The diet and horses with Equine Metabolic Syndrome (EMS)
Horses with Equine Metabolic syndrome have special dietary needs, below is an article published in the American Journal Of Farriery 2014 relating to our work (Phytorigins/Equibiome).
Introduction to Equine Metabolic Syndrome (EMS)
Equine Metabolic Syndrome is a body condition that starts with raised blood glucose levels and progresses into insulin resistance, obesity and laminitis. Recent research has shown that Metformin may be ineffective at normalising glucose/insulin levels in horses. Is it possible therefore to add a beneficial functional food to the diet (in a similar way to adding plant sterols to lower cholesterol in humans) in the form of an extract from two indigenous plants actively sought out and eaten by freely grazing horses, thus preventing the onset of IR and life-threatening bouts of laminitis. Research has shown that the plant compounds in question are able to both prevent and diminish fat (adipose tissue) whilst at the same time are able to exert an anti-diabetic effect. One of the plant compounds has the ability to prevent glucose from reaching the bloodstream from the gut thus avoiding laminitis from starch overload.
Some animals that have EMS and suffer from laminitis are confined to limited exercise or no exercise at all because of the instability of the laminae. In these conditions, many owners find strict calorie-counting diets difficult and stressful and worry that horses on a diet and stabled for long periods often in solitary conditions suffer a poor quality of life. Some horses struggle to lose weight, particularly in obesity-prone animals aptly named good doers who survive on fresh air and this type benefit hugely from the addition of an anti-adipocyte compound to speed up weight loss and help regulate insulin/glucose levels.
Equine Metabolic Syndrome (EMS) was first recognized by veterinarians in 2002 and is considered to be a set of clinical symptoms including obesity, insulin resistance and laminitis.
The syndrome is similar to Met S, the human version, and is considered to be a disease of our time and a body condition that precedes other serious life threatening conditions such as diabetes and heart disease.
Many veterinarians will prescribe Metformin, a synthetic anti- diabetic drug to help normalise insulin and glucose levels. Its affect when given to people with type 2 diabetes is to lower blood glucose by up to 40% more than in people given dietary advice and asked to count calories. Clearly a medicine or compound that promotes weight loss is desirable as humans and horses alike are often unable to lose weight quickly enough to benefit their health
Type 2 diabetes is defined as high blood glucose and low levels of circulating insulin and is thought to increase tissue sensitivity to circulating insulin however in horses both high levels of blood glucose and insulin have been recorded. In a recent study on the effect of oral administration of metformin, on insulin sensitivity in insulin resistant ponies, published in the Veterinary Journal, researchers found that Metformin had little positive effects and a question was raised about the bioavailability of this synthetic drug.
In the light of this study and with no anti- diabetic drugs available for horses; still the most important goal for vets and equine practitioners is to halt the progress of Equine Metabolic Syndrome from raised blood glucose levels into insulin resistance thus potentially avoiding the further and more life threatening effects of laminitis.
Clinical signs of Equine Metabolic Syndrome (EMS)
One of the most important risk factors and components of EMS is the presence of adipose fat deposits on the neck, at the top of the tail and around the sheath. The fat deposits or BMI can be measured using a weight tape and a score of greater than 3 for the neck area can be considered an indication that the animal has EMS. The description for a score of 3 is ” Crest enlarged or thickened so that fat is deposited in the middle of the neck rather than towards the poll or withers giving it a mounded appearance, crest fills cupped hand and starts to lose its side to side flexibility”
Some horses and ponies can have a fairly lean overall appearance and still have the cresty necks and fat pads above the tail.
White adipose tissue is no longer considered as just fat designed to store energy but it is in fact more of a hormone and it plays a part in regulating physiologic and pathologic processes, including immunity and inflammation. Furthermore, cross-talk between lymphocytes and adipocytes can lead to altered immune regulation. Adipose tissue produces and releases a variety of proinflammatory and anti-inflammatory factors, including the adipokines leptin, adiponectin, resistin, and visfatin, as well as cytokines and chemokines, such as TNF-alpha, IL-6, monocyte chemoattractant protein 1, and others.
It would be clearly advantageous if certain beneficial and inexpensive ingredients could be added to the daily diet of affected or at risk animals that were able to assist in the regulation of glucose thus improving health and avoiding the full blown onset of insulin resistance and laminitis.
Over the past 4 years a combined EU funded research project has been underway looking initially at anti oxidants content of indigenous plants eaten by horses allowed to graze freely. The digested plants were then analysed for active plant compounds at the analytical chemistry department at Bangor University in North Wales
A herd of eight pure bred Welsh Mountain Section A ponies have grazed un-hindered over an ancient Iron Age settlement named Caer Carreg Y Fran (Fort of the Ravens) The hill fort is a scheduled monument monitored by the Royal Commission and the Welsh-based Cadw, the land has barely changed in hundreds of years and its use by grazing animals has been closely monitored for the last forty years to preserve the environment. The 25 acre site contains a wide variety of plants on a mixture of heathland, grass, marsh, ancient woodland and rocky outcrop.
Two of the ponies included in the trial are from families known to suffer from recurrent laminitis, all of the ponies were bred in the area and are from pedigrees of a pure North Wales line.
The ponies ate a surprisingly predictable and regular rota of plants depending on the season. At certain times of the year, some plants are far more attractive than at other times. In particular young silver birch twigs, young holly leaves in late winter early spring and wild blueberries in the Autumn each containing a mass of medicinal anti-oxidants. Historically gorse, holly and silver birch have been fed to horses as a replacement for hay.
Initially researchers were looking at anti- oxidant content but then chemical analysis with chromatography revealed the presence of two distinct plant chemicals with anti diabetic and blood glucose lowering abilities.
One particular plant compound with a long history of research and several patents for its medicinal properties is an active called ecdysterone this compound was found in 5% of all the wild plants that the ponies had access to.
. The most significant amount was found in Chenopodium Alba (Fat Hen, Lambs Quarter) this plant was most frequently sought out by laminitis and obesity prone horses along with another commonly found plant with an iminosugar that prevents glucose reaching the blood stream from the gut.
Chenopodium Alba is grown as a crop in India and Africa and was eaten instead of spinach in medieval times and has been found in the stomachs of Danish bog bodies and storage pits in Iron Age and Roman sites. Nowadays it is served as a vegetable in several exclusive London restaurants as it has a less bitter flavour than spinach. It is known as an invasive weed in America and Europe and in the UK it is grown alongside sugar beet as a trap crop to the beet leafhopper insect.
Research has shown that the effective level of ecdysterone needed to reduce adipose tissue and lower blood glucose is very dose-dependent, at higher levels it is less effective. As the plant contains high levels of nitrates it is better fed as a stabilised extraction rather than as forage.
Phytoecdysteroids are triterpenes that have been shown to reduce fat body mass and have a beneficial effect on glucose levels in the body with an effect similar if not greater than that of Metformin. A triterpene is a precursor to a steroid and research has shown that ecdysteroids have anabolic but not androgenic activity and bind to IGF-1 binding sites in an advantageous manner.
The ecdysteroids are able to exert a lowering effect on glucose and lipid levels in the blood thus lessening the damaging effect and delaying the onset of insulin resistance. As EMS in its early stages is in fact a body condition defined by raised blood glucose levels in obese ponies it is possible that a more beneficial health state may be attained by the regular addition of ecdysterones to the diet.
The added benefit is the reduction in the size of the lipids in the adipose tissue and a decrease in the amount of fat laid down on the neck and at the top of the tail.
In a pilot study of over 100 horses with a body score of greater than 3 for adipose deposits, within 2 weeks of receiving the additive in the daily feed ration the adipose deposit scores had fallen to a score of 2 or less.
Equine Metabolic Syndrome (EMS) and self-selection of plants with beneficial plant active compounds
Since this article was published in 2014 we have continued to work to help end the misery of laminitis/EMS, we have done further studies relating to the effect of ecdysterone and other plant compounds on the microbiome.