Reference Sheet for Nutrition Experts June 12 2014

A study of the preventable causes of death in the USA published in 2009, estimated that the number of deaths caused by the insufficient levels of the dietary Omega-3 intake were around 84,0001

 

 Long Chain PolyunsaturatedOmega-3 Fatty Acids: EPA and DHA
 Quick Reference Guide for Nutrition Experts

 

 

Understanding Long Chain Polyunsaturated Omega-3 acids (LCPUW3) EPA and DHA

 Omega-3 fatty acids are chains of Carbon atoms with the acid (COOH) end and the methyl (CH3) end, and with Hydrogen atoms attached to some Carbon atoms

Omega-3 means that the first double bond between Carbon atoms occurs at the 3rd carbon atom from the methyl end (referred to as “omega”)

Polyunsaturated – some Hydrogen atoms are replaced with double bonds between carbons, thus it is unsaturated in many places from Hydrogen.

Long Chain – typically refers to the fatty acids with more than 18 Carbon atoms in the chain

Fatty Acid – they are called fatty, because the natural form of the fatty acids, triglycerides, were first derived from natural fats and oils

 

EPA - Eicosapentaenoic acid 20:5n-3

 

DHA - Docosahexaenoic acid 22:6n-3

Eicosa = 20 (is the # of carbon atoms in the fatty acid chain)

Penta = 5 (# of double bonds chain)

Enoic = an acid with double bonds

Docosa = 22 (is the # of carbon atoms in fatty acid chain)

Hexa = 6 (# of double bonds)

Enoic = an acid with double bonds

 

Omega-3 fatty acids are essential to human diet

Even though EPA and DHA can be created by the body from ALA (18:3n-3), it only happens in very limited quantities (less than 5%)2, 3. Apart from that limited conversion, a human body cannot synthesize them. This places EPA and DHA in one category with vitamins and minerals: they are all essential nutrients that cannot be made by the bodies and have to be consumed from either diet or dietary supplements

 

Food Sources

EPA and DHA are also called “marine Omega-3 fatty acids” - the best food sources of EPA and DHA are cold water fatty fish. The wild-caught Salmon species offer the highest content of EPA and DHA along with the lowest levels of Mercury. Other good sources of EPA and DHA that are also low in Mercury are Pollock, anchovy, canned sardines, shrimp, scallop, and clams. Most other fish species high in EPA and DHA are also high in Mercury and should not be consumed frequently4,5.

 

Why we need LCPU Omega-3 fatty acids

EPA and DHA play both structural and functional roles.

Structurally, LCPUW3-s are a component of every cell in every tissues and every organ of the body, including brain, eyes, blood cells, skin etc. They are a structural part of the cell membranes and give them the necessary fluidity and flexibility6.

 

Functionally, -

  • DHA produces an epigenetic signal that turns on the BDNF (brain derived neurotrophic factor) gene, and the latter activates neurogenesis and neuroplasticity in the brain7
  • EPA is a precursor of a certain type of prostaglandins, hormone-like compounds, which serve as catalysts for a large number of processes within cells and tissues. For example, prostaglandins are involved in regulation of the immune function, blood clotting, contraction and relaxation of artery walls, inflammation, and cell growth8
  • Human beings evolved on a diet with a ratio of omega-6 to omega-3 fatty acids of ~1 whereas in Western diets the ratio is over 15-to-1 9.In addition to carrying out its own functions, Omega-3 derived prostaglandins exert anti-inflammatory effect by balancing and counteracting Omega-6 derived prostaglandins10.
  • EPA and DHA are necessary for the gene expression. They interact directly with DNA as well as with proteins that affect the processing of transcription factors11
  • There has been extensive research on the multiple health benefits of Omega-3; and so far FDA has approved a statement that “Supportive but not conclusive research shows that consumption of EPA and DHA omega-3 fatty acids may reduce the risk of coronary heart disease.”

How much Omega-3 do we need to consume

To experience health benefits of Omega-3, it should be consumed consistently over a period of time. 8% and above is the level of Omega-3 in the red blood cells membrane that has been linked to improved health and longevity12. The research shows that moving the average Americans’ Omega-3 level of 4% to the target 8% is time and dose dependent and takes:

                           1 g of EPA+DHA a day – 6 months

                           2 g of EPA+DHA a day – 3 months

                           3 g of EPA+DHA a day – 2 months13

 

Official recommendations and other facts for the Omega-3 intake

  • Recommended Omega-3 consumption varies by country and is led by Japan that recommends consuming > 2 g of EPA + DHA per day14.
  • American Academy of Nutrition and Dietetics and Dietitians of Canada recommend that healthy adults should consume at least 2 servings of fatty fish a week or 500 mg of EPA+DHA a day15
  • American Heart Association recommends that adults with documented Coronary Heart Disease consume 1 g of EPA+DHA per day, and adults with hypertriglyceridemia take 2 – 4 g of EPA+DHA per day16

Greenland Inuits whose surprisingly low level of heart disease started the interest in the fish oil, consume around 4g of EPA and DHA a day (from seal and fish)17

 

References

  1. Danaei G, Ding EL, Mozaffarian D, et al. The Preventable Causes of Death in the United States: Comparative Risk Assessment of Dietary, Lifestyle, and Metabolic Risk Factors. PLoS Medicine. 2007; 6(4):e1000058
  2. Gerster H. Can adults adequately convert alpha-linolenic acid (18:3n-3) to eicosapentaenoic acid (20:5n-3) and docosahexaenoic acid (22:6n-3)? International Journal for Vitamin and Nutrition Research. 1998;68(3):159-73
  3. Brenna JT, Salem N Jr, Sinclair AJ, et al. Alpha-linoleic acid supplementation and conversion to n-3 long-chain polyunsaturated fatty acids in humans. Prostaglandins, Leukotriens and Essential Fatty Acids. 2009;80:85-91.
  4. FDA. Mercury Levels in Commercial Fish and Shellfish (1990-2010). Retrieved from: http://www.fda.gov/food/foodsafety/product-specificinformation /seafood/foodbornepathogenscontaminants/methylmercury/ucm115644.htm 
  5. USDA. Nutrition and Your health: Dietary Guidelines for Americans. Appendix G2, Addendum A. EPA and DHA Content of Fish Species. Retrieved from: http://www.health.gov/dietaryguidelines/dga2005/report/html/table_g2_adda2.htm
  6. Zimmermann MB. Burgerstein's Handbook of Nutrition: Micronutrients in the Prevention and Therapy of Disease. New York: Thieme. 2001; 89
  7. Wu A, Ying Z, and Gomez-Pinilla F. DHA dietary supplementation enhances the effects of exercise on synaptic plasticity and cognition. Neuroscience. 2008 August 26; 155(3): 751–759
  8. DeCaterina, R Basta, G. N-3 Fatty acids and the inflammatory response – biological background. European Heart Journal Supplements. 2001 3; Suppl D: D42–D49
  9. Simopoulos AP. The importance of the omega-6/omega-3 fatty acid ratio in cardiovascular disease and other chronic diseases. Experimental Biology and Medicine (Maywood). 2008; 233: 674–688
  10. Wildman R.E.C (ed.). Handbook of Nutraceuticals and Functional Foods, 2nd Edition. CRC Press. 2006; 233-234
  11. Deckelbaum RJ, Worgall TS, Seo T. N−3 Fatty acids and gene expression1,2,3,4. The American Journal of Clinical Nutrition. 2006; Volume 83 (6): S1520
  12. Farzaneh-Far R, Lin J, Epel ES, et al. Association of marine omega-3 fatty acid levels with telomeric aging in patients with coronary heart disease. Journal of the American Medical Associations. 2010; 303(3):250-257.
  13. Harris WS. The Omega-3 Index: Clinical Utility for Therapeutic Intervention. Current Cardiology Reports. 2010 (Sept). 12:503–508
  14. Ministry of Health, Labor, and Welfare, Japan. Dietary Reference Intakes for Japanese. Tokyo: Ishiyaku Publishers; 2009. Retrieved from: http://www.mhlw.go.jp/houdou/2004/11/d1/h1122-2b.pdf
  15. Kris-Etherton PM, Innis S. Position of the American Dietetic Association and Dietitians of Canada. Journal of the American Dietetic Association. 2007; 107:1599-1611
  16. Kris-Etherton PM, Harris WS; Appel LJ. Omega-3 fatty acids and cardiovascular disease: New Recommendations from the American Heart Association. Arteriosclerosis, Thrombosis and Vascular Biology. 2003; 23:151-152
  17. Bang HO, Dyerberg J, Sinclair HM. The composition of the Eskimo food in north western Greenland. American Journal of Clinical Nutrition. 1980; 33:2657-61

 

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