Free Radicals & Antioxidants: How They Impact Your Horse’s Health

What are Free Radicals?

The body does require free radicals in order to help with brain function and fighting disease, but too many can be harmful.

What causes Oxidative Stress?

Although free radicals are produced naturally in the body, certain factors can accelerate their production. These include (but are not limited to):

• Strenuous exercise – as horses exercise, their oxygen intake increases to meet the demands of muscles and this process produces free radicals
• Stress – situations that increase stress or anxiety levels such as competition, transport, clipping, moving homes, extreme weather/cold etc can increase free radical production
• Environmental factors – exposure to allergens, chemicals, pesticides and other environmental factors can cause free radicals
• Diet – feeds high in polyunsaturated oils can increase the need for antioxidants. These include plant based oils like corn, sunflower, soya, rapeseed as well as things like oats, soyabeans, flax and sunflower. That is not to say that any of the above are all bad, just that when fed in higher levels it is important to balance them with sufficient antioxidant support. 
• Aging – production of free radicals increases as part of the natural aging process, hence why older equines require increased levels of dietary support. 
• Infection and/or immune cell activation 
• Inflammation

What are the symptoms of oxidative stress?

You may not always be able to tell that your horse is experiencing oxidative stress as it involves tiny, microscopic changes that go on behind the scenes and symptoms may be subtle at the outset. Prolonged oxidative stress can lead to:

• Poor performance – horses may not perform at their best, suffer higher levels of fatigue, muscle pain, sweat excessively and recover more slowly. 
• Reduced appetite – horses suffering from oxidative stress may appear disinterested in feed and eat less as a result, sometimes becoming “fussy feeders”.
• Depression – they may become lethargic and depressed.
• Stress – the above symptoms can lead to higher levels of anxiety as a result of internal chemical processes within the horse’s body.
• Respiratory problems and/or fever 

If your horse is showing any of the above symptoms for a sustained period (particularly if they have a fever, stop eating or are struggling to breathe) you should consult your veterinarian immediately. 

Free Radicals vs Antioxidants

Free radicals and antioxidants are two different types of molecules that influence how the body works and the body needs both to function properly.

Horses (like humans) convert the food they eat into energy. This normal and necessary process leads to the production of free radicals which are simply a byproduct of digestion. Whilst free radicals get a bad rep, as with most things they are not all bad – they support the immune system and are crucial in other body processes such as cognitive function. But they are only needed in low to moderate levels and an overload can cause problems.

Free radicals are unstable – which means they are missing one electron. In order to be “complete” they search for electrons they can take from other molecules within the body to become stable or “complete”. This puts healthy molecules within the body at risk as if the free radical scavenges an electron from them, they will in turn become damaged and unstable. 

Antioxidants are the superhero of the body. They donate one of their electrons to a free radical, making it complete so it does not need to steal from other molecules within the body. They assist with keeping balance within the body. When there are insufficient antioxidants to satisfy the free radicals, they go scavenging within the body and your horse experiences oxidative stress as a result.

How to Reduce Oxidative Stress

Antioxidants exist naturally in many foodstuffs and vitamins C and E are powerful antioxidants – particularly in their natural form (shown to be twice as effective as their synthetic counterparts). It is important to consume antioxidants from a variety of sources as there is no single antioxidant or superfood responsible for (or capable of) knocking out all the free radicals. Providing your horse with a range of antioxidant sources (particularly those from natural sources) will ensure they can work together for the greatest health benefits. Antioxidants are present in a variety of foods, below are just some examples of the types and where they naturally occur:

• Vitamin C – high levels of natural vitamin C are present in rosehips, hawthorn, nettle, blueberries, papaya, mango and strawberries. All of which horses can eat and indeed love!
• Vitamin E – most hay/haylage in the UK is deficient in vitamin E and levels decrease the longer it is stored, so it is particularly important to ensure your balancer and/or supplements provide sufficient top up of this vitamin if your horse does not have regular access to good quality pasture. Natural vitamin E (which is the only type used in Equell supplements) has been shown to be twice as effective as its synthetic counterpart. Alternative sources of vitamin E include plant oils such as rapeseed/sunflower/corn/soya oil as well as grapeseed extract which is a very potent form of vitamin E. 
• Selenium – an antioxidant found in many natural foods including whole grains (oats/corn/barley), garlic, bananas and sunflower seeds. Care must be taken to avoid selenium toxicity in horses. Whilst it is very rare, you should check levels in forage and any compound feeds/supplements that you feed together to ensure they fall within safe levels.
• Beta Carotene – a carotenoid, which is a group of coloured pigments that act as antioxidants. Present in many fruits and vegetables including blueberries, beetroot, carrots and sweet potatoes, it is also found in herbs and spices such as oregano and cinnamon. Beta Carotene is also a precursor to vitamin A, which is essential for healthy skin, eyes and the immune system. 

There are many other great forms of natural antioxidants including those found in chicory, seaweed, fenugreek, ginger, psyllium, lemon balm, passionflower, ashwaganda, spirulina, licorice and ginseng to name but a few!

Feeding a species-appropriate, varied diet is the most important point to take from this article. Providing your horse with a variety of natural antioxidants and prebiotic fibres is key to supporting microbiome diversity in the gut and overall health and wellbeing. Which is why at Equell, we include a variety of plant fibres in every supplement we develop - putting your horse's health at the forefront of what we do.

~ The Equell Team