Why do obese cats develop insulin resistance?
Metabolic syndrome has been studied in depth in human medicine and is associated with very high mortality and morbidity. It is directly related to a sedentary lifestyle and poor eating habits, and its prevalence continues to rise in developed countries. Weight gain and an excessive accumulation of fat result in serious associated diseases in cats. Beyond the observable mechanical and cutaneous clinical signs, recent evidence suggests that an increase in oxidative stress due to the accumulation of adipocytes creates a proinflammatory state in obese cats – metabolic syndrome.
Metabolic syndrome has been studied in depth in human medicine and is associated with very high mortality and morbidity. It is directly related to a sedentary lifestyle and poor eating habits, and its prevalence continues to rise in developed countries.
The development of this syndrome has also been reported in obese cats. This short video illustrates the pathological mechanisms of insulin resistance, lameness and other problems derived from obesity:
From increased adipocytes to reduced insulin sensitivity
As cats gain weight, their body composition changes as their body fat percentage increases. The accumulation of adipocytes generates large deposits of fat that obstruct blood supply and cause cellular hypoxia in the tissues. This leads to the infiltration of macrophages which release inflammatory mediators, thereby producing a proinflammatory state in the cat:
- increased expression of inflammatory cytokines (TNF-α, IL-6)
- reduced expression of anti-inflammatory adiponectin in adipose tissue
- higher plasma concentration of acute phase proteins (α-1-acid glycoprotein and haptoglobin)
This inflammatory state may explain the decrease in insulin sensitivity. Every kilo gained by a cat corresponds to a 30% reduction in insulin sensitivity.
Insulin resistance and hyperglycaemia
In the case of insulin resistance, tissue cells cannot draw glucose from the bloodstream, which leads to a hyperglycaemic state.
In turn, circulating insulin will induce the hydrolysis of lipids into glycerol and fatty acids which accumulate in the blood as cholesterol, triglycerides and phospholipids. This situation is called metabolic syndrome.
Metabolic syndrome multiplies the risk of diabetes by a factor of 5.
How can we reverse insulin resistance and metabolic syndrome?
The first and most important step is to implement a weight-loss plan for the cat. This will contain both strategies for increasing caloric expenditure and dietary changes.
A weight-loss diet adapted for obese cats features an energy restriction of 20–30%, is high-protein and low-fat, and contains natural fibres and a balanced supply of nutrients. It helps with muscle maintenance, while also enhancing the feeling of satiety.
The addition of a metabolic booster, in the form of citrus flavonoid supplementation, has produced significant improvements in oxidative stress markers (i.e., inflammatory markers) and the lipid profile.
Weight loss helps protect against diabetes, since it normalises insulin sensitivity. The Affinity Petcare R&D department has reported significant improvements in glucose metabolism markers (18% reduction in fructosamine, 40% reduction in basal insulin and 21% amylase reduction) after just 3 weeks of treatment with the Advance Veterinary Diets Obesity diet.
Finally, the cat’s natural behavioural instincts must be stimulated to elicit physical activity. An environment that allows cats to climb and play will encourage exercise.
