How does starch turn into sugar?

Did you know that...

starch is broken down into glucose in the horse's small intestine? If you have a horse that is sensitive to sugar, you should not only pay attention to the sugar content of the ration, but also to the starch content.

When horses chew on concentrate, they break the grains. This way, the starch in the grains, which is packed in a coat of fibers and cells, can reach the enzymes that are supposed to digest the starch. This digestion takes place in the small intestine. There, the amylase enzymes break down the starch into sugars. The sugars from the starch, together with the simple sugars from the grains, are absorbed into the blood through the intestinal wall. There, they make the blood glucose levels rise, which results in energy.

It is very important that this process runs smoothly and that all starch in the meal is digested; however, this is not always the case. In fact, there is only a limited amount of amylase available. If there is not enough amylase available for the amount of starch in the small intestine, the undigested starch will pass through to the large intestine and will cause problems over there. This is not the case for simple sugars, because they do not need the amylase in order to be absorbed by the intestinal wall.

Here are some tips to prevent undigested starch from entering the large intestine:

  • Give concentrate over several feedings.
    This way there will only be limited amounts of starch at the same time in the small intestine.
  • Use easily digestible starch sources.
    Cornstarch is poorly digestible, whereas oats can be digested well in the horse's small intestine.
  • Or you should make the starch from cereals more easily available by treating them.
    Puffed maize, for example, is more easily digestible.

Advantages and disadvantages of sugars and starch 

+ Good energy source for healthy horses

When horses ingest sugar and starch, the sugar level (read glucose level) in their blood will increase. The body will respond by producing insulin. This insulin ensures that the glucose is absorbed by the body’s cells, where it can serve as fuel.

- Too much sugar increases the risk of insulin resistance

Large sugar quantities cause fluctuations in the blood sugar levels, and therefore increase the risk of insulin resistance. Horses that are already insulin resistant must avoid even small quantities of sugar and starch.

IMPORTANT: A horse owner knows what his horse needs. A competition horse can use sugar and starch well as energy source, whereas horses with metabolic problems definitely can do without starch and sugar. For this last group, you should add up the sugar and starch content in order to make a choice in feed.

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