The last two posts have highlighted my worry of a potential surge in medical problems in dogs caused by improperly formulated homemade dog food. My concern in writing the articles was that the various strategies of those feeding homemade were based on assumptions that would necessarily lead to unbalanced diets.
Moreover, recent studies at UC Davis have documented that 95% of all homemade dog food recipes found online and in popular books to be nutritionally inadequate. Thoughtful comments from a reader highlighted why routine veterinary monitoring, especially blood test, will not detect most dietary insufficiencies.
What Are the Essential Nutrients for Dogs?
Daily dogs need adequate quantities of:
1) Total Protein and Specific Amino Acids (from protein) – arginine, histidine, isoleucine, leucine, lysine. methionine, phenylalanine, taurine, threonine, tryptophan, valine
2) Total Fat and Specific Fatty Acids – linoleic acid, alpha linolenic acid, docosahexaenoic acid (DHA) and eicosapentaenic acid (EPA)
3) Vitamins – A, D, E, K, B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B6 (pyridoxine), B9 (folic acid) and B12 (cobalamin)
4) Minerals - calcium, chloride, copper, iodine, iron, magnesium, manganese, phosphorus, potassium, selenium, sodium and zinc
What Routine Canine Blood Tests Do Not Include
1) No measurements of essential amino acids
2) No measurements of total dietary fat or specific essential fatty acids
3) No measurements of any vitamins
4) No measurements of 6 of the 12 essential minerals
What Do Routine Canine Blood Tests Evaluate?
Complete Blood Count (CBC) : Measures the number, size and hemoglobin (molecule responsible for transporting oxygen and carbon dioxide) content; the number and type of infection fighting white blood cells; the number of platelet cells (important for clotting). Certain types of anemia, or decreased red blood cells, can suggest iron or vitamin B12 deficiencies.
Serum Biochemistry : Evaluates liver, kidney, and pancreas function; measures cholesterol, total blood protein, albumin (protein important for retaining water in blood vessels), glucose, chloride, calcium, magnesium, potassium, sodium and thyroid hormone.
Why Are Routine Blood Test Inadequate to Evaluate the Diet?
1) As you can see blood levels of very few nutrients are included in routine blood tests. Each nutrient requires individual tests that are more expensive the entire routine blood panel.
2) With the exception of iron or vitamin B12 deficiencies, a CBC tells little about dietary balance.
3) Constant blood levels of calcium, phosphorus and magnesium are necessary for heart and nerve function. Dietary deficiencies will cause a release in hormones to dissolve bone to maintain vital blood levels. Uncorrected this will result in eventual osteoporosis but the blood work will always be normal until all bone is gone. The condition is generally diagnosed by x-rays because a dog spontaneously breaks one or several bones or is showing severe weakness.
Blood vessels must maintain a certain level of protein or water will leak from the veins into the abdominal or thoracic cavity. Muscle provides an adequate source of protein if the diet does not contain adequate amounts. The body will continue to take protein from muscle to maintain adequate blood amounts. Low levels of protein in the blood will not show-up until muscle is depleted to critically low levels.
Potassium, sodium and chloride levels are also important for heart, nerve and other body functions so the body will maintain deficiencies in the diet by altering kidney function to reabsorb these minerals from the urine. It is not until very late stages of deficiency when heart, nerve and other organs fail that indications of deficiency may be suspected. But it cannot be proved by the blood tests.
Taurine deficiency causes congestive heart failure like that in the bulldog on an incomplete vegan diet. On admission to the emergency hospital the routine blood work was normal and it required an echocardiogram and a special test for taurine levels to diagnosis the dietary deficiency.
I could go on with other examples, but I think you probably get the point.
The Bottom Line
I did not write these posts to discourage homemade dog food. Quality, nutritious homemade dog food is my business because I think it is the best dog food. The point is that deficient homemade diets cannot be detected by routine veterinary monitoring and are generally discovered after a problem rises to a critical level. Nutritious homemade diets are not as easy to formulate as internet chatter would suggest.
Providers of homemade recipes should be able to demonstrate the exact amount of all 42 daily essential nutrients in recipes and supplement recommendations. We do that with all of our recipes and hope others will also.
Dr. Ken Tudor,
THE DOG DIETITIAN