Oral Tolerance

Optimal nutrition from the start to avoid allergies

The term “oral tolerance” describes the process in which the gastrointestinal tract learns to recognize the absorbed food as nutrients and not create an immune reaction. This insures that there is no allergic reaction to the food eaten. When gaining oral tolerance, the immune system first makes a distinction between all foreign substances taken in, whether they are potentially dangerous (pathogen) or harmless (nutrients). Through various lymphocytes that suppress immune reactions and certain messenger substances,the immune system gets the signal not to attack dissolved molecules of the absorbed food. Due to the high antigen specificity of oral tolerance process, a defense against pathogens still takes place.

The process of oral tolerance thus prevents a puppy who is just beginning to eat solid foods from developing allergic reactions to these heretofore foreign substances and ensures that the puppy is still protected against pathogens. Research on oral tolerance is not very advanced, so not all processes and influencing factors are known.

Food allergies in the canine population have increased dramatically in the last fifty years. This is probably due to the fact that puppies that are weaned with processed pet food products have a higher tendency to not develop oral tolerance to certain nutrients. There are a number of reasons for this.
It is highly unnatural that a puppy or kitten eats 20-100 different nutrients at once, as is typical with a processed pet food product. It usually takes a few days for an oral tolerance to a nutrient to develop. The more different new nutrients arrive at the same time in the digestive system, the more likely it is that oral tolerance will not be achieved for all of the nutrients. In addition, puppies are often weaned too early, at an age when they do not yet have the ability to develop oral tolerance.

It is thought that the oral tolerance process takes place from the sixth week of life, but it is not certain at what age a puppy attains this ability. I think it may begin earlier, because I always start feeding in the middle of the fourth to the beginning of the fifth week of life and have not experienced any problems with food intolerances or allergies in the dogs I have bred.

Another reason for failing oral tolerance is poor digestibility or bioavailability of the food. Dogs often develop allergies to grains or the gluten contained therein. Grains generally tend to cause inflammatory responses in the digestive system. Also, grains and other plant foods are poorly digested by canines. When too many undigested food particles are absorbed through the intestinal barrier, the chances of an increased immune response are particularly high. As a result, the oral tolerance either does not take place in the first place or can be lost again later in life. Highly digestible foods such as meat, eggs, dairy products and even cooked rice hardly leave any intact food particles behind during digestion before they enter the intestine, so that an oral tolerance can easily take place.

Allergies that the mother of the puppies has also play a role. Antibodies against foods can be passed on to the puppies with the mother’s milk and prevent oral tolerance to the food to which the mother is allergic. If the antibodies are preserved in the puppy, he may also develop an allergy to that food.

Last but not least, early vaccination may affect oral tolerance. In vaccinations there are often foreign proteins, against which an organism, in this case the puppy, can form antibodies which can lead to the loss or hindrance of oral tolerance.

Oral tolerance should be taken into account when weaning puppies and kittens.

That means simply:

  • Start weaning as late as possible
  • Feed as few new foods in a meal as possible
  • Feed highly digestible and bioavailable food (raw food diet)
  • Do not feed the puppies foods to which the mother is allergic
  • Vaccinate as late as possible and as little as necessary