High Iron – Why To Avoid It and Weeds

Equine Insulin Resistance Iron

Two main sources – Weeds and High-Iron Supplements

 You will only get this information on our website. 

This is original research.


Horses doomed to dirt lots are going to eat anything they see – even weeds.  Horses need grass and turnout, not weeds.  We tested several weeds to show why they are no good.  Equine Insulin Resistant horses need their iron levels controlled to help in lowering Insulin.

crabgrass  plantain


Equi-Analytical Lab – July 2009













Crab Grass





High Iron






High Iron






High Iron






High Iron

Grass Pasture at the Same Site









Documented: Weeds are high reservoirs of Iron. Weeds raise Insulin and need to be avoided.  Surprisingly, their sugar/starch content is not high.

chickgrass Horses will seek out certain weeds like Chickweed.  The super high Iron causes HUGE INSULIN SURGES leading to foot pain.  Horse Insulin will increase if your horse is constantly receiving high iron from weeds.  Iron levels in horses can be controlled by proper field management or if the horses are on a dry lot, to eradicate weeds.  Often people will say he is “only on a small lot with some weeds to eat so he is not exposed to high sugars.”  This study shows that those weeds can get your horse’s Insulin elevated by high iron.

Science of why to avoid High Iron in Equine Insulin Resistance

  • “Metabolism of Insulin reduced with increased Iron stores leading to peripheral hyperinsulinemia.” Diabetes 2002.
  • Evidence high Iron overload leads to skeletal muscle being effected, the main effector of Insulin.  Diabetes 2002.
  • High iron leads to toxic-free radicals.  Diabetes 2002.
  • Inflammatory cytokines increase Iron uptake and deposition leading to Insulin increases.  Diabetes, 2002.
  • Iron in high levels leads to Insulin Resistance. Alim. Pharmaco Ther. 2005.
  • Decreasing Iron stored can increase Insulin sensitivity. Clin. Chem 2005.
  • Systemic Iron overload contributes to abnormal glucose metabolism and elevated Insulin. Diabetes Care 2007.
  • Excess Iron in the body increases susceptibility to bacterial infections.  Horse Nutrition, Davies, 2009.
  • Equine cases where chronic Laminitis attacks were alleviated by removing excess Iron supplements from diet.  Feed your horse like a horse, J. Getty, 2010.
  • Michigan State University looked at blood ferritin (iron) levels and effects on Insulin.  Horses with high ferritin had higher Insulin responses.  “If a horse is overweight or not given sufficient exercise, then it might warrant trying to give feed stuffs lower in Iron or, more importantly, not giving as much feed or feed higher quality.” Dr. Neilson, 2012, J. Zoo Wild Med.  bluestar Click here to see Dr. Nielsen’s article.
  • box-labtestedsafeHigh Iron directly disrupts fat cell metabolism.  Fat cells (adipocytes) breakdown is higher when blood iron levels are normal.  “Transferrin and iron induces Insulin Resistance of glucose transport in adiopocytes.”  Dr. A. Green, 2006, Metab Clin/Experim.


  • Ferritin can also lower a hormone Adiponectin which helps in Insulin sensitizing. “As Ferritin increased Adiponectin decreased.” Animals fed high iron diet had lower Adiponectin also. “Serum Ferritin was negatively associated with Serum Adiponectin.” Dr. Gabrielsen, 2012, J. Clin Invest.  bluestar Click here to see Dr. Gabrielsen’s article.

 Supplements which to use and which to avoid


A.  Commercial supplement grains are ok due to about 700 ppm Iron and are only fed at a 1 pound rate, so are getting only about 300 ppm total.  They are ok to feed.


  • Mineralized salt blocks – contain high levels of iron that your horse does not need if they have Equine Insulin Resistance.saltblock
  • Liquid blood builders with words like: “Super Cell”, “Mega” “Red Cell” “Iron” “with added high Iron”. Good for race horses but NOT horse Insulin Resistance.
  • Many vitamin/mineral powders are very high Iron – if not on the label, call and ask.  If they can’t tell you, do not get it.  If you want, you can send it to Equi-Analytical Labs to make sure.
  • High Iron will interfere with Thyroid Powder Action – you need to be aware not to add more iron to the diet.  bluestarClick here for the article on Drugs that Inhibit Levothyroxine Absorption.

Only use Vitamin/Mineral Supplements that are below 100 mg per 132 grams powder. Many are over 200 mg. They are ok for racehorses but not for Equine Insulin Resistant horses.

How to test to see if my horse’s iron is too high?

a. A serum iron test in equine chemistry panels is NOT, by itself, accurate. It can show normal and the horse’s iron levels are high.
b. Best, more accurate is a 3-test combination of:

• Serum blood level
• TIBC blood level
• Ferritin blood level

c. Your Veterinarian’s normal lab will NOT be able to do this test. It requires a special lab at Kansas State Veterinary School.

• Test is $49.00, results in one (1) week.
• Your vet will collect blood (red top tubes), within 30 minutes spin and harvest serum and place in a plastic tube, freeze solid, FedEx to:


Kansas State University Vet Diagnostic Lab
Attn: Sue Chavey
Dept: DM/P Comparative Hematology
1800 Denison Avenue
Manhattan, KS 66506

They even do these three tests on Elephants and Beluga Whales!



What can cause problems in Equine Iron Test results?

a. Pregnant mare can see total serum iron drop and TIBC level go up.
b. Liver disease makes TIBC go down and serum iron go up.
c. Infections, severe inflammation can make ferritin go up even if there is no excess iron intake. So if painful in the middle of Laminitis, it is not time to test iron.
d. High ACTH (Cushings perhaps) will make TIBC go down.
e. Progesterone hormones like Regumate might make TIBC go up.



Waterboss Iron Reduction FilterIn many parts of the country, the water can be high Iron.  You can quickly see this if the sinks and toilets have iron staining.  In some barns, filters are available to lower Iron.  In many barns and fields, filters are not practical.  The key is to do what you can by avoiding weeds and Iron supplements that cause Insulin to go up.

Many clients have put a Waterboss Filter in the barn to reduce the iron.  Only $350.00.  Can get at HomeDepot. bluestarClick here for the link to the Waterboss Filter.


blueribbonClick here to see 26 ways HEIRO is the Best Choice and why the winner over other products.

Proper diet and exercise is essential for horse health. This product is a supplement to help maintain horse health.  This product is not intended to diagnose, treat, cure, or prevent disease.