Gastric ulcers are one of the most common health problems seen in high-performance horses, especially racehorses and other Thoroughbreds in active training. Long hours of exercise, travel, stall confinement, and changes in feeding routines all increase stress on the stomach and digestive system. Owners and trainers routinely search for nutritional strategies to reduce the risk of ulcers or help them heal.
A recent study looked at whether different types of dietary fats — specifically polyunsaturated fatty acids (PUFAs) — could influence a horse’s chances of developing severe squamous gastric ulcers. These ulcers form in the upper portion of the stomach, which is more sensitive to acid. The researchers sought to determine:
1. Do certain fatty acid supplements change the types of fats found in a horse’s blood?
2. Do those changes relate to better protection against ulcers?
To answer those questions, scientists worked with thirteen fit Thoroughbred horses in race training. Each horse underwent gastroscopy (a camera exam of the stomach), blood testing, and a standardized 4,600-meter exercise test designed to mimic the stress of training. Horses were tested before receiving any supplements and after taking each supplement for three months. Two different oil blends were compared:
- Short-chain PUFA (SC-PUFA) blend: corn and flax oil, providing linoleic acid (LA) and alpha-linolenic acid (ALA).
- Long-chain PUFA (LC-PUFA) blend: a combination of borage or safflower oil (providing gamma-linolenic acid, GLA) and fish oil (providing EPA and DHA).
Each horse received both supplements at different times during the study (a “crossover” design).
Why Fatty Acids Matter in Ulcer Protection
Fatty acids serve many roles in the body, but one of the most important for gastric health is their ability to form signaling molecules called prostaglandins. These compounds help regulate stomach acid, mucus production, blood flow, and healing of stomach tissue. One specific prostaglandin — PGE₂, made from the fatty acid arachidonic acid (AA) — is known to help protect the stomach during stress.
The body can make protective long-chain fatty acids like AA, EPA, and DHA from shorter-chain fats such as LA and ALA. However, this conversion process is slow and limited in horses. As a result, simply feeding flax or corn oil doesn’t reliably raise the levels of the important long-chain fatty acids needed to support prostaglandin production.
What the Study Found
1. Only long-chain fatty acid supplements changed blood fatty acids in a meaningful way.
Horses fed the LC-PUFA supplement showed clear increases in the long-chain fatty acids:
- GLA
- DGLA
- Arachidonic acid (AA)
- EPA
- DHA
At the same time, the levels of the short-chain fatty acids LA and ALA went down — indicating that LC-PUFAs were being absorbed efficiently.
In contrast, the SC-PUFA supplement (corn + flax oil) did not raise the horses’ levels of long-chain fatty acids. This supports earlier research showing that horses cannot convert short-chain fats like ALA into EPA or DHA at useful levels.
2. Horses with more long-chain fatty acids in their red blood cells had fewer severe ulcers.
Before supplementation, 38% of horses had severe squamous ulcers (grade 3–4). After three months on the LC-PUFA supplement, that number dropped to 8%.
Horses receiving SC-PUFAs saw almost no improvement (38% before vs. 23% after).
Across all horses, those suffering severe ulcers consistently had lower levels of GLA, DGLA, AA, and EPA in their red blood cells. This suggests that these fatty acids — and the prostaglandins they help form — play a protective role in the stomach lining.
3. GLA appears especially important.
Although GLA is technically a short-chain fatty acid, horses were able to convert it efficiently into DGLA and AA, both of which are needed for prostaglandin production.
Interestingly, the LC-PUFA supplement not only increased EPA and DHA from the fish oil, but also increased AA because of the GLA provided. This is important because AA is the key building block for PGE₂, the prostaglandin most closely tied to gastric protection.
What This Means for Horse Owners and Trainers
The study strongly suggests that feeding long-chain omega fatty acids — especially blends containing GLA, EPA, and DHA — may help reduce the risk of severe squamous gastric ulcers in training horses.
Key takeaways include:
- Horses struggle to turn flax-based omega-3s (ALA) into EPA and DHA. This means flaxseed and corn oil may not offer the stomach-protective benefits owners expect.
- Long-chain omega supplements work better because they bypass the horse’s inefficient conversion process.
- GLA may be especially useful, helping increase AA and the prostaglandins linked to stomach protection.
- Dietary ratios matter, but the type of fatty acid appears more important than the omega-6:omega-3 balance alone.
- Realistic training conditions matter. Unlike many studies that artificially induce ulcers, this one evaluated naturally-occurring ulcers under typical exercise stress — making the results more relevant to everyday management.
The Bottom Line
This research shows that Thoroughbreds in race training are more likely to maintain a healthier stomach lining when supplemented with long-chain polyunsaturated fatty acids , especially a blend containing GLA, EPA, and DHA . These fats significantly increase the horse’s ability to produce protective prostaglandins and are associated with a clear reduction in severe squamous gastric ulcers.
While no supplement replaces good management practices — consistent forage access, reduced stall confinement, and appropriate training intensity — LC-PUFAs offer a promising nutritional tool for protecting equine athletes from a common and performance-limiting condition.
Read the entire research paper here.
~ with files from KER
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