Essential Fatty Acids
Introduction
Little known to most laypersons, there is a group of fats known as the essential fatty acids that cannot be manufactured by the body and must be consumed for survival. There are two major groups of essential fatty acids broadly designated as the omega-3, and omega-6 fatty acids. These fats have wide ranging biochemical applications in the body usually related to proper functioning of the cell membrane and protein receptors embedded within the cell membrane. Omega-6 fatty acids go on to form substances that promote inflammation and cause the blood to clot. Omega-3 fatty acids perform the opposite function: they reduce inflammation and decrease the tendency to form blood clots. The body performs an incredibly complex balancing act between these two substances to meet the needs of the body.
An Alarming Decline of Omega-3 in the Diet
150 years ago, the American diet typically contained an equal ratio of omega-6 and omega-3 fatty acids. The standard American diet ("SAD") now has a ratio of omega-6 to omega-3 of 20-30:1. A major cause for this shift has been the farm production of vegetables and grains which have far higher ratios of omega-6 to omega-3 as compared to their wild counterparts. Making matters worse, these same grains are also used as feed for meat production on farms, further depressing the amount of omega-3 compared to omega-6 in our diets. Currently, the major sources of omega-3 include cold water fish, flax, walnuts, and soybeans.
A problem with the essential fatty acids is their unstable nature. Due to their chemical structure they are easily oxidized causing them to go rancid in a short period of time, they burn easily at low temperatures and are liquid at room temperature. The food industry has addressed these problems by artificially hydrogenating vegetable oils to create the dreaded trans-fatty acids. Hydrogenated vegetable oils allow margarine to remain solid and easier to spread, keeps peanut butter solid at room temperature, and allows inexpensive vegetable oils to be used as cooking oils at the high temperatures required for frying foods without burning. Trans-fatty acids decrease the levels of omega-3 fatty acids in the body by inhibiting its formation.
Health Implications of Diminished Omega-3
With a significant reduction in omega-3, the body is now unable to perform its balancing act between omega-6 and omega-3 which causes a predominance of inflammation and tendency to form blood clots. Inflammatory disorders such as rheumatoid arthritis, asthma, hay fever, eczema, ulcerative colitis, and Crohn's disease are exacerbated. The tendency to increase the formation of blood clots increases the incidence of heart attacks and strokes. There exists within the cell a key protein known as PPAR that plays a key role in the cell responding to insulin and is highly dependent on proper levels of omega-3. Deficiencies of omega-3 will worsen diabetes significantly.
The brain is another organ that is sensitive to deficiencies in omega-3. Certain fatty acids such as omega-3 make up 20% of the dry weight of the brain, therefore it is not surprising that omega-3 plays an important role in normal brain functioning. Within the last 100 years, the incidence of depression has been increasing, and the age of onset of depression has been decreasing in the western world. While some have argued that this may be explained by increased stress in our society, many have felt the rise in depression may be caused by the steady decline in omega-3 in our diets. Interestingly, several controlled medical studies have shown that the addition of omega-3 in the diets of depressed patients improved depressive symptoms significantly.
Though not yet shown in clinical studies, other degenerative neurological disorders and mood disorders such as Alzheimer's disease, age related memory loss, macular degeneration, attention deficit hyperactivity disorder, and anxiety could theoretically respond to omega-3 supplementation.
Conclusions
At a minimum, our diets should include a significant amount of cold water fish such as salmon, mackerel and herring one to three times a week, but environmental mercury is always a concern. The only plant product with a high amount of omega-3 is flax, and ingesting 2-3 tablespoons per day would be a reasonable recommendation. Flaxseed oil is also available in a pill form and may be a more convenient form to consume at a dose of 1-2 grams per day. Unfortunately, no more than fifteen percent of the omega-3 (alpha linolenic acid) is converted to the more important EPA and DHA of fish oil Fish oil capsules are the most widely available form of omega-3 supplementation. A typical 1000 mg (1 gram) capsule will contain two forms of omega-3: 300mg of EPA (eicosapentaenoic acid), and 200 mg DHA (docosahexaenoic acid) for a total dose of 500 mg per capsule of omega-3. It would be reasonable to supplement with 2-4 1000 mg capsules of fish oil per day. If you decide to supplement with fish oil, it is extremely important that the manufacturer certify that the fish oil is free of toxic contaminants such as mercury, dioxin, and heavy metals which are sometimes found in fish. It would be prudent to supplement with Vitamin E 200-400 IU a day if you are taking additional omega-3 to help prevent the oxidation of the rather delicate omega-3 molecule.
Bibliography
Logan, Alan C. Neurobehavioral Aspects of Omega-3 Fatty Acids: Possible Mechanisms and Therapeutic Value in Major Depression. Alternative Medicine Review 2003; 8(4):410-425.
Sudak, Nancy. Essential Fatty Acids. The Art, Science & Practice of Holistic Medicine. Fourth Annual American Board of Holistic Medicine Review Course. 427-440. October 12, 2003.
Lloyd Ito, MD
12/21/03