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Omega 3 is a type of fat that the human body cannot produce on its own, which is why it is called 'essential'. To understand what an Omega 3 is, we need to go over a little bit of chemistry. Fats are made from a long chain of carbon atoms, like this:
[[File:O3 - carbon chain.jpg|none|thumb|500px|A simple chain of carbon atoms]]
These carbon atoms can be joined together with a single bond or a double bond. The double bonds are important, because the they cause a bend in the chain, whereas the single bonds are straight.
[[File:O3 - Double Bond.jpg|none|thumb|500px|A double bond showing the bend]]
That means that the mix of single and double bonds creates different shaped fats and our bodies make use of these different shapes to do different things, like make hormones. If there are no double bonds, then this is called a saturated fat, a single double bond is a mono unsaturated fat, and two or more double bonds are poly unsaturated fats.
* It is believed that only about 5% of the shorter, plant based Omega 3 oils can be converted to the longer chain variants we need.
* A fat and an oil are the same thing, but fats are solid at room temperature while oils are liquid. Typically a fat is saturated and an oil is unsaturated as the double bonds change the melting point.
* While there are some concerns that Omega-3 might raise blood sugar levels, this is probably only true for type-2 diabetics that take high doses (>8g/day).
** A review of studies in the late 1980s/early 1990s showed that high levels of omega-3 supplementation in type-2 diabetics raises fasting glucose<ref name="Nettleton1995"/>.
*** Type-2 diabetics had higher fasting glucose levels after taking 18g/day of fish oil for a month<ref name="Glauber-1988"/>.
*** Giving type-2 diabetics 8g/day of fish oil impaired the effect of a blood glucose lowering medication (glyburide )<ref name="Zambon-1992"/>.
*** Type-2 diabetics given 8g/day of fish oil had higher fasting glucose levels and increased post-prandial glucose<ref name="FridayChilds1989"/>.
*** A study giving 10g/day of fish oil or safflower oil adversely affected glycemic control in type-2 diabetics, but this may be due to the increased calorie intake (900 Calories/day)<ref name="BorkmanChisholm1989"/>.
** However, it is believed that these increases were due to the high levels of supplementation<ref name="NettletonKatz2005"/>.
*** Obese patients with impaired glucose tolerance (IGT) had no change in fasting blood glucose levels, nor a change in glucose response when given 30ml of fish oil for two weeks<ref name="FaschingRatheiser1991"/>.
*** A meta-analysis of 18 trials covering 823 patients concluded that fish oil had no statistically significant effect on fasting glucose of type-2 diabetics<ref name="MontoriFarmer2000"/>.
*** Overweight hypertensive patients given 3.65g fish oil daily for 16 weeks had no change in glucose or insulin response , though the combination of fish oil and weight loss improved glucose and insulin response more than weight loss alone<ref name="Mori-1999"/>.
* The 2003 American Heart Association statement concluded that ''"Omega-3 fatty acids have been shown in epidemiological and clinical trials to reduce the incidence of Cardiovascular disease"'', though they noted that the recommended intake is unclear<ref name="Kris-Etherton2003"/>.
=References=
<references>
<ref name="BorkmanChisholm1989">M. Borkman, D. J. Chisholm, S. M. Furler, L. H. Storlien, E. W. Kraegen, L. A. Simons, C. N. Chesterman, Effects of Fish Oil Supplementation on Glucose and Lipid Metabolism in NIDDM, Diabetes, volume 38, issue 10, 1989, pages 1314–1319, ISSN [http://www.worldcat.org/issn/0012-1797 0012-1797], doi [http://dx.doi.org/10.2337/diab.38.10.1314 10.2337/diab.38.10.1314]</ref>
<ref name="FaschingRatheiser1991">P. Fasching, K. Ratheiser, W. Waldhausl, M. Rohac, W. Osterrode, P. Nowotny, H. Vierhapper, Metabolic Effects of Fish-Oil Supplementation in Patients With Impaired Glucose Tolerance, Diabetes, volume 40, issue 5, 1991, pages 583–589, ISSN [http://www.worldcat.org/issn/0012-1797 0012-1797], doi [http://dx.doi.org/10.2337/diab.40.5.583 10.2337/diab.40.5.583]</ref>
<ref name="Kris-Etherton2003">P. M. Kris-Etherton, Fish Consumption, Fish Oil, Omega-3 Fatty Acids, and Cardiovascular Disease, Arteriosclerosis, Thrombosis, and Vascular Biology, volume 23, issue 2, 2003, pages 20e–30, ISSN [http://www.worldcat.org/issn/10795642 10795642], doi [http://dx.doi.org/10.1161/01.ATV.0000038493.65177.94 10.1161/01.ATV.0000038493.65177.94]</ref>
<ref name="MontoriFarmer2000">V. M. Montori, A. Farmer, P. C. Wollan, S. F. Dinneen, Fish oil supplementation in type 2 diabetes: a quantitative systematic review, Diabetes Care, volume 23, issue 9, 2000, pages 1407–1415, ISSN [http://www.worldcat.org/issn/0149-5992 0149-5992], doi [http://dx.doi.org/10.2337/diacare.23.9.1407 10.2337/diacare.23.9.1407]</ref>
<ref name="Mori-1999">TA. Mori, DQ. Bao, V. Burke, IB. Puddey, GF. Watts, LJ. Beilin, Dietary fish as a major component of a weight-loss diet: effect on serum lipids, glucose, and insulin metabolism in overweight hypertensive subjects., Am J Clin Nutr, volume 70, issue 5, pages 817-25, Nov 1999, PMID [http://www.ncbi.nlm.nih.gov/pubmed/10539741 10539741]</ref>
<ref name="Glauber-1988">H. Glauber, P. Wallace, K. Griver, G. Brechtel, Adverse metabolic effect of omega-3 fatty acids in non-insulin-dependent diabetes mellitus., Ann Intern Med, volume 108, issue 5, pages 663-8, May 1988, PMID [http://www.ncbi.nlm.nih.gov/pubmed/3282462 3282462]</ref>
<ref name="Zambon-1992">S. Zambon, KE. Friday, MT. Childs, WY. Fujimoto, EL. Bierman, JW. Ensinck, Effect of glyburide and omega 3 fatty acid dietary supplements on glucose and lipid metabolism in patients with non-insulin-dependent diabetes mellitus., Am J Clin Nutr, volume 56, issue 2, pages 447-54, Aug 1992, PMID [http://www.ncbi.nlm.nih.gov/pubmed/1636624 1636624]</ref>
<ref name="FridayChilds1989">K. E. Friday, M. T. Childs, C. H. Tsunehara, W. Y. Fujimoto, E. L. Bierman, J. W. Ensinck, Elevated plasma glucose and lowered triglyceride levels from omega-3 fatty acid supplementation in type II diabetes, Diabetes Care, volume 12, issue 4, 1989, pages 276–281, ISSN [http://www.worldcat.org/issn/0149-5992 0149-5992], doi [http://dx.doi.org/10.2337/diacare.12.4.276 10.2337/diacare.12.4.276]</ref>
<ref name="Nettleton1995">Joyce A. Nettleton, Omega-three Fatty Acids and Health, date 31 December 1995, publisher Springer, isbn 978-0-412-98861-5</ref>
<ref name="NettletonKatz2005">J Nettleton, R Katz, n-3 long-chain polyunsaturated fatty acids in type 2 diabetes: A review, Journal of the American Dietetic Association, volume 105, issue 3, 2005, pages 428–440, ISSN [http://www.worldcat.org/issn/00028223 00028223], doi [http://dx.doi.org/10.1016/j.jada.2004.11.029 10.1016/j.jada.2004.11.029]</ref>
</references>
=Further reading=
* [[The Runners Diet]]
