Explaining the Importance of Omega-3 and Omega-6 Fatty Acids in the Training Diet.

Essential fatty acids (EFA) are necessary in proper brain and nervous system function and for building new cells. Although they are essential for good health, these fatty acids cannot be made by the body. We must obtain EFA from dietary sources. The two primary EFAs are the omega-3 and omega-6. Plant derived omega-3 fatty acid is called alpha-linolenic acids, marine derived omega-3 is also know as eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA). Omega-6 fatty acids are also called linoleic acid.

The role of EFAs in human nutrition has long been recognized. Research links EFA intake with reduced risk for coronary heart disease (CHD), improving blood cholesterol levels and regulating the inflammation. This is beneficial for all individuals, regardless of physical activity level. However there is recent evidence, of great interest to triathletes, demonstrating a link between intake of EFA and improved fatty acid metabolism with increased fat oxidation and reduced fat synthesis. This could be good news for triathletes, so let’s take a closer look at the research and the benefits of EFAs.

Omega 3 and Cardiovascular Disease
Physical activity has been shown to be beneficial to cardiovascular health by promoting desirable blood lipids and lowering cholesterol and blood pressure. However, the heart is a muscle, and long-term endurance training puts a great deal of strain on the heart itself. Maintaining a proper diet and including EFA will help protect the endurance athlete’s heart.

Three epidemiological studies have shown that moderate consumption of fish rich in omega-3 was linked to lower CHD mortality and additional research has shown that men who ate at least 35 grams or more of fish daily had a reduced risk of death from sudden heart attack. The specific mechanism or mechanisms behind the observed effects are not known. Possible explanations offered by researchers are: 1. Promotion of regular heart beat, 2. Reduction of blood clotting, 3. Improved blood lipid levels (increases HDL, while reducing LDL and triglycerides) 4. Anti-inflammatory properties and 5. Reduction in blood pressure.

EFA and Inflammation
Inflammation is the leading cause of pain in athletes. Swelling and redness will result in lost training days and high intakes of anti-inflammatory medications can lead to damage of the stomach lining. There are three types of prostagalindins that regulate inflammation – PGE1 and PGE3 reduce inflammation while PGE 2 is pro-inflammatory. A balanced intake of omega-3 and omega-6 fatty acids will promote desirable prostaglandin levels which will reduce inflammation. A 2003 study links intake of marine derived omega-3 with reduced exercise-induced inflammation. This nutritional therapy is not only useful in athletes, but there is evidence to suggest the anti-inflammatory effects are beneficial to individuals with psoriasis, rheumatoid arthritis and autoimmune diseases.

Moreover, inflammation in the lungs can lead to bronchoconstriction in athletes. Supplemental omega-3 has been shown, in fact, to reduce bronchoconstriction and improve lung function in elite athletes. Better lung function means improved aerobic exercise capacity. As such, further investigation into the benefits of omega-3 and exercise induced asthma is warranted.

EFA and Athletic Performance
There are many anecdotal reports of improved performance with diets high in EFA, but there are limited human studies providing hard scientific evidence. There is, however, very promising research being done on animals. A study of swimming performance in salmon (2004) shows that salmon fed a diet low in omega-3 fatty acids did not swim as well as their counterparts fed an omega-3 rich diet. Another study looked at the effect of omega-3 supplementation on swimming performance in rats. Rats supplemented with omega-3 had an increase in FABP, a protein that brings fatty acids to the cells to be oxidized for energy, but no increase in triglycerides, indicating a diet high in omega-3 may help burn fat for energy without storing fat. Another study in rats compared body composition in groups of animals fed equivalent high fat diets from various sources – beef fat, mono-unsaturated fat, and omega-3 fat. The rats fed the high omega-3 diet had less stored fat, less fat cells and smaller fat cells. If translation from animals to humans is possible, these results indicate that EFA consumption may positively affect swimming performance (and arguably other forms of exercise) most likely by the promotion of fat burning with an accompanying reduction in fat storage.

How much should be consumed?
In the modern diet, the average American consumes a great deal of omega-6 fatty acids as they are in many of the foods we eat. Omega-3, on the other hand, are much more difficult to obtain. Typically the ratio of omega-6 to omega-3 is between 10:1 and 25:1, but could be as high as 50:1 in some individuals who eat a highly processed diet. Historically humans ate food much higher in omega-3 and omega-6 consuming a ratio much closer to 2:1. The ideal ratio is suggested to be less than 4:1 omega-6 to 3. The US National Institutes of Health recommends 650 mg/day of EPA and DHA and 2 gm/day of alpha-linolenic acid, along with 4 gm/day of linoleic acid. The Food and Drug Administration recognizes intakes up to 3 grams/day of omega-3 to be generally regarded as safe. However, there is some concern over the large-scale contamination of the worldwide fish supply. With that said, it may be advisable for triathletes to limit intake of all fish to 12 ounces per week. Environmental contaminants such as polychlorinated biphenyls (PCBs) and methylmercury are more likely to accumulate in the flesh than in the oil, therefore, safety concerns apply to eating fish, but likely not to ingesting fish oil supplements. Fish oil and flaxseed oil supplements are viable options to increase intake of omega-3 fatty acids. The complex structure of these fats makes them very chemically reactive and prone to spoilage, so make sure the supplements are in a dark bottle to protect them from light, keep them in a cool place away from heat, and keep the container tightly capped to protect from air.

The best way to create a favorable ratio of omega 3 to omega-6 is to either supplement your diet with omega-3 or increase intake of foods rich in omega-3. The table below identifies food and supplemental sources of omega-3 fatty acids.

  • Fish Amount in ounces required to provide 1 gm DHA+EPA
  • Tuna: Light canned in water 12
  • White canned in water 4
  • Fresh 2.5-12
  • Salmon: Atlantic Wild 2-3.5
  • Atlantic Farmed 1.5-2
  • Sardines 2-3
  • Haddock 15
  • Cod: Atlantic 12.5
  • Pacific 23
  • Catfish 15-20
  • Sole/Flounder 7
  • Trout 3-3.5
  • Shrimp/Crab/Clam 8.5-12.5
  • Scallop 17.5
  • Herring 1.5-2
  • Mackerel 2-8.8
  • Oils Grams of oil required to provide 1 gram EPA+DHA
  • Cod Liver Oil 5
  • Standard Fish Body Oil 3
  • Omega 3 Fatty Acid Concentrate 2
  • Nut and Vegetable Oils Grams of alpha-linolenic acid per Tablespoon
  • Canola Oil 1.3
  • Flaxseed/Linseed Oil 8.5
  • Flaxseeds 2.2
  • Walnut Oil 1.4
  • Walnuts 0.7

While the use of supplemental EFAs has been indicated to improve performance in laboratory animals, and to a limited extent in humans, it has not been definitively proven. Careful addition of EFAs, and all supplements, should be considered for optimal performance under the supervision of a qualified sports nutritionist.

Happy training!
Molly Gerster, MS, RD
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Kris-Etherton P, Harris W, Appel L. Fish comsumption, fish oil, omega 3 fatty acids, and cardiovascular disease. Circulation. 2002; 106;2747-2757.
Phillips T, Childs A, Dreon D, Phinney S, Leeuwenburg C. A dietary supplement attenuates IL-6 and CRPafter eccentric exercise in untrained males. Med Sci Sport Exerc.2003 Dec;35(12):2032-7.
Simopoulos A. The importance of the ratio of omega-6/omega-3 essential fatty acids. Biomed Pharmacother. 2002 Oct; 56(8):365-79.
Wagner G, BalfryS, Higgs D, Lall D, Farrell A. Dietary fatty acid composition affects the repeat swimming performance of Atlantic Salmon in seawater. Comp Biochem Physiol A Mol Integr Physiol. 2004 Mar; 137(3):567-76.

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