Dietary Care for Managing Difficult Metabolic Cases

Recent studies provide strong foundational evidence for the efficacy of a novel botanical extract with the potential to support normal post-prandial glucose levels and the resulting insulin responses.

By
Emily Smith, MS
Emily Smith, MS
Platinum Performance®

Emily Smith, MS, has been an equine nutritionist at Platinum Performance® for over 15 years and has a passion for answering technical nutrition questions and finding the best diet for the individual horse. She has written many articles including The Power of Vitamin E, Feeding Frenzy: A Forage First Approach and The Joint File.

, Platinum Performance®

New Research Shows Innovative Ingredients Provide Advanced Support for Healthy Glucose and Insulin Response Targeting Sugar Absorption for Insulin Dysregulation

Equine metabolic syndrome, or EMS, is a complex health condition affecting up to 43% of horses worldwide. Characterized by insulin dysregulation (ID), affected horses react by producing abnormally high insulin levels in response to normal dietary sugar loads or other stimuli. While the condition itself is not life threatening when diagnosed and managed early on, EMS is a risk factor for laminitis — a painful and often debilitating disease when the laminae of the hoof separates from the coffin bone. Horses with EMS also have been shown to have increased systemic inflammation, a rise in circulating reactive oxygen species (ROS) resulting in cellular damage, poor fertility, susceptibility to musculoskeletal injury and other systemic effects related either directly to EMS, obesity or to a combination.

EMS can be challenging and frustrating to manage. Affected horses have ID where the cells, over time, can become insulin resistant or less sensitive to the effects of the hormone produced by the pancreas that regulates blood sugar. The cell receptors for insulin do not respond appropriately and more insulin is needed to control blood glucose. Obesity is a key risk factor. However, not all EMS horses are overweight, making early diagnosis sometimes a challenge.

A holistic approach combining weight management, exercise (if possible), medication and targeted nutrition — including the control of sugar content in feed — can provide the best results for this multifaceted condition. Recent equine research reveals an alternative pathway to supporting healthy metabolic function by slowing sugar absorption into a more controlled release while the horse is eating. The positive effects of a novel combination of white mulberry (Morus alba) extract with yeast extracts, which provide pre- and postbiotics, and vitamin C, an antioxidant, promote more normal, healthy blood glucose levels, insulin response and provide significant support for metabolic horses.

Sugar Shock: High-Risk Carbohydrates for EMS

Sugar content in the diet is critically important for an EMS horse due to the insulin dysregulation component. Affected horses are especially sensitive to dietary simple sugars and starches, collectively known as non-structural carbohydrates, or NSCs. These specific carbohydrates are important to monitor as they cause spikes in blood glucose and insulin. Controlling dietary sugar is one of the most effective ways to manage EMS symptoms. It helps control insulin levels, reduces the risk of laminitis and supports a healthy weight.

Carbohydrates to Keep in Check:

  • Simple sugars (water-soluble carbohydrates or WSCs) include: glucose, fructose and sucrose. These are quickly absorbed in the small intestine, causing rapid increases in blood glucose and insulin.
  • Starches are made up of long chains of glucose often found in cereal grains like corn, oats and barley. Starches are digested into glucose in the small intestine and are considered very insulinogenic and strongly trigger insulin release, which is dangerous for EMS horses.
  • Fructans are chains of fructose stored in plants especially cool-season grasses like Kentucky bluegrass, fescue and perennial ryegrass. They tend to be highest in spring and fall pastures. Fructans are not digested in the small intestine like other sugars, although some breakdown from gastric acid and small intestinal fermentation can occur. Instead, they are primarily fermented in the hindgut, predominately producing lactic acid as a result of fermentation. This type of sugar may not directly raise blood glucose but can disrupt gut health and potentially contribute to laminitis via other mechanisms.

While calculated dietary modifications paired with regular exercise provide adequate support in some horses, certain cases may require additional therapeutic intervention.

While calculated dietary modifications paired with regular exercise provide adequate support in some horses, certain cases may require additional therapeutic intervention.

Using Nutrition in the EMS Treatment Plan

Nutritional management of EMS primarily consists of a combination of weight control and limiting the amount of simple sugars in the diet. Generally speaking, a nonstructural carbohydrate (NSC) level below 10% in the total diet is considered ideal. NSCs comprise the intracellular component of plants, including starch, simple sugars and fructans, excluding most indigestible carbohydrates such as cellulose, hemicellulose and lignin.

Hay is the cornerstone of the EMS diet. Hay testing is important in determining its sugar content as opposed to a visual assessment — examining the color and condition of the grass — that is not an accurate indicator of NSC levels. If hay tests higher than desired in sugars, soaking it for 30-60 minutes in cold water will reduce water-soluble carbohydrates (WSCs) by 30-50%. (Dispose of the water, however). NSC content in a single field can vary both within one cutting as well as between cuttings, so a previously low NSC hay batch from a given grower does not guarantee a low NSC content. Alfalfa tends to maintain a lower NSC content but can occasionally have high levels, partly due to the storage of depot sugars as starch by legumes instead of fructans. The high protein content in alfalfa may also trigger insulin spikes, and therefore should be carefully considered.

Grains tend to be high glycemic feeds, primarily as a source of starch, with NSC levels ranging from 51.6% in barley to 74.2% in corn. For this reason, most grains should be avoided.

While EMS is primarily an issue with sugars and their effect on insulin in dysregulated horses, the impact of systemic inflammation, oxidative stress and dysbiosis (an imbalance in the community of microorgansims in the gut), not only as underlying triggers but also as ongoing systemic stressors, cannot be ignored. Management should include offsetting oxidative load, gastrointestinal stress and systemic inflammation, in addition to supporting healthy glucose and insulin response. While calculated dietary modifications paired with regular exercise provide adequate support in some horses, certain cases may require additional therapeutic intervention.

EMS horses are typically overweight or obese, and excess sugar contributes to calorie overload. Reducing dietary sugar supports weight loss, which in turn helps improve insulin sensitivity.

EMS horses are typically overweight or obese, and excess sugar contributes to calorie overload. Reducing dietary sugar supports weight loss, which in turn helps improve insulin sensitivity.

Three Ways Controlling Sugar Controls EMS

  1. Manages Insulin Resistance - EMS horses have a reduced ability to respond to insulin properly. Consumption of high levels of sugar (especially simple sugars and starch) cause blood glucose spikes. To manage this, the body produces more insulin. Chronically high insulin levels (hyperinsulinemia) are directly linked to laminitis.
  2. Mitigates Laminitis Risk: - One of the most serious consequences of EMS is laminitis, a painful and potentially debilitating inflammation of the hoof laminae. High insulin levels (caused by sugar-rich diets) are now understood to be a primary trigger for laminitis in EMS horses — even without mechanical overload (excessive weight bearing on the opposite supporting limb) or toxins. Managing sugar and starch intake is crucial to prevent laminitis episodes.
  3. Supports a Healthy Weight: - EMS horses are typically overweight or obese, and excess sugar contributes to calorie overload. Reducing dietary sugar supports weight loss, which in turn helps improve insulin sensitivity.

How Does DNJ Work?

  • Blocks Carbohydrate Breakdown: With a structure similar to glucose, DNJ can bind to the α-glucosidase enzyme and block the breakdown of certain carbohydrates.
  • Reduces Sugar Absorption: By blocking some carbohydrates from being digested, DNJ can slow the release of sugars into the bloodstream.
  • Supports Metabolic Health: Lowering postprandial (after-meal) glucose and insulin responses helps maintain healthy metabolic function.

Novel Nutrients that Battle EMS

Strategic supplementation has the potential to effectively support this at-risk population. Established research supports the addition of antioxidants as well as pre- and postbiotics for proper maintenance of oxidative and gastrointestinal homeostasis. More recent studies provide strong foundational evidence for the efficacy of a novel botanical extract with the potential to support normal post-prandial glucose levels and the resulting insulin responses.

White Mulberry (Morus alba)

The leaves and bark of the white mulberry tree have been used for more than 2,000 years as a natural way to support blood sugar, cholesterol, normal inflammation and more. These health benefits are mainly associated with a naturally occurring iminosugar, where a nitrogen atom replaces the typical oxygen atom in the sugar ring. This small organic molecule found within the white mulberry leaf contains a compound called 1-Deoxynojirimycin, or DNJ. By blocking a specific enzyme, DNJ prevents the breakdown of larger sugars into more simple sugars (i.e., glucose and sucrose), strategically impeding carbohydrate breakdown and reducing sugar absorption. This leads to a slower, more controlled release of sugars into the bloodstream.

Prebiotic and Postbiotic Yeast Extracts

The gut microbiota is an essential player in the regulation of systemic inflammation, glucose metabolism and insulin sensitivity. Dysbiosis, or an imbalance in the gut microbiota, has been associated with metabolic disorders, including insulin resistance. While traditional management strategies often focus on diet modification and exercise, emerging evidence suggests that unique pre- and postbiotic yeast extracts may offer significant benefits in supporting equine metabolic health by supporting gut health, intestinal barrier integrity and normal inflammation — key drivers in healthy metabolic function. While prebiotics are non-digestible fibers that promote the growth of beneficial gut bacteria, postbiotics are bioactive compounds produced by probiotic microorganisms during fermentation that contribute to maintaining gut health and normal levels of inflammation.

Vitamin C

Vitamin C, also known as ascorbic acid, plays a critical role in equine antioxidant defense mechanisms. Horses with EMS and ID often experience increased oxidative stress, a condition characterized by an imbalance between the production of ROS and the availability of antioxidants to neutralize them. Studies have shown that antioxidant supplementation, including vitamin C, can support normal insulin responses in both humans and animals.

The Research

Evaluating the Proprietary White Mulberry Leaf Extract

Researchers at the University of Georgia investigated the application of a proprietary white Mulberry leaf extract in a metabolic equine population.

Phase I: Response

Six healthy adult horses were assessed while being fed escalating doses of a proprietary white Mulberry leaf extract over four weekly intervals. A reduction in fasting insulin and postprandial glucose in these healthy horses suggests that supplementation may have benefits beyond horses with existing metabolic health concerns.

Phase II: Dosing

Five horses needing metabolic support were given five dosages (0 to 5,000 mg twice daily) in ascending sequence for seven days. The results showed that the two highest doses promoted normal fasting insulin levels following an oral sugar test.

Phase III: Timing

Sixteen horses needing advanced metabolic support were assessed to confirm optimal timing of supplementation and duration of effect. Oral sugar tests were performed at 0, 1, 2 and 3 hours after administration, and they confirmed effectiveness is dose and time dependent with the best results immediately following administration and the highest dose showing results up to 3 hours after administration while peak insulin concentrations remained lower up to 1-hour after administration.

Whitfield-Cargile C, Coleman M, Hart K, Gomes, D, Berghaus L. Evaluation of the safety and efficacy of 1-deoxynojirimycin (DNJ) in horses with insulin dysregulation. University of Georgia, Athens, GA, USA; 2025.

Decoding Sugars on a Forage Analysis

When feeding metabolic horses, it is often recommended to send hay and pasture samples to be analyzed for specific sugar and starch content. The goal is to keep total NSC (WSC + starch) below 10% to avoid triggering insulin spikes and laminitis. Managing these specific carbohydrates through careful forage and feed selection is essential to keeping the horse healthy.

Types of Carbohydrates and Their Role in the Equine Diet

Fiber Horses are uniquely capable of using fiber from forage sources to fulfill a huge part of their energy requirements due to the ability to ferment fiber via specialized microflora in the hindgut. In fact, the fermentation of fiber has the capability to supply the horse with 30-70 percent of its total digestible energy requirements. Structural Carbohydrate (Plant Fiber)
Helpful because it provides a significant amount of digestible energy and essential to maintain intestinal motility and a healthy microbial environment in the hindgut.
Fructan Fructan content in grass is tolerated by most horses at moderate levels. However, as fructan levels rise, especially after times of rapid grass growth or grass stress, elevated intake of these pasture sugars can result in health issues like colic and pasture associated laminitis, particularly in susceptible horses. Non-Structural Carbohydrate
High levels of starch and sugar can have health repercussions as their breakdown results in excessive amounts of glucose. Insulin controls glucose moving into and exiting cells. A higher amount of insulin is needed to control glucose levels when digesting foods high in starch and sugar. Over time, the cells can become less sensitive to the effects of insulin; they become insulin resistant. Fructans must be fermented in the hindgut and at high levels can acidify the hindgut potentially leading to colic and pasture associated laminitis.
Sugar Amounts from cereal grains should be limited for all horses.
Starch Because starch digestion results in more energy and calories available than the digestion of fiber, grains are often used to provide horses in work with extra fuel. For high performance horses relying on increased levels of starch, it may be beneficial to split meals into multiple servings daily (less than 4 lbs/meal). Horses at maintenance do best on a lower starch content in their diet. Horses with the following conditions are good candidates for a low starch or forage-only diet: obesity, insulin resistance, metabolic syndrome, chronic colic, laminitis, developmental orthopedic diseases, polysaccharide storage myopathy and recurrent exertional rhabdomyolysis (tying-up).

Feeding EMS Horses

Things to Do

  • Feed low-NSC hay (less than 10%; ideal is often 8-10%) as the bulk of the diet. Test all hays and pasture grasses for sugar and starch content.
  • Soak hay to reduce sugar content. Discard water before feeding.
  • Balance the diet with a daily comprehensive omega-3 wellness supplement that includes vitamins, amino acids and trace minerals to complement forage.
  • Supplement with white mulberry extract, antioxidants, like vitamin C, and pre- and postbiotics.
  • For low-sugar supplement carriers, choose unmolassed, soaked beet pulp or hay pellets.

Things to Avoid

  • Sudden diet changes.
  • Grains (corn, oats, barley, etc.), grain mixes and sweet feeds with molasses or corn syrup.
  • Sugary treats like sugar cubes, apples or even carrots.
  • Pasture grazing, especially in the spring and fall.

Key Carbs on a Hay or Pasture Analysis:

  • WSC (Water-Soluble Carbohydrates) are simple sugars + fructans and should be less than 10%.
  • ESC (Ethanol-Soluble Carbohydrates) include mostly simple sugars (glucose + sucrose) and are more insulin-relevant than WSC.
  • Starch includes digestible starches and should be less than 4%.
  • NSC (Non-structural Carbohydrates) include WSC + starch (sometimes ESC + starch). The total NSC should be less than 10% for EMS horses.

Feeding for Wellness: The First Step to a Healthy Metabolism

Since 1996, Platinum Performance® has been committed to promoting wellness in horses, with a philosophy that food is medicine and preserving the fact that a natural grazing diet is essential to every horse’s health. What a horse eats affects its entire body, beginning at the cellular level and impacting how the animal looks, feels and behaves. Studies support providing a balanced diet with adequate fiber levels, calories, essential fatty acids, antioxidants, amino acids, vitamins and minerals will supply the body with a strong foundation for daily wellness and tissue repair, and will fuel growth in young horses. The daily diet affects a normal, healthy inflammatory response, can limit oxidative stress and supports immune health — all critical for systemic health and longevity.

Inflammation can profoundly affect equine health. A normal inflammatory response (a reaction to injury, irritation or infection) can help a body heal, while a prolonged or exaggerated response can be harmful and is involved in most health concerns. Food plays a role. What you feed your horse also can promote or maintain normal levels of inflammation. The most natural equine food — fresh pasture grass — is anti-inflammatory and naturally contains many essential and beneficial nutrients including an ideal ratio of essential fatty acids. As a grazing herbivore, horses have evolved on a natural foraging diet that contains a fatty acid ratio of up to five times the total amount of omega-3 fatty acids than omega-6 fats. Because of this, horses are often considered “omega-3 animals” and thrive on a grass-based diet. Omega-3 and omega-6 fats are both necessary for the well-being of the animal — omega-3s support anti-inflammatory reactions, while omega-6s support pro-inflammatory reactions — but the dietary ratio is critical to maintain normal, healthy levels of inflammation.

Not all horses have access to fresh grass, and a typical modern equine diet often includes a combination of forage, cereal grains, grain-based commercial feeds or concentrates. The equine digestive system is not designed to support a diet high in grain intake. Cereal grains and grainbased feeds provide excessive amounts of sugar or starch and an unhealthy ratio of essential fatty acids. Common feeding practices that include meal settings made up of grains and grain-based concentrated feeds have caused a widespread inverse essential fat ratio, drastically increasing the omega-6 fat concentration in the diet while decreasing the total amount of omega- 3 fats. It has been estimated that the typical diet of the horse today provides up to 18 times more omega-6 than omega-3 fatty acids, and likely higher, promoting inflammation. Also, when grass is cut, dried and stored to make hay, most of the fragile fatty acids and fat-soluble vitamins are quickly oxidized and destroyed. Supplementation with omega-3 fatty acids can help rebalance the fatty acid profile toward that of a natural grazing diet and support normal levels of inflammation.

Antioxidants are another important component of feeding for wellness. Free radicals are unstable molecules produced as a byproduct of normal metabolism, or in response to exercise, inhalation of dust and air pollutants, and exposure to ultraviolet light. These molecules can also become excessive following an injury or a disease. Oxidative stress occurs when there is an imbalance between the production of free radicals and the body’s ability to neutralize them with antioxidants. Oxidative stress can overpower the horse’s ability to internally defend itself and may result in tissue damage. Additionally, high oxidation levels may inhibit immune health. Antioxidants internally scavenge and neutralize free radicals and prevent or limit oxidative stress. Providing dietary antioxidants can address oxidative stress in exercising horses, horses with health conditions or other variations of bodily stressors including a high-grain diet. Familiar antioxidants are vitamins C, E and beta-carotene, which is converted into vitamin A in the small intestine. Moreover, the trace minerals copper, zinc, manganese, iron, and selenium are essential for the internal formation of enzymatic antioxidants.