Negative reports are regularly written about all types of sources of carbohydrate in dog food (above all wheat and maize). Are the statements correct or have they gained a life of their own through repetition? Or is their origin to be found in marketing and promotion, and are the people who thought them up trying to put readers on the wrong track?
The diet of the ancestors of our dogs, the wolves, was very diverse. This varied from herbivores, they could catch small rodents, carcasses, excretion (faeces from grazers such as horses) and so on, in fact all of these food substances derived from plant and seed eaters. These seeds are mostly derived from various grass types. The generic name for these grass seeds is grain. It is generally known
that wolves, as soon as they have killed a large grazing animal, first eat the stomach contents, including the half digested plants and seeds. If for example they catch a mouse or lemming, this is eaten whole, including stomach and intestinal contents. It comes down to the fact that part of the diet consisted/consists of carbohydrates (the half digested plants and seeds). Carbohydrates are, just like protein and fat, essential in the diet of wolves, and thus also in the diet of our dogs.
Because the ancestors of our dogs increasingly frequently looked for food in human settlements (wandering nomads and hunter gatherers), they slowly adapted to a feeding pattern of more starch and less meat. Recent genetic research has revealed that there are differences between wolves and dogs in respect of digestion of starch. During the process of domestication the digestive system of the ancestors of dogs became slowly more adapted to digesting starch because they, just like people, often had to be content with mostly bread and porridge. Seeds were at least easy for people to store. So a large part of the diet of the first dogs also comprised carbohydrate from seeds.
For pregnant and lactating bitches it is even essential that the diet contains a certain amount of carbohydrates. If the bitch receives too little carbohydrates during pregnancy and lactation the chance of recently born puppies surviving is low. From the above it appears that since the beginning of time seeds (i.e. grain) form a significant part of the diet of wolves and even more so in the case of the diet of the ancestors of our dogs.
Reference is made a number of times above to “half digested plants and seeds”. If the starch in the seeds (grain) is not sufficiently pre-digested, the carbohydrates (because of the short intestine of dogs), are insufficiently digestible in the small intestine, and arrive raw (as starch) in the large intestine. Here fermentation takes place, resulting in the formation of gas and diarrhoea. In the wild, seeds are actually pre-digested by the enzymes and bacteria in the digestive system (stomach and intestines) of the prey.
For use in dog food the raw grains (and other products containing starch such as roots and tubers) must therefore be “pre-digested”, in other words: the starch must be “broken open” so that the carbohydrates are accessible for further digestion in the intestine of the dog. Even for people, whose intestines are seven times as long in relative terms, roots, raw grain and tubers (for example potatoes), are impossible or difficult to digest and cause the formation of gas, intestinal cramp, and watery faeces. This “breaking open”, or “unlocking”, of the starch happens if the product is heated (cooked) for a certain period of time. Because this unlocking, above all during extrusion (crunchy pellets that remain floating on water), is insufficient, due to the length of heating time being too short, problems with digestion arise, with intestinal complaints as a consequence.
Because of these problems people have the tendency to regard all food containing grain as equally bad. However when the grain (rice, maize, wheat and sorghum) is properly unlocked, these are valuable sources of essential nutrients. Another reason why people talk negatively about grain is the instance of gluten allergy. Gluten allergy (Coeliac disease) can only be caused by grains containing the substance gliadin, for example wheat, but occurs less amongst dogs than is popularly believed. Often the intestinal problems described above are the result of incompletely unlocking the grain, and are interpreted as “gluten allergy”. Maize, rice and sorghum contain no gliadin.