Strictly speaking, there are two EFAs: linoleic acid (LA, an omega-6) and alpha-linolenic acid (ALA, an omega-3). There are some other conditionally essential fatty acids, which include gamma-linolenic acid (GLA), arachidonic acid (AA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). All four of these fatty acids can be made by the cells in the body – “can” being the operative word. And, all of them are needed by the body for optimal functioning. There are a number of interfering factors that make these fatty acids become dietary essentials for some people. For example, to a limited extent, alpha-linolenic acid can be converted in the body to EPA and DHA, the longer chain omega-3 fatty acids found in fish.³ Alpha-linolenic acid (ALA) is not the same as EPA or DHA, and some reports suggest it has functions in addition to providing the starting material for EPA and DHA.⁴ Factors that inhibit essential fatty acid conversion include damaged food substances (particularly trans-fatty acids found in margarine, shortening, and hydrogenated fats, as well as sugar and refined grain products), illness, genetic inadequacies, and nutrient deficiencies. Excesses of omega-6 fatty acids from modern commercial vegetable oils inhibit the pathway of omega-3 conversion as well.^{1 2} On the other hand, researchers have found that curcumin, the principal bioactive compound in turmeric, enhances the conversion of alpha-linolenic acid into DHA, helping to increase levels in the brain.⁵

Modern diets can contain as much as 30% of calories as polyunsaturated oils, but scientific research indicates that this amount is far too high. In native populations whose intake of polyunsaturated fats comes from the small amounts found in legumes, grains, nuts, vegetables, fish, flaxseeds, olive oil, and animal fats (but not from commercial oils), the amount consumed is nearer 4% of total calories.^{6 7}

Excess consumption of oils that are dominantly omega-6 has been shown to contribute to a large number of conditions including heart disease; immune system dysfunction; damage to the liver, reproductive organs and lungs; digestive disorders; depressed learning ability; impaired growth; and weight gain.^{8 9} The bottom line is that consumption of polyunsaturated oils such as corn, soy, cottonseed, sunflower, and safflower should be limited. While the body needs some polyunsaturated oils, they are best taken in through the whole food form, such as a handful of sunflower seeds or other fresh seeds or nuts¹⁰ —foods in nature’s package to protect them from deterioration.

Essential Fatty Acid Balance

Reducing the use of vegetables oils and increasing the intake of wild-caught fish, grass-fed meats, flax, and other omega-3 sources will help to provide a more favorable balance of omega-6 to omega-3 fatty acids. The ideal dietary ratio of omega-6 to omega-3 fatty acids is thought to be between 1:1 and 2:1.¹¹ The ratio in the American diet is estimated to range between 15:1 and 30:1, due to high use of vegetables oils, processed foods, and meats (and fish) raised on omega-6 rich corn and soy.¹⁰ When there is an overabundance of omega-6 fatty acids in the diet, the body’s ability to utilize alpha-linolenic acid is inhibited. This causes a host of reactions, as mentioned above. Cold water fatty fish, such as wild salmon, tuna, and sardines, are the best sources of DHA and EPA. Eating at least two portions of wild fatty fish, from clean cold waters, per week, or using a fish oil supplement, can provide sufficient DHA and EPA in a diet that also minimizes omega-6s from processed foods and vegetable oils.

Supplementing EFAs

Generally, there is no need to supplement with linoleic acid (omega-6), since it is so abundant in the American diet. However, supplements of omega-3 fatty acids may be needed to prevent deficiency and to balance the high intake of omega-6s.

Cod Liver Oil

Cod liver oil is extracted from cod liver and is a source of vitamins A and D as well as EPA and DHA. Fish oils are extracted from the flesh of fatty fish like anchovies, sardines and mackerel, and are good sources of EPA and DHA (but not vitamins A and D). EPA and DHA supplements derived from algae are available for persons averse to consuming fish. A recommended intake of EPA + DHA for reducing risk of cardiovascular disease is 500 milligrams/day; for treating existing cardiovascular disease, the recommendation is 1 gram/day.¹² These recommendations, based on epidemiologic and controlled clinical studies, are higher than earlier recommendations, which were intended merely to prevent deficiency of omega-3 fatty acids (manifested in impaired visual acuity and learning deficit).¹¹ Whether the recommendations for preventing and treating heart disease are sufficient for other conditions associated with low omega-3 fatty acid intake remains to be established. Flax oil is a good source of ALA; however, research suggests that one has to take up to 10 times more flax oil than fish oil to get a comparable amount of EPA. Two tablespoons of freshly ground flaxseed provide the same amount of alpha linolenic acid as would ½ teaspoon flaxseed oil, along with lignans and other healthful compounds found in the whole seed.

People who supplement with fish oil should take additional vitamin E supplements (several hundred IUs) to protect EPA and DHA within the body from oxidative damage.¹⁴

References

1. Enig, M. Know Your Fats. Bethesda Press, Silver Spring, MD, 2000.
2. Fallon S & Enig M. Tripping down the prostaglandin pathway. Price-Pottenger Nutrition Foundation Health Journal 1999; 20(3).
3. Mantzioris E et al. Dietary substitution with an alpha-linolenic acid-rich vegetable oil increases eicosapentaenoic acid concentrations in tissues. Am J Clin Nutr 1994; 59:1304-1309.
4. Harris WS. n-3 fatty acids and serum lipoproteins: human studies. Am J Clin Nutr 1997; 65(5suppl):1645S-1654S [review].
5. Wu A, Noble EE, Tyagi E, et al. “Curcumin boosts DHA in the brain: Implications for the prevention of anxiety disorders.” Molecular Basis of Disease. May 2015;1852(5): 951-961 https://doi.org/10.1016/j.bbadis.2014.12.005
6. Lassere, M et al. Lipids 1983; 20(4):227.
7. Enig M & Fallon S. The Skinny on Fats. Found at www.westonaprice.org. Published 1999. Found on Dec 18th, 2001.
8. Crayhon, R. Nutrition Made Simple. M Evans and Company, New York, 1994.
9. A general review of citations for problems with polyunsaturated consumption is found in Pinckney ER & Pinckney C: The Cholesterol Controversy, 1973, Sherbourne Press, Los Angeles, 127-131; research indicating the correlation of polyunsaturates with learning problems is found in Harmon D et al, J Am Geriatrics Soc 1976, 24(1):292-298; Meerson Z et al, Bull Exp Biol Med 1983, 96(9):70-71; regarding weight gain: Valero et al, Levels of linoleic acid in adipose tissues reflect the amount of linoleic acid in the diet. Ann Nutr Metab 1990, 34(6):323-327; Felton CF et al, Lancet 1994, 344:1195-1196.
10. Murray RK et al. Harper’s Biochemistry 23rd edition. Appleton and Lang, 1993, p. 235.
11. Ross, J. The Diet Cure. The Penguin Group, New York, NY, 2000.
12. Gebauer SK et al. n-3 fatty acid dietary recommendations and food sources to achieve essentiality and cardiovascular benefits. Am J Clin Nutr 2006; 83(6):S1526-S1535.
13. Ghafoorunissa IM. N-3 fatty acids in Indian diets: comparison of the effects of precursor (alpha-linolenic acid) vs product (long-chain n-3 polyunsaturated fatty acids). Nutr Res 1992; 12:569-582.
14. Wander RC et al. Effects of interaction of RRR-tocopheryl acetate and fish oil on low-density-lipoprotein oxidation in postmenopausal women with and without hormone-replacement therapy. Am J Clin Nutr 1996; 63:184-193.