A new study from the University of Kentucky and the U.S. Department of Agriculture suggests that compounds found in hops, flowers used primarily for beer making, could help control the microbiological problems that lead to pasture laminitis.

Lush pasture grass can contain high levels of a carbohydrate called fructan, which when ingested by a horse accelerates the growth of certain bacteria in his large intestine. This, in turn, leads to a buildup of lactic acid that can trigger laminitis, a potentially devastating inflammatory hoof condition.

Because hops, the female flowers of the hop plant, contain beta acids that have antibacterial properties, the Kentucky researchers postulated that they may help slow the growth of harmful bacteria in the horse’s gut.

To test this theory, the researchers added beta acids from hops to solutions combining fructan with equine bowel bacteria. They found that the acids inhibited the bacteria’s production of lactic acid and prevented the solution’s pH from becoming too low (acidic).In a follow-up trial, the researchers tested the effects of the extract on Streptococcus bovis, one of the bacteria primarily responsible for fermenting bowel fructans. When a sample of this bacteria in a fructan-rich solution was exposed to hops extracts, the number of viable organisms was significantly reduced.

The researchers conclude beta acids from hops have potential to prevent bacterial buildups that trigger laminitis, but they do not recommend that they be given to horses until more research is done. They caution that this was a laboratory study, and the safety and efficacy of giving hops to horses have not yet been tested. 

Reference: “Inhibition of fructan-fermenting equine faecal bacteria and Streptococcus bovis by hops (Humulus lupulus L.) beta acid,” Journal of Applied Microbiology, April 2014

This article first appeared in EQUUS issue #442.