A colourful diet ensures essential polyphenols for the horse

A colourful diet ensures essential polyphenols for the horse

Polyphenols also provide many wellbeing-supporting compounds for the horse’s body

Polyphenols are a group of compounds found in plants. They are not nutrients like vitamins or trace elements, but rather plants’ “secret weapons.” Most commonly, polyphenols are plant pigments or aromatic compounds produced by plants, such as flavonoids, antioxidants, phenolic acids, and lignans. Polyphenols are not essential to the body in the same way as nutrients, but their importance for health and wellbeing may be far greater than is currently known. Knowledge is increasing continuously, and research on polyphenols is ongoing.

Polyphenols in berries, vegetables, and seeds

Plants produce polyphenols primarily to defend themselves and protect against external threats such as diseases, microbes, pests, UV radiation, and frost. Coloured compounds also attract pollinators. Polyphenols are abundant in coloured berries, fruits, vegetables, seeds, grains, legumes, green tea, and grape skins. The darker the colour of a plant or berry, the richer it is in polyphenolic compounds. In particular, health-promoting anthocyanins are present in the highest amounts in dark berries.

Currently, tens of thousands of different polyphenolic compounds are known, including phenolic acids, flavonoids, stilbenes, lignans, anthocyanins, tannins, and polymeric lignans. Researchers believe that many more polyphenols remain undiscovered in the plant kingdom. The most common dietary polyphenols are flavonoids, of which more than 4,000 types are known. The wellbeing-supporting effects of flavonoids are based on their ability to act as antioxidants, preventing harmful oxidative reactions even more effectively than vitamins. In addition, they may enhance the activity of certain enzymes beneficial to wellbeing and protect nerve cells. Antioxidants also help maintain immune defence.

Antioxidants are important for horses and dogs in hard training

The antioxidant effect is of particular interest to owners of sport horses and dogs. Oxidative stress caused by exertion can damage tissues and weaken immune defence, and preliminary studies suggest that antioxidants can reduce this stress. Oxidative stress also slows recovery from exertion. Among vitamins, the best-known antioxidants are vitamins E and C, and as noted, many plant polyphenols are rich in antioxidant compounds.

The most well-known “anti-oxidation agent” for sport horses and dogs is vitamin E. It is a fat-soluble vitamin essential for normal muscle, immune system, and nervous system function. Horses usually obtain vitamin E from fresh grass or from fortified feeds. Competition, intense training, and stress increase the need for antioxidants that counter oxidative stress in both horses and dogs. Vitamin E is also important for pregnant and growing animals.

Another vitamin known for its antioxidant properties is vitamin C. It works together with vitamin E to reduce free radicals in the body. Normally, a horse produces sufficient vitamin C itself, but competition, stress, and hard training can reduce plasma vitamin C levels. In such cases, vitamin C intake should be increased to support immune function. Vitamin C also participates in the body’s own collagen synthesis, which is essential for joint health.

Various wellbeing benefits from polyphenols

Polyphenols have been found to have several biologically active and beneficial properties, including antioxidant, anti-allergenic, antiviral, antimicrobial, anti-proliferative, anti-mutagenic, and anti-carcinogenic effects. Polyphenols are believed to help prevent inflammation and bacterial growth. They can also activate the body’s own antioxidant enzymes. For example, birch leaves may reduce inflammation, while lingonberries and cranberries appear to support urinary tract health. Curcumin, the bright yellow compound in turmeric, has been studied and shown to support joint health and immune function.

Ageing horses

Studies conducted in horses suggest that polyphenols such as curcumin and resveratrol from grapes may help combat inflammation and the natural ageing process. As horses age, low-grade chronic inflammation becomes more common, contributing to conditions such as laminitis and osteoarthritis. Many experts suggest that adding polyphenols to the diet of older horses could improve overall wellbeing and reduce inflammation. Supplementing polyphenols in senior horses may reduce the need for anti-inflammatory drugs and thus lower the risk of side effects such as diarrhoea, kidney disease, and gastric ulcers. Anecdotal evidence from New Zealand suggests that flavonoids may also promote muscle recovery in endurance horses.

Gut microbes

Recent studies have shown that, in addition to fibre, polyphenols may influence gut microbiome health and composition. Polyphenols are transported into the body along with fibre, and it is suspected that some of the health benefits of fibre are actually due to polyphenols. However, the effects of polyphenols on the gut have been studied much less than fibre itself, so their mechanisms are not yet fully understood. It is likely that fibre and polyphenols have synergistic benefits, meaning that together they are more effective than separately.

Carbohydrate metabolism and blood sugar

Some polyphenol metabolites are absorbed in the large intestine, which is why polyphenols are thought to potentially affect carbohydrate metabolism and insulin resistance. Altered carbohydrate digestion and absorption are key contributors to elevated blood glucose levels (hyperglycaemia). Recently, researchers have begun studying the role of polyphenols in managing high blood sugar, as they have no known side effects and are considered effective and safe. Promising studies have been conducted in animals and humans, although long-term studies are still lacking. It is estimated that the blood sugar–lowering effect of polyphenols is due to reduced carbohydrate absorption, improved insulin secretion, and their anti-inflammatory and antioxidant effects. Some studies also suggest that polyphenols inhibit fat cell growth. This is relevant when considering the nutrition and management of laminitis-prone, metabolic, or Cushing’s-affected horses and dogs.

Dietary diversity ensures polyphenol intake

Polyphenols are absorbed differently in different animals. Some are absorbed as such, while others are absorbed via gut bacteria. Often, different compounds enter the bloodstream and tissues than those originally consumed in the diet.

Among berries, blackcurrant ranks at the top nutritionally. It contains more vitamin C than strawberries, raspberries, redcurrants, blueberries, and lingonberries combined. It has the second-highest fibre and anthocyanin content after blueberries. Vegetables and fruits of different colours (beetroot, carrot, apple, grapes), berries (blackcurrant, sea buckthorn, cranberry, rose hip), seeds (chia, hemp, pumpkin, fenugreek), and other plant parts (dandelion leaf, blackcurrant leaf, yarrow, calendula, spirulina) together provide a diverse range of polyphenols for horses and dogs.

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