Essential Fatty Acids
Essential fatty acids are necessary for our health, but aren't synthesized in the body, so we must get them through the diet. The two types of essential fatty acids are omega-3 fatty acids and omega-6 fatty acids.
Omega-3 fatty acids get their name from their chemical configuration - they have their first double bond between the third and fourth carbon atoms on the chain. The omega-3 acid that we cannot make in our bodies is alpha-linolenic acid, or ALA. From this fatty acid we can make the other omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). ALA is found in flax seed and flaxseed oil, walnuts and walnut oil, pumpkin seeds, canola oil, mustard oil, soybean oil and tofu. EPA and DHA are found in fish oils. Even though we can synthesize these, most people don't make very large quantities and could use a good dietary source of fish oils or a supplement.
Omega-6 fatty acids have their first double bond between the sixth and seventh carbon. Linoleic acid, or LA is the essential omega-6 fatty acid. Once we get LA in our diet, we can use it to synthesize arachadonic acid, another necessary omega-6 fatty acid. LA is found in nuts and plant oils such as brazil nuts, pine nuts, sunflower seeds, pecans, safflower oil, sunflower oil, corn oil, soybean oil, and sesame oil. Meats also contain omega-6 fatty acids.
It is rare to find a deficiency of omega-6 fatty acids in Western diets. In fact, most Americans tend to have too much omega-6 compared to omega-3. You should have about 4 times the amount of omega-6 as omega-3, but Americans tend to have anywhere from 10 to 30 times the amount of omega-6. Maybe this is due to the large amounts of oils and fried foods we eat. This unbalanced ratio can lead to some of the health problems discussed below. You can get a higher ratio of omega-3 fatty acids by avoiding foods fried in vegetable oils, eating less meats, eating more fish, flax seed, walnuts and other specific sources of these fatty acids, or taking a fish oil supplement.
There is a lot of evidence showing that omega-3 fatty acids can protect against cardiovascular disease, reduce the risk of heart attack and reduce the risk of sudden cardiac death in people who already have heart disease. The American Heart Association recommends eating fish at least twice weekly. There is evidence that omega-6 fatty acids also protect against heart disease, but the studies don't show as strong a relationship as for the omega-3 fatty acids.
Studies also show that omega-3 fatty acids can reduce inflammation, especially in those with rheumatoid arthritis or joint pain. Other less conclusive areas that could use more study are beneficial effects for people with inflammatory bowel disease, asthma, protection for organ transplant patients, development of eye sight in infants, age-related macular degeneration, depression, bipolar disorders and schizophrenia. For more information on studies with essential fatty acids, see the Mayo Clinic website, or the Linus Pauling Institute.
The information on this page is not meant to be used in treatment of medical conditions. Please seek the advice of a physician about any medical condition or symptom. Those with medical conditions should consult a medical professional about the appropriateness of taking dietary supplements or diet therapy, and how these methods will interact with their medications.
LINKS
Fish Oil Direct Nutritional Directory
Phytochemical Society of North America
Phytochemical Society of Europe
For detailed information about the chemical structure, formula, and molecular weight of various phytonutrients, visit
The US Dept of Agriculture.
Phytochemicals also gives detailed information on specific phytochemicals.
Search for herbs at the Sloan Kettering Memorial Cancer Center website.