenic) acid in your daily diet?
The following foods are especially rich in the omega-3s.
Algae, including spirulina
Should you buy omega-3 supplements?
A word about supplements. Fish oil and flax seed oils are extremely sensitive to light and to air oxidation. They arenít good practical sources. If you buy them, choose a store that keeps them refrigerated and buy in small quantities.
Omega-3 Fatty Acids and Heart Disease
Finally, a comment about omega-3 fatty acids and the diet-heart disease connection. The lack of omega-3 fatty acids in the American diet deserves as much attention as the idea that excess saturated fat and cholesterol are the chief dietary factors in heart disease. The food manufacturing industry takes advantage of public fears and sells foods lower in saturated fat and cholesterol. Ironically, at the same time, the industry knocks omega-3 fatty acids right off the dining table.
© 2001, Ross Hume Hall. All