Insulin resistance

Dangers of a sugar rush

The amount of glucose in the blood is tightly controlled by hormones which help to maintain a constant blood sugar level. When a feed high in sugar and starch is eaten large quantities of glucose are released from the food and absorbed into the bloodstream. When the blood sugar level rises, insulin is released which triggers the uptake of sugar into the tissues and muscles, and triggers the liver and muscles to turn glucose into glycogen, which is stored. This is the normal process that helps maintain normal body functions.

Changes in insulin sensitivity

Moving the horse’s lifestyle and diet away from how they would live in the wild places them at potential risk of ill health. For example the long term feeding of sugar and starch based meals may lead to changes in insulin sensitivity resulting in insulin resistance (Kronfeld et al, 2005).

The feeding fasting cycle

In the wild, a horse would never normally repeatedly experience elevated blood glucose. Meal feeding creates what is known as the “feeding and fasting cycle” where circulating levels of glucose and insulin rise and fall in peaks and troughs. The abnormally high levels of insulin cause insulin receptors to become less sensitive, which then contribute to insulin resistance.

How might insulin resistance effect your horse

Insulin resistance is related to several metabolic conditions in humans including obesity, type 2 diabetes, cancer and heart disease. In horses, insulin resistance has been implicated in diseases such as laminitis, Cushing ’s disease, and obesity.

The exact causes of insulin resistance are not yet fully understood. Although more research is needed there is good reason for reducing sugar and starch in the diets of horses that are at an increased risk of becoming insulin resistant (e.g. native ponies, overweight, sedentary or elderly animals).

How you can help

There are a number of ways to reduce the risk of insulin resistance developing;

  • Keep your horse at a lean healthy weight
  • Provide plenty of opportunity to exercise
  • Feed a diet that reduces the effects of the “feeding fasting cycle”
  • Choose feeds which are proven in feeding trials to produce a low glycaemic response.