DO LAMINITIS AND TYPE 2 DIABETES HAVE A COMMON CAUSE?
A common starting point for both equine laminitis caused by equine metabolic syndrome (EMS) and for human type 2 diabetes caused by human metabolic syndrome (MS) is an elevated resting level of insulin, the hormone responsible for the regulation of blood glucose (sugar) in the body. In horses and people, insulin resistance develops early in the course of metabolic disease. In people it can eventually lead to type 2 diabetes, and in horses it results in the development of laminitis, a potentially painful crippling foot condition.
Laminitis causes the coffin bone, inside the horse’s foot, to lose its normal attachment to the hoof wall. This results in the bone moving downward into the sole causing inflammation and extreme pain. A prevalent form of laminitis, known as “endocrine [endocrinopathic] laminitis,” is often associated with eating grass in the spring and fall of the year when the sugar levels in pasture grasses are at their highest. This diet can produce very high insulin levels in some grazing horses, which is a significant risk factor for laminitis. Today, endocrine
Could some change in our agricultural practices early in the 20th century have influenced the microbial composition of our soils? A microbial imbalance in soil and plant foodstuffs might alter the gastrointestinal microbiome of both horses and people and contribute to elevated insulin levels and disease in a genetically predisposed subset of their populations. Interestingly, in spite of numerous hypotheses, a satisfactory explanation for the reason that obesity and type 2 diabetes have become so prevalent in the human population around the world is still lacking.
Do equine laminitis and human type 2 diabetes share a common environmental cause? Research that examines the similarities and differences between equine and human metabolic syndromes may reveal more about the underlying causes of equine laminitis and type 2 diabetes in humans. Rational treatments based on a more complete understanding of the disease mechanisms could benefit both humans and horses.— Donald M. Walsh, DVM