There are dozens of Vitamin E supplements for horses available on the market. Powder or liquid, synthetic or natural, with or without selenium and with or without grape extract. Do you know what is best? In this blog, we tell what you should pay attention to so that you can make the right choice for your horse.

Avoid overdose of vitamin E (and selenium)

It is possible to give too much vitamin E to your horse, so be careful with it. Overdose can cause horses to absorb other nutrients and minerals less well. Negative effects have been shown at doses five to ten times higher than the daily maintenance of 1000 IU for a 550 kg horse. Also be careful with vitamin E supplements that contain selenium. Although many horses can use a little bit of selenium, especially since Dutch hay often contains little selenium, this mineral can already be toxic in concentrations of eight times the daily dose. So pay close attention to how much selenium your horse's total ration contains (including hay, concentrates and any vitamin chunks). The recommended daily dose of selenium is approximately 1 mg per day for an adult horse.

α-tocopherol is best absorbed

When you start looking for a good vitamin E supplement for horses, things quickly get complicated. Vitamin E is the main fat-soluble antioxidant found in food. It consists of eight related vitamin E compounds. Together you call this the vitamin E complex. They are four tocopherols and four tocotrienols:

• α-, β-, γ- and δ-tocopherol
• α-, β-, γ- and δ-tocotrienol

The most absorbable compound from the vitamin E complex is α-tocopherol. This substance is therefore usually used in supplements. Most α-tocopherol is naturally found in wheat germ oil, but if you want to use that for your horse, you should give one liter or more a day. That is of course not feasible. An advantage of wheat germ oil is that it also contains Omega-6 fatty acids, which are important for the absorption and effect of vitamin E. It also contains a number of other vitamin E compounds that reinforce each other in effect. But since a liter of wheat germ oil per day is not feasible, it is best to combine wheat germ oil with natural-equal vitamin E.

Synthetic or natural vitamin E?

There are many supplements on the market that contain vitamin E. It is important to know when choosing a good supplement that there is a big difference in absorption between the different variants. The cheaper vitamin E, also called synthetic vitamin E, is poorly absorbed by horses. It varies a bit per animal, but it is usually a waste of money to feed this form of vitamin E to your horse. It is simply not absorbed into his blood, but goes out again with the manure. An example of such a synthetic form of vitamin E is dl-α-tocopherol acetate. This compound is found in various supplements available in the Netherlands. Natural or nature-equal vitamin E is much better absorbed by horses and is therefore much more useful. Both d-α-tocopherol and RRR-α-tocopherol fall under the natural vitamin E. However, it has been proven that the isomer RRR-α-tocopherol is best absorbed; this is for example in wheat germ oil. But… these natural compounds can also come from a factory. Then the product is called "natural vitamin E" because the molecular formula is exactly the same as that of vitamin E, which you can obtain from wheat germ oil, for example. But it has been made artificially. However, the absorbability is the same, so it is a great product for your horse. It would be better to call this type of vitamin E natural-equal rather than natural. Because many supplements market this artificial variant as natural vitamin E and do not indicate it. So there are 3 types of vitamin E:

• Synthetic (is dl-α-tocopherol acetate): it is difficult to absorb
• Nature-equal (RRR-α-tocopherol): just as absorbable as natural ones
• Natural (d-α-tocopherol and RRR-α-tocopherol): highly absorbable

Grape extract is a powerful antioxidant

Grape seeds and skins are a byproduct of wine production, from which you can obtain an extract that is an excellent source of natural antioxidants. This extract protects against oxidative stress, or the free radicals that are released during muscle damage caused by training and stress. The effect is therefore very similar to that of vitamin E. Grape extract provides detoxification and strengthens the immune system of animals. Grape extract is rich in polyphenols and proanthocyanidin, which is also known as oligomeric proanthocyanidin (OPC). These are the dark blue dyes that are found in plants, especially in the skin and seeds. They also make blueberries so healthy, for example. As an antioxidant, OPC is 20 times stronger than vitamin C and 50 times stronger than vitamin E. It is a good means to protect animal cells against oxidative stress.

Conclusion: in any case choose a natural and / or natural-equal variant

If you are looking for a vitamin E supplement, choose at least a natural variant (wheat germ oil) that is supplemented with a natural-equal vitamin E (RRR-a-tocopherol). A supplement based on wheat germ oil is preferred, because it contains several forms of vitamin E and also omega 6 for improved absorption. An addition of grape extract is also recommended so that the antioxidant effect of the supplement is even greater.   Sources https://www.sciencedirect.com/science/article/pii/B9781855734630500102 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4988453/ https://academic.oup.com/nutritionreviews/article/76/3/141/4781933 https://cvm.msu.edu/research/faculty-research/comparative-medical-genetics/valberg-laboratory/selecting-a-vitamin-e-supplement Regina Brigelius-Flohe . Bioactivity of vitamin E. Nutrition Research Reviews(2006),19, 174–186. https://www.cambridge.org/core/services/aop-cambridge-core/content/view/D6E1DC656A31C4920B2A339862D97BFE/S0954422407202938a.pdf/bioactivity-of-vitamin-e.pdf https://academic.oup.com/nutritionreviews/article/76/3/141/4781933 https://www.vetmed.ucdavis.edu/labs/finno-laboratory/vitamin-e-horses