Answer: Industry waste!
Beet pulp is a very common ingredient in many different pet foods. It has long been recognized as a popular feed additive for horses and other livestock and, more recently, has also been added to many dog and cat foods. There are many reported benefits to using beet pulp in animal foods, but there is also some controversy concerning its use. Beet pulp is included in pet foods, because they differ in their chemical composition and physiochemical properties, which determine fiber fermentability and affect physiological outcomes. Some people confuse beet pulp with the common garden vegetable. Beet pulp is the by-product of the extraction of raw sugar from commercially grown sugar beets.
Sugar beets are grown in huge quantities for the production of sugar. After the sugar has been extracted, the remaining pulp contains very little sugar, but is valuable as a fibre and energy source.
Beet pulp as ingredient is not always highlighted, but a significant number of dog foods predicates that it supports gut health. Beet-pulp fibre allegedly promotes digestion of nutrients, intestinal motility, firm stools and good bacteria in the large intestine. Sugar-beet pulp contains about 50% non-fermentable and 20% fermentable fibres.
All these fibres are resistant to the dog’s digestive enzymes, but the fermentable ones are broken down by the bacteria in the lower intestinal tract. Dry dog food with added beet pulp typically includes less than 5%. The non-fermentable fibres in beet pulp end up in stool, together with bacterial products of the fermentable fibres. Recent research data (1) indicate that beet pulp in dry dog food impairs digestion. An average inclusion rate of 3.1% beet pulp raised daily faeces output by 14%. Stool bulk was increased due to higher contents of both water and solids. The extra solid matter in the large intestine holds water and so moistens stool. Dietary beet pulp accelerated the flow of alimentary tract contents toward the anus and increased the frequency of defecation.
In summary, beet pulp lowers macronutrient digestion and expands stool bulk. Other indicators of canine gut function are not convincingly improved. Prevention of intestinal disorders has gone unaddressed until now.