Minerals and the Insulin Resistant Horse

Minerals have direct and indirect involvement in virtually every action in the body, and have important effects on Insulin Resistance (IR) or its consequences. IR is different in the horse than in the human, but the same basic principals apply.  There is evidence of activated antioxidant defenses in the tissues of IR horses.

Building the horse’s own antioxidant basic defenses is most effective. This includes the SOD, catalase and glutathione peroxidase enzyme systems as well as the antioxidants glutathione, CoQ10, carotenoids and vitamin A, flavanoids, vitamin E and C. Glutathione is particularly widely distributed.

SOD absolutely requires copper and zinc. Catalase requires iron which is not an issue as the typical equine diet supplies plenty of iron.

Glutathione activity depends on Selenium, a very common deficiency.  Selenium is also essential for the generation of the active form of thyroid hormone, T3, from T4.  Selenoproteins, important to immune function, are just beginning to be looked at in depth. Both IR and PPID horses are prone to inflammatory and allergic-type immune reactions rather than using the more sophisticated arm of the immune system.

Zinc is a commonly deficient mineral. Low serum Zinc is associated with IR and type 2 diabetes in humans and rats. Supplementation of Zinc supports  defenses against type 2 diabetes in rat models. Exactly why has not been determined. It is known that Zinc is important on several levels, involved in insulin release and sensitivity as well as being an antioxidant in SOD.

Like Zinc, Copper is critical for SOD function. Copper deficiency causes IR and fatty liver in rats. Low liver Copper is found in human fatty livers. Deficiency is also linked to higher liver iron in IR, a known problem in IR horses too.

Magnesium has been associated with IR for forty years with hundreds of human papers dedicated to the subject. Magnesium is not a treatment, but by correcting a deficiency it makes the disease easier to control.

Magnesium dietary intake and magnesium status – whole body levels – are both associated with strong defenses against IR and they deteriorate when someone develops IR. It becomes a cycle you need to stay on top of to allow stabilization.

A 2013 study included almost 2000 non-diabetic subjects followed for 15.6 years. 1 Magnesium intake was a “significant protective factor” against type 2 diabetes, including progression from IR to diabetes. Researchers could predict who would most likely become IR by looking at their magnesium levels.

Magnesium increases insulin receptor number and sensitivity in experimental rodent IR. Magnesium deficiency interferes with insulin signaling. Deficiency has also been linked to activation of allergic and inflammatory reactions.

Iodine is essential to production of thyroid hormone. Low iodine status has been identified in human patients with type 2 diabetes. Normal thyroid function is required for insulin sensitivity.

IR horses may also have low thyroid hormone levels in some cases. This is probably euthyroid sick syndrome, meaning it is an effect rather than a cause. In most of these horses, with correct levels of Selenium and Iodine, and control of IR, the levels will rise again. Low thyroid is not a primary part of the syndrome but can make some horses very depressed and lethargic. Thyroid supplementation can be used but by addressing the above you will not need supplementation long term.

Chromium has been important for people probably due to processed foods being stripped of many essential minerals. It is required for a normal cellular response to insulin. The exact dietary requirement is unknown, but supplementation in IR horses is not helpful in most cases. Grass absorbs chromium very efficiently and soil levels are abundant in most areas. We have observed a problem only when horses are eating hay grown on alkaline soils where the plants may not absorb the chromium as readily. 

It’s not as fancy as a pricey magic bullet supplement but the best place to start supporting your IR horse on a low sugar and starch diet is with balanced intake of key minerals.

Eleanor Kellon, VMD


About Dr. Kellon

Graduate of University of Pennsylvania Veterinary School. Owner of Equine Nutritional Solutions, www.drkellon.com, industry and private nutritional consultations, online nutritional courses. Staff Veterinary Expert at Uckele Health and Nutrition.
This entry was posted in Equine Nutrition and tagged , , , , , , , , , , . Bookmark the permalink.

21 Responses to Minerals and the Insulin Resistant Horse

  1. charlotte garrett says:

    two of my ir an cushing horse are on a ration balancer adding poly copper an zinc be ok to add to there feed,,,they also get remission for ir founder prone horses ,,iam in a high iron area of north carolina

    • Dr. Kellon says:

      I would strongly encourage you to get a hay analysis done because there can be other issues in your area, like a high phosphorus and inverted calcium: phosphorus ratio that will also impact how much magnesium you need to be balanced. The only way to tell you need more zinc and copper (or manganese) is to analyze the hay.

  2. Emma Jönsson says:

    Quetsion: Potassium increases kortisol and kortisol increases insulin (simply put). A lot of hays and and grasses are very high in potassium, at least here in northern Europe, and potassium is frequently used to fertilise the pastures. Why doesn’t anyone seem to talk about this? The analysises of foraage I have seen tha last couple of years will provide a huge amount of excess potassium. Could’nt this be part of the problem for horses? What if we tried to balance the potassium better for our horses? Why isn’t there any research on this?

    • Dr. Kellon says:

      High potassium stimulates aldosterone release, not cortisol. All forages are higher in Potassium than the horse requires because of the key role it plays in plant metabolism. This isn’t a problem because the kidneys very quickly filter out any excess. Blood levels stay normal.

  3. Cecelia W says:

    My vet told me to activate my insulin intolarant horse’s ghyroid gland. What does that mean?

  4. Dr. Kellon says:

    Let me back up briefly here. Humans eat a very varied diet. Potato, bread and pasta are all “starches” but have different vitamin and mineral profiles so things tend to balance out over time. Small pet animals may eat the same food every day but it has been balanced. The balance is important because minerals compete with each other for absorption. So do vitamins. When the horse gets the same meal 24/7 for months the imbalances are very important.

    The hay analysis gives you some protein information and the important minerals. If you are properly trained you can use that information to figure out what your horse needs. The IR and non-IR horse have the same basic requirements as a starting point but many IR horses are iron overloaded so the balance is even more critical for them. Deficiencies also worsen over time on unbalanced diets so senior horses have more difficulty.

  5. Clare Jackson says:

    So can you please advise on what supplement should be fed to my two Cushings (one has just got over laminitis) horses to keep their vit/min bala ce correct? I am slowly going mad trying to work out the best one!

  6. Mike France says:

    What is the best way to have your horse checked by someone who understands the essential levels and how to supplement for deficiencies?

    • Dr. Kellon says:

      You need your diet checked, not your horse. This includes hay analysis and any other things you are feeding. You can get a private consultation with a nutritionist, or Uckele customer service will do it for you to my specifications, or you can learn to do it yourself with my NRC Plus class (details at http://www.drkellon.com).

  7. HippoLogic says:

    Could you enlighten me about what SOD means? A minimum Daily Doses or something? Thanks.

  8. Sarah says:

    Also wondering. How much to give of each?
    Is there an good supplement that contains all of these?

  9. Brycie says:

    Agree but how do u know how much of these minerals to give

    • Dr. Kellon says:

      Ideally you do a hay analysis. Second best is to get advice from someone who knows the regional profiles for where your hay was grown and the hay types.

      • Brycie says:

        SO when I do a hay analysis – will the results tell me what I need to add – I guess I’m kind of lost here – I know humans have normal values of what is recommended for each mineral / vitamin – Is there a chart of what I am to strive for – and is this the same for my other non metabolic horses??

        Thank You 🙂

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.