Changes

==Roles in the Body==

==Roles in the Body==

#'''Skin and Hair Coat:''' Epidermal keratinocytes secrete the LA-enriched phospholipid, ceramide, in both dogs and cats, which enhances cell cohesion and creates an effective water barrier.<ref>Elias PM, ''et al.'' (1980)''' The permeability barrier in essential fatty acid deficiency: Evidence for a direct role of linoleic acid in barrier function.''''' J Invest Dermatol ''1980;74:230-233. </ref> Increased intake of ALA may blunt the conversion of LA to AA,<ref name="Rees" /><ref name="Bauer" /> allowing for more LA to be incorporated into ceramide. Ratios of LA:ALA of 2.6:1 to 26:1 have been proposed for optimal skin and coat health.<ref name="NRC">National Research Council (NRC). (2006) '''Fat and Fatty Acids In Nutrient Requirements for Dogs and Cats. '''2006 ''Washington, DC: National Academies Press'' p.81-110.</ref>

#'''Skin and Hair Coat:''' Epidermal keratinocytes secrete the LA-enriched phospholipid, ceramide, in both dogs and cats, which enhances cell cohesion and creates an effective water barrier.<ref>Elias PM, ''et al.'' (1980)''' The permeability barrier in essential fatty acid deficiency: Evidence for a direct role of linoleic acid in barrier function.''''' J Invest Dermatol ''1980;74:230-233. </ref> Increased intake of ALA may blunt the conversion of LA to AA,<ref name="Rees" /><ref name="Bauer" /> allowing for more LA to be incorporated into ceramide. Ratios of LA:ALA of 2.6:1 to 26:1 have been proposed for optimal skin and coat health.<ref name="NRC">National Research Council (NRC). (2006) '''Fat and Fatty Acids In Nutrient Requirements for Dogs and Cats. '''2006 ''Washington, DC: National Academies Press'' p.81-110.</ref>

#'''Inflammation:''' Eicosapentaenoic acid is incorporated into cellular membrane and competes with AA for cyclooxygenase (COX) and lipoxygenase (LOX) enzymes. Inflammatory [[Nutrition Glossary#Eicosanoids|eicosanoids]] produced from EPA (series-3 prostaglandins, prostacyclins and thromboxanes and series-5 leukotrienes) are less pro-inflammatory than those produced from AA metabolism.<ref name="NRC" /> Though not considered an essential fatty acid, increased intake of EPA in conjunction with a decrease in AA intake has been suggested as an aid in the management of inflammatory conditions such as [[Contact Dermatitis|allergic dermatitis]],<ref>Mueller RS, ''et al.'' (2005) '''Plasma and skin concentrations of polyunsaturated fatty acids before and after supplementation with n-3 fatty acids in dogs with atopic dermatitis.''''' Am J Vet Res'' 2005;66:868-73.</ref> nephritis,<ref>Brown SA, ''et al.'' (2000)''' Effects of dietary polyunsaturated fatty acid supplementation in early renal insufficiency in dogs. '''''J Lab Clin Med ''2000;135:275-286.</ref> and [[osteoarthritis]]<ref>Roush JK, ''et al. '' (2010)''' Multicenter veterinary practice assessment of the effects of omega-3 fatty acids on osteoarthritis in dogs. '''''JAVMA ''2010;236:59-66. </ref> in dogs. Supplementation of EPA has also been shown to be beneficial in older healthy dogs<ref>Hall JA, ''et al.'' (1999)''' Effect of dietary n-6 to n-3 ratio on complete blood and total white cell counts, and T cell populations in aged dogs. '''''AJVR ''1999;60:319-327.</ref><ref>Hall JA, ''et al.'' (1999)''' Influence of dietary long-chain n-3 fatty acids from menhaden fish oil on plasma concentrations of α-tocopherol in geriatric beagles.''''' AJVR ''1999;63:104-110.</ref> as well as those with heart disease.<ref>Freeman LM, ''et al. '' (1998) '''Nutritional alterations and the effect of fish oil supplementation in dogs with heart failure.''''' JVIM ''1998;12:440-448.</ref> Supplementation with higher levels of EPA in people undergoing cancer treatment may also result in a decrease in circulating IL-6 levels and improvement in lean body mass and appetite<ref>Barber MD, ''et al.'' (2001)''' Effect of a fish oil-enriched nutritional supplement on metabolic mediators in patients with pancreatic cancer cachexia.''''' Nutr Cancer'' 2001;40:118-24.</ref><ref>Fearon KC, ''et al.'' (2003)''' Effect of a protein and energy dense N-3 fatty acid enriched oral supplement on loss of weight and lean tissue in cancer cachexia: a randomised double blind trial.''''' Gut'' 2003;52:1479-86.</ref>. This specific effect of EPA on lean body mass and appetite has not been studied in dogs and cats, but EPA supplementation may be beneficial to help decrease inflammation secondary to radiation therapy in dogs with nasal tumours.<ref>Hansen RA, ''et al.'' (2011)''' Menhaden oil administration to dogs treated with radiation for nasal tumors demonstrates lower levels of tissue eicosanoids. '''''Nutr Res'' 2011;31:929-36.</ref> Additionally, dogs with [[lymphoma]] (stage 3a) had an improvement in short-term survival when fed a diet supplemented with EPA and DHA among other nutrient modifications<ref>Ogilvie GK, ''et al''. (2000)''' Effect of fish oil, arginine, and doxorubicin chemotherapy on remission and survival time for dogs with lymphoma: a double-blind, randomized placebo-controlled study. '''''Cancer ''2000;88:1916-28.</ref>. These effects have not been demonstrated in cats or in dogs with other types of cancers.

#'''[[Inflammation]]:''' Eicosapentaenoic acid is incorporated into cellular membrane and competes with AA for cyclooxygenase (COX) and lipoxygenase (LOX) enzymes. Inflammatory [[Nutrition Glossary#Eicosanoids|eicosanoids]] produced from EPA (series-3 prostaglandins, prostacyclins and thromboxanes and series-5 leukotrienes) are less pro-inflammatory than those produced from AA metabolism.<ref name="NRC" /> Though not considered an essential fatty acid, increased intake of EPA in conjunction with a decrease in AA intake has been suggested as an aid in the management of inflammatory conditions such as [[Contact Dermatitis|allergic dermatitis]],<ref>Mueller RS, ''et al.'' (2005) '''Plasma and skin concentrations of polyunsaturated fatty acids before and after supplementation with n-3 fatty acids in dogs with atopic dermatitis.''''' Am J Vet Res'' 2005;66:868-73.</ref> nephritis,<ref>Brown SA, ''et al.'' (2000)''' Effects of dietary polyunsaturated fatty acid supplementation in early renal insufficiency in dogs. '''''J Lab Clin Med ''2000;135:275-286.</ref> and [[osteoarthritis]]<ref>Roush JK, ''et al. '' (2010)''' Multicenter veterinary practice assessment of the effects of omega-3 fatty acids on osteoarthritis in dogs. '''''JAVMA ''2010;236:59-66. </ref> in dogs. Supplementation of EPA has also been shown to be beneficial in older healthy dogs<ref>Hall JA, ''et al.'' (1999)''' Effect of dietary n-6 to n-3 ratio on complete blood and total white cell counts, and T cell populations in aged dogs. '''''AJVR ''1999;60:319-327.</ref><ref>Hall JA, ''et al.'' (1999)''' Influence of dietary long-chain n-3 fatty acids from menhaden fish oil on plasma concentrations of α-tocopherol in geriatric beagles.''''' AJVR ''1999;63:104-110.</ref> as well as those with heart disease.<ref>Freeman LM, ''et al. '' (1998) '''Nutritional alterations and the effect of fish oil supplementation in dogs with heart failure.''''' JVIM ''1998;12:440-448.</ref> Supplementation with higher levels of EPA in people undergoing cancer treatment may also result in a decrease in circulating [[Cytokines#Important cytokines|IL-6]] levels and improvement in lean body mass and appetite<ref>Barber MD, ''et al.'' (2001)''' Effect of a fish oil-enriched nutritional supplement on metabolic mediators in patients with pancreatic cancer cachexia.''''' Nutr Cancer'' 2001;40:118-24.</ref><ref>Fearon KC, ''et al.'' (2003)''' Effect of a protein and energy dense N-3 fatty acid enriched oral supplement on loss of weight and lean tissue in cancer cachexia: a randomised double blind trial.''''' Gut'' 2003;52:1479-86.</ref>. This specific effect of EPA on lean body mass and appetite has not been studied in dogs and cats, but EPA supplementation may be beneficial to help decrease inflammation secondary to radiation therapy in dogs with nasal tumours.<ref>Hansen RA, ''et al.'' (2011)''' Menhaden oil administration to dogs treated with radiation for nasal tumors demonstrates lower levels of tissue eicosanoids. '''''Nutr Res'' 2011;31:929-36.</ref> Additionally, dogs with [[lymphoma]] (stage 3a) had an improvement in short-term survival when fed a diet supplemented with EPA and DHA among other nutrient modifications<ref>Ogilvie GK, ''et al''. (2000)''' Effect of fish oil, arginine, and doxorubicin chemotherapy on remission and survival time for dogs with lymphoma: a double-blind, randomized placebo-controlled study. '''''Cancer ''2000;88:1916-28.</ref>. These effects have not been demonstrated in cats or in dogs with other types of cancers.

#'''Growth:''' Docosapentaenoic acid is taken up by brain and retinal tissues where it is converted to DHA. Docosahexaenoic acid is incorporated into retinal rods and brain tissue,<ref name="Zicker" /><ref name="Heinemann" /> and is conditionally essential for normal brain and retinal development.

#'''Growth:''' Docosapentaenoic acid is taken up by brain and [[Eye - Anatomy & Physiology#The Wall (retina, uvea and sclera)|retinal tissues]] where it is converted to DHA. Docosahexaenoic acid is incorporated into retinal rods and brain tissue,<ref name="Zicker" /><ref name="Heinemann" /> and is conditionally essential for normal brain and retinal development.

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File:Omega 3.jpg|Role of omega-3 fatty acids in the body<br>© Diffomédia/Masure

File:Omega 3.jpg|Role of omega-3 fatty acids in the body

File:Omega inflammation.jpg|EPA and AA compete for COX and LOX enzymes

File:Omega inflammation.jpg|EPA and AA compete for COX and LOX enzymes

</gallery></center>

</gallery></center>

==Consequences of Omega-3 Deficiency==

==Consequences of Omega-3 Deficiency==

#'''Growth''': Puppies fed DHA deficient diets will grow normally, but show poor response to learned behaviour and visual acuity tests compared with puppies fed diets enriched with DHA.<ref name="Zicker" /><ref name="Heinemann" />  Kittens fed DHA deficient diets during gestation and lactation also have poor retinal and visual development.<ref name="Pawlosky11" />

#'''Growth''': Puppies fed DHA deficient diets will grow normally, but show poor response to learned behaviour and visual acuity tests compared with puppies fed diets enriched with DHA.<ref name="Zicker" /><ref name="Heinemann" />  Kittens fed DHA deficient diets during gestation and lactation also have poor retinal and visual development.<ref name="Pawlosky11" />

#'''Adult Maintenance''': Clinical signs of ALA deficiency in adult dogs and cats are similar to LA deficiency (i.e. seborrheic dermatitis), but are relatively mild and easy to miss.<ref name="NRC" />

#'''Adult Maintenance''': Clinical signs of ALA deficiency in adult dogs and cats are similar to LA deficiency (i.e. [[Seborrhea|seborrheic dermatitis]]), but are relatively mild and easy to miss.<ref name="NRC" />

==Toxicity==

==Toxicity==

Excess intake of ALA without a concurrent increase in LA resulting in a ratio below 2.6:1 (LA:ALA) may interfere with LA uptake into ceramide and the conversion of LA to AA,<ref name ="Zicker" /> but toxicity studies are lacking.  

Excess intake of ALA without a concurrent increase in LA resulting in a ratio below 2.6:1 (LA:ALA) may interfere with LA uptake into ceramide and the conversion of LA to AA,<ref name ="Zicker" /> but toxicity studies are lacking.  

Excess EPA intake can cause [[Platelet Abnormalities|platelet abnormalities]] and bleeding disorders in cats,<ref>Saker KE, ''et al''. (1998) '''Manipulation of dietary (n-6) and (n-3) ratio fatty acids alters platelet function in cats. '''''J Nutr ''1998;128:2845S-2647S</ref> though this effect has not been demonstrated in dogs<ref>Boudreaux ML, ''et al.'' (1997)''' The effects of varying dietary n-6 to n-3 fatty acids ratios on platelet reactivity, coagulation screening assays, and antithrombin II activity in dogs.''''' JAAHA ''1997;33:235-243.</ref>. Dogs fed excessive amounts of the omega-3 long-chain polyunsaturated fatty acids, EPA and DHA, have shown impaired wound healing<ref>Mooney MA, ''et al.'' (1998)''' Evaluation of the effects of omega-3 fatty acid containing diets on the inflammatory stage of wound healing in dogs. '''''AJVR ''1998;59:859-863.</ref><ref>Scardino MS, ''et al.'' (1999)''' The effects of omega-3 fatty acid diet enrichment on wound healing. '''''Vet Derm ''1999;10:283-290. </ref> as well as impaired cellular immunity.<ref name="Wander">Wander RC, ''et al''. (1997)''' The ratio of dietary (n-6) to (n-3) fatty acids influences immune system function, eicosanoid metabolism, lipid peroxidation and vitamin E status in aged dogs.''''' J Nutr ''1997;127:1198-1205.</ref>

Excess EPA intake can cause [[Platelet Abnormalities|platelet abnormalities]] and [[:Category:Haemostasis and Bleeding Disorders|bleeding disorders]] in cats,<ref>Saker KE, ''et al''. (1998) '''Manipulation of dietary (n-6) and (n-3) ratio fatty acids alters platelet function in cats. '''''J Nutr ''1998;128:2845S-2647S</ref> though this effect has not been demonstrated in dogs<ref>Boudreaux ML, ''et al.'' (1997)''' The effects of varying dietary n-6 to n-3 fatty acids ratios on platelet reactivity, coagulation screening assays, and antithrombin II activity in dogs.''''' JAAHA ''1997;33:235-243.</ref>. Dogs fed excessive amounts of the omega-3 long-chain polyunsaturated fatty acids, EPA and DHA, have shown impaired wound healing<ref>Mooney MA, ''et al.'' (1998)''' Evaluation of the effects of omega-3 fatty acid containing diets on the inflammatory stage of wound healing in dogs. '''''AJVR ''1998;59:859-863.</ref><ref>Scardino MS, ''et al.'' (1999)''' The effects of omega-3 fatty acid diet enrichment on wound healing. '''''Vet Derm ''1999;10:283-290. </ref> as well as impaired [[Innate Immunity Cellular Responses|cellular immunity]].<ref name="Wander">Wander RC, ''et al''. (1997)''' The ratio of dietary (n-6) to (n-3) fatty acids influences immune system function, eicosanoid metabolism, lipid peroxidation and vitamin E status in aged dogs.''''' J Nutr ''1997;127:1198-1205.</ref>

==Dietary Sources==

==Dietary Sources==

<references />

<references />

[[Category:Fatty Acids]]

[[Category:Fatty Acids]]