Vitamin D Deficiency has Many Dangers for Horses

Tuesday, November 16, 2010
Posted by Lynndee

Vitamin D for horses? Yes, indeed. Research indicates that many horses suffer from Vitamin D deficiency, just as do many people, and the health implications for horses are just as serious. Like many mammals, horses need sunlight to aid in the production of Vitamin D, but a good many horses spend a lot fewer hours in the sun than nature intended. Modern-day horses are stall-bound, turned out at night during the summer months and when outside are covered by blankets and sheets. And, for many horses there is also the problem of having dark skin. Darker skin produces less Vitamin D from sunlight. All of these things reduce a horse’s access to sunlight and contribute to Vitamin D deficiency. Yet, despite the vast amount of recent research on the dangers of Vitamin D deficiency in humans, few seem to be talking about the dangers to horses.


In a natural state, horses have ample access to sunshine and thus, Vitamin D deficiency is a more recent equine health issue, but one of growing concern. “Animal skin produces Vitamin D3,” said Dr. Marvin Hausman MD, a medical scientist and clinician who focuses on developing natural nutritional supplements for horses and people. “But ultraviolet light comes in at a wrong angle for any location above 34 degrees North Latitude. UV is the main light source for Vitamin D production in the skin of horses and humans and that is why Canada is so concerned about Vitamin D deficiency in humans.”

The main function of both Vitamin D2 and D3 in horses, as well as in humans, is to control the absorption, transport and deposition of calcium and phosphorus. Research indicates that without Vitamin D, horses have difficulty absorbing calcium. If calcium cannot be absorbed through the digestive process, the body might begin to withdraw calcium from bones. “Most processed horse feeds and hay don’t have adequate amounts of Vitamin D,” Hausman said.

The health impacts on horses with Vitamin D deficiency can be many. Researchers in equine health believe that Vitamin D deficiencies in horses contribute to such problems as lameness, swollen joints, weak bones and teeth, and a number of cancers, including melanoma. Hausman notes the following other potential health implications for Vitamin D-deficient horses:

- Decreased immune system function
- Susceptibility to infections because of a weakened immune system
- Insulin resistance with blood sugar issues
- Tying up disease – rhabdomyolysis, which is essentially a chronic muscle inflammatory condition
- Poor muscle recovery time and cramping after exercise
- Poor reaction to stress resulting from travel, training and competing
- A greater potential to develop laminitis because of the link between laminitis and insulin resistance

Research on the health benefits of Vitamin D supplementation indicates that Vitamin D, because it strengthens the immune system, might actually better protect people against illnesses such as influenza. Hausman is the founder of Total Nutraceutical Solutions, a leading international biotech nutritional supplement company that produces medicinal mushroom-based supplements for horses and people. In a few weeks, TNS is releasing a new human mushroom-based nutritional supplement that will provide, in a single capsule, as much Vitamin D as 10 glasses of Vitamin D-fortified milk. “Just in time for the flu season,” Hausman said.

Because the physiology of horses and humans have many similarities, Hausman said research on the impacts of Vitamin D on humans provides great insight into the impacts on horses. And one problem seen in many horses that such research indicates Vitamin D might help is ulcers.

“Ulcers are associated with inflammation within the bowel or gut wall,” Hausman said. “There is evidence that the anti-inflammatory nutrients within certain mushrooms, such as Vitamin D, can nutritionally assist the human body in battling inflammatory ulcer disease. So it’s safe to assume that if helps prevent ulcers in humans that it would also help prevent ulcers in horses.”

Hausman is such a believer in the health benefits of Vitamin D for horses and humans that he worked with researchers at Pennsylvania State University to develop a technique to enhance Vitamin D levels in mushrooms.

“Food scientists at Penn State developed a process that naturally increases Vitamin D levels in the mushrooms we use in our nutritional products,” Hausman said. “Mushrooms produce D2 naturally. Our mushrooms may start at 240 IUs of D2 per 100 grams of mushroom powder, but after one minute of our patented UV light technology the amounts increase in one minute or less to over 400,000 IUs.”

Hausman said there are different receptors for D2 and D3 in the various tissues and organs of both horses and humans. People and horses need both forms. They should get the most they can of D3 from sunlight and UV light, but that doesn’t eliminate their need for Vitamin D2 supplementation. While D3 is what the skin of the body produces with the help of sunlight, D2 is also needed as an additional dietary supplement.

“D2 is vegan,” Hausman said. “D3 is animal based and not very clean as a synthetic. It generally comes from sheep wool grease or lanolin. D2 is natural, completely vegetarian and is contained within a whole food. No additives, no extracts, and you get exactly what you personally eat or feed your horse.”

Hausman challenges anyone who doubts the effects of Vitamin D deficiency in horses to take a test. “I would argue that nearly every horse has a Vitamin D deficiency because of their modern lifestyle. The way to prove it is to ‘kick the tires’ so to speak. Put your horse on Vitamin D supplements for 30-60 days and you will see a difference. You’ll never go back to letting your horse have this deficiency.”

Horse owners wanting to take up this challenge can order the Vitamin D-rich EquiSANO nutritional supplement online. To learn more about the importance of Vitamin D for both horses and humans visit