Dogs need vitamins. They are critical for growth and maintenance of good health. A diet lacking in a vitamin can produce a variety of nasty symptoms. On the other hand, too much of a vitamin will produce other symptoms.
Vitamins are divided into two groups: fat-soluble and water-soluble. The fat-soluble vitamins are A, D, E and K. The water-soluble vitamins include B12, biotin, C, choline, folic acid, niacin, pantothenic acid, pyridoxine (B6), riboflavin (B2), thiamine (B1), and B12.
Vitamins occur naturally in food, and can be purified into a crystalline powder. In the manufacture of most dog foods, the processing method destroys some vitamins. These are added back so the final product has a balanced amount of the necessary vitamins.
Fat-soluble vitamins are absorbed in the intestine just like any other dietary fat. These vitamins are then stored in fatty tissues. Most animals have enough of a reserve to carry them through times of deprivation.
Water-soluble vitamins are not stored in the body. Water, passing through the body daily, carries these vitamins away. They must be replaced every day.
Vitamin A is necessary for the production of visual pigment found in the retina’s rod cells. It also is important for bone growth and reproduction functions, and maintenance of epithelial tissue such as skin and the respiratory, urogenital and digestive tracts.
Young dogs are more susceptible to vitamin A deficiency than adult dogs. They have less storage space, and have not had the time to build up reserves.
Some vitamin A deficiency symptoms include stunted growth, loss of weight and appetite, night blindness, reproductive failure, a nervous incoordination (staggering walk), and xerophthalmia, which is an eye disease. Too much vitamin A has been associated with irregular and defective bone growth.
Vitamin D is critical to the dog’s ability to use calcium and phosphorus. These two minerals are required for bones and cartilage to develop properly. Without adequate vitamin D, the young will develop rickets, and adults will develop osteomalacia – two types of bone deformities.
Vitamin E is an antioxidant. It protects the cell membranes throughout the body from oxidative damage, which changes the nature of the cell. Vitamin E keeps muscles from degenerating and maintains proper reproductive performance. Vitamin E must be properly balanced with the mineral selenium.
Vitamin K is essential for normal blood coagulation and clotting. Deficiencies show up as bleeding that doesn’t stop.
The water-soluble vitamins are not stored and are washed out of the body every day. A deficiency is more likely than a toxicity.
Thiamin (vitamin B1) promotes a good appetite and normal growth. It is required for basic carbohydrate metabolism and thus, energy production. Deficiency of thiamin is rare, and is usually caused by an anti-thiamine factor in the diet. A deficiency will show up as anorexia or cardiovascular disturbances.
Riboflavin (vitamin B2) promotes growth and is involved in several enzyme systems. It’s also important in carbohydrate and amino acid metabolism. Puppies need more riboflavin than adult dogs. Deficiency symptoms may include weight loss and dry, flaky skin.
Pyridoxine (vitamin B6) is import-ant to nitrogen metabolism and red blood cell formation. Deficiencies show up as anorexia and poor growth. In severe cases, convulsions may occur.
Pantothenic acid is required for energy metabolism. It is a component of coenzyme A, a carrier protein in the process of metabolizing protein. Slow growth and loss of hair may be signs of a deficiency.
Niacin is a constituent of many coenzymes which help cells process carbohydrates, proteins and fats. A niacin deficiency in dogs shows up as a darkening of the tongue called Black Tongue Disease.
Vitamin B12 is a coenzyme necessary for normal DNA synthesis. It’s important for proper folic acid metabolism, so a deficiency in one can lead to a deficiency in the other. Slow or retarded growth is the main symptom of a deficiency. Pernicious anemia, where vitamin B12 is not absorbed properly in the intestine, results in a deficiency.
Folic acid is related to B12 metabolism and a variety of other bodily biochemical reactions. Slow growth and poor appetite are also symptoms of folic acid deficiency.
Biotin is a component of several enzyme systems. Symptoms of deficiency are nonspecific, but dermatitis is one which is sometimes seen.
Choline is involved in proper trans-mission of nerve impulses. It is also a component of certain fats.
Vitamin C is not required in the diet of dogs, as their body can synthesize it. People cannot do this. Vitamin C participates in a number of body development functions such as the formation of intracellular substances of the teeth, bone and soft tissue. Scurvy is the classical symptom of vitamin C deficiency in man. It is swollen and bleeding gums with a loosening of the teeth.
It’s not usually necessary to give your dog a vitamin pill. Most animals get all of the vitamins they need from a good, commercially produced diet.