Known as essential fatty acids, omega-3 and 6 fatty acids are needed by the body for a plethora of functions — from building healthy cells to maintaining efficiency of vital organs like the brain, heart and nervous system. Since these fatty acids cannot be synthesized by our body, we are totally dependent on our diet to meet our body’s needs. Here’s a brief overview of the different omega fatty acids.
1. Omega-3 polyunsaturated fatty acids (PUFAs)
This essential fatty acid exists in three nutritionally pertinent forms:
- ALA (alpha-linolenic acid);
- DHA (docosahexaenoic acid);
- EPA (eicosapentaenoic acid).
- ALA, the shortest omega-3, comes from plant sources like walnuts, soybean oil, canola oil, flaxseed, some leafy vegetables as well as meat and milk products from animals raised on pasture. EPA and DHA, the longer omega-3 fatty acids, are both found in marine algae and fish which feed on these algae; fish oil supplements, and fortified products.
According to a large body of evidence, the omega-3 fatty acids provide an ocean of far-reaching health benefits and have been shown to:
Decrease risks of cardiovascular diseases, cardiac arrhythmias and stroke;
- Lower blood pressure;
- Decrease serum triglyceride levels;
- Delay the progression of atherosclerosis;
- Reduce inflammation;
- Alleviate autoimmune diseases;
- Reverse liver disease in neonates;
- Enhance cognitive function in older adults by protecting telomeres;
- Prevent flaky and dry skin.
But not all omega-3s are equal: while ALA also benefits overall health, it does so to a lesser degree compared to EPA and DHA — to be assimilated by the body, ALA needs to be converted to EPA and DHA. Conversion of ALA to EPA is slow and only 5% of the DHA is converted to EPA1. The conversion to DHA is even slower and less than 2% of the ALA is converted2.
The American Heart Association (AHA) recommends that healthy people consume at least two servings — one serving is 3.5 ounces of cooked fish — of a variety of oily fish such as tuna, salmon and sardines per week while including ALA-rich foods in the daily diet. The AHA also advises people with coronary heart disease to eat about one gram of EPA and DHA daily, preferably from fatty fish.
2. Omega-6 polyunsaturated fatty acids
There are two types of omega-6 PUFAs:
- LA (linoleic acid) — found in vegetable oils such as corn, safflower, sunflower and soybean oils.
- AA (arachidonic acid) — found in meats, eggs, and some fish.
While omega-6 PUFAs play an important role in brain function, as well as normal growth and development, some scientists suggest that these PUFAs compete with omega-3 for the same enzymes when the intake is disproportionate—hence, the ratio of these two PUFAs is very important. Based on studies, the optimal omega-6:omega-3 ratio is 1:1. Unfortunately, today that ratio is about 16:1 because we consume too much vegetable oil (that includes products containing these oils) from seeds and grains and because the meat and dairy products we enjoy come mostly from animals fed with omega-6–rich grains. The natural diet of cows, for instance, is grass (which is rich in omega-3) and feeding them with omega-6 rich grains has changed the fatty acid composition of their meat and meat accordingly.
The problem with the disparity between the consumption of these two PUFAs had serious health consequences. For example, a profusion of omega-6 fatty acids coupled with an inadequate intake of omega-3 fatty acids augments the risk of developing cardiovascular disease, cancer, osteoporosis, arthritis, mental health disturbances, obesity, diabetes, and inflammation3.
Putting Balance into Practice
Omega-6 fatty acids may well be essential but we need only two plain slices of whole wheat bread to meet our requirements. You may also want to choose grass-fed beef and derived products; follow a Mediterranean diet and increase your fish consumption.
3. Omega-9 monounsaturated fatty acids (MUFAs)
Also known as oleic acid, the omega-9 fatty acids are monounsaturated fats abundant in olive oil, safflower oil, canola oil, avocado, eggs, dairy products and nuts such as almonds and peanuts. Although omega-9 fatty acids are non-essential (our body can produce what it needs), the intake of these heart-healthy fats is recommended. Moreover, most dietary sources of MUFAs are also rich in the antioxidant vitamin E.
1. Jenkins, DJA, Josse AR. (2008) Fish oil and omega-3 fatty acids. CMAJ. 178(2):150.2. Davis BC, Kris-Etherton PM. (2003) Achieving optimal essential fatty acid status in vegetarians: Current knowledge and practical implications. Am J Clin Nutr.78 (3 Suppl):640S-646S
3. Simopoulos AP. (2008) The importance of the omega-6/omega-3 fatty acid ratio in cardiovascular disease and other chronic diseases. Exp Biol Med. 233:674-688.