What’s Your IQ for Vitamin E and Horses?

Take our 15-question quiz to see how much you know about the important nutrient vitamin E and horses.

Vitamin E is an essential nutrient that supports your horse’s muscles, nerves, immune system, and more. But how well do you really understand the connection between vitamin E and horses—and how to meet your horse’s needs? Test your knowledge with this research-backed quiz.

1. Which systems in the horse’s body benefit from vitamin E?

a. Muscles and nerves b. Immune c. Reproductive d. All of the above

ANSWER: d.  Vitamin E plays a critical role in multiple body systems. It guards tissues against potentially damaging oxidative stress, an imbalance of free radicals and antioxidants in your body that leads to cell damage. It mostly affects the cells in the tissues of the muscle, nerve, and immune system. Vitamin E is a natural antioxidant that helps keep the balance in the body. It supports muscle health, helps maintain normal nerve function, and contributes to immune and reproductive health. In fact, a century ago it was known as “anti-sterility factor X” after a study in rodents found that its addition to their diet (via lettuce) corrected sterility.

2. Why is vitamin E is considered an “essential nutrient”?

a. The body cannot produce it in sufficient quantities b. It is required for normal bodily function c. It must be provided by the diet d. All of the above

ANSWER: d.  Vitamin E is classed as an “essential nutrient” because horses can’t synthesize the nutrient themselves. Therefore, they must obtain it entirely from their diet and cannot function normally without it. The best source of vitamin E is fresh green grass, but a horse’s vitamin E levels can drop when he is on winter pasture or if his stabling or competition routine means he doesn’t have continual access to good pasture. This is why many horses’ diets need vitamin E supplementation. Vitamin E is a powerful antioxidant that helps reduce effects of the oxidative stress that can damage muscles, nerves, and immune response.

3. Which of the following is the most bioavailable form of vitamin E?

a. Natural water-soluble liquid b. Natural liquid c. Natural powder

ANSWER: a.  Vitamin E is a fat-soluble nutrient, which makes absorption slower unless it’s converted to a water-soluble form before the horse ingests it. A natural, water-soluble liquid like Elevate® W.S. allows for rapid and efficient absorption in horses. That’s especially helpful for horses who need fast support, like those who are recovering from illness or under stress.

4. Which of the following is NOT a reason natural vitamin E is considered more effective than synthetic?

a. Natural vitamin E is excreted faster b. It has greater bioavailability c. It is preferentially absorbed and retained in the body’s tissues.

Answer: a.  Research shows that natural vitamin E (d-alpha-tocopherol or d-alpha-tocopheryl acetate) is more bioavailable—more efficiently absorbed and used in equine tissues—than synthetic forms. This means smaller amounts of natural vitamin E can have a greater impact. Synthetic forms are less bioavailable, are excreted faster from the horse’s system, and are not retained as efficiently in equine tissues.

5. When reading a product label, you can tell that the product contains synthetic vitamin E when the label says:

a. d-alpha tocopherol b. d-alpha tocopheryl acetate c. dl-alpha tocopherol

Answer: c.  Synthetic forms are labeled as dl-alpha tocopherol or dl-alpha-tocopheryl acetate. Look for d-alpha tocopherol (the most bioavailable form of natural vitamin E) or d-alpha-tocopheryl acetate on the label to confirm the product contains natural vitamin E. Often times, if a label says just “vitamin E,” it is the synthetic version.

6. How much vitamin E does a horse maintained on green pasture typically consume in a day?

a. 500 international units (IU) b. 1,200 IU c. 2,000 IU

ANSWER: c. Fresh pasture is rich in vitamin E. Horses grazing full-time on healthy grass typically ingest about 2,000 IU per day—enough to meet their antioxidant needs without supplementation.

7. True or False: You can ensure your horse gets enough vitamin E by feeding unlimited hay.

ANSWER: False.  Fresh forage (such as green pasture grass) is the best source of vitamin E. Horses maintained full time on green pasture typically consume 2,000 IUs of vitamin E a day. That’s more than enough to satisfy their antioxidant needs, but vitamin E levels in grass drop sharply once it is cut. Hay provides about 10 times less vitamin E than fresh forage does.

Horses’ daily vitamin E requirements can vary according to their situation. For example, young horses who are growing, horses with demanding workloads, and senior horses typically require more vitamin E in their diets to offset oxidative stress. Studies also have shown that horses with neurological disease can benefit from supportive vitamin E.

8. True or False: Grains and commercial feeds are good sources of natural vitamin E.

ANSWER: False.  Corn, oats, and barley contain some vitamin E but in relatively low amounts of around 10 to 20 IUs per kilogram. That means you’d have to feed 7-10 pounds of feed a day to get even half as much vitamin E as a horse can get from grazing full time on fresh pasture. And most vitamin E added to commercial feed is synthetic, not natural—so it is less readily absorbed by or retained in the horse’s body.

9. How can you test your horse’s vitamin E status?

a. Blood sample b. Fecal sample c. Hair sample

ANSWER: a.  A blood test measuring plasma alpha-tocopherol levels is the standard and most accurate method for assessing a horse’s vitamin E level. Testers do not use air and fecal tests for this purpose.

10. What is a typical (adequate) blood plasma vitamin E level for horses?

Note: µg/ml, or micrograms per milliliter, is the standard measurement used in determining whether a horse is getting enough vitamin E

a. 1.5-2 µg/ml b. >2 µg/ml c. 3-4 µg/ml

ANSWER: b.  A level greater than 2 µg/ml is considered to be adequate. Horses with access to fresh pasture commonly maintain plasma vitamin E levels between 3 and 4 µg/ml. At levels below 1.5 µg/ml, a horse’s vitamin E level is considered to be deficient. At that level, horses may be at increased risk for neuromuscular and immune dysfunction, especially if they are already under physical or metabolic stress.

11. True or False: You do not need to feed additional fat or oil when you supplement with a natural vitamin E powder.

ANSWER: True.  Vitamin E needs a certain amount of fat or oil to be absorbed in the small intestine. But high-quality natural vitamin E powders, such as Elevate® Maintenance Powder, are designed for effective absorption without needing to be paired with extra fat or oil. This makes it easy to use in a wide range of feeding programs.

12. True or False: Injectable forms of vitamin E are an easy, efficient way to maintain a horse’s vitamin E levels.

ANSWER: False.  There are no injectable straight vitamin E products approved for horses. There is an approved injectable selenium/vitamin E product, but it contains only 68 IUs of vitamin E per milliliter, meaning it takes a 10-milliliter dose to get to just 680 IUs of vitamin E. Additionally, there is a risk of adverse reactions with an injectable, especially when combined with selenium. Supplementing your horse’s diet with natural vitamin E, and especially water-soluble natural vitamin E, is a far more efficient way to maintain adequate levels of this critical nutrient.

13. Does selenium also need to be present in adequate quantities for vitamin E to work?

a. Yes, one is useless without the other b. No, but they support similar functions c. Only in high-performance horses

ANSWER: b.  Vitamin E and selenium both support antioxidant defense in the horse, but they aren’t dependent on each other. A deficiency in one doesn’t prevent the other from working, but the other will be required in a greater quantity to work to its full potential. For hard-working horses, those in breeding programs, or horses whose diets are low in selenium, a formulation like Elevate® Se can provide a highly bioavailable and safe source for both selenium and vitamin E.

14. Signs of inadequate vitamin E in performance horses include:

a. Stiff or sore muscles b. Early fatigue and poor recovery from exercise c. Reluctance to move forward freely d. All of the above

ANSWER: d.  In performance horses, low vitamin E may show up as generalized muscle soreness, poor recovery, reduced energy, and stiffness or reluctance to move forward. These are all signs of oxidative stress and insufficient antioxidant support. A 1992 study by McMeniman and Hintz suggested that horses with low plasma vitamin E will have a lower tolerance for exercise, highlighting the nutrient’s importance in the equine athlete’s diet.

15. What form of vitamin E is recommended for rapid absorption in horses under stress or with acute needs?

a. Powder b. Water-soluble natural liquid c. Standard oil-based liquid

ANSWER: b.  A horse’s tissues quickly and effectively absorbs water-soluble natural vitamin E, such as Elevate® W.S. Subsequently, this makes it ideal for horses recovering from illness, injury, or showing neurological signs. This form bypasses the fat-processing step needed for absorption, allowing a horse quicker access to the vitamin’s benefits.

Explore the Elevate® family of natural vitamin E products at kppusa.com.