Sugar Fungus In Horse Feeds - The Horse's Advocate Podcast #172

The first time I heard the words "Sugar Fungus" used with horses, I thought it might be a new, and possibly harmful, reportable disease. I braced myself for the thought that another new disease was invading the world of horses, and that there may not be a cure. However, to my surprise, I learned that sugar fungus is the translation of a common yeast called Saccharomyces: Sacro meaning sugar, and myces meaning yeast (from the Greek). This yeast is generally beneficial, supporting digestive processes in both animals and humans. This yeast appears in baker's yeast, brewer's yeast, and sourdough starter. The most common species is Saccharomyces cerevisiae, widely recognized for its role in fermentation. Saccharomyces cerevisiae, which is commonly added as an ingredient in commercial horse feeds. In this podcast, I discuss what it is, the common forms found in horse feeds, and the proposed benefits of adding it. I then discuss what many call "unintended consequences," or the possible downstream effects of many foods and food additives. I describe the Polyol Pathway (aka the Sorbitol Pathway) and how yeasts are known triggers, along with high-glycemic foods, such as grains. The overall effect of adding yeasts to grains may be an increase in fructose production, leading to aggressive behavior, increased body fat, and decreased mitochondrial efficiency. As always, none of this has been shown to occur in horses because studies have been performed only in humans and lab animals; however, most studies using Saccharomyces cerevisiae added to a grain feed to help horses with stress indicate that feeding an all-forage diet before stressful events may be just as effective.