Only two essential fatty acids are known to be essential for humans: alpha-linolenic acid (an omega-3 fatty acid) and linoleic acid (an omega-6 fatty acid).[1] The biological effects of the ω-3 and ω-6 fatty acids are mediated by their mutual interactions. Closely related, these fatty acids act as competing substrates for the same enzymes. The biological effects of the ω-3 and ω-6 fatty acids are largely mediated by essential fatty acid interactions. The proportion of omega-3 to omega-6 fatty acids in a diet may have metabolic consequences.[2] Unlike omega-3 fatty acids and omega-6 fatty acids, omega-9 fatty acids are not classed as essential fatty acids because they can be created by the human body from monounsaturated and saturated fatty acids, and are therefore not essential in the diet.

Ratio of omega-6 to omega-3 fats in the diets of hunter-gatherers

It has been claimed that among hunter-gatherer populations, omega-6 fats and omega-3 fats are typically consumed in roughly a 1:1 ratio.[3][4][better source needed] At one extreme of the spectrum of hunter-gatherer diets, the Greenland Inuit, prior to the late Twentieth Century, consumed a diet in which omega-6s and omega-3s were consumed in a 1:2 ratio, thanks to a diet rich in cold-water fish (which are a rich source of omega-3s) and completely devoid of omega-6-rich seed oils.[5]

Optimal ratio of omega-6 to omega-3 fats

To date, "no one knows what the optimal ratio in the diet is for these two families of fats."[6] Science writer Susan Allport writes that the current ratio in Japan is associated with a very low incidence of heart and other diseases. A dietary ratio of 4:1 produces almost a 1:1 ratio of highly unsaturated fatty acids (HUFAs) in cell membranes."[6][clarification needed]

In a study with rats, a dietary ratio of 4:1 showed significant favorable effects on learning performance and pain tolerance.[7]

Andrew Stoll, M.D., Director of the Psycho-pharmacology Research Laboratory at Harvard's McLean Hospital, who advocates the consumption of the two fats in a 1:1 ratio, states, "Once in the body, omega-3 and omega-6 fatty acids follow parallel pathways, continually competing with each other for chemical conversion to various structures and molecules inside and outside the cells. Given this mechanism, it makes sense that the two fats might be required in approximately equal amounts."[8]

Both Stoll and Allport assert that present-day diets in the developed world have departed dramatically from this ratio. It has been estimated that in developed countries, the ratio of omega-6s to omega-3s is closer to 15:1[9] Another estimate is that "[t]he diet consumed by the typical American tends to contain 14–25 times more omega-6 fatty acids than omega-3 fatty acids."[10]

According to a 2009 review by the American Heart Association, instead of avoiding ω-6 fats, the ω-6:ω-3 ratio should be decreased by consuming more ω-3 fats. The conversion rate of linoleic acid (LA) into arachidonic acid is very low with a diet high in linolenic acid.[11]

The maximum ω-6:ω-3 ratio allowed in dog food by the AAFCO is 30:1.[12]

Fish

Food Citation Serving size (g) Omega-6 fatty acids (mg) Omega-3 fatty acids (mg) Omega-6 : omega-3 ratio
Salmon, wild, raw [13] 100 172 2018 1 : 11
Sardines, canned in oil [14] 1 can
(92 g) 		3260 1362 2 : 1
Sardines, canned in water [15] 1 can
(92 g) 		655 1457 1 : 2
Tuna, canned in water [16] 1 can
(165 g) 		14 460 1 : 31
Tuna, canned in oil [17] 1 can
(171 g) 		4588 345 13 : 1
Mackerel, canned [18] 1 can
(361 g) 		357 4970 1 : 13
Herring [19] 100 g 246 2418 1 : 10

Nuts and seeds

Food Citation Serving size (g) Omega-6 (mg) Omega-3 (mg) Omega-6 : omega-3 ratio
Almonds, dry roasted [20] 100 12065 6 2010 : 1
Cashews [21] 100 7782 62 125 : 1
Chia seeds [22] 100 5785 17552 1 : 3
Coconut, raw [23] 100 366 - -
Flax seeds [24] 100 5911 22813 1 : 4
Hazelnuts, filberts [25] 100 7832 87 90 : 1
Hemp seeds [26] 100 56000 22000 3 : 1
Macadamia nuts, dry roasted [27] 100 1720 259 6 : 1
Pecans [28] 100 20630 986 21 : 1
Pistachios, raw [29] 100 13200 254 52 : 1
Poppy seed [30] 100 28291 273 103 : 1
Pumpkin seeds, whole, roasted [31] 100 8759 77 114 : 1
Sesame seeds, whole, dried [32] 100 21372 376 57 : 1
Sunflower seeds, kernels, dried [33] 100 23048 74 311 : 1
Walnuts [34] 100 38092 9079 4 : 1
Lentils, mature seeds, cooked, boiled, without salt [35] 100 137 37 4 : 1

See also

References

  1. ^ Whitney Ellie; Rolfes SR (2008). Understanding Nutrition (11th ed.). California: Thomson Wadsworth. p. 154.
  2. ^ Bibus, Doug; Lands, Bill (April 18, 2015). "Balancing proportions of competing omega-3 and omega-6 highly unsaturated fatty acids (HUFA) in tissue lipids". Prostaglandins Leukot. Essent. Fatty Acids. 99: 19–23. doi:10.1016/j.plefa.2015.04.005. PMID 26002802.
  3. ^ Andrew Stoll, The Omega-3 Connection. New York: Simon and Schuster, 2001, p. 43. "Populations maintaining historic omega-6 to omega-3 ratios (approximately 1 to 1) are protected from many of the scourges of the modern age."
  4. ^ Simopoulos, Artemis P. (2010-09-01). "The omega-6/omega-3 fatty acid ratio: health implications". Oléagineux, Corps gras, Lipides. 17 (5): 267–275. doi:10.1051/ocl.2010.0325. ISSN 1258-8210.
  5. ^ William Lands, Fish, Omega-3 and Human Health. Urbana, Illinois: APCS Press, 2005, p. 10.
  6. ^ a b Susan Allport, The Queen of Fats: Why Omega-3 Fats Were Removed From the Western Diet and What We Can Do to Replace Them. Berkeley: University of California Press, 2007, p. 115.
  7. ^ Yehuda, S.; Carasso, R. L. (1993-11-01). "Modulation of learning, pain thresholds, and thermoregulation in the rat by preparations of free purified alpha-linolenic and linoleic acids: determination of the optimal omega 3-to-omega 6 ratio". Proceedings of the National Academy of Sciences of the United States of America. 90 (21): 10345–10349. Bibcode:1993PNAS...9010345Y. doi:10.1073/pnas.90.21.10345. PMC 47771. PMID 7901853.
  8. ^ Andrew Stoll, The Omega-3 Connection. New York: Simon and Schuster, 2001, p. 40.
  9. ^ Simopoulos, AP (2002). "The importance of the ratio of omega-6/omega-3 essential fatty acids". Biomedicine & Pharmacotherapy. 56 (8): 365–79. doi:10.1016/S0753-3322(02)00253-6. PMID 12442909.
  10. ^ http://umm.edu/health/medical/altmed/supplement/omega6-fatty-acids[permanent dead link]
  11. ^ Harris, WS; Mozaffarian, D; Rimm, E; Kris-Etherton, P; Rudel, LL; Appel, LJ; Engler, MM; Engler, MB; Sacks, F (17 February 2009). "Omega-6 fatty acids and risk for cardiovascular disease: a science advisory from the American Heart Association Nutrition Subcommittee of the Council on Nutrition, Physical Activity, and Metabolism; Council on Cardiovascular Nursing; and Council on Epidemiology and Prevention". Circulation. 119 (6): 902–7. doi:10.1161/CIRCULATIONAHA.108.191627. PMID 19171857.
  12. ^ "AAFCO methods for substantiating nutritional adequacy of dog and cat foods (proposed for 2014 publication)" (PDF). AAFCO. 2013.
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  18. ^ "Fish, mackerel, jack, canned, drained solids". Self Nutrition Data, Condé Nast. Archived from the original on 2018-06-26. Retrieved 2019-02-15.
  19. ^ "Fish, herring, Pacific, cooked, dry heat Nutrition Facts & Calories". Self Nutrition Data, Condé Nast. Archived from the original on 2018-06-12. Retrieved 2019-02-15.
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  22. ^ "Seeds, chia seeds, dried Nutrition Facts & Calories". Self Nutrition Data, Condé Nast. Archived from the original on 2019-02-04. Retrieved 2019-02-15.
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  25. ^ "Nuts, hazelnuts or filberts Nutrition Facts & Calories". Self Nutrition Data, Condé Nast. Archived from the original on 2018-07-10. Retrieved 2019-02-15.
  26. ^ Rodriguez-Leyva, D.; Pierce, G. N. (2010). "The cardiac and haemostatic effects of dietary hempseed". Nutrition & Metabolism. PubMed Central. 7: 32. doi:10.1186/1743-7075-7-32. PMC 2868018. PMID 20409317.
  27. ^ "Nuts, macadamia nuts, dry roasted, without salt added Nutrition Facts & Calories". Self Nutrition Data, Condé Nast. Archived from the original on 2018-07-20. Retrieved 2024-01-11.
  28. ^ "Nuts, pecans Nutrition Facts & Calories". Self Nutrition Data, Condé Nast. Archived from the original on 2018-06-20. Retrieved 2019-02-15.
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  30. ^ "Spices, poppy seed Nutrition Facts & Calories". Self Nutrition Data, Condé Nast. Archived from the original on 2018-11-30. Retrieved 2019-02-15.
  31. ^ "Seeds, pumpkin and squash seeds, whole, roasted, without salt Nutrition Facts & Calories". Self Nutrition Data, Condé Nast. Archived from the original on 2018-12-30. Retrieved 2019-02-15.
  32. ^ "Seeds, sesame seeds, whole, dried Nutrition Facts & Calories". Self Nutrition Data, Condé Nast. Archived from the original on 2018-11-26. Retrieved 2019-02-15.
  33. ^ "Seeds, sunflower seed kernels, dried Nutrition Facts & Calories". Self Nutrition Data, Condé Nast. Archived from the original on 2018-07-07. Retrieved 2019-02-15.
  34. ^ "Nuts, walnuts, english (Includes USDA commodity food A259, A257) Nutrition Facts & Calories". Self Nutrition Data, Condé Nast. Retrieved 2023-02-27.
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