Flaxseed (Linum usitatissimum) supplementation associated with reduced skin test lesional area in horses with Culicoides hypersensitivity.

Abstract: The purpose of this study was to quantify the effect of flaxseed (Linum usitatissimum) supplementation on the skin test response of atopic horses. Six horses that displayed a positive skin test for allergy to extract from Culicoides sp. participated in the 42-day, placebo-controlled, double-blind, cross-over trial. Results showed that supplementation with flaxseed for 42 days in our experimental horses reduced the mean skin test response to Culicoides sp. This observation was concurrent with a significant decrease in the long-chain saturated fatty acids; behenic acid (22:0) and lignoceric acid (24:0), in the hair of horses receiving flaxseed. There was also a significant decrease in aspartate aminotransferase, and increase in serum glucose in the treatment animals at specific sampling points. It was concluded that; in this small pilot study, flaxseed was able to reduce the lesional area of the skin test response of atopic horses, alter the fatty acid profile of the hair, reduce inflammation, and did not elicit any negative side-effects in the experimental horses.
Publication Date: 2002-11-07 PubMed ID: 12418783PubMed Central: PMC227015
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
  • Clinical Trial
  • Journal Article
  • Randomized Controlled Trial
  • Research Support
  • Non-U.S. Gov't


This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research study investigates the effect of flaxseed supplementation on the skin reactions of horses with a certain type of allergy. The researchers found a notable reduction in the skin test response area when horses were given flaxseed supplements for a given period of time.

Study Design and Participants

  • The research was a 42-day placebo-controlled, double-blind, cross-over trial, meaning that neither the researchers nor the participants knew which treatment they were receiving and both the flaxseed and placebo were given to each horse at different times.
  • The study involved six horses that had shown an allergic reaction to the Culicoides sp. extract via a skin test, indicating the presence of Culicoides hypersensitivity.

Flaxseed Supplementation and Its Effect

  • Flaxseed supplementation was given to the horses for 42 days.
  • The results showed that flaxseed supplementation meant a significant reduction in the skin testing response in horses allergic to the Culicoides sp. extract.
  • Following the flaxseed consumption, the researchers observed an associated decrease in the long-chain saturated fatty acids – behenic acid (22:0) and lignoceric acid (24:0) – in the horses’ hair.

Other Findings

  • While the researchers couldn’t definitively establish causation, a significant decrease was noted in aspartate aminotransferase – an enzyme linked to liver function and inflammatory processes. This decrease was along with the horses’ response to flaxseed supplementation at specific data collection times.
  • An increase in serum glucose in the treatment animals was also observed at specific phases of the trial.
  • No negative side effects were observed in the horses that received the flaxseed supplementation, suggesting that it was well-tolerated.


  • The study provides initial evidence that flaxseed supplementation might help in reducing the skin testing response against Culicoides sp. in horses.
  • Furthermore, the consumption of flaxseed showed alterations to the fatty acid profile in the horses’ hair and decreased markers of inflammation, suggesting further avenues for exploration in the role of flaxseed supplementation for managing horse allergies.

Cite This Article

O'Neill W, McKee S, Clarke AF. (2002). Flaxseed (Linum usitatissimum) supplementation associated with reduced skin test lesional area in horses with Culicoides hypersensitivity. Can J Vet Res, 66(4), 272-277.


ISSN: 0830-9000
NlmUniqueID: 8607793
Country: Canada
Language: English
Volume: 66
Issue: 4
Pages: 272-277

Researcher Affiliations

O'Neill, Wendy
  • Nutraceutical Alliance, Guelph, Ontario. woneill@nutraceuticalalliance.com
McKee, Sharyn
    Clarke, Andrew F

      MeSH Terms

      • Animals
      • Aspartate Aminotransferases / blood
      • Blood Glucose
      • Ceratopogonidae
      • Cross-Over Studies
      • Dermatitis, Atopic / etiology
      • Dermatitis, Atopic / pathology
      • Dermatitis, Atopic / prevention & control
      • Dermatitis, Atopic / veterinary
      • Dietary Supplements
      • Double-Blind Method
      • Fatty Acids / analysis
      • Flax
      • Hair / metabolism
      • Horse Diseases / etiology
      • Horse Diseases / pathology
      • Horse Diseases / prevention & control
      • Horses
      • Phytotherapy
      • Pilot Projects
      • Skin Tests / veterinary
      • Treatment Outcome


      This article includes 20 references
      1. Rosenkrantz WS. Systemic/topical therapy.. Vet Clin North Am Equine Pract 1995 Apr;11(1):127-46.
        pubmed: 7634162doi: 10.1016/s0749-0739(17)30337-1google scholar: lookup
      2. Kleider N, Lees MJ. Culicoides hypersensitivity in the horse: 15 cases in southwestern british columbia.. Can Vet J 1984 Jan;25(1):26-32.
        pmc: PMC1790502pubmed: 17422351
      3. Anderson GS, Belton P, Kleider N. The hypersensitivity of horses to culicoides bites in british columbia.. Can Vet J 1988 Sep;29(9):718-23.
        pmc: PMC1680856pubmed: 17423117
      4. Evans V. Canadian Horse Industry Research Study. Strategic Equine Marketing, 1998.
      5. Wright R, Cation J. 1996 Horse Industry Report. Ontario Ministry of Agriculture, Food and Rural Affairs, 1996.
      6. Baker KP, Quinn PJ. A report on clinical aspects and histopathology of sweet itch.. Equine Vet J 1978 Oct;10(4):243-8.
      7. Scott DW, Miller WH Jr, Reinhart GA, Mohammed HO, Bagladi MS. Effect of an omega-3/omega-6 fatty acid-containing commercial lamb and rice diet on pruritus in atopic dogs: results of a single-blinded study.. Can J Vet Res 1997 Apr;61(2):145-53.
        pmc: PMC1189391pubmed: 9114966
      8. Lloyd D, Thomsett LR. Essential fatty acid supplementation in the treatment of canine atopy: a preliminary study. Vet Dermatol 1989;1:41u201344.
      9. Bond R, Lloyd DH, Craig JM. The effects of essential fatty acid supplementation on intradermal test reactivity in atopic dogs: a preliminary study. Vet Dermatol 1993;4(4): 191u2013197.
      10. Whelan J, Broughton KS, Kinsella JE. The comparative effects of dietary alpha-linolenic acid and fish oil on 4- and 5-series leukotriene formation in vivo.. Lipids 1991 Feb;26(2):119-26.
        pubmed: 2051893doi: 10.1007/BF02544005google scholar: lookup
      11. Vaughn DM, Reinhart GA, Swaim SF, et al. Evaluation of effects of dietary n-6 to n-3 fatty acid ratios on leukotriene B synthesis in dog skin and neutrophils. Vet Dermatol 1994;5(4): 163u2013173.
      12. Cunnane SC, Ganguli S, Menard C, Liede AC, Hamadeh MJ, Chen ZY, Wolever TM, Jenkins DJ. High alpha-linolenic acid flaxseed (Linum usitatissimum): some nutritional properties in humans.. Br J Nutr 1993 Mar;69(2):443-53.
        pubmed: 8098222doi: 10.1079/bjn19930046google scholar: lookup
      13. Pizzey G. The animal industry as an emerging new market for flaxseed. In: Pearson, W. ed. Complimentary Therapies: A New Vision in Animal Health. Guelph: Equine Research Centre, 1999:9u201317.
      14. Lewis LD. Equine clinical nutrition: feeding and care. Williams and Wilkins, Baltimore, 1995.
      15. Friberg CA, Logas D. Treatment of culicoides hypersensitive horses with high-dose n-3 fatty acids: a double-blinded crossover study. Vet Dermatol 1999;10:117u2013122.
      16. Oomah BD, Mazza G, Kenaschuk EO. Cyanogenic compounds in flaxseed. J Agr Food Chem 1992;40:1346u20131348.
      17. Cheville NF. Introduction to Veterinary Pathology. Ames: Iowa State University Press, 1988:443.
      18. McMaster JD, Jenkinson DM, Noble RC, Elder HY. The lipid composition of bovine sebum and dermis.. Br Vet J 1985 Jan-Feb;141(1):34-41.
        pubmed: 4039612doi: 10.1016/0007-1935(85)90124-1google scholar: lookup
      19. Nikkari T. Comparative chemistry of sebum.. J Invest Dermatol 1974 Mar;62(3):257-67.
        pubmed: 4206501doi: 10.1111/1523-1747.ep12676800google scholar: lookup
      20. Hug DH, Dunkerson DD, Hunter JK. The degradation of L-histidine and trans- and cis-urocanic acid by bacteria from skin and the role of bacterial cis-urocanic acid isomerase.. J Photochem Photobiol B 1999 May;50(1):66-73.
        pubmed: 10443033doi: 10.1016/S1011-1344(99)00072-Xgoogle scholar: lookup


      This article has been cited 4 times.
      1. Sembratowicz I, Ziu0119ba G, Cholewinska E, Czech A. Effect of Dietary Flaxseed Oil Supplementation on the Redox Status, Haematological and Biochemical Parameters of Horses' Blood.. Animals (Basel) 2020 Nov 30;10(12).
        doi: 10.3390/ani10122244pubmed: 33265987google scholar: lookup
      2. Saastamoinen M, Su00e4rkiju00e4rvi S. Effect of Linseed (Linum usitatissimum) Groats-Based Mixed Feed Supplements on Diet Nutrient Digestibility and Blood Parameters of Horses.. Animals (Basel) 2020 Feb 10;10(2).
        doi: 10.3390/ani10020272pubmed: 32050686google scholar: lookup
      3. Lomas HR, Robinson PA. A Pilot Qualitative Investigation of Stakeholders' Experiences and Opinions of Equine Insect Bite Hypersensitivity in England.. Vet Sci 2018 Jan 9;5(1).
        doi: 10.3390/vetsci5010003pubmed: 29315275google scholar: lookup
      4. Khol-Parisini A, van den Hoven R, Leinker S, Hulan HW, Zentek J. Effects of feeding sunflower oil or seal blubber oil to horses with recurrent airway obstruction.. Can J Vet Res 2007 Jan;71(1):59-65.
        pubmed: 17193883