06/14/2026
Let's Decode Carbohydrates
Non Structural Carbohydrates (NSC) describe the starch and sugar content.
• % Starch + % WSC = % NSC
Water Soluble Carbohydrates (WSC) contain both sugar and fructans.
• Sugar is digested in the small intestine
• Fructans are digested in the large intestine
• % WSC - % ESC = % Fructans
Because of the limitations of NSC, most nutritionists are moving away from this value and are instead evaluating feeds based on the starch, water soluble carbohydrate (WSC) and ethanol
soluble carbohydrate (ESC). ESC’s are a subset of water soluble carbohydrates that do not include fructans. Ultimately, these three fractions can be used to compare feeds for horses with
different carbohydrate-related problems.
For horses with insulin resistance, Cushing’s disease, or EPSM/PSSM—all of which can’t tolerate large swings in blood sugar, you should select feeds that are low in starch and ESC. This implies there will be less carbohydrate digested and absorbed from the small intestine, which results in less of a glycemic response.
For horses with a history of diet-related laminitis, you should select feeds that are low in starch and WSC. The less starch and fructans reaching the hindgut should mean less opportunity for excessive fermentation and large intestinal disturbances that could trigger laminitis.
Did you know that Bluebonnet has just released a feed that is transparent on the tag with BOTH ESC and WSC Values??