NSC and Metabolic Horses

NSC and Metabolic HorsesNSC and Metabolic Horses

I have written at least 7 blogs and countless group posts on this subject but confusion continues to reign, in large part because of the persistence in using NSC to evaluate safety of forages for horses with hyperinsulinemia.

This idyllic image can become a nightmare for a horse with metabolic syndrome

NSC (Nonstructural Carbohydrate)

Just this month, the vet and professional version of a large, well recognized magazine for horse owners came out with an article packed with reference to NSC. NSC = nonstructural carbohydrates, things that are not part of the fibrous cellulose or hemicellulose, which are also carbohydrates.

A carbohydrate is any molecule consisting of carbon, hydrogen and oxygen, usually with an oxygen to hydrogen ration of 1:2. This includes all fibers, glycogen, fructan, the woody lignan in trees and bushes as well as simple sugars and starches.

For horses with metabolic syndrome, the only dietary carbohydrate elements of concern are those that can be digested and cause an insulin spike. This includes simple sugars (ESC or enzymatically determined on the hay/pasture analysis) and starch. That’s it. Fructan is also included in NSC but fructan is a fermentable fiber. It cannot cause an insulin spike.

For more details see this open letter to the AAEP from this time last year (click here) and this article on the AAEP web site (click here).


Fructan is a storage form of sugar, like glycogen in meat. It is not a sugar itself. Carb restricted diets include plenty of meat because it does not cause an insulin spike like sugars or starch.

Huge amounts of pure fructan, given to a horse on an empty stomach all at once, by stomach tube, can cause laminitis. To cause laminitis in just one foot takes 8.25 pounds of pure fructan or 13 pounds of pure fructan to produce a systemic reaction from hind gut inflammation. (500 kg horse).

By comparison, a horse eating an average North American hay takes in about 7 oz of fructan over the course of an entire day, diluted by all the other compounds in the diet. It’s just not an issue.

For more reading go to http://www.ecirhorse.org.


- Eleanor Kellon, VMD

Copyright © 2023 Uckele Health & Nutrition Inc. All rights reserved. Privacy Policy