I am getting questions from several platforms asking if it’s true that sweet potatoes are a treatment for equine gastric ulcers and metabolic problems.
There is some evidence (not in horses) that beta-carotene, the pigment in sweet potatoes, may protect from or help heal gastric ulcers but it never does this on its own without help from other nutrients or drugs, and is mostly useful when there is a deficiency state.
The proposed mechanism is antioxidant activity neutralizing the reactive oxygen species generated by Helicobacter pylori infection – but equine gastric ulcers don’t involve H. pylori. The average horse is also already getting from 300 to 1000 mg/day of beta-carotene from hay or pasture, compared to about 100 mg/lb in sweet potato.
They are definitely a bad idea for EMS horses. The theory is the soluble fiber will slow and reduce glucose absorption and insulin levels. That effect is seen in humans but not in horses. They are also not that great a source of soluble fiber, about 6 g/lb. High soluble fiber foods form a gel in water – e.g. beet pulp, flax, chia. Even hay and grass have soluble fiber in the form of pectin and beta-glucans in their cell walls. I couldn’t find an exact amount of soluble fiber in forages but if it’s even 0.5% that’s a significant amount when you consider how much they eat.
Soluble fiber aside, sweet potatoes are 40% starch. It is highly digestible starch and will be digested to glucose in the small intestine, causing an insulin spike.
If a horse does not have problems with insulin, a few small pieces of sweet potato as a treat would be OK but don’t expect health benefits beyond beta-carotene – and you can get more of that from carrots on a per calorie basis.
Eleanor Kellon, VMD
Dr. K's Horse Sense 