Unfortunately, symptoms of nutritional deficiencies or toxicities are not specific and the same symptoms could be caused by multiple other diseases. Routine blood tests will not detect nutritional deficiencies or toxicities.
If a nutritional abnormality is suspected, tests for the individual nutrient are required. These tests are typically $200-$400 per nutrient. The cost of the test is the main reason nutritional deficiencies and toxicities go undiagnosed.
This difficulty to diagnose makes it very important that a dog's food diet be complete for all 42 nutrients.
Toxic levels shown below, occur when too much of a particular nutrient is present in the food. Especially of concern are oil soluble vitamins because they stay in the body longer than water soluble vitamins.
The list below can give you some idea of the sorts of concerns that are involved:
Protein & Amino Acids: Both total dietary protein and 12 essential amino acids
Deficiency- Decreased appetite, stunted growth, weight loss; methionine- skin redness and swelling, foot pad dermatosis/hyperkeratosis
Toxicity- None reported
Fats & Fatty Acids: Both total dietary fat and 3 essential fatty acids
Deficiency- Decreased appetite, coarse dry fur w/ severe seborrhea, moist fungal and bacterial skin infections, decreased visual acuity, retina abnormalities, weakness, decreased cognitive development.
Toxicity- Chronic inflammatory conditions (Omega 6), delayed wound healing (Omega 3), delayed blood clotting time (Omega 3)
Vitamin A
Deficiency- Anorexia, weight loss, ataxia, xerophthalmia, conjunctivitis, corneal opacity/ulceration, skin lesions, pneumonitis, decreased immune function
Toxicity- Elevated liver enzymes, fatty liver, prolonged clotting time, premature closure of epiphyseal plate, osteoporaotic diaphysis and decreased length of long bones in growing pups
Vitamin D
Deficiency- Bone development and integrity
Toxicity- Hypercalcemia, soft tissue mineralization, kidney failure, bone abnormalities (increased long bone mineralization and diameter)
Vitamin E
Deficiency- Muscle degeneration and weakness including cardiac muscle, retinal degeneration, edema, red cell fragility
Toxicity- None. Extreme doses may interfere w/ Vitamin D and K absorption and metabolism
Vitamin K
Deficiency- Excessive bleeding, anemia
Toxicity- None
Vitamin B1 (Thiamin)
Deficiency- Depression, ataxia, parparesis, torticollis, circling, tonic-clonic seizures, weakness
Toxicity- No oral toxicity
Vitamin B2 (Riboflavin)
Deficiency- Anorexia, weight loss, decreased activity, hypothermia, decreased respiratory rate, ataxia, semicoma, flaking dermatitis of abdomen and medial surfaces of hind limbs, corneal opacity w/vascularization, watery or purulent discharge
Toxicity- No oral toxicity
Vitamin B3 (Naicin)
Deficiency- Anorexia, weight loss, inflammation and ulceration of buccal pharyngeal mucosa, hypersalivation, often ropy and bloody, bloody diarrhea due to intestinal mucosa damage, neuronal degeneration
Toxicity- Bloody diarrhea
Vitamin B5 (Panothenic Acid)
Deficiency- Rapid respiration and heart rate, seizures, gastritis, enteritis, intussusception, decreased antibody production, hepatic lipidosis
Toxicity- None
Vitamin B6 (Pryidoxine)
Deficiency- Anorexia, weight loss and sudden death in puppies, muscle twitching, ataxia, seizures, microcytic, hypochromic anemia, cardiac hypertrophy and dilation, demyelination of peripheral nerves
Toxicity- Ataxia, impaired coordination, muscle weakness, loss of balance, demyelination of dorsal funiculi and roots
Folate
Deficiency- Weight loss, decreased hemoglobin, anemia, cleft palates
Toxicity- None
Vitamin B12 (Cobalamin)
Deficiency- Anemia, neutropenia, megoblastic changes in marrow
Toxicity- None
Choline
Deficiency- Weight loss, vomiting, hepatic lipidosis,
Toxicity- Anemia, decreased hemoglobin
Calcium
Deficiency- Osteoporosis, pathological bone fractures
Toxicity- Osteochondrosis, radius curvature, stunted growth
Chloride
Deficiency- Hypochloremia, hypokalemia, alkalosis, weight gain ceased, weakness, ataxia
Toxicity- None
Copper
Deficiency- Loss of hair pigmentation, decreased growth, hyperextension of distal phalanges
Toxicity- Vomiting, hepatopathy, death
Iodine
Deficiency- Goiter, alopecia, weight gain, reduced thyroid hormone
Toxicity- Increased lacrimation, hypersalivation, nasal discharge, flaky, dry skin and fur
Iron
Deficiency- Anemia (microcytic, hypochromic), decreased hemoglobin, poor growth, pale mucous membranes, lethargy, weakness, diarrhea, hematochezia, melana
Toxicity- Oxidative tissue damage, gastrointestinal damage, death
Magnesium
Deficiency- Hyperextension of carpal joints, hind-leg paralysis, mineralization of thoracic aorta
Toxicity- None
Manganese
Deficiency- None reported in dogs, bone deformities and reproductive problems in livestock
Toxicity- None
Phosphorus
Deficiency- Poor growth rates
Toxicity- None, hyperparathyroidism possible
Potassium
Deficiency- Neck muscle paralysis, cervical ventroflexion, hindlimb paralysis, decreased cardiac function
Toxicity- None reported, ventricular fibrillation and cardiac arrest speculated
Selenium
Deficiency- Muscle degeneration and edema
Toxicity- Microcytic, hypochromic anemia
Sodium
Deficiency- Dehydration symptoms (increased heart rate, hematocrit, hemoglobin, water consumption and out put)
Toxicity- Vomiting
Zinc
Deficiency- Skin lesions
Toxicity- Gastroenteritis, hemolytic anemia, lethargy
