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The Overweight Horse - leptin resistance could be the clue


This world is a spooky place. Over the last few days I’ve been asked about Folic Acid, Leptins and Vitamin C. Must be something going on in the Parallel Universe because these three subjects then appeared in my groups FB box on my personal page. Too coincidental to ignore! (Who else read The Celestine Prophesy back in the 90's?!)

I’ll post on the other two another time, but the subject of Leptin has really caught my eye this week, specifically related to our Cookie who, no matter how we monitor her diet, has a fairly hefty crest and fat pads likened to the Duchess’s front and the Cook’s behind. And I’m also more than aware that we’re on the cusp of Spring, and with it comes the green stuff, which is when Cookie really balloons. I see Cookie every day so sometimes it's tricky for me to tell, but I can usually judge from Deb, our trimmer, who either reports that Cookie's looking good (!), or like last visit, err, Cookie could do with losing a liiiiiiitle bit of weight, ahem.

I’ve been seeing ‘Leptins’ mentioned often recently on the ECIR Yahoo page, then just yesterday I was asked about Leptins being the cause for an owner who’s struggling with her PPID horse’s weight/diet. So off I went to swat.

Leptin is a friendly master hormone in the body that controls hunger and feelings of satiety - it tells the brain that we’re full and we can stop eating. It’s secreted from adipose (fat) tissue, and works perfectly well for the normal-weight horse.

So, knowing that it’s the fat cells which produce the Leptin hormone, you’d be forgiven in thinking that more Leptin instruction would be produced by our porkier equines to signal the body to eat less food and normalise weight.

Not necessarily so, unfortunately. Our cresty equines, and especially those labelled Metabolic or with Endocrine issues, don’t always get the Leptin message, which means they may have become leptin resistant.

As with all hormone issues, Leptin resistance is a complex issue with no singular cause, 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
(yep, know that)
• High insulin levels (and that too)
• High stress levels (obvious, especially for our PPID-ers)
• Overeating (you don’t say …)

I’ll put my hands in the air now and say that all of us with cresty equids know – and work around – the above pointers already, so I know what you’re going to say – “We all know this stuff!” But despite our best efforts, why does Cookie, and all those other horses whose owners I hear from, hold onto their crests and fat pads?

It’s the devil and the deep blue sea. We’re told our horses are overweight and we need to restrict their feed/calories. But it doesn’t work. As Juliet Getty 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.”

And let’s not forget that we can’t leave our horses standing for long periods of time without food, unless we want to risk acidity and ulcers. I personally follow the ad-lib theory, where my horses have a constant supply of hay so they don’t stress that there won’t ever be food, thus they self-regulate their intake and don’t overeat. This works for my lot, yet Cookie still balloons.

There’s also the ‘vicious cycle’ risk. If our horses do lose a bit of weight, the leptin level will drop. And guess what, when leptin levels drop, the leptin hormone signals the horse to eat more, potentially gaining back all of the body fat lost! Restricting forage is also extremely detrimental, especially for our PPID equines, because the stress involved increases cortisol, which then induces elevated insulin, which promotes fat storage, and so we’re back where we started.

It’s well known these days that those fat pads and crests indicate insulin resistance, and that if we don’t take all care possible, the risk of laminitis is very real. In human health, high levels of Leptin (and the accompanying Leptin resistance) is directly tied to insulin levels, high blood pressure, obesity, heart disease and stroke, as well as blood sugar issues. Sound familiar? They can also decrease fertility, speed up the aging process and contribute to obesity.

I’m not saying that Leptin resistance is definitely the case for Cookie, but it could be that for those of us with horses that just have to look at grass and balloon, it MAY BE because they have Leptin resistance. Dr Kellon says that all IR horses have Leptin resistance. “However, not all Leptin-resistant horses are IR,” says one poster on a forum whose horse is leptin-resistant but not IR. She continues, “It seems from my reading that the two resistances co-occur because insulin increases leptin concentration.”

From what I’m reading, to make lasting health changes, lose weight and keep it off, we have to fix the Leptin levels. However, Leptin resistance and its related problems are a complex issue involving the Endocrine system, and reversing them requires more than simple calorie restriction.

According to an article (human health) in the Huff.Post (http://www.huffingtonpost.com/…/long-term-weight-loss---m_b…): “The problem is not in the production of leptin, but rather, studies show that the majority of overweight individuals who are having difficulty losing weight have a leptin resistance, where the leptin is unable to produce its normal effects to stimulate weight loss. This leptin resistance is sensed as starvation, so multiple mechanisms are activated to increase fat stores, rather than burn excess fat stores. Leptin resistance also stimulates the formation of reverse T3, which blocks the effects of thyroid hormone on metabolism.”

In other words, the body thinks it’s starving and keeps telling the body to eat more.

Juliet Getty’s theory is that it’s about inflammation, which if you ask any bio-chemist they’ll no doubt agree. “Body fat produces inflammatory molecules known as cytokines. These substances have two negative impacts: first, cytokines disrupt insulin action, reducing the cells’ insulin sensitivity, making your horse store more body fat. And second, and very important, cytokines impair the neurons in the brain’s hypothalamus, which is the area that normally responds to leptin.”

So is the answer about reducing inflammation?
Getty says that by reducing inflammation, “the brain will more than likely become more responsive to leptin, thus controlling the horse to stop eating when full." She recommends ad-lib forage to eliminate stress (I use double-netted haynets). Movement, as always, is key, and allegedly we'll have “a formula for success.”

Getty's Recommendations:
• Improve protein quality by feeding several sources: mixed grasses, linseed (micronized), copra, hemp seeds, chia seeds – (these latter have positive omega 3 levels as well which are non-inflammatory).
• Avoid simple starches, refined foods, sugars and fructose, any sweetened feeds, cereals, grains, wheat middlings and rice bran.
• Avoid omega 6 oils which are highly inflammatory, i.e. anything labeled ‘vegetable’, soya oil, corn oil, etc, and anything labeled ‘lightly coated in soya oil’ etc.
• Feed a min/vit supplement with high amounts of antioxidants, particularly vitamins E & C.
• Offer anti-inflammatory herbs such as green tea, spirulina, turmeric, boswellia, meadowsweet.

I also found these tips:
• Consuming protein and healthy fats first thing in the morning will help promote satiety and give the body the building blocks to produce hormones.
• Save exercise for later in the day. If there is Leptin resistance this may be an additional stress on the body. Let the body relax first thing, then add in the exercise.
• Remove all toxins! These are a stress on the body – switch off non-organic and processed foods wherever possible!

So what can I do here for Cookie? Thing is, I already do the ‘bring in during the day, out at night’ regime from spring-autumn, with ad-lib mixed-meadow hay and an overnight muzzle. She already gets Copra and linseed, with a bespoke herbal supplement made up from a mix of our CushSupport and LamiProne organic herbs which includes Meadowsweet, a well-known anti-inflam. She also gets our EquiVitaA-Ultra with the Spirulina. So I'm pretty much there. I could always give her a herbal green-tea in with her Copra soaking which would be no bother.

Here’s an exciting thing though. I read about one other possible supplement on the forum mentioned above, where the poster’s vet recommended supplementing with Alcar/L-carnitine, 1500mg 2 x/week. Alcar is a supplement many of you are starting to talk to me about, specifically in PSSM/EPSM-type scenarios. There have also been some interesting posts on the Phoenix Forum with very positive Alcar stories.

The poster also found “one piece of equine research ... on the specific subject of l-carnitine and leptin (actually just the abstract- http://www.ncbi.nlm.nih.gov/pubmed/19320933), seems from the abstract to indicate that l-carnitine actually boosts blood concentration of leptin. A 2004 study on swine by Woolworth et. al.- again I can only get at the abstract- had similar results.”

She does go on to say that she’s not sure whether increasing blood leptin levels above an already abnormally high concentration would promote, rather than improve, leptin resistance. But she did say that she saw l-carnitine being touted as a potential ‘weight loss drug’. “The last time I spoke to a physician about this, albeit not an endocrinologist, I was given to understand that that advertisement isn't entirely spurious, so I assume there is something I am missing about how leptin resistance works and/or about how l-carnitine works with leptin.”

The best bit though, is that she’s edited her post 6-months later to say:

“Update post 10: after 6 months of L-carnitine supplementation, leptin blood levels decreased from abnormally high to within normal range, above median. Not a controlled experiment.”

This is good enough for me. I’ve ordered a 500g bag of L-Carnitine and I’m going to start Cookie on it alongside introducing Siberian Ginseng into her daily mix which helps support body systems and cellular function disrupted by stress, with a bit of assistance towards energy levels.

I’ll keep you posted!