No Grains - Please!

Brenda Hagel © 2003

We know that dogs are carnivores. Their teeth are fashioned to rip flesh, not grind food as the herbivore does. They have simple stomachs and a short acidic intestinal tract that is ideal for digesting meat. The dog does not as readily digest grains and vegetables as it does meat and bone. Although dogs have somehow managed to adapt somewhat to the inclusion of carbohydrates in their diet, their body prefers a food high in animal protein.

Grain makes up a considerable portion of both commercial and a number of homemade feeding programs. The use of grains in dry processed pet foods became popular because it is a less expensive source for energy than fat or protein. Insufficient biological protein in a dog’s diet can cause deficiencies, which is reflective in diseases that may include skin and chronic ear infections, reproductive, heart, kidney, bladder, thyroid and adrenal gland malfunctions. It is a well known fact that dogs do not have a dietary requirement for carbohydrates. There are requirements for essential fatty acids and essential amino acids (protein), but there is no known necessity for carbohydrates. Dogs do have a metabolic requirement for glucose, which can be produced within the body or through diet. Metabolic pathways in the liver and kidney can use other nutrients to produce glucose. Therefore, sources of dietary carbohydrate are not necessary if protein and fat intake are adequate to provide the needed precursors of glucose.

The history of human nutrition tells us that grain products came to be as a result of the agricultural revolution. The inclusion of grain in the dog’s diet probably began about this time through their evolution as companions to humans. Unfortunately, grains aren’t all they are made out to be and it’s taken a very long time to make this discovery.

There are many important issues to consider about the nutritional value of grains. Most refined grain products act more like simple sugars in the body, meaning they are broken down into blood sugar quickly after being eaten. In other words, they have high glycemic ratings. On the other hand, vegetables, with the exception of root vegetables, potatoes and most fruits, have low to moderate glycemic ratings. Foods that elevate blood sugar produce harmful molecules called free radicals, which accelerate aging. Excess glucose reacts with and damages proteins in the body, which also ages tissues. Research is indicating that diets based on low glycemic carbohydrates improve blood sugar metabolism as well as reducing hunger. However, as useful as the glycemic index is for evaluating food’s effects on blood sugar levels, it is sometimes overvalued. To get a true understanding of how healthful various carbohydrates are you also need to consider the amount of carbohydrates different foods supply. The carbohydrate density of a food is determined by the amount of digestible carbohydrates in the food less the grams of fiber. For example, foods that have low glycemic ratings, such as leafy green vegetables, are low in carbohydrates. If you evaluate carbohydrates by both their glycemic index and carbohydrate density, refined grain products rate worse than almost any other food.

Are whole grains any better? At first glance, whole grains may appear to contain more nutrients and blood regulating fiber. Due to their higher fiber content, they tend to rate lower on the glycemic index. The more grains are processed, the more they tend to raise blood sugar. Nonetheless, whole grains have their shortcomings, including high carbohydrate content, antinutrients that impair absorption of minerals such as calcium, iron and zinc and lectins that interfere with intestinal and immune function.

Refined grains are missing more than a dozen nutrients found in whole grains, so it’s natural to assume that whole grains are much higher in nutrients. Unfortunately this isn’t the case. Grains do not contain vitamin C, an antioxidant that is important for immunity, protection against allergies, skin health and cancer. Grains do not contain vitamin A or vitamin A precursors such as beta-carotene that is important for the health of mucous membranes. Vitamin A reinforces immunity and helps to prevent both heart disease and cancer. Grains are poor sources of the B vitamins in comparison to the calories they provide. You would have to provide a lot of grain in a dog’s diet to provide adequate amounts of vitamin B as is available in meat sources. Antinutrients in grains, called pyridoxine glucosides, reduce vitamin B6, which is important for a healthy immune system and hormonal balance.

Vitamin B12 is absent in grains, an important nutrient for nerve and brain health and protection against anemia. Grains contain low levels of bioavailable biotin, so necessary for the metabolism of fatty acids. As well, grains alter the metabolism of vitamin D whose job is important for bone health and a strong immune system.

Grains contain low levels of calcium and other factors that contribute to poor calcium metabolism. They are lower in protein and the essential amino acid lysine than animal proteins. Protein is vital for maintaining lean body mass, tissue repair and a strong immune system. Grains do not contain taurine or carnitine. Taurine is a conditionally essential amino acid and carnitine is a vitamin-like nutrient that is needed for energy metabolism. Grains are low in fat, but contain a very high ratio of omega 6 to 3 essential fatty acids. A poor omega 6 to omega 3 ratio promotes insulin resistance and has proinflammatory effects.

A high intake of phytate from whole grains can potentially lead to deficiencies of iron or calcium unless suitable supplementation is provided as with traditional pet foods. Studies have found that retention of zinc in the body is inversely related to the level of phytate in the diet. The phytate in grains not only inhibits the absorption of zinc in the grains themselves but also the zinc available in foods that are eaten with it. Antinutrients such as phytates in grains are believed to have evolved as a defense mechanism so the grains could protect themselves from insects or animals. Besides phytates, a few other antinutrients in grains include alkylresorcinols that have been shown to stimulate increased production of platelet thromboxane, which promotes inflammation. Alpha-amylase inhibitors induce adverse effects on pancreas cells and pancreatic over-activity. Protease inhibitors hinder the activity of digestive enzymes that help break down protein.

Lectins are glycoproteins that have the potential to interfere with the body’s hormonal balance, metabolism and health. Lectins induce structural changes in the intestine that increases gut permeability and contribute to bacterial overgrowth. Once they cross the protective barrier of the gut wall and enter the bloodstream, lectins fool the immune system into reacting to proteins that would not normally be affected, resulting in autoimmune disorders. Autoimmune diseases include arthritis, thyroid disease, liver disease, inflammatory bowel diseases, diabetes, systemic lupus, allergies and skin diseases. Grains provide a lot of carbohydrates and calories, some fiber and nutrients, but also many antinutrients. Dogs fed commercially prepared dry dog foods eat a lot of grains, which are not appropriate for their inherent needs.

For permission to reproduce this article email bhagel@quadrant.net