The Dog Food Project
I've seen a look in dogs' eyes, a quickly vanishing look of amazed contempt, and I am convinced that basically dogs think humans are nuts. - John Steinbeck
A better food makes a big difference!

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Commercial Dry Foods
Introduction Label Information 101 Identifying better products Ingredients to avoid Product List
Specific Product Groups
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Meat vs. Meat MealNew! Choosing the right food Feeding Puppies Feeding Senior Dogs Canine Obesity Is too much protein harmful? Grading kibble - easily? "Five Star Foods"
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Questions on Diet Myths about Feeding The Yuck Factor Where the money goes Natural Supplementation Menadione (Vitamin K3) Nutrient Requirements Links & Resources
Nutrition Primer
Nutrient Overview Water Protein Fat Carbohydrates Fiber Vitamins Minerals Essential Fatty Acids Probiotics

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Probiotics and Prebiotics

Probiotics are friendly bacteria that aid digestion and absorption of nutrients. They help to keep harmful bacteria from colonizing and creating digestive problems, and thus support the body in fighting illness and disease. If beneficial bacteria become depleted or the balance is disturbed, potentially harmful (pathogenic) bacteria can overgrow, causing health problems.

  • Common names for probiotics you will find in supplements are various strains of bacillus (lichenformis, subtilis), lactobacillus (acidophilus, lactis, plantarum, salivarius), bifidobacterium (bifidum, longum), streptococcus (faecium, lactis) and enterococcus (faecium). These are beneficial bacteria that colonize the gut and provide support for the body: they complete digestion of nutrients the body can not utilize fully without this assistance, produce vitamins and other metabolic compounds, provide protection against pathogenic bacteria by creating an unfavorable environment for these "bad" microbes, support the immune system, decrease mutagenic or carcinogenic activity and other benefits. Many of them have not been fully explored and documented yet, but it is known that laboratory animals with a healthy, supportive intestinal flora and fauna are healthier than their counterparts without.
  • Two specific bacteria, lactobacillus bulgaricus and streptoccus thermophilus work differently: they are starter cultures used to ferment milk to make yogurt. These bacteria do not reach the gastrointestinal tract alive, due to the conditions in the stomach and small intestine and thus do not colonize the gut, so their health benefits are different from the above mentioned probiotics. They do improve lactose digestion and are said to enhance the immune system.

Prebiotics are complex sugars that serve as nutritional basis for probiotics. These complex sugars are not broken down by the normal digestive process and are also defined as "nondigestible fiber". Added to the diet they increase the chances of beneficial bacteria growing and thriving in the intestine. In dog food, the most common ones used are beet pulp (in moderate amounts, otherwise it's just a filler!) and chicory root extract.

Now you may ask why it would be so important to have probiotics and prebiotics in a dog food, after all none of the "leading brands" mention them anywhere, right? Think about what a dog eats, day in day out, for his whole life if he is fed commercial food. Even if it is good quality food, it is highly processed from its natural state, which destroys or depletes many of the important dietary components.

Manufacturers of premium foods make an effort to reintroduce these components after processing the kibble. Their foods do not just supply the "bare minimum" of nutrients for your dog to survive but are formulated to keep him healthy and fit and let him thrive. To actually benefit from probiotics, it is critical that you are supplementing the correct types (see blue box above) and also in sufficient amounts. Probiotics are live microbes that are negatively affected by improper storage, such as exposure to excessive heat or moisture. If you doubt that your dog gets adequate amounts, add a probiotic supplement or yogurt with appropriate live cultures to the diet.

I was asked recently whether apple cider vinegar with its antibiotic properties would negatively affect the probiotics in cultured yogurt or supplements if eaten at the same time.

Since I didn't know the answer, I contacted Mary Ellen Sanders, Ph.D. of Dairy & Food Culture Technologies in Centennial, CO. Here is her answer:

I would say that mixing vinegar in your stomach with probiotics could run the risk of killing some of them off. So it would be prudent to take them either with other food so that you neutralize the acid or at different times (an hour apart should be fine).

Probiotics and their benefits are an interesting topic and supplementation can often help with many health issues, from digestive upsets to chronically inflamed ears. On this page I just want to give a short introduction and not confuse with too many details - if you want to learn more, please visit the US Probiotics website, it has a wealth of information.