Importance of Starch and Carbohydrates
Article obtained from www.royalcanin.com
Starch is actually a complex of glucose polymers, which are branched to varying degrees depending on the plant from which they originate and are tangled into a lumpy ball called a starch grain. Digestion of starch requires amylases, enzymes produced by the pancreas.
Starch can be made much more digestible by cooking it. It is found in grains (wheat, corn, rice, etc.) and potatoes, and provides quick energy if well cooked. Rice added to dog food should be sticky so that it is digestible and will not cause diarrhea. Two cooking processes are used for complete dry dog foods: extrusion (kibble) and steam flaking (gravy). Both processes ensure that starch is completely cooked, and so is digestible.
Carbohydrates are nutrients found almost exclusively in plants. The basic elements of carbohydrates are simple sugars with names ending in -ose, the most common being glucose, the basic component of starch and cellulose. Other carbohydrates, such as pectins and gums, are more complex molecules composed of uronic acids arising from oxidation of the simple sugars. Some of these carbohydrates (such as starch and sugars) are digestible and can be assimilated by the dog, while the indigestible carbohydrates (also called fiber or cellulose) stimulate and regulate the passage of food through the intestine.
Like all animals, dogs have a metabolic requirement for glucose, which is both a source of energy needed for certain organs such as the brain, and a component required for the synthesis of many other biological molecules. Unlike most other animals, dogs can maintain their blood-sugar levels even if no carbohydrates are present in their diet. They are able to use certain amino acids found in proteins for glucose synthesis. Thus, there is no risk of glucose deficiency in a dog's diet.
Digestible carbohydrates include lactose, which is important for puppies.
Lactose aids digestion and absorption of nutrients. It also plays a role in synthesizing nutrients required for metabolism (ex. folic acid).
Bitch milk contains half as much lactose (the sugar found milk) as cow's milk. Puppies do use lactose, but they have a limited ability to digest it, so overconsumption always leads to digestive problems. When feeding puppies any milk other than bitch's milk, it is imperative to take this into account and ensure that the substitute does not contain too much lactose. Adult dogs have an even more limited ability to digest lactose, so consumption of milk can lead to diarrhea