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The Metabolic Horse

- IR/EMS

If there’s one client enquiry I hear more often than probably any other, it’s metabolic-related.

Usually a PPID/IR horse, very often with gut discomfort (bloating/gas), at risk of - or in the throes of - laminitis,often footsore or with high pulses. They're off grass, and on ad-lib hay. Welcome to my world; that of the metabolic equine.

This is very close to my heart as out of my four horses, three are carb-intolerant natives, one Cushings, the other two IR.

I was first introduced to the equine metabolic world around a year after I got Murphy, my Connemara, back in 2000. He was aged 7 (he’s now 24), had just had his first spasmodic colic episode with me, had a crest the size of a small country, and the vet declared him insulin resistant.

I’m the first to put my hand in the air and say that in those early days I really struggled to balance his system. There was so little information or science available - all vets could offer was ‘avoid molasses’ and ‘get them off grass’, yet despite my many questions, there was little response coming back regarding the how and why of this metabolic state Murf was afflicted with. Interestingly, the only advice on laminitis at that time was focusing on it being purely a hoof condition instead of, as we now know today, a systemic gut/endocrine condition with the resulting laminitis one of many symptoms thereof.

Thankfully, almost 2-decades on, I know a whole lot more about this syndrome. Needless to say my horses are micro-managed to within an inch of their lives, and touch all the wood in the world, and other than one close low-grade lami episode a few summers ago, they’re in pretty good shape.

Owners and vets now recognise an equine metabolic syndrome (EMS) among horses, symptoms ranging from obesity to chronic laminitis. Also known as pre-cushing's, cushingoid, or IR (insulin resistant), the metabolic horse is uncompromisingly carb-intolerant, full stop. Which means a lifestyle on grass is the EMS’ horse’s enemy, because grass is carb-rich in what's known as simple sugars, namely fructose, sucrose and glucose.

Ironically, being grass/carb-intolerant is also the worst prognosis a horse can have, as a horse is evolved to live their life on grass. Just not this ridiculously over-rich, over-starched green stuff that we have here in the UK.

What makes it worse is that the equine foregut can’t digest the grass fructans, so they head straight to the hindgut where they ferment, causing the starch/sugar microbes (the bad guys) to go into overdrive, gobbling it up, killing off the beneficial microbes, breaking the cellular integrity of the gut wall, and producing lactic acid.

Cue the pH value dropping. Cue acidosis (as in an acidic state, not excess release of acid - the hindgut has no acid-secreting cells). Cue destruction of the healthy fibre-digesting bacteria to die which lowers the gut pH value even further. Cue the release of endotoxins (a toxin which is released after destruction of the beneficial microbes' cell wall); cue these same toxins leaking through the damaged gut wall into the bloodstream, creating an inflammatory reaction. Cue inflamed laminae which can occur literally with hours. Cue a high colic risk depending on the severity of the gut damage and risk of large intestine blockage due to critical changes in the gut environment.

So what’s this metabolic syndrome all about?

In essence we’re dealing with the human equivalent of Type 2 diabetes, which is a vicious cycle of crave the next sweet treat. It’s an addiction, almost, because the metabolism is demanding its sugar top-up. The reason for this is all down to hormone changes resulting in adverse hormone messages sent out by those ‘fat pads’. Conventional medicine still has Type 2 diabetes pegged as a blood sugar problem, yet in reality, it's all about insulin resistance and faulty leptin signaling (leptin being the appetite-control hormone), caused by chronically elevated insulin which blocks leptin levels. In other words, it's a diet-derived condition.

Appetite is increased because of insulin’s effect on the brain chemistry. The insulin blocks leptin, so the body becomes more leptin resistant, so the brain never gets the “we're full” signal. Instead, it thinks the body's starving. The pleasure-based reward center is triggered, driving the brain to demand more sugar and fuel the sugar addiction.


Fructose just makes matters worse. It heads straight to the liver where it starts manufacturing fat, triggering more insulin resistance and causing chronically elevated blood insulin levels, driving the body to store everything eaten as even more belly fat. Over time, the liver develops what's known as ' fatty liver', which generates more inflammation. Chronic inflammation causes more weight gain and diabesity. Another problem with fructose is that it doesn’t send informational feedback to the brain, signaling that a load of calories just hit the body. And so the cycle continues.

You can't treat a metabolic syndrome with a pill, because metabolic diseases such as diabetes are dictated by lifestyle, primarily diet. However, there's good news coming out for human-driven Type 2 diabetes in that it's now showing to be reversible via intermittent fasting and water-only fasting.

A recent case series paper published in BMJ Case Reports by Dr. Jason Fung, details how fasting can be used as a therapeutic alternative for Type 2 diabetes. As noted by the authors: "… demonstrates the effectiveness of therapeutic fasting to reverse insulin resistance, resulting in cessation of insulin therapy while maintaining control of blood sugars. In addition, these patients were able to lose significant amounts of body weight, reduce their waist circumference and also reduce their glycated hemoglobin levels."

Which is great news for humans. Not so great for our horses because their gut system is simply not evolved to 'fast' for long periods of time, so we have to manage the metabolic equine a different way.

To quote Dr Fung further, he explains IR in an easy-to-understand way:"You have to use metabolic treatments, which is why using fat for fuel is so important … Remember, the glucose goes into the cell, and insulin resistance is when the glucose doesn't go out of the cell. So, for years we've used this paradigm of lock and key.

That is, the cell is sort of gated off. Outside the cell there's blood, and when insulin comes around it turns the key, opens the gate and glucose goes in. So, if insulin is there, why is the glucose not going in? You can measure the insulin and the insulin level is high. You can look at the insulin receptor, the gate is completely normal.

So, [conventional medicine] said something like, 'Well, maybe there's something gumming up the mechanism. It's stuck in the lock so it doesn't open properly, therefore the glucose can't get into the cell. There's a huge problem with this sort of paradigm, because if that is happening, the cell has no glucose and should be starving.

You should be losing lots of weight; you'd have a very thin liver. All your fat should just melt away, because if you think about untreated Type 1 diabetes, where you don't have enough insulin, that's exactly what happens. The cell literally starves and everything just wastes away … But that's not what's happening here.

In Type 2 diabetes you see that people are generally obese, they have large abdomens … What's happening instead is that it's actually an overflow syndrome. The cell can't accept any more glucose because it's jam packed full of glucose already.

That's the reason you have insulin resistance. Insulin is trying to move glucose into the cell but the cell is full … So, it's really an overflow mechanism …

That's also why your liver is full — it's a big fatty liver. The liver is busy trying to get rid of all this glucose by turning it into fat … Now, if Type 2 diabetes and insulin resistance are the same sort of thing, it's really about too much sugar. That's the bottom line.

And if you understand that the whole problem is too much sugar, then the solution is not to use more insulin to jam more glucose into an already full cell. The key is to get rid of it all. So, what you want to do is: 1) Don't put more sugar into your system, because you have too much sugar in already, and 2) burn it off."


Simples. So let's get back to our metabolic horses. A horse termed metabolic is insulin resistant (IR). Insulin is the hormone primarily responsible for transporting glucose in the bloodstream into the cells, to be used as a source of energy. Insulin’s role is to act as the gateway for the body’s cells to move the glucose in the blood to the muscles, where it is then converted/used as energy. If this doesn’t happen, the glucose levels in the blood increase, which triggers excessive insulin release which leads to elevated levels of insulin, which can be seen in a blood sample.

Here’s the rub, and it may sound like I'm repeating myself. Elevated glucose leads to elevated insulin. Elevated insulin leads to excess body fat. Excess body fat leads to more insulin being released into the blood, and the body becomes 'insulin resistant'. And ... elevated glucose and insulin is considered toxic and can trigger laminitis.


Horses affected with IR have signs similar to Cushing's, such as abnormal deposits of fat and being prone to laminitis. The ‘cresty’ neck is basically a hormone factory that manufactures many signalling chemicals that have a major impact on the health of the horse, including laminitis.

Like Type 2 diabetes in humans, equine IR is thought to be associated with obese horses, and here’s where laminitis becomes a real risk, because elevated insulin and abnormal glucose metabolism causes changes in the vascular and cellular level of the foot, which leads to inflammation of the laminae.

Typically, our native horses are predisposed to this disease because they have such a good survival mechanism; their systems are evolved to survive on what us humans call ‘fresh air’. Give them a few acres of lush green grass and they simply don’t need, and as a result can't utilise the high glucose they're consuming from the grass as an energy fuel to stay healthy.

Managing the metabolic horse

The best prevention for IR/EMS horses is by not allowing our horses to become obese. Monitor weight, focus on a high fibre, low sugar, low carb diet which means no grain, dried-forage based (preferably soaked and drained to remove soluble sugars) and nutrients via forage-balanced minerals, together with restricted, monitored access to grass. However, it’s very important NOT TO STARVE the weight off your horse – they need all the nourishment they can get and must have a balanced, nutrient-rich, species-appropriate diet.

The IR horse, well, any horse for that matter, must have continuous forage/hay to eat, otherwise, apart from the acid-related foregut ulcerogenic risk, they’ll go into manic overdrive, panicking about where their next food is coming from. This brings on stresses of its own which we need to avoid in order to prevent the negative stress hormone (cortisol, which for the record also induces elevated insulin) being released. A wild horse can simply wander off and find more food, but the domesticated horse is entirely dependent on how we manage them.

Which means, starving the IR pony to slim is absolutely not the way to go. I’ll quote here from the ECIR group who dedicate their lives to supporting the IR/Cushings horses:

“The primary treatment for equines with IR only, and for equines with both Cushing's and IR, is a low carb and mineral balanced diet. Any grain products and pasture turnout should be eliminated until all signs of IR are totally absent and reintroduced only with extreme caution. Low carbohydrate hay or forage products should be fed. The ECIR Group has found that ESC + Starch at 10% or less by testing, or hay soaked and drained to remove soluble sugars, can be fed safely to all but the most severe IR horses. Attempting to achieve weight loss by reducing feed intake below 1.5% of body weight can worsen IR and precipitate Hyperlipemia. Hyperlipemia is an alteration in fat metabolism resulting in elevated triglycerides and cholesterol and is a potentially life threatening condition, especially in ponies, so DON'T STARVE the weight off your horse or pony.” Dr Eleanor Kellon, Head Vet, ECIR Group

Here’s breaking news – those crests and fat pads aren’t officially made of ‘fat’. Those crests are ‘adipose tissue’, formed as a result of the excess insulin/blood glucose. These pads of adipose tissue are almost a separate organ in themselves, created by the endocrine (hormone) system, which continues to release instructions to the body that it’s hungry, because … the body has now become leptin resistant. So let's talk a little more about the leptin hormone.

This is a relatively new subject having only really been studied in the last few years, but very much related to the IR/EMS horse (and Type II human). In the case of the EMS horse it's really important for us human carers to attempt to get our heads around it.

So to leptin, and it's a friendly master hormone in the body that controls hunger and feelings of satiety. Grehlin is the master hormone that says the body's hungry; leptin is the one that says the body's full so stop eating. Leptin is secreted from adipose (fat) tissue, and works perfectly well for the normal-weight horse or human.

So, knowing that it’s the adipose (fat) tissue cells which produce the leptin hormone, you’d be forgiven in thinking that our IR cresty equines would produce more of the leptin’s “we’re full” instruction to signal the body to eat less food and normalise weight.

Not so, unfortunately. Our cresty equines, and especially those labelled metabolic/IR/Cushings, have become leptin resistant, which means they're no longer receiving the message that they’re not hungry any more. In other words, they're only hearing the grehlin hormone so the body thinks it’s permanently starving and keeps telling the body to eat more.

As with all hormone issues, leptin resistance is a complex issue and as I type, probably still not fully understood, but there are many factors that can negatively impact leptin levels including (and I quote from esteemed sources) :

• High fructose, simple carbs and grain consumption
• High insulin levels
• High stress levels
• Overeating

All kind of obvious I know …

For those of us who've been here, we all know how difficult it is to shift that crest. We know our horses are overweight and we need to restrict their feed/calories, but this doesn’t work, which is why our cresty equines stay cresty. As Juliet Getty (Equine Nutritionist) says: “The reason is simple – dieting restricts calories, which lowers the metabolic rate. Weight loss may occur at first, but the body goes into “survival mode” and starts to hold on to fat and becomes sluggish in burning calories, making it extremely easy to put all the weight back on.”

Restricting forage is also detrimental, especially for our metabolic equines, because the stress involved increases the stress hormone cortisol, which then induces elevated insulin, which promotes fat storage, and so we’re back where we started. Ad lib is the way, but double-netted to slow the eating process down.

For the record, Dr Kellon says that all IR horses have leptin resistance, so there we go; whether we like it or not we should be factoring leptin resistance into to the whole IR/EMS scenario. Which links us nicely to ...

... The amino acid L-Carnitine, which is thought to help lower leptin resistance which stems from those cresty pads. When I was swatting all things leptin for Murphy (around 2013/14), I came across an interesting article on a forum, written by another horse owner who was also struggling, as follows:

“I read one piece of equine research (a 2004 study by Woolworth et al) ... on the specific subject of l-carnitine and leptin … which indicates that l-carnitine boosts blood concentration of leptin.”

Which implies a greater chance of the leptin message being heard. She also said at the time that coincidentally she saw L-Carnitine being touted as a potential human weight loss drug. She wrote: “The last time I spoke to a physician about this, albeit not an endocrinologist, I was given to understand that the advertisement isn't entirely spurious, so I assume there is something I'm missing about how leptin resistance works and/or about how l-carnitine works with leptin.”

Very generously, she edited her post 6-months later to say: “Update … after 6 months of l-carnitine supplementation, leptin blood levels decreased from abnormally high to within normal range, above median. Not a controlled experiment.”

To recap the first line in the ECIR para, IR horses need a low carb, nutrient-balanced diet by way of minerals and vitamins, especially the ones that our UK forage is deficient in. Micronutrients (minerals and vitamins) are the key to getting the body and system rebalanced, and for Murf, other than his herbal support, I really noticed positive changes in his hoof integrity with mineral balancing.

Naturally I restriced his grass intake (track system with hay stations), and also put together a blend of herbs which became our MetaTonic. This gave Murf's filtration organs a gentle daily detox alongside blood cleansers and the all important gut support to prevent toxins leaking into the bloodstream and sending a disrupted blood supply directly to his hooves. Murf was incredibly gassy and bloated from the carb overload so I also included a generous helping of carminative (fennel) to help prevent the gut bloat - it's also said to help curb appetite.

The blend also contains Galega (Goat’s Rue), which is known to help regulate blood glucose levels. This is the herb that was originally synthesised by scientists to create Metformin, which is the first drug of choice for human Diabetes Type II.

I also added L-carnitine into his feedbowl, and it seemed like the final part of the puzzle. This got him to a point where his gut and brain no longer crave food any more; he’s now a really mellow, balanced, sweet old man, who no longer mugs me for food. He also has a much looser, freer, peripheral movement as well. All three of my natives, Murf, Cookie and Mac, are on the blend and they’re all doing great – I no longer set up a track system and - newsflash - they all live out 24/7 (I still put hay out pretty much all year round to 'dilute' the grass). We don't get pulses or hoof heat, and as for their crests, while not completely vanished, definitely softer and reduced.

Pulling all this together, here’s what I’d suggest to support rebalancing the metabolic syndrome to regulate itself back to manageable - I'll just add in a quick disclaimer here that this is what works for me - it may not work for everyone so naturally seek opinions/advice:

  • Manage grass intake, and meanwhile feed at least 2% of ideal bodyweight in soaked hay/day. Soaking hay for 30-mins hot water/60-mins cold water (maximum times), will help remove up to 30% of the sugars and make it safer to feed. Small mesh hay nets are a great way to make the hay rations last longer.
  • Relook at feedbowl diet, as low starch as possible. Agrobs do a fantastically low starch chaff, namely their Leitchgenus at just 2% starch, which is great to use in the feedbowl as a supplement carrier.
  • Keep the beneficial intestinal microbes populated by way of a probiotic, and feed them with prebiotics.
  • If your horse is off grass completely, remember that hay alone will not a nourished, healthy horse make. For the metabolic horse where hay plays a vital part in the diet due to grass restriction, supplementing the deficient minerals to balance our UK forage and hay is essential. See our EquiVita range, and specifically our EquiVita-ProBPlus, which includes Yea-Sacc probiotic and Vits C & E, the latter two which are lost in the drying process of grass to hay.
  • Don't forget adding micronised Linseed for the essential omega-3 (again lost in hay); feed 20g/100kg bodyweight summer, double this in winter.
  • Also, don't forget Salt, a level tablespoon, double this if in hard work/sweating.
  • Support the syndrome with our organic herbal MetaTonic blend.
  • Add the amino acid L-Carnitine – 2g/100kg bodyweight. I buy mine here: https://www.tradeingredients.com/Acetyl-L-Carnitine
  • Apple cider vinegar - it's super-nutrient rich, but specifically it’s high volume of acetic acid may be the most significant of these components for metabolic health, including lymphatic drainage and the body’s natural detoxification processes, which for the IR horse is highly beneficial. Even better, according to new research, ACV’s acetic acid is also showing to benefit the number of energy-producing mitochondria in the body’s cells by stimulating an important metabolic pathway known as PGC-1 alpha. This pathway largely controls mitochondrial function within the cells, which is important if we’re doing all we can to reduce our horses’ blood glucose levels. PGC-1 alpha increases the mitochondrial functional capacity when energy needs are high and reduces it when they are low.So, by adding ACV to the feedbowl, you may actually be able to improve your horse’s mitochondrial efficiency and produce more cellular energy.

    New research is also showing that ACV is what’s known as a thermogenic, which is the process of burning body fat to generate body heat. Researchers have found that ACV can turn on genes to signal the body to accumulate and store less fat, and can make the body feel more full and suppress appetite. (In one 12-week Japanese study, one group of individuals drank a beverage containing one tablespoon of ACV. Another group drank a beverage with two tablespoons ACV. A a third group had a drink with no vinegar. At the end of the study, the people who drank either of the beverages with vinegar showed less signs of metabolic syndrome compared to the no-vinegar group.)

    (Note – when buying ACV, make sure it has ‘The Mother'. In the perfect world you want organic, raw, unfiltered, and unprocessed apple cider vinegar, which is murky and brown. An apple cider vinegar without the mother and its beneficial enzymes and probiotics isn’t worth buying.)

And if the dreaded laminitis develops?

The majority of laminitic events these days are due to metabolic issues, so having a PPID/IR/EMS horse certainly makes them more prone. And let's not forget that laminitis is ultimately a symptom of what’s gone wrong further up.

In the immediate term it's about alleviating the symptoms. Cold therapy hits the inflammation and heat, so cold hosing is the first step - ice buckets if you've access to ice. Then pain-relief and anti-inflammatories - I prefer not to go the bute/danilon route because of the added toxicity residue they impose on an already compromised, toxic system, so if you’re looking for a natural solution, have a look at our organic Pain support.

For herbal nutrition - ONLINE SHOP

For mineral hoof support, see our EQUIVITA MINERAL SOLUTIONS - ONLINE SHOP