Fibre for All

Posted on 21st February 2025 and written by Dengie Feeds

Written by Katie Reeve and Tracey Hammond

With so much information at our fingertips it can feel like we are being constantly bombarded with advice. At this time of year the “New Year, New You” messages are still reverberating around our heads and they will soon be followed with suggestions on “How to lose weight quickly to be bikini-ready for the summer holidays season!” Unfortunately, navigating these messages can be a minefield and there are a lot of diets that can only be described as fads for which there is little, if any, evidence.

However, there is a key message that has a scientific basis and that is we should all eating more fibre and increasing the range of plants we include in our diet to support the gut microbiome and general health. In fact, February is the month of the UK Flour Millers “Fibre February” campaign which has this key message at its heart. At Dengie, we love fibre and so this is a great opportunity to compare and contrast fibre in both our and our horse’s diets.

Why the fascination with fibre?

There’s long standing awareness that eating plenty of fibre helps to ‘keep you regular’, aka makes you poop. Over time, however, other benefits of eating fibre and a diverse range of plants have been identified but are perhaps, less well known. The British Dietetic Association (BDA) in their ‘Fibre Factsheet’ advise that consuming a high fibre diet increases the population of good bacteria in your gut which supports your immune system against inflammatory disorders and allergies and appears to reduce the risk of chronic diseases like cardiovascular disease, type 2 diabetes and bowel cancer.

In horses, too little fibre has health implications too. When combined with a higher starch or cereal intake, it is associated with an increased risk of problems such as colic, gastric ulcers and laminitis. In contrast to humans, horses have evolved as trickle feeders and would naturally spend an average of 16-18 hours every day grazing and foraging on high fibre materials. They are therefore generally considered to have both a psychological and a physiological need to chew. Similarly to humans, a lack of fibre in the horse can also have negative consequences for the bacterial population in the hindgut which can ultimately compromise immune function and is also thought to have effects on behaviour and mood.

What is the gut microbiota?

The gut microbiota is the term used to describe the population of bugs that reside within the digestive tract. Horses have evolved to survive on plant material which is high in fibre. Fibre has a complex structure, and mammals don’t possess the enzymes required to break it down. Instead, they rely on trillions of bacteria and other microorganisms like fungi and protozoa to break it down by microbial fermentation. The number of bacterial cells in the horse’s digestive tract is thought to be more than 10 times that of all the tissue cells in the whole body, which highlights their importance.

Microbial fermentation produces short chain fatty acids (SCFAs), including acetate, propionate and butyrate, which are absorbed through the intestine and converted to glucose or fat for energy use or storage, making fibre one of the main energy sources for the horse. Diet type can affect the levels of different SCFAs produced in different parts of the gut, with a high fibre diet producing significantly greater levels of butyrate and acetate in the large colon compared to a high starch diet (Raspa et al., 2022). Since butyrate is an important energy source for the cells lining the intestine, which are called colonocytes, providing sufficient fibre in the diet is key for maintaining the function of the intestinal barrier and supporting gut health. Similarly, in humans, diets that are low in the right carbohydrates for our microbiota to utilise, result in a reduced microbial diversity and a reduced production of SCFAs.

Mucus lines the colon in both horses and humans and offers protection to the gut cells. It is also where microbes reside and studies have shown that when there isn’t enough fibre, bacteria will utilise the mucus as a source of nutrients and so erode the protective layer (Desai et al., 2016). This leaves the gut more vulnerable to acidity which compromises the joins between cells known as ‘tight junctions’. When the tightness of the joins is weakened, pathogens and substances that wouldn’t normally escape from the gut into the body can now do so and, unsurprisingly, can cause poor health and disease in the host.

Lots of different factors can influence the composition and diversity of the gut microbiota in both horses and people. From birth, the digestive tract is rapidly colonised with microorganisms and factors such as age, genetics, diet and even whether we live in urban or rural areas all have an impact on the microbiota species richness and diversity. In humans, our early microbial diversity can also be influenced by whether we are born naturally or via C-section! (Jakobsson et al., 2014).

Disturbance to the population of bugs in the gut (known as dysbiosis) can occur as a result of many different things over the course of our lifetimes. In humans, factors contributing to dysbiosis include smoking, depression, stress, use of medication (especially antibiotics), disease and diet (Thursby and Juge, 2017). In the horse, stress, disease and medications can of course all be relevant, but dietary factors including a sudden change of diet are often the most significant.  Fibre-digesting bacteria are important for keeping harmful species of bacteria at bay and they thrive in a consistent environment. Sudden changes to the diet can cause bacteria to die off as their environment becomes less hospitable. This can result in the production of toxins which may lead to problems such as colic. It’s therefore really important to avoid sudden dietary changes, not only to the bucket feed, but also to the forage and grazing, with any adjustments being made gradually over at least 7-14 days.

Where does fibre come from?

In a nutshell fibre comes from plants but humans and horses consume different types and amounts of plants. In fact, even the way that fibre is analysed and reported is different which means that in human nutrition the term dietary fibre is used, whilst on a bag of horse feed you will see the term crude fibre. Legally this is the analytical method and figure that feed manufacturers must display and it is considered the most appropriate as historically, bagged feed has typically included little if any forage. When analysing forage, the measures of neutral detergent fibre (NDF) and acid detergent fibre (ADF) are more valuable as they help us to assess how digestible the fibre in the forage is and, as there is more indigestible fibre in forages than other feed materials, it is more useful for assessing forages than it would be for bagged feeds.

There are some foods that provide a higher level of fibre in our own diets, yet if we were to feed lots of them to a horse, we would not provide sufficient fibre! Great examples of this are oats and linseed which are considered good sources of dietary fibre for humans but certainly wouldn’t for horses. Data from INRAE-CIRAD-AFZ feed tables give reference values for crude fibre in oats at 11.5%, and linseed at 9.1%. Comparing these to forages such as dehydrated grass at 23.4% and wheat straw at 37.5% you can see there’s a big difference.

We also need to consider the feeding rate and other nutrients these ingredients supply. Using the same reference tables, oats supply 36.8% starch. Whilst starch is considered a slow release source of energy for humans, it is not the same for horses. As a result the amount of starch needs to be limited in the horse’s diet to limit digestive disturbance. Based on the current advice of no more than 1g of starch per kg of bodyweight per meal, or 2 g of starch per kg of bodyweight per day (Willing et al, 2009) the feeding of oats should be limited to 1.3kg per meal or 2.65kg per day for a 500kg horse. In the horse’s diet we therefore use oats sparingly when we need extra energy in a concentrated form from starch. We certainly aren’t using them as a key source of fibre!

How much fibre do we need?

Based on the Scientific Advisory Committee on Nutrition (SACN) 2015 Carbohydrates and Health Report, the recommended daily carbohydrate intake should be approximately 50% of our daily energy intake and dietary fibre intake should be 30g per day, which was an increase on previous recommendations.

In the media you will also see that we are advised to increase the diversity of plants in our diet as well – specifically we should be aiming for 30 plant points per week. Professor Tim Spector and Dr Megan Rossi are two vocal advocates for promoting increased diet diversity and eating more plants. The recommendation of 30 plant points originated from research by McDonald et al (2018) who discovered that consuming a variety of about 30 different plant species each week emerged as key strategy for nurturing a healthy gut microbiome and therefore overall wellbeing. By consuming a wider range of plants we are offering a range of food for our gut microbiome.

In comparison, horses as herbivores eat plants and so 100% of the horse’s daily energy intake often comes from fibrous feedstuffs especially forage. Precisely how much fibre a horse requires is not known; recommendations instead are for minimum amounts of forage which might seem surprising but reflects the fact that we are feeding them not only to maintain digestive health but also to promote good welfare. At minimum, the current consensus is that all horses and ponies should have access to 1.5% of their bodyweight on a dry matter (DM) basis of forage daily (Harris et al., 2016). This equates to 7.5kg dry matter for a 500kg horse or 8.8kg of hay as fed (assuming the hay is 85% DM). If we can feed more without them putting on weight then this is advocated.

Are we getting enough fibre?

For humans the short answer is no. The latest National Diet and Nutrition Survey reports that in all age groups, the mean intake of fibre was below the government recommendations. For adults aged 19 to 64 years and 65 years and over, mean intakes were 19.7g and 18.7g respectively. Only 6% of adults met the 30g daily recommendation.

Again, statistics in horses are lacking, but the groups most likely not to receive sufficient forage are:

• Performance horses – there is a traditional belief that fibre cannot meet the energy needs of those in hard work
• Dieting horses – dietary restriction is necessary to ensure horses don’t become overweight
• Horses with dental issues – if diets are not adjusted appropriately to provide fibre in a form they can manage to chew

Exploring these issues in more detail is key to reducing the risk of insufficient fibre being fed. It is important to remember that an increase in the horse’s workload does not automatically mean you need to increase the use of traditional mixes and cubes, that supply higher levels of starch and lower levels of fibre, to meet their energy requirements. High fibre feeds and forage can provide plenty of energy in a slow-release form, and studies have shown that performance horses can utilise fibre as an energy source – the key is ensuring there is sufficient, high quality, digestible fibre in the ration for the horse to make use of. When it comes to the type of fibre in the bucket, alfalfa is a really digestible source of quality fibre which makes a significant contribution to energy requirements, especially when combined with oil. Recent studies have shown that even high level competition horses can be sustained on rations using hay and alfalfa with only a very small proportion of cereals without any detriment to performance and muscle tone (Martin et al., 2023), demonstrating that a high fibre diet can work just as well for supporting performance without the need to feed high levels of cereals.

For horses who are good doers or overweight, there can be a tendency to over-restrict fibre intake, and historically levels as low as 1% of bodyweight on a dry matter basis have been suggested. With increased research and understanding, this level is now no longer considered acceptable on a long-term basis for good health in the horse. When it comes to managing the overweight horse, measures can be implemented to manage calorie intake, with the fundamental aim being to promote more chews for less calories. This can include options such as utilising straw to replace up to 50% of the forage ration and soaking the hay. When soaking hay for long periods e.g. 10-12 hours it is advised to increase intake from 1.5% to 1.8% of bodyweight on a dry matter basis to allow for the loss of dry matter that occurs in the soaking process (Rendle et al., 2018).

Barriers to fibre intake

One big barrier to fibre consumption in the human diet is the perception that fibre is boring. This couldn’t be further from the truth especially when consuming a variety of plants and improving flavour with herbs and spices. Unfortunately, the perception that fibre is boring extends to how people feed their horses and we are often asked on the Dengie Feedline about whether it is necessary to add a mix, cube, or mash to make a horse’s diet more interesting.

We always advise that the focus first and foremost should be on providing fibre in the form that encourages the horse to chew, as the horse has evolved as a grazing herbivore and this behaviour is important for their welfare. Interestingly, research has identified that when horses are fed a complete pelleted feed which provides insufficient chew time, they are motivated to press a panel for a food reward of hay rather than pellets. The researchers suggest this reflects the horse’s preference for fibre ingestion and/or chewing behaviour (Elia et al., 2010).

There are anthropomorphic factors to consider too. When cooking for our families we like to see a clean plate as an indication that our family has enjoyed the meal we have prepared for them. Whilst we also like to see our horses tucking into their bucket feed that we have made for them, our perspective should be different. A slower rate of intake and a longer feeding time is much more beneficial for an animal that has evolved to spend around 16 hours a day eating. For those horses and ponies with health issues, this slow rate of intake is particularly important. Horses and ponies with equine metabolic syndrome (EMS) have an exaggerated insulinaemic response to meals which is a risk factor for them progressing to laminitis. If we can slow the rate of intake we can reduce the insulinemic response to eating which is key to avoiding further issues (Jansson et al., 2021).

For humans there is no doubt that cost and financial pressures can be a barrier to increasing fibre intake in our diets as well. Government data in the UK indicates that in the last 10 years, consumer prices for fruit have increased to a greater extent than for other food groups such as milk and cereals, and sugar and confectionery (DEFRA, 2024).

In contrast for the horse, feeding a high fibre diet is fortunately often more economical. Feeding a good quality forage as the basis for the diet is the best place to start. Higher quality forages will make a greater contribution to the horse’s energy and nutrient requirements so can result in less reliance on the bucket feed. For horses who maintain their weight well on forage alone, simply adding a broad-spectrum vitamin and mineral supplement alongside a chopped fibre to slow the rate of intake can be a really economical option. There are other barriers to overcome though, not least locating the most appropriate forage for a particular horse or pony!

Boosting Fibre Intake

Dr Megan Rossi the Gut Health Doctor in her recent interview on the TED Health podcast make some really simple recommendations – ‘inclusion not exclusion’ and choosing from the ‘super 6’ at every meal. The super 6 being defined as legumes, whole grain, fruit, vegetables, herbs & spices, and nuts & seeds.

In the currently available equine literature, there’s not enough information to indicate whether we need to increase our horse’s plant diversity. In practice, the horse’s plant intake is already diverse as there are multiple types of grass and other plants in the sward in their paddock. The typical horse’s diet will also include forage such as hay, haylage and straw and many different types of fibre in their bucket feed including alfalfa, sugar beet, soya hulls, oatfeed and wheatfeed. They all supply fibre of different composition.

If you watch any horse grazing with a hedge around their paddock, you are likely to see them spend a proportion of time eating from the hedgerow as well. You may notice this behaviour more at times of year when there is less fibre in the grass such as in the spring, or when there is less grass available to eat. In the stabled horse many of us like to provide diversity in our horse’s diet with the use of hedgerow haynets which also provide some enrichment as our horses sort through the different components to find the tastiest bits!

Can we counter low fibre diets with digestive aid supplements?

A plethora of supplements exist for both the horse and human purporting to promote gut health. These include probiotics, the “friendly bacteria” which work by literally topping up the numbers of beneficial species in the gut. In her interview on the TED Health podcast, Dr Megan Rossi advised that we shouldn’t rely on probiotics to keep us healthy and that the core focus should still be on consuming a healthy and diverse high fibre diet. There is currently no evidence to suggest that we ought to be taking a probiotic every day for good gut health, but they may be beneficial at times when the microbiome is likely to be disrupted, such as when taking a course of antibiotics. The NHS highlights that probiotics for humans are generally safe but they are classed as a food rather than a medicine and so should not be considered as an alternative approach for managing health conditions.

When it comes to horse nutrition, you shouldn’t find any probiotics that contain live bacteria as none have been approved for use in horse feeds or supplements. Instead, in products that say they contain probiotics, you should only find live yeast – most commonly Saccharomyces cerevisiae. These are approved for use in horses and have met legal requirements to demonstrate safety and efficacy. Live yeast are fungi that break down the structure of fibre allowing the bacteria that reside in the gut easier access to break it down. More efficient fibre fermentation can help to promote weight gain and provide more nutrients such as B vitamins. Again, a digestive supplement for horses should not be considered as an alternative to medication, but can be beneficial for horses and ponies who experience higher levels of stress such as those travelling and competing.

References

• BDA (2021) Food Fact Sheet Fibre [online] Fibre-food-fact-sheet.pdf [Accessed 7th January 2025]
• DEFRA (2024) Accredited official statistics: Food statistics in your pocket [online] https://www.gov.uk/government/statistics/food-statistics-pocketbook/food-statistics-in-your-pocket#uk-consumer-price-changes-by-food-group-june-2014-to-june-2024 [Accessed 29th January 2025]
• Desai, M.S., Seekatz, A.M., Koropatkin, N.M., Kamada, N., Hickey, C.A., Wolter, M., Pudlo, N.A., Kitamoto, S., Terrapon, N., Muller, A. and Young, V.B. (2016). A dietary fiber-deprived gut microbiota degrades the colonic mucus barrier and enhances pathogen susceptibility. Cell, 167(5), pp.1339-1353.
• Elia, J.B., Erb. H.N., Houpt, K.A. (2010) Motivation for hay: Effects of a pelleted diet on behaviour and physiology of horses. Physiology & Behaviour, 101, pp. 623-627.
• Harris, P.A., Ellis. A.D., Fradinho, M.J., Jansson, A., Julliand, V., Luthersson, N., Santos, A.S., and Vervuert, I. (2016) Review: Feeding conserved forage to horses: recent advances and recommendations. Animal, pp. 1-10
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• Jansson, A., Harris, P., Davey, S.L., Luthersson, N., Ragnarsson, S., Ringmark, S. (2021) Straw as an Alternative to Grass Forage in Horses—Effects on Post-Prandial Metabolic Profile, Energy Intake, Behaviour and Gastric Ulceration. Animals, 11, pp2197. https:// doi.org/10.3390/ani11082197
• Jakobsson, H.E., Abrahamsson, T.R., Jenmalm, M.C., Harris, K., Quince, C., Jernberg, C., Björkstén, B., Engstrand, L. and Andersson, A.F. (2014) Decreased gut microbiota diversity, delayed Bacteroidetes colonisation and reduced Th1 responses in infants delivered by caesarean section. Gut, 63(4), pp.559-566.
• Rendle, D., McGregor Argo, C., Bowen, M., Carslake, H., German, A., Harris, P., Knowles, E., Menzies-Gow, N., Morgan, R. (2018) Equine obesity: current perspectives, UK-Vet Equine, 2 (5) Septermber/October 2018 (Downloaded from magonlinelibrary.com on April 4, 2019)
• Raspa, F., Vervuert, I., Capucchio, M.T., Colombino, E., Bergero, D., Forte, C., Greppi, M., Cavallarin, L., Giribaldi, M., Antoniazzi, S. and Cavallini, D. (2022) A high-starch vs. high-fibre diet: Effects on the gut environment of the different intestinal compartments of the horse digestive tract. BMC Veterinary Research, 18(1), pp.1-11.
• Scientific Advisory Committee on Gut Health (2015) Carbohydrates and Health [online] Carbohydrates and Health [Accessed 7th January 2025]
• Willing, B., Voros, A., Roos, S., Jones, C., Jansson, A., Lindberg, J.E., (2009) Changes in faecal bacteria associated with concentrate and forage-only diets fed to horses in training. Equine vet J. 41, pp.908-914