Any time a horse owner walks into a feed or tack store, or just searches online, there appear to be more and more supplements on the physical and virtual shelves. Many of these are nutritional supplements intended to provide supplemental amounts of nutrients required by horses. Meanwhile, many are considered nutraceuticals and contain compounds that may have other biologically relevant roles.
It becomes a challenge for horse owners to sort between the fads and the science, and in fact it is challenging even for nutritionists to keep track of all of the new research and products! That said, a dietary evaluation by an equine nutritionist is usually a good place to start to determine if your horse actually needs any additional nutrients supplemented to their diet. Following that, there may be additional benefits with some of these biologically active compounds, even when they come from interesting sources!
A pretty consistent area of interest is in the role of omega-3 fatty acids and their potential anti-inflammatory effects. To review, unsaturated fatty acids can be categorized based on the location of their first double bond – if they occur on the omega-3 carbon or the omega-6 carbon. Within the body these two types of fatty acid chains can be elongated to compounds that may be biologically relevant with respect to inflammatory properties. In general, omega-3 fatty acids tend to be anti-inflammatory, with the longest of these fats, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), having anti-inflammatory and immune-supporting benefits. Meanwhile the elongation of omega-6 fatty acids tends to support pro-inflammatory pathways. Therefore, sources of omega-3 fatty acids are of interest, particularly those with high amounts of the longer fats.
Marine sources are the most potent source of EPA and DHA, with fish oils being commonly fed to horses, although palatability and odours might be of concern. However, there is recent interest in the feeding of krill oil (krill are small crustaceans), that appears to be a more biologically available source of EPA and DHA and has natural antioxidants within it compared to fish oil. Recent research has also investigated sources of 2-dihomo gamma linolenic acid (DGLA), from safflower oil and ahiflower oil. While DGLA is an omega-3 fatty acid, it also has anti-inflammatory properties. Camelina oil is another popular source of omega-3 fatty acids, with good amounts of alpha-linolenic acid (~35%) and containing natural sources of vitamin E. Of course, hemp seed oil has about 22% alpha-linolenic acid.
Another major group of supplements are those with anti-oxidation properties. Many biological processes, in particular exercise, produce reactive oxygen species or other agents that can contribute to cellular damage and injury. Antioxidants function to convert these into more stable compounds.
Vitamin E is an important nutrient with anti-oxidative properties that works primarily in conjunction with selenium and glutathione. Vitamin C and beta-carotene also have anti-oxidative properties. However, there are additional non-nutritional compounds that may be protective. For example, resveratrol (most notably found in red wine) has been shown to have both anti-inflammatory and anti-oxidative properties in humans and lab animals, and was shown to decrease lameness scores in horses following its supplementation. It was also shown to have some anti-oxidative and protective effects on aged horses.
Shitake mushrooms have been long recognized by eastern medicine for their immune benefits, anti-inflammatory and cholesterol-lowering properties, as well as their nutritional properties (they are a good source of some B vitamins, vitamin C and vitamin D). Indeed, the supplementation of mushrooms to horses resulted in lower levels of cholesterol, as well as changes in other blood parameters.
Coenzyme Q10 (ubiquinone) is a component of mitochondrial aerobic energy production – and supplementation increases its content within the muscle. Supplementation with CoQ10 appears to alter the energy production pathway that could result in reduced oxidative components being produced. Further, when CoQ10 was supplemented with N-acetyl cysteine (as a source of the amino acid cysteine, which is needed for glutathione synthesis) in fit Thoroughbreds, glutathione content was increased. Much more research is required to document true benefits for the use of these ingredients.
Another area where there appear to be some novel products is with respect to prebiotics, probiotics and postbiotics. Yeasts and many probiotics have been studied for numerous years, though prebiotics and postbiotics are becoming more common. Prebiotics are compounds that feed the microbes within the digestive tract (such as different types of fibre), probiotics are live bacteria or yeasts that inoculate and/or support the gut microbiota, while postbiotics refer to the products produced by microbes that have health benefits.
Prebiotics, such as ActiveAge (Purina Animal Nutrition) or Amaferm (Biozyme Inc), probiotics such as Actisaf SC47 (Phileo-Lesaffre), and postbiotics such as TrueEquine (Diamond V) are all examples of “newer” products for supporting gut health. TrueEquine was shown to reduce inflammatory markers in joints following an inflammatory challenge, while ActiveAge appeared to reduce inflammation and support joint health in horses. Actisaf has been shown to improve digestibility of fibre in horses, and an in vitro study showed higher pH concentrations (less acidic) in cecal fluid following “feeding”.
Of course, an added challenge is that some products contain “complexes” or “proprietary blends” – which makes it hard to know exactly what ingredients may be in your products. Chatting with a company salesperson can generally help you understand their products, and may also help you get a feel for their credibility.
Remember, you can – and should – always ask to see the research on any product or ingredients within them. If you want an unbiased opinion, work with your equine nutritionist to help you figure out what nutrients you need, and if any supplements might be complimentary for your horse.