Although the body readily makes most of the fat that it needs from dietary starch or sugar, humans lack the ability to make essential fatty acids (EFAs) and must get them in food. EFAs are found in all foods but are most abundant in certain oils. They come in two distinct families, based upon their chemical structure. The two EFA families are not interchangeable and, in fact, tend to compete with one another in the body's metabolic pathways.

The larger family called "omega-6" EFAs are abundant in many vegetable seed oils, including corn, sunflower and safflower. Deficiency of omega-6 EFAs causes impairment of growth and fertility, hormonal disturbances and immunologic abnormalities. An excess of omega-6 EFAs may promote the development of cancer. People living in North America and Europe have relatively high levels of omega-6 EFAs in their diets, because of the increasing consumption of vegetable oil during the twentieth century.

The smaller family, called "omega-3" EFAs, is most concentrated in fish oils. It is also found in green leafy vegetables and in the flesh of animals that feed on grass and leaves. The human brain is rich in omega-three EFAs; their deficiency causes abnormalities in the development and function of the nervous system as well as immune defects. The past century has witnessed a systematic depletion of omega-three EFAs from the Western diet because of changes in food choice and in techniques of animal husbandry and food processing. Some theorists have traced the origins of numerous different diseases to a lifetime depletion of omega-3 EFAs.

Extensive research published since 1985 has demonstrated that fish oils have the ability to prevent disorders as apparently unrelated to one another as cancer, heart attacks, migraine headaches, and premature births, and to reverse the effects of conditions as different as psoriasis, ulcerative colitis, rheumatoid arthritis and cystic fibrosis.

Some indications that an EFA deficiency or imbalance are present are:

dry skin

the need to use moisturizing creams and lotions

"chicken skin"

the presence of tiny rough bumps, usually on the back of the arms

dry or unruly hair

dandruff

soft, fraying or brittle nails

menstrual cramps

premenstrual breast tenderness to name a few.

A person who has these symptoms will often find that they improve dramatically by supplementing an otherwise healthy diet with pharmaceutical grade fish oil.

Virtues of GLA

Although most people consume more than enough of the omega-6 EFAs, there is a small but significant proportion of the population who are unable to properly metabolize omega-6 EFAs and will benefit from supplementation with oils that are rich in omega-6 in their converted form. The three most useful omega-6 rich oils are evening primrose oil, borage oil and black currant seed oil, all of which are sold in capsule form.

These oils contain a special EFA called gamma-linolenic acid (GLA), which allows the body to overcome the most common impediment to proper utilization of omega-6 EFAs. Although experimental data indicate that feeding large doses of omega-6 rich oils, such as corn oil or safflower oil, can promote the growth of cancer, there is no evidence that feeding GLA in the form of primrose oil contributes to cancer. Quite the contrary, primrose oil behaves like the omega-3 rich oils in fish in actually preventing tumour growth in experimental animals.

The usual requirement for GLA among those who need it is supplied by taking four to six capsules of evening primrose oil, two to three capsules of borage oil, or three to four capsules of black currant seed oil every day (assuming each capsule contains five hundred milligrams of oil). It would be a good idea to reserve the use of GLA supplements for people whose dryness does not respond to omega-3 supplementation from fish oil. Because the omega-3 and omega-6 EFAs compete with one another in the body, feeding fish oil to a person who needs GLA may actually increase that person's omega-6 deficit, making the skin dryer or the breasts more tender - although this is extremely rare. An increase in these symptoms with omega-3 supplements is almost surely a sign to switch to GLA, OR to add in some GLA - lack of response is usually a reason to add GLA. Controlled studies have demonstrated there are benefits for GLA in people suffering from arthritis, eczema and premenstrual syndrome – but omega-3 from fish oil is always the first and most important nutrient to supplement. Remember that EFA therapy does not treat disease, it improves cellular function, thus bringing about improvement or remission of symptoms.