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Fiber in the Diet updated 6-20-2021

Feeding your EPI pet the right diet can make a HUGE difference in it’s health… however finding the right diet may be tricky.

To best manage EPI in an EPI dog, “most” dogs do better with a low fiber diet (especially if a commercial diet)… but not all. We strongly recommend starting with a low fiber food. However, once the dog is stable, if you want, try adding more fiber (or a higher fiber content food) to see if/how well your EPI dog can tolerate it. The reason why fiber can be a problem is because fiber can inhibit the efficacy of the enzymes from anywhere between 0% and 50%- -and we have no idea who is affected and by how much from one EPI dog to the next. SO we err on the side of caution. Start with a low fiber food.

However to best manage SID in an EPI dog, sometimes a tiny amount of fermentable fiber needs to be added.

Confusing???  YES!


Dogs and cats have shorter digestive tracts than humans and are basically carnivorous meaning that their nutritional requirements overall are better served with meat vs. plant materials . However, much of the food we purchase for our pets does have some fiber in it, so it would be better for us (and our pets) if we understood the various types of fibers and how they function…. (1) why so many of the grains in various pet food can be detrimental to our EPI pets  (2) and yet why “some” EPI pets do better with some grain while others do not do well on the same product (3) and then why sometimes a certain type of fiber (prebiotic) needs to be added to a recommended low fiber diet.

GRAINS and VEGETABLES both are composed of fiber and carbs.  Fiber from grains is the bran (the husk). The role of short-chain fatty acids (SCFA) in the interplay between diet, gut microbiota, and host energy metabolism may also play a part in SID/SIBO in EPI dogs. Short-chain fatty acid formation at fermentation of indigestible carbohydrates. When you understand which Fiber and Carbs agree with your dog and in what portion…. and you have learned to feed a diet that optimally agrees with your individual EPI dog, that is when we see the best response to EPI treatment!

Usually finding the right diet for the EPI pet is the last cornerstone of effectively managing EPI.

My hope with this FIBER page is that if we understand the various types of fiber and their functions that this will better help us understand how diet can make a huge difference in our EPI pet’s response to EPI management.

According to extensive research by dog food companies such as Eukanuba and IAMs, dogs and cats maximized nutrient digestibility with optimal crude fiber levels from  a range of 1.4 to 3.5%.
However we know we cannot apply this to EPI dogs and cats simply because:

  • (1) fiber can interfere with the function of pancreatic replacement enzymes needed to manage EPI (sometimes reducing enzyme effectiveness by up to 50% )
  • (2) and fiber can also inhibit some nutrient absorption.

So, not only do “most” EPI pets do better on low fiber food…. if possible it would be even better if we could understand what type of fiber best agrees with our EPI pet… because some fibers are actually needed!

Currently the veterinary nutritionists are now focusing more on “how” fermentable a fiber is and whether a highly fermentable or poorly fermentable fiber is better and for which dog/condition. They are beginning to suspect that which fiber better agrees with which dog depends on a multitude of factors, such as underlying health issues, gut flora and the metabolic response of that particular dog.

Fiber can be classified by its physical properties. In the past, fibers were commonly referred to as soluble and insoluble. This classification distinguished whether the fiber was soluble in water. However, this classification is being phased out in the nutrition community. Instead, most fibers that would have been classified as insoluble fiber are now referred to as nonfermentable and/or nonviscous and soluble fiber as fermentable, and/or viscous because these better describe the fiber’s characteristics2. Fermentable refers to whether the bacteria in the colon can ferment or degrade the fiber into short chain fatty acids and gas. Viscous refers to the capacity of certain fibers to form a thick gel-like consistency. The following table lists some of the common types of fiber and provides a brief description about each.

Table 2.1532 Common types of nonfermentable, nonviscous (insoluble) dietary fiber

Fiber Description
Cellulose Main component of plant cell walls
Hemicellulose Surround cellulose in plant cell walls
Lignin Noncarbohydrate found within “woody” plant cell walls

Table 2.1533 Common types of fermentable, viscous (soluble) fiber

Fiber Description
Hemicellulose Surround cellulose in plant cell walls
Pectin Found in cell walls and intracellular tissues of fruits and berries
Beta-glucans Found in cereal brans
Gums Viscous, usually isolated from seeds

Non-Fermentable food sources that are also non-viscous fiber include whole wheat, whole grain cereals, broccoli, and other vegetables. This type of fiber is believed to decrease the risk of constipation and colon cancer, because it increases stool bulk and reduces transit time 

Fermentable, viscous fiber can be found in oats, rice, psyllium seeds, Slippery elm, soy, and some fruits. This type of fiber is believed to decrease blood cholesterol and sugar levels, thus also lowering the risk of heart disease and diabetes, respectively4. Its viscous nature slows the absorption of glucose preventing blood glucose from spiking after consuming carbohydrates. It lowers blood cholesterol levels primarily by binding bile acids, which are made from cholesterol, and causing them to be excreted. As such, more cholesterol is used to synthesize new bile acids.

In commercial dog foods…. a label may claim that there is only 6% fiber content…. but… with an EPI pet it makes a HUGE difference if that 6% fiber is composed mainly non-fermentable fiber or fermentable fiber AND by how much!!!

Chemically speaking, dietary fiber consists of non-starch polysaccharides such as arabinoxylans, cellulose AND other plant components that are resistant dextrins, inulin, lignin, waxes, chitin, pectins, beta-glucans and oligosaccharides.

Fermentable Fiber

What is ‘fermentable’ fiber? Some fiber will ferment in the colon, producing compounds that help support colon health, and possibly have other benefits. Most soluble fiber is highly fermentable. Pectins (found in apples and berries) and the fiber in oats are examples of fiber with a large fermentable component. Inulin and oligofructose are also highly fermentable, as is resistant starch. But this also is not cut and dry… although fermentable fiber might be beneficial… too much fermentable fiber may cause inflammation in the colon.  SO…. how much is too much… it all depends on how each individual dog processes the fiber!

Fermentable fibers are the fibers that the friendly gut bacteria are able to digest (ferment) and use as fuel.
This increases the number and balance of friendly gut bacteria, which also produce short-chain fatty acids with powerful health benefits

Fermentable fibers include some things like pectins, beta-glucans, guar gum, inulin, and oligofructose.

  •    Highly fermentable fiber results in poor stool quality. Foods rich in highly fermentable fiber are cabbage, pectin and guar gum.
  •    Moderately fermentable fiber results in adequate production of short-chain fatty acids and maintains excellent stool quality. Examples of foods rich in  moderately fermentable fiber are beet pulp and rice bran.
  •   Slow fermentable fiber doesn’t result in adequate production of short-chain fatty acids and is found in plant hull cellulose. This type of fiber is helpful in weight management as it increases bulk and thus the dog feels full even though he has consumed lesser amounts of food.

Too much fiber can cause problems as can too little fiber.  Just the very nature of EPI and the relationship of fiber with enzymes require that many  EPI dog and cat patients need to consume lower fiber content in their diet. But depending on the individual animal and what is going on in their gut like SID (small intestinal dysbiosis) that needs to be better managed) many may need a little bit of specific “prebiotic” fiber.  And here in lies the conundrum, as different fibers (even in the same category) have different fermentation rates and to some degree, the microbiome of each

  • Research now suggests that fermentable fiber to a diet can be especially beneficial for animals especially those that develop SDIS/SIBO). Fibers that moderately ferment in the intestinal tract have been shown to create a therapeutic amount of short-chain fatty acids (called SCFAs). There is much exciting research evolving with regards to prebiotics in relation to this. Prebiotic soluble fibers containing inulin or oligosaccharides are being looked at in giving relief to IBD. Inulin is advantageous because it contains 25-30% the food energy of sugar or other carbohydrates and 10-15% the food energy of fat. As a prebiotic fermentable fiber, its metabolism by gut flora yields short-chain fatty acids  which increase absorption of calcium,[17] magnesium,[18]and iron,[19] resulting from upregulation of mineral-transporting genes and their membrane transport proteins within the colon wall. Among other potential beneficial effects noted above, inulin promotes an increase in the mass and health of intestinal Lactobacillus and Bifidobacterium populations. Inulin is best found in Chicory root and Jerusalem Artichoke.
  • Here’s how much inulin is in 3.5 ounces (oz), or 100 grams (g), of the following:
    • chicory root, 35.7–47.6 g
    • Jerusalem artichoke, 16–20 g
    • On the flip side….. it appears that too much of a good thing (SCFA) might actually cause gastrointestinal discomfort.  (SCFAs) act as fuel to build up healthy intestinal cells, feed good bacteria, and provide bulk for better movement of materials through the gut, reduce the amount of potential fuel available for bad bacteria to use…. but with some dogs, too much of these SCFAs may actually cause a problem… so it can be a fine line of providing enough SCFA without giving too much!!!

~ Large-bowel function is particularly influenced by insoluble, poorly fermentable fiber sources.
~ Mucosal function is affected by fiber sources that are more soluble and highly fermentable. (Psyllium, Slippery Elm)
~ Lignin, an insoluble fiber, may alter the fate and metabolism of soluble fiber (Slippery Elm also has lignins in it)

…………………….and now you know WHY how little or how much of which fiber in a diet for an EPI dog/cat can be so confusing!    ……………

Needless to say, this explains why finding the right diet can be so tricky and why veterinarian nutritionists are concerned when we say “grain-free”.  It really is not necessarily grain-free but rather low fiber that we should consider for a diet for most (not all)  and even then it will depend on the individual animal which type of fiber (if any) it can tolerate or needs to avoid or include at a low dose.

The overall consensus is that for “most” EPI animal patients do best with a LOW FIBER diet....   

So…. which type of fiber and how much can your dog digest…… YOU need to be the judge! This is why it is HIGHLY advisable to do trial and error with food.

1. Start with a low 4% or less fiber content food first… and adjust more or less fiber from there.

2. Record what fiber types are included in diets (ingredients and % of /portions) that work and the diets that don’t work….. ALWAYS watch the diet output (the poo!), the volume, color, texture and frequency for 3-5 days before implementing the next change.  This will help you determine which ingredients appear to agree or not agree with your individual EPI patient.

 We, at Epi4dogs, have been able to help most pet owners help their pets achieve a normal well-functioning digestive systems…. most times… the last piece of the puzzle has been finding the right diet. It may take some time, and many tweaks.. all depending on your dog’s individual system’s requirements…. but it can and has been done with a little bit of patience and a lot of support from others who have found the perfect diet for their EPI pet and are willing to share their experiences with others!

Research:  Dr. Anne Mosseler,   Starch/Fiber & EPI MiniPigs

Starch Origin and Thermal Processing Affect Starch Digestion in a Minipig Model of Pancreatic Exocrine Insufficiency


This research was performed by Dr. Anne Mosseler of the University of Veterinary Medicine, Hannover, Germany, The Institute of Animal Nutrition. 

Dr. Mosseler does EPI research with mini-pigs.  Epi4Dogs and Dr. Mosseler have kept in touch over the years, and interestingly enough, her most recent research supports what many of our Epi4Dogs members on the FORUM have observed…that when managing an EPI patient, one must be careful of the:

  • fiber content,
  • fiber type and
  • fiber portion.

A most stunning revelation with Dr. Mosseler’s study was that out of the 4 carb/fibers that Dr. Mosseler tested, peas was by far the least digestible with the EPI mini-pigs…. well…..interestingly enough, members of the Epi4Dogs forum have noticed the same problem with many of our EPI dogs.

Dr. Mosseler did a limited study with 4 carbs and the pea starch had the least digestibility.

The most telling part of the research that relates directly to fiber and our EPI dogs, is the following excerpt… but please feel free to read the entire research (provided by Dr. Mosseler (THANK YOU Dr. Mosseler!!) and please share with your vet with regards to the importance of diet in optimally managing EPI.

“……… The challenge in nutrition of CF patients with PEI is therefore to enrich the diet with moderate levels of fibre (10-30 g / day) to ensure passage rate and to minimise risk of obstipation or constipation [11, 13] without negative effects like enhancing the amount of food intake needed, satiety [37] and forced intestinal gas production. Another side effect that might be of relevance is the reduction in enzyme activity of substituted enzymes by dietary fibre. However, this effect is strongly related to the type of dietary fibre used with 1.5g% of pure cellulose having no effect on amylase and trypsin activity and only very little effect on lipase activity [38]. In patients with PEI a SIBO and an increased bacterial fermentation is often observed resulting in symptoms like diarrhoea, meteorism, abdominal pain, flatulence and impaired wellbeing [3]. With modern pancreatic enzyme replacement therapy (PERT) maldigestion and malabsorption as well as SIBO can be controlled, but in some patients problems still occur [1]. The further characterisation of fibre sources seems to be of greatest relevance as meteorism and flatulence not only affect patients well being, but also might impair food intake. The fibre enrichment of the diet should be done deliberated as energy expenditure / requirements are increased in patients with CF and the intake of food rich in fibre raises the risk for malnutrition as diets rich in fibre are in general less digestible and have a lower energy density. The use of highly concentrated fibre sources might be way out to achieve a sufficient fibre supply to prevent DIOS (Distal Intestinal Obstruction Syndrome) without causing negative side effects like uptake of bulky food or food with a low energy density which might raise the risk of reduced energy uptake or malnutrition. There are several fibre concentrates available differing in chemical composition. The two ligno-cellulose products used in this study did not cause any relevant in-vitro gas production and had positive effects on faeces quality (soft but formed faeces). Taking into account the very high fibre content of these supplements (~ 60 %) it is possible to enrich the diet with a relevant amount of fibre (10 g) without markedly increasing the amount of food. This is especially relevant when considering the recommendation of opting for a diet with high energy density for patients with PEI [19].

Regarding low in-vitro gas production MC, FC, OC can be recommended for a fibre enrichment of the diet. Interestingly, PF (Pea Fiber) which is a common fibre source in human dietetics  caused the highest in-vitro gas production. Furthermore pH dropped significantly after addition of PF  also indicating a much higher fermentation rate. Taking all data into account FC and OC seem to be recommendable to increase fibre intake even in patients with PEI. 

Determining the in-vitro gas production is a completely non-invasive method and allows differentiation of the extent of fermentation of different fibre sources. The screening of different food stuffs under the aspect of minimizing gas production is easy to perform and might help to improve patients well being. It seems noteworthy that even the addition of only 1 g of PF as a fibre source caused a net gas production of 120 ml of gas in this study. It was previously shown [33] that fermentation of starch caused very high in-vitro gas production when incubated with ileal chyme of PL-pigs (up to 160 ml / g substrate). As a good nutritional status is crucial for CF patients [21,36] introducing fibre into the diet should be critically proven by a dietetic supervision and not recommended for all patients. Nonetheless, in patients with symptoms of DIOS or abdominal pain due to extensive loading of the colon with faeces the enrichment of diet with a ligno-cellulose fibre might be helpful to normalize gut function although [16,17] found no association between fibre intake and DIOS or constipation in CF. However, it should be taken into account that diets for CF patients are low in fibre in general according to recommendations and that this fact might mimic effects of fibre in the cohort (as all patients have a low fibre supply). [16] stated a lower fibre uptake in patients with DIOS, indicating that an increased fibre supply might be feasible. More precise characterisation of fibre seems to be crucial to optimise fibre supply in CF and PEI patients. Although fermentable fibre is of benefit for healthy people, in patients with maldigestion and SIBO the use of non-fermentable fibre seems to be more beneficial. Looking forward it seems necessary to do more experimental and clinical work to estimate the practical consequences of an enrichment of the diet with fibre. Aspects like effects on satiety, passage rate, water binding capacity as well as intestinal microflora should be taken into account. The use of in-vitro tests to quantify gas production might be a valuable measure to screen different fibre sources and to exclude those fibre sources that might have negative side effects like excessive gas production.

Conclusions: The use of a highly concentrated fibre source (ligno-cellulose) might reduce the negative side effects of fibre sources usually used while promoting passage rate and reducing the risk of DIOS. These fibre sources are neutral in flavour and taste and can be easily added to drinks or food. ” ……….

Research:   Dr. Penny Watson,  Carbohydrates