The Power of Omega-3 Fatty Acids for Racehorses

Equine exercise-induced pulmonary hemorrhage (EIPH) is a common and often debilitating condition affecting performance horses, specifically those involved in activities such as racing and high-intensity sports. While numerous management strategies have been employed to mitigate the effects of EIPH, research has highlighted the potential benefits of Omega-3 fatty acids in supporting respiratory health in horses.

Understanding EIPH in Horses

EIPH, simply put, is where blood accumulates in the lungs during intense exercise, therefore compromising respiratory function. The most visible sign of EIPH is blood in the horse’s nostrils. EIPH can lead to respiratory distress, reduced/impaired performance, and long-term complications if not managed. Increased pressure and mechanical stress cause the rupture of small blood vessels within the lungs. The causes of EIPH are certainly multifactorial, involving multiple factors such as high speed, capillary fragility, and increased blood pressure.

Omega-3 Fatty Acids

Omega-3 fatty acids are essential for many physiological functions within the body. The three main types of Omega-3 fatty acids are ALA (alpha-linolenic acid), EPA (eicosapentaenoic acid), and DHA (docosahexaenoic acid). While ALA is primarily found in plant sources, EPA and DHA are abundant in fatty fish and certain marine organisms.

Here are three common sources of Omega-3 fatty acids for horses:

Fish Oil: Fish oil is a rich source of EPA and DHA, the two types of Omega-3s with potent anti-inflammatory properties.

Algal Oil: Derived from microalgae, specifically certain strains such as Schizochytrium and Ulkenia, which is rich in DHA and EPA. Algal oil is unique in that it provides a sustainable and vegan alternative to marine-based omega-3 oils.

Flaxseed: Flaxseed is a plant-based source of ALA, a precursor to EPA and DHA. For horses to utilize sources of ALA they must first be converted into EPA and, subsequently, DHA. This conversion rate is relatively inefficient in horses and therefore, while ALA can contribute to a horse’s omega-3 intake, it may not provide the same level of benefits as direct supplementation with pre-formed EPA and DHA from marine sources. 

This is why here at O3 Animal Health we have chosen to utilize sustainably produced fish oil in our equine products. These formulas are all natural, human grade and patented.

Interestingly, preliminary studies have shown that the presence of just DHA alone does not have a marked effect on EIPH, however providing both DHA and EPA reduces the effects of EIPH, thus showing the benefits of ensuring both sources are present.

Mechanisms of Omega-3 Action in EIPH

One of the key benefits of Omega-3 fatty acids lies in their ability to help regulate inflammatory response. Chronic inflammation is often associated with many health issues, including conditions of the respiratory system. In horses, managing inflammation in the lungs could have a positive influence on EIPH.

By helping to promote a normal inflammatory response, Omega-3s help to maintain a balanced immune response. In the context of EIPH, this effect may contribute to reducing the damage caused by exercise-induced stress on the blood vessels in the lungs.

Omega-3 fatty acids have also been shown to widen blood vessels and improve blood flow. This effect is particularly important in EIPH, where the rupture of small blood vessels contributes to the bleeding in the lungs. Improved blood flow can potentially reduce the strain on the blood vessels in the lungs, lowering the risk of hemorrhage.

Omega-3 fatty acids are essential components of cell membranes, contributing to their fluidity and stability. This is crucial for the integrity of the cells lining the pulmonary blood vessels. Strengthening cell membranes can make them more resilient to the mechanical stresses associated with intense exercise, potentially reducing the likelihood of vessel rupture.

Additional support – Vitamin E

Within one study the Omega 3 supplement contained Vitamin E. Vitamin E is a potent antioxidant that helps protect cells from damage caused by free radicals. Equine Omega Complete and Equine Omega Vitamin E both contain substantial levels of all natural Vitamin E. This form penetrates the blood/brain barrier. 

When horses are supplemented with omega-3 fatty acids, the increased presence of these beneficial fats also increases the need for antioxidants like Vitamin E. Fatty acids are prone to oxidation, the byproducts of which can be harmful to cells and Vitamin E can protect against this oxidative stress.

Horses engaged in strenuous activities may benefit from additional Vitamin E supplementation to support muscle function and reduce the risk of exercise-induced muscle damage.

Both omega-3 fatty acids and Vitamin E contribute to a well-functioning immune system. Horses under stress or undergoing intense physical activity may be more susceptible to infections, and thus these dietary additions can help support the immune response. Furthermore, Vitamin E complements Omega 3 fatty acids promoting a balanced inflammatory response.

The use of Omega-3 fatty acids and Vitamin E in managing EIPH horses represents a promising avenue for proactive respiratory support. However, it is essential to approach any supplementation as part of a comprehensive management plan, involving veterinary consultation, gradual introduction, and attention to the overall nutritional needs of the horse.

O3 Animal Health has products that provide DHA and EPA in conjunction with natural vitamin E. Equine Omega Complete is an excellent product for use in racehorses where respiratory health is a major concern as well as those where it is not a concern but merely for general health. For those horses needing greater vitamin E support, Omega Vitamin E is an excellent choice.


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Bayly, W. et al. Effect of different protocols on the mitigation of exercise-induced pulmonary hemorrhage in horses when administered 24 hours before strenuous exercise. J Vet Intern Med. 2019.

Erickson, H. et al. Review of Alternative Therapies for EIPH. Journal of Applied Phys. 2001.

Portier K, de Moffarts B, Fellman N, et al. The effects of dietary N-3 and antioxidant supplementation on erythrocyte membrane fatty acid composition and fluidity in exercising horses. Equine Vet J Suppl. 2006.

Kirschvink, N. et al. The oxidant/antioxidant equilibrium in horses . The Vet Journal. 2008

O’Connor-Robinson, C, Lawrence, L.M., Lawrence, A.C., Janicki, K. (2004) The effect of dietary fish oil supplementation on exercising horses. Journal of Animal Science.