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Vegetable oils in the diet of horses with ulcers

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There are many oils commonly used in horse nutrition. These include corn oil, soybean oil, canola oil, flaxseed oil, coconut oil, fish oil, and vegetable oil (a mixture of corn and soybean oils). Hemp oil for horses is a relatively new addition to this group but has a long tradition as a healthy and beneficial oil, dating back to the Ming dynasty. But do vegetable oils prove effective in the diet of horses with ulcers?


The idea of feeding horses corn oil for stomach ulcers arose after the publication of an article by Cargile and colleagues in 2004. This article is open access, so it can be read for free (see at the bottom of the post). However, the authors likely derived this idea from a study conducted on rats in 1987, which showed that feeding rats corn oil prevented experimentally induced digestive ulcers (Jayaraj and colleagues, 1987).

Cargile and colleagues (2004) found that administering 45 ml of corn oil daily for 5 weeks reduced stomach acid secretion in response to stimulation of acid secretion by a drug mimicking the action of the gastrin hormone (which stimulates stomach acid secretion under normal conditions). However, this study was methodologically weak and poorly designed, as it used only 4 ponies, and the treatment sequence was not random. A problem with this study was that the authors did not perform gastroscopy on the horses to diagnose stomach ulcers. Nevertheless, this did not prevent the promotion of administering 45 ml of corn oil daily to horses with stomach ulcers.

In contrast, the group of Frank and Andrews from the University of Tennessee published a much more robust study in 2005 (Frank and colleagues, 2005). Unlike the previous one, this study used a very solid experimental design and 8 horses (6 weeks of feeding in a randomly crossed Latin square 4 X 4 with 5-week breaks).

Corn oil is mostly a highly processed and cheap oil. Oils such as coconut, hemp, and flaxseed are mainly cold-pressed. This method preserves natural antioxidants, such as vitamin E and vitamin A as beta-carotene, as well as omegas 3, 6, 9. Most corn, soybean, and canola oils are heat-processed at temperatures up to 180 degrees, then subjected to a hexane solvent bath. Hexane is a byproduct of petroleum and is classified as a neurotoxin. The oils are then neutralized with caustic soda (sodium hydroxide). The next processing step is bleaching, which removes chlorophyll and carotenoids. The final process is deodorization, which uses compressed steam at temperatures of 500 degrees or more. Since natural antioxidants, such as vitamin E and vitamin A, are destroyed in this process, stabilizers such as BHT and BHA are added to the oil.

Corn oil is one of the richest in inflammation-promoting Omega 6 fatty acids and very poor in anti-inflammatory Omega 3 fatty acids (ratio 5:1). Among its Omega-6 acids, it additionally lacks GLA.

The only advantage of corn oil is that it is relatively low in saturated fats.


  • 45 ml of corn oil in one poorly designed and very small study (4 animals) slightly reduced gastric acid secretion in ponies. This study did not include gastroscopy of the stomachs.

  • In a larger and better-designed study, feeding 240 ml daily of refined rice bran oil, raw rice bran oil, or corn oil for 5 weeks had no effect on stomach ulcers.

  • In most cases, it is highly processed and is one of the richest in inflammation-promoting Omega 6 fatty acids (does not contain GLA) and very poor in anti-inflammatory Omega 3 fatty acids.

  • Currently, the only value of feeding horses with stomach ulcers corn oil is its use as a replacement for starch.

What oil should be given to a horse with ulcers?

When choosing an oil for the diet of a horse with ulcers, guide yourself by the ratio of omega-3 to omega-6 and the content of GLA, which has anti-inflammatory properties. One of the best oils you can give your horse suffering from ulcers is cold-pressed hemp seed oil from a reputable source.

Hemp oil (or hemp seed oil) is a unique oil because it contains all the identified essential fatty acids known as omegas. It provides not only Omega 3 and Omega 6 but also Omega 9. What really distinguishes hemp oil for horses among other oils is the presence of GLA (gamma-linolenic acid) and SDA (an effective precursor of DHA and EPA).

olej z nasion

GLA (Gamma-Linolenic Acid) is a regulator of prostaglandins, hormone-like substances that act as chemical messengers in the cell. Their physiological effects include the regulation of inflammatory states. There are two dominant types of prostaglandins: PGE-1, the anti-inflammatory prostaglandin, and PGE-2, the pro-inflammatory prostaglandin. GLA increases the production of PGE-1, thereby lowering the level of PGE-2. Misoprostol, a commonly used drug for gastrointestinal ulcers in horses, is a synthetic form of PGE-1.

Prostaglandins are also involved in increased secretion of protective mucus in the gastrointestinal tract, making GLA from hemp oil an important component for horses with ulcer issues.


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.  

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. 

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.  

Effects of corn oil on the gastric mucosa of horses with induced ulcer

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