08/07/2023
ADDING OIL TO YOUR HORSES' DIET WILL NOT TREAT OR PREVENT EQUINE GASTRIC ULCERS!
Despite what you may have heard from many people, including vets, or read on social media or horse forums, adding OIL to your horses' diet will NOT treat or prevent gastric ulcers! But reducing STARCH will!
If you reduce the STARCH in your horses' diet by removing high starch ingredients like RICE BRAN (42%), WHOLE OATS (41%), MAIZE/CORN (72%), WHOLE BARLEY (60%), WHEAT BRAN (23%) or OAT BRAN (48%), this may help resolve gastric ulcers if your horse has them and/or prevent gastric ulcers developing in the future.
Where OIL comes in is that if you replace the energy coming from STARCH with energy from OIL, the OIL DOES NOT CONTRIBUTE TO GASTRIC ULCERS.
The idea to feed corn oil to horses with gastric ulcers goes back to a paper published in 2004 by Cargile et al. This paper is actually open access so you can read it for free (see bottom of post). However, these authors likely got the idea from a 1987 study in rats which showed that feeding oil to rats prevented experimentally induced peptic ulcers (Jayaraj et al., 1987).
Cargile et al. (2004) found that 45ml of corn oil a day for 5 weeks decreased gastric acid secretion in response to stimulation of acid secretion with a drug that mimics the action of the hormone gastrin (which stimulates gastric acid secretion in the body under normal conditions).
The Cargile et al. (2004) study was WEAK and POORLY designed as it only used 4 ponies AND the order of treatments were not randomised. The problem with this study is that the authors DID NOT GASTROSCOPE THE HORSES TO LOOK FOR GASTRIC ULCERS. However, this does not seem to have stopped people promoting 45ml of corn oil a day as a treatment for horses with gastric ulcers.
In contrast, Frank Andrews group at the University of Tennessee published a significantly more robust study in 2005 (Frank et al. 2005). NONE OF THE OIL TREATMENTS HAD ANY EFFECT ON PREVENTING OR REDUCING GASTRIC ULCERS!
SUMMARY
• 45ml of CORN OIL in one poorly designed and very small study (4 animals) slightly decreased gastric acid secretion in ponies. This study DID NOT scope the stomachs.
• In a larger and properly designed study, feeding 240ml per day of refined rice bran oil or crude rice bran oil or CORN OIL for 5 weeks HAD NO EFFECT ON GASTRIC ULCER FORMATION.
• There is no value to feeding CORN OIL to horses. It is highly processed and is one of the highest in inflammation-promoting Omega 6 fatty acids and very low in anti-inflammatory Omega 3 fatty acids.
• At the present time the ONLY value of feeding oil to horses with gastric ulcers is if it is used to REPLACE STARCH...i.e the benefit it REMOVING STARCH from the diet NOT adding oil.
• If you are going to feed oil to your horse then the best thing you can feed is cold-pressed linseed oil balanced with added Vitamin E.
BOTTOM LINE - Adding OIL to your horses' existing diet will make not treat or prevent gastric ulcers. Reducing STARCH in your horses' diet will help your horse to recover from gastric ulcers and or reduce the risk of future gastric ulceration. If your horse needs the energy that was being provided by starch then use oil instead.
REFERENCES
Cargile JL, Burrow JA, Kim I, Cohen ND, Merritt AM. (2004) Effect of dietary corn oil supplementation on equine gastric fluid acid, sodium, and prostaglandin E2 content before and during pentagastrin infusion. J Vet Intern Med. Jul-Aug;18(4):545-9.
https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1939-1676.2004.tb02583.x
Jayaraj AP, Tovey FI, Clark CG, et al. (1987) The ulcerogenic and protective action of rice and rice fractions in experimental peptic ulceration. Clin Sci (Lond); 72:463–466. http://www.clinsci.org/content/72/4/463.long
Frank N, Andrews FM, Elliott SB, Lew J. (2005) Effects of dietary oils on the development of gastric ulcers in mares. Am J Vet Res. Nov;66(11):2006-11. https://avmajournals.avma.org/doi/abs/10.2460/ajvr.2005.66.2006