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Fiber in the Diet

Feeding your EPI pet the right diet can make a HUGE difference in it’s health- however finding the right diet may be tricky. The most important dietary fact when feeding an EPI animal is that most times it needs to be a low fiber diet……
….but that is where the simple ends and the difficult begins…..   



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…. and why so many of the grains in various pet food can be detrimental to our EPI pets and yet why “some” EPI pets do better with some grain while others do not do well on the same product.

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.

There are different types of fiber such as SOLUBLE and INSOLUBLE fiber and within these two fiber classifications is another consideration, and that is how FERMENTABLE the different fibers are.

Previously the focus was on soluble vs. insoluble fiber….. but more recently…..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.

Complicating things further is that both types of fibers Soluble/Insoluble + Fermentable/Poorly Fermentable are usually found together in the same plant, but classification is often made by which fiber type is more predominant and/or the different fiber types are attributed to different portions of the plant.

On 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 of soluble fiber such as sweet potato or insoluble fiber such as sweet potato skins (discussed below)

Both soluble and insoluble fiber are called DIETARY fiber.  Dietary is known to influence bowel habit and gastrointestinal mucosal cell morphology and function.

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.

Dietary Fiber
Dietary fiber may inhibit enzymatic activity but in varying degrees  according to experiments using both soluble and insoluble fibers such as wheat bran, cellulose, guar gum, pectin, psyllium and lignin.  Inhibition seems to also be dependent on incubation time; proportional to fiber concentration and inversely related to enzyme level.

Soluble fiber dissolves easily in water. Think “gel”. Some foods rich in soluble fiber are fruits, oats, some beans, barley, and vegetables. Such foods result in an increased absorption of nutrients. This type of soluble fiber actually slows digestion down. Because of this, it has a tendency to stabilize blood glucose, and permit better absorption of nutrients. It tends to reduce blood cholesterol. It also increases satiety, so individuals aren’t inclined to eat as much. Sources of soluble fiber include flax, beans, peas, oatmeal, berries, apples, and some nuts and seeds. (Please note though that in general, peas are not very agreeable with most EPI dogs)

Insoluble fiber doesn’t dissolve in water- -however retains water. Some foods rich in insoluble fiber are vegetables, whole grains, and wheat bran. It is tough, and it doesn’t easily break down. Insoluble fiber tends to increase the “speed of transit” through digestive systems, and increases regularity of bowel movements.

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!

  •    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 most  EPI cat and dog patients need to consume lower fiber content in their diet. But depending on the individual animal and what is going on in their gut, some may need a little bit of fiber.  And here in lies the conundrum.

Soluble Fiber:   some examples   

  • legumes (peas, soybeans, lupins, other beans)
  • oats, rye, chia, barley
  • some fruits (plums, berries, bananas, insides of apples, pears)
  • some vegetables (broccoli, carrots, Jerusalem artichokes)
  • root tubers and root vegetables (sweet potatoes) however the skins are insoluble
  • psyllium seed husk (a mucilage soluble fiber), flax seeds
  • nuts

Insoluble Fiber:    some examples

  • whole grains
  • wheat, corn bran
  • nuts, seeds
  • potato skins
  • lignins
  • some vegetables (green beans, cauliflower, zucchini, celery)
  • some fruits (avocado, unripe bananas)
  • skins of some fruits (kiwi, tomatoes)

Potential sources of fiber in a pet’s commercial diet 

  • beet pulp
  • rice bran
  • flaxseed
  • psyllium husk
  • dried peas and beans
  • barley
  • oats/oat bran
  • pectin
  • fruit and vegetables (carrots, apples, etc.)

1. Different fibers (even those in the same category) have different fermentation rates.

2. Some research suggests adding soluble fiber to the diet can be especially beneficial for animals especially those that develop secondary bacterial overgrowth (small intestinal bacterial overgrowth or 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)

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!!!

3. Large-bowel function is particularly influenced by insoluble, poorly fermentable fiber sources.

4. Mucosal function is affected by fiber sources that are more soluble and highly fermentable.

5. Lignin, an insoluble fiber, may alter the fate and metabolism of soluble fiber

Fiber definitions

The US Dept of Agriculture previous definition of fiber was the part of plants that were resistant to the digestive enzymes… however, the new definition of fiber is the components of plants that resist digestive enzymes including lignin and polysaccharides and resistant starches along with inulin and oligosaccharides.

The US Food and Nutrition Board assembled a panel that came up with the following definitions:
Dietary fiber consists of nondigestible carbohydrates and lignin that are intrinsic and intact in plants. This includes plant nonstarch polysaccharides (for example, cellulose, pectin, gums, hemicellulose, and fibers contained in oat and wheat bran), oligosaccharides, lignin, and some resistant starch.
Functional fiber consists of isolated, nondigestible carbohydrates that have beneficial physiological effects in humans. This includes nondigestible plant (for example, resistant starch, pectin, and gums), chitin, chitosan, or commercially produced (for example, resistant starch, polydextrose, inulin, and indigestible dextrins) carbohydrates.
Total fiber is the sum of dietary fiber and functional fiber. It’s not important to differentiate between which forms of each of these fibers you are getting in your diet. Your total fiber is what matters.

Identifying Soluble & Insoluble foods 

Most foods containing fiber contain both soluble and insoluble fiber to certain degrees, with some having a higher degree of one fiber or the other.
1.The food is a whole grain, nut, legume or seed. These foods contain both soluble and insoluble fibers..
2. The food looks fibrous. Foods like sweet potatoes and carrots look very fibrous. This is good indication that the food is high in fiber.
3. The food is a whole fruit or vegetable. Processed fruits and vegetables tend to retain soluble nutrients, but lose the fiber. The best way to get the fiber from fruits and vegetables is to eat them whole.
4. The food becomes soft and creates a sauce when cooked. Foods like beans, oats and rice contain starch and fiber that are responsible for the creamy consistency. This is a good indication the food will be high in soluble fiber.
5. The food is a fruit, vegetable or whole grain and does not dissolve readily in your mouth. A good example of this is potato skin; it is edible, but requires extra chewing. The same is true for many fruits, like pears and apples. This is a good indication the food contains fair amounts of insoluble fiber.
6. Many processed foods have added fiber, either to replace what was lost during processing or add extra health benefits. If these foods do not state added fiber on the label, check the nutrition facts panel and ingredient statement to find out. The food should contain 1 or more g of dietary fiber. This can be naturally occurring or it can be added. The added fiber is considered functional fiber, but may also be classified as dietary fiber. Some of the added fibers, that are mostly soluble, are cellulose, gums (guar gum, carrageenan, etc.), inulin, and pectin. Some of the added fibers, that are mostly insoluble, are polydextrose and bran.
7.  Psyllium fiber, a common fiber supplement sold under the brand name Metamucil, is 70% soluble fiber and 30% insoluble fiber and has the health benefits of both types of dietary fiber.
8. Too much fiber in the diet can cause bloating and gas, and it may interact with certain medications.
9. The Institute of Medicine has recommended moving away from the terms soluble and insoluble for fiber, and, instead, using fermentability and viscous to describe the different types of dietary fiber. Nutritionists feel that measuring these instead of solubility gives a more accurate portrayal of the health benefits of fiber by category.

Soluble and insoluble fiber are the labels most commonly used to describe fiber. However, two other properties of fiber are turning out to be important: fermentability (how easily the fiber ferments in the colon), and viscosity (the ability to gel with water) of the fiber, which may be more important than solubility.

(From Wikipedia )

Chemically defined as oligosaccharides occurring naturally in most plants, inulins have nutritional value as carbohydrates, or more specifically as fructans, a polymer of the natural plant sugar, fructose. Inulin is typically extracted by manufacturers from enriched plant sources such as chicory roots or Jerusalem artichokes for use in prepared foods.[15] Subtly sweet, it can be used to replace sugar, fat, and flour, is often used to improve the flow and mixing qualities of powdered nutritional supplements, and has significant potential health value as a prebiotic fermentable fiber.[16]

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.

Vegetable gums

Vegetable gum fiber supplements are relatively new to the market. Often sold as a powder, vegetable gum fibers dissolve easily with no aftertaste. In preliminary clinical trials, they have proven effective for the treatment of irritable bowel syndrome.[20] Examples of vegetable gum fibers are guar gum and acacia Senegal gum.

Mechanism of Fiber

The main action of dietary fiber is to change the nature of the contents of the gastrointestinal tract, and to change how other nutrients and chemicals are absorbed.[1][2] Soluble fiber binds to bile acids in the small intestine, making them less likely to enter the body; this in turn lowers cholesterol levels in the blood.[3] Soluble fiber also attenuates the absorption of sugar, reduces sugar response after eating, normalizes blood lipid levels and, once fermented in the colon, produces short-chain fatty acids as byproducts with wide-ranging physiological activities (discussion below). Insoluble fiber is associated with reduced diabetes risk, but the mechanism by which this occurs is unknown.[21]


…………………….and now you know WHY finding the right diet 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%’s/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