Low Starch Diets: Manage Carbohydrates to Your Horse's Best Advantage

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What about Fibre?
Fibre falls into the category of complex polysaccharides that cannot be digested by mammalian enzymes in the stomach and small intestine of the horse. Complex carbohydrates including fibre sources such as hemicellulose cellulose and some complex sugars such as fructan polysaccharides and pectin pass right through the foregut of the horse into the hindgut where the cecum and large intestine are located. Polysaccharides are fermented by the population of bacteria that live in the cecum and become substances called volatile fatty acids VFA. VFAs move through the gut wall into the bloodstream where they are transported to the liver. The liver converts VFAs into glucose if the animal needs energy for work growth or other physiological requirements or into body fat if no extra energy is required. Hindgut fermented carbohydrates are sometimes a safer source of energy for the metabolically challenged horse as they do not cause fluctuations in glucose or insulin levels.
Why do some horses need low starch diets?
Large meals of high sugar or high starch feeds will result in a rapid increase in blood glucose in the horse. This in turn results in a compensatory increase in blood insulin levels. Horses with metabolic issues related to obesity old age or inactivity are much more likely to be insulin resistant a condition in which increasing levels of blood insulin are required by the animal to regulate blood glucose levels. Animals that are insulin resistant are more likely to experience chronic laminitis or acute laminitic episodes as well as reduced immune function and other health issues. Insulin resistant horses do best when fed diets low in readily digestible carbohydrates such as starch.
There are other metabolic disease conditions for which low starch diets are necessary. Horses with Polysaccharide Storage Myopathy PSSM are actually unable to effectively store glucose in their cells to act as energy reserves. Horses with PSSM frequently have a normal glucoseinsulin metabolic process but are genetically compromised so that when glucose is taken into the cell through the actions of insulin it is stored in a molecular form that cannot be utilized by the muscle when energy is needed for work. These horses hit the wall when doing work because the muscle cannot metabolize the glucose stores glycogen for energy. These horses also do much better on low starch diets where energy is provided either through hindgut fermented carbohydrates such as pectin or cellulose or through