Apple cider vinegar (ACV) has been given to animals and taken by humans for many years, primarily for its reputed effects on the blood, to help ease arthritic joints and as an anti-obesity therapy. It is widely fed by horse owners, both in the water and mixed into the feed, and is usually fed to horses for joint health and to reduce gut stones (enteroliths). It might enhance the absorption of minerals in the gut, so help the horse get more out of his diet.
Researchers have been aware for two decades that vinegar reduces the blood glucose and insulin responses to a (non-structural) carbohydrate-containing meal in both healthy humans and those with diabetes. The mechanisms for this effect – via studies in humans and rates – are proposed to be:
- Reduced stomach (gastric) emptying rate
- Reduced activity of carbohydrate-digesting enzymes (saccharidases)
- Enhanced glycogen repletion in liver and muscle
Vinegar has also been shown to increase short-term satiety, of the feeling of fullness/that the appetite has been fulfilled, so could help to reduce feed intake. Some participants in research trials had moderate weight loss after taking vinegar daily with their food.
Some researchers have proposed that vinegar may have physiological effects similar to metformin, a drug that is used to treat insulin resistant and obese horses and ponies, which is believed to reduce blood glucose levels and increase insulin sensitivity.
Although horses rarely suffer from actual diabetes, many are affected with disturbed body glucose handling and insulin resistance and would benefit from supplementation or treatment that could improve insulin sensitivity. Insulin resistant horses and ponies are at risk of the debilitating condition laminitis, which can be difficult to control.
Although researchers are yet to investigate the effect of supplementary dietary vinegar on horses’ blood sugar and insulin levels, it is likely to have a similar effect, so adding a daily serving of apple cider vinegar to your overweight or laminitis-prone horse and ponies or those with equine metabolic syndrome could be beneficial, especially when they have access to grass that may contain high levels of sugar and fructans.
Of course, management, exercise, low sugar, fructan and starch diets and appropriate weight loss regimes are also important for health in overweight and laminitis-prone horses and ponies, and those affected with equine metabolic syndrome.