According to PetfoodIndustry.com:
"Prebiotics are food for probiotic, live microbial species that are capable of colonizing the intestine once ingested. Due to myriad issues, probiotics often struggle to colonize and remain colonized in the intestine.
One method to overcome this problem is to use synbiotics, a combination of prebiotics and probiotics, which increases the persistence of the bacteria in the intestinal tract. Persistence is improved by providing a preferred food for the probiotic, thus promoting bacterial growth and enhancing colonization."
Another reason dietary fiber is added to pet food is to increase satiety (a feeling of fullness) in dogs and cats, which helps with weight loss programs for overweight and obese animals.
The title of the article linked above is actually 'Benefits of Dietary Fiber in Companion Animal Diets.' As regular readers of my newsletter know, one of my goals is to steer pet owners away from commercially available dog and cat foods with added fiber.
Fiber in pet food often comes from grains and other undesirable sources, and there's usually way too much of it added to the ingredient mixture. Your carnivorous dog or cat has no biological requirement for food high in fiber, or for grains and other starches.
I find it disingenuous at best of the pet food industry to try to position the addition of inexpensive fiber fillers in dog and cat food formulas as 'beneficial' to pets.
Let's take a closer look at the two 'benefits' of dietary fiber discussed in the linked article.
Claim #1: Added Fiber is a Source of Prebiotics
Prebiotics are non-digestible food ingredients which feed the growth of intestinal bacteria. They are complex sugars and include fructo-oligosaccharides (FOS), inulin and oligofructose.
FOS is produced from the natural fermentation of sugar cane. Inulin is found naturally in chicory root, garlic and onions (do not feed onions to pets). Oligofructose is a breakdown product of inulin.
When prebiotics within the large intestine are fermented by bacteria, short-chain fatty acids (SCFA) are produced. SCFAs provide a number of benefits to your pet's GI tract. They provide the cells with energy, keep things moving through the intestines, and reduce both inflammation and overgrowth of unfriendly bacteria.
That's the good news about prebiotics. However, they aren't right for every animal.
Marketing claims for prebiotics position them as feeding only friendly, healthy bacteria in the digestive tract. But research indicates this is not the case – prebiotics nourish unhealthy bacteria as well. If your pet has a very fit gut full of primarily healthy bacteria, prebiotics may be beneficial and probably won't cause a problem.
But if your dog or cat has a GI condition such as inflammatory bowel disease (IBD), irritable bowel syndrome (IBS), dysbiosis (leaky gut), malabsorption, maldigestion, 'sensitive stomach,' or most importantly, SIBO (small intestinal bacterial overgrowth), prebiotics are not what you want to feed your pet's compromised digestive tract.
Pets with yeasty guts have a significant worsening of their condition when fed prebiotics. Remember, prebiotics are complex sugars, and sugar feeds yeast.
The most common type of prebiotic added to popular pet food formulas is beet pulp, a fibrous material found in sugar beets. Dried beet pulp is not an ideal source of prebiotics, just as the majority of affordable processed pet food is not an ideal source of nutrition for your dog or cat.
Higher quality commercial pet foods containing prebiotics will typically list them as fructo-oligosaccharide, chicory root, and/or garlic. Those are the ingredients to look for if your pet has a very healthy gut with none of the usual GI conditions seen in so many dogs and kitties today.
In my opinion, however, if you feed a balanced, commercial raw diet or prepare balanced homemade meals for your otherwise healthy pet, you don't need to add prebiotics unless your holistic vet specifically recommends them for some reason.
If your pet has occasional digestive upsets or has undergone antibiotic therapy, for example, you can supplement the diet with a high quality pet probiotic to help re-colonize the GI tract with healthy bacteria.
Claim #2: Added Fiber Assists in Weight Loss
This claim is, in my opinion, nonsense.
The idea behind adding extra fiber to pet food is it makes companion animals feel full. Not only is this a fallacy, as I'll discuss shortly, but your dog's or cat's biological requirement for fiber is small. This means your pet's body isn't designed by nature to efficiently process all those carbohydrates.
Too much fiber can block absorption of necessary nutrients into the small intestine. Excess fiber can create a barrier which prevents antioxidants, vitamins and trace minerals from being absorbed into your pet's GI tract.
While fiber may make your dog or cat feel temporarily full, if it's displacing protein in the diet, your pet will remain under nourished at the all-important cellular level. A chronic deficiency of nutrients delivered to the cells of your pet's body can result in feelings of constant hunger. This is a sign your carnivorous dog or cat isn't getting sufficient protein to adequately sustain his biology.
Overweight pets fed high fiber diets marketed as 'low fat' or 'weight loss' often end up gaining rather than losing weight. They are constantly hungry due to a deficiency of protein, and their misinformed owners try to help by feeding larger and larger amounts of high fiber foods. It's a vicious cycle in which a dog or cat is overfed and overweight, but under nourished.
If your pet is overweight, do the following:
- Implement portion control. Remember that regardless of her weight, your pet still needs a diet high in protein. Feed your dog or cat a high protein, low carb diet and moderate the portions to control the amount of calories she consumes each day. Free feeding is not the way to have a slim, trim pet.
- Exercise your pet. An overweight body slims down by moving more and eating less. So along with calorie restriction through portion control, you’ll want to create a good exercise program for your dog or cat. Daily aerobic activity is one of the best ways to build muscle tone, and muscle tone decreases the amount of fat your pet carries around. Muscle mass also increases metabolism, which helps burn calories.
- Minimize treats. Occasional treats are fine, but make them protein-based and feed very small amounts. Make sure to include the calories in treats as part of your portion control plan.