Cushing's/Metabolic Syndrome In Horses
Equine Cushing's Syndrome, also referred to as Equine Metabolic Syndrome, has been diagnosed in horses in record numbers in recent years, with the condition also now being seen in younger horses. This disorder is difficult to successfully treat with conventional medicine but recent research suggests that dietary, nutritional, and stress factors contribute to the disease, and that it is a malady of the modern, domesticated horse.
Cushing's/Metabolic Syndrome is a disease of the pituitary gland, a small grey gland attached to the base of the brain. It is often referred to as the master gland of the body since the hormones that it secretes regulate many bodily processes including STH, a growth hormone; TSH, a thyrotropic hormone that regulates the thyroid; and ACTH, an adrenocorticotropic hormone that regulates the adrenal glands.
In Cushing's/Metabolic Syndrome the pituitary gland becomes 'hyper', producing too much ACTH hormone that then causes the adrenal glands to produce excess amounts of cortisol and corticosterone. These are steroids that act on carbohydrate metabolism and affect the metabolism of bone, muscle, nerves, heart, blood, and the intestines. They are also important anti-stress hormones and natural anti-inflammatories from which cortisone is derived and after which synthetic steroid medications such as cortisone are fashioned.
The symptoms of Cushing's/Metabolic Syndrome, as a result of high cortisol levels, can include: sweating, increased thirst, frequent urination, fatigue, anemia, curly hair, incomplete shedding of the hair coat, weight problems, muscle wasting, poor immunity, lowered immunity to intestinal parasites, compromised intestinal wall integrity, enlarged liver, and laminitis.
Laminitis/founder likely occurs as a result of two factors:
1) The increased levels of cortisol catabolize (break down) proteins that weaken and inflame connective tissue and lamellar structure within the feet. This resulting damage and inflammation (as well as possible poor trimming practices) restricts blood flow creating soreness, pain, and poor nutrient delivery further deteriorating the health of the hoof.
2) Damage to the intestinal wall ('leaky gut') enables bacteria and other intestinal toxins to leak into the bloodstream and to the feet causing inflammation. This condition, of course, is the primary cause of all 'grass and grain founder' (with or without a Cushing's diagnosis) since the intestinal damage most often occurs as a result of over-feeding, mal-digestion, over-medication with antibiotics and non-steroidal anti-inflammatories such as phenylbutazone ( Bute), and stress. A 'leaky gut'' can not only be responsible for the auto-intoxication of the feet but of the liver, endocrine glands, and the musculo-skeletal system.
Cushing's/Metabolic Syndrome also causes a general build-up of lactic acid (due to stress and poor oxygenation) that interferes with muscle function, endurance, metabolism, immunity, and hoof health, exacerbating laminitis.
Cushing's/Metabolic Syndrome in some horses can be caused by tumours of the pituitary gland (horses seldom get adrenal tumours) or through long-term or excessive use of steroid medication (e.g. cortisone creams, cortisone injections, and steroidal eye drops). However, many horses that have no pituitary tumour or history of steroids are being diagnosed with Cushing's. We must assume then that any other situation that raises cortisol levels (e.g. diet and/or stress) has the potential to either cause, create symptoms similar to, or mimic the Syndrome itself, making it difficult to diagnose. (However, the treatment program outlined in this paper has been developed to address the symptom profile regardless of the diagnosis).
Diet and feeding programs are critical in the management of Cushing's/Metabolic Syndrome and laminitis since the ingestion of excessive sugars and refined carbohydrates, low-fibre diets, and over-feeding increase insulin and cortisol levels and destroy digestive microflora (friendly bacteria that ensure adequate digestion and prevent colon toxicity.) Insulin is produced by the pancreas to lower blood sugar levels after eating, however excessive insulin 'rushes' as produced by the above-mentioned dietary imbalances eventually either cause decreased insulin levels leading to high blood sugar (diabetes), erratic insulin levels leading to low blood sugar (hypoglycemia), and/or Syndrome X, an insulin resistance syndrome whereby insulin receptors (in the liver, muscle, and fat cells) become damaged and cannot transport glucose effectively. 'Syndrome X' horses are easy keepers who become very efficient at storing fats (since the sugars have nowhere else to go) in various places including cresty necks and pot bellies. All of these blood sugar conditions cause the adrenal glands to produce increased cortisol levels, thus exacerbating Cushing's symptoms, including laminitis.
Stress levels also have a significant impact on Cushing's/Metabolic Syndrome. The pituitary gland is directly affected by the hypothalamus, a portion of the brain that is linked to our emotions. When the hypothalamus becomes stimulated with negative emotions it directs the pituitary to release increased levels of ACTH to increase the cortisol levels. Continually high cortisol levels lead to suppression of the immune system. The aged horse is particularly prone to this since the older horse is unable to turn off the cortisol response to stress as quickly as the younger horse.
Thyroid problems are often mistaken for Cushing's since low thyroid function can cause the pituitary gland to over-react by producing more Thyroid Stimulating Hormone. The thyroid gland is also sensitive to poor nutrition, and auto-intoxication from a 'leaky gut'. A suspected thyroid condition should be addressed with a combination of appropriate nutrients and homeopathic remedies.
All horses are different and their individual needs must be considered. However, these guidelines are most helpful in correcting many of the underlying factors.
1) All high carbohydrate feeds should be eliminated - no sweet feed, beet pulp, molasses, or concentrated grains, such as sweet feed or soybean meal. It is a good idea to avoid grains of any kind, especially in the beginning of a health program. Horses that are protein-deficient/ underweight should be individually assessed. Wheat bran (up to 2 cups daily) should be used to increase dietary fibre, which slows down sugar absorption.
2) Avoid all vegetable oils or fat-enriched supplements; oils and fats cause increased cortisol (cortisol is required for fat metabolism), slows digestion (horses should be 'hay-burners'), and can damage the circulatory system, the intestines, and the liver (horses do not have a gallbladder).
3) Alfalfa, protein-rich, should be eliminated since alfalfa can decrease iodine absorption (critical for glandular function), over-stimulate the pituitary, tax the digestive system, and cause various inflammations throughout the body with excess protein. The equine digestive system is designed to extract energy from fibre, not from protein. A mixed grass low-protein hay (8%-12%) and/or a (not too rich) pasture is recommended.
4) Feed small, frequent feedings since large, infrequent feedings also cause increased levels of cortisol and insulin, as well as an increase in hydrochloric acid. A horse's digestive system is designed to ingest small amounts of food all day long, similar to grazing.
5) Beware of feeding foals and younger horses high sugar commercial feeds which could set the stage for existing or future insulin problems.
6) Regular exercise is extremely beneficial in re-balancing blood sugar levels, reducing stress levels, reducing cortisol levels, and ensuring proper hoof mechanism. Twenty four hour free movement is highly recommended.
7) Reduce stress levels! Isolation from other horses, confinement, no free exercise, boredom, over-medication, and poor nutrition contribute to almost all equine disease.
The following supplement protocol has proved to be very helpful for horses with Cushing's/Metabolic Syndrome and/or laminitis.
To be given daily for up to 60 days and then re-evaluated:
1) Probiotics (Riva's Remedies Pro-Colon) - 1 to 2 tsp daily (replenishes inadequate microflora)
2) Psyllium seed powder, comfrey leaf - (Riva's Remedies Pro-Dygest) - ¼ cup daily (fibre supplement and intestinal detoxification)
3) Chromium - 500 mcg daily (regulates sugar metabolism)
4) DMG - 2,000 mg daily (reduces lactic acid and inflammation; improves oxygenation to break down blood sugar)
5) Coenzyme Q10 - 200 mg daily (anti-oxidant; improves immunity)
6) Folic Acid - 5 mg daily (aids metabolism)
7) The homeopathic combination remedy, Acti-Cort (Riva's Remedies liquid - ingredients: insulin, ACTH, Lac.ac., Strep., 30ch) has also shown its worth - 2 ml twice daily, duration depending on individual (helps the body with insulin, cortisol, and blood sugar balancing)
As with all health conditions, an individual homeopathic and nutritional assessment is highly recommended since each horse is biochemically and psychologically unique with very different requirements.
This is an informational article only and is not intended to replace veterinary or professional care.
About the Author:
Marijke van de Water, B.Sc., DHMS is a Homeopathic Practitioner and Equine Health Specialist with a private practice in Armstrong, B.C., Canada. She specializes in Homeopathic Medicine and Clinical Nutrition and has treated hundreds of horses with an emphasis on formulating natural health programs to restore optimum health. She teaches dynamic seminars and workshops in natural medicine for both horses and people and is the founder of Riva's Remedies, an herbal and homeopathic product line for horses (www.rivasremedies.com). She can be reached at 1-800-405-6643 or firstname.lastname@example.org.