These days, potato is increasingly used as a starch source in feed to justify use of the “grain-free” descriptor.
Potatoes originate from the Andes Mountains in South America and were only introduced to Europe in the Middle Ages, having been discovered by the Spaniards in approximately 1500 AD.
Potatoes belong to the nightshade family and naturally contain the glycoalkaloid poisons Solanine and Chaconine to deter insects.
It is widely known that eating the berries of the potato plant is exceptionally harmful to health. The poisonous substance contained in the berries is also found in the potato itself (but at lower levels). If you were to feed a dog a product containing potato all its life, there is a high risk that the poisonous substances could be stored in their body with all the associated negative consequences.
Glycoalkaloids have the adverse effect of attacking the intestinal villi and intestinal wall, amongst others. This is most common in younger animals or animals with poor intestinal health. The intestinal villi shrink in size and reduce in number. New intestinal villi are also unable to develop. As a result, digestion and absorption of nutrients decreases considerably and the animals’ growth and development start lagging behind. Glycoalkaloids are not destroyed by heating or cooking potatoes. In other words, these substances are not destroyed during the feed production process either.
Naturally, humans also ingest these substances when eating potatoes, but because humans have a far more varied diet nowadays, they consume a far lower level of glycoalkaloids compared to dogs that have received feed containing potato all their lives.
Feed products containing potato are known to be considerably harder to digest compared to feed containing maize, wheat, rice or sorghum.
Bear in mind that potatoes, unlike grains, did in no shape or form occur in the range of foods eaten naturally by the wolf. All prey animals such as rodents, birds and large grazing animals avoid potatoes because of the toxic substances.