We all like to think we are doing the best for our performance dogs, so what about supplements? There are hundreds of vitamin and mineral supplements on the market. Should you be using them? Commercially prepared dog foods are usually balanced and rarely are deficient or excessive in vitamins or minerals. So as long as you are feeding a high quality, highly digestible food, chances are you don’t need to use supplements. However, if you are feeding your performance dog a homemade or combination diet, excess or deficiencies of vitamins or minerals could be possible and supplements may be necessary.
V itamins are classified into two groups: fat-soluble vitamins and watersoluble vitamins. Fat soluble vitamins include A, D, E, and K. These vitamins require fat to help them cross intestinal cell membranes. Water-soluble vitamins include the B-complex vitamins composed of thiamin (B1), riboflavin (B2), niacin, pyridoxine (B6), pantothenic acid, biotin, folic acid, cobalamin (B12), cholineitamin, and vitamin C (ascorbic acid).
Vitamin A is important for vision, bone growth, reproduction, and maintenance of skin and epithelial tissues. It also is important for proper health of mucous membranes that line the intestinal and respiratory tracts. Vitamin A comes from both animal sources (such as egg yolk, fish liver oil, liver and milk) and plant sources. Carotenioids, synthesized by plant cells, is another source of vitamin A for dogs. Of the carotenioids, beta-carotene is the most plentiful and has the highest activation level. Research as recently shown that beta-carotene plays an important role in keeping the dog’s immune system healthy to combat disease and injury.
Vitamin D is important for normal bone development and maintenance, and it helps to regulate calcium and phosphorus absorption and metabolism. Vitamin D can be ingested orally and absorbed through the skin upon exposure to sun – a source of UV light. It can be stored in the liver, muscle, and fatty tissue for future use.
Vitamin E is a potent antioxidant. Antioxidants prevent oxidation which destroys and injures normal tissues. Tocopherols (a type of vitamin E) are commonly used as natural preservatives in dog foods to stop oxidation of fat and prevent rancidity. Likewise, vitamin E stabilizes lipids (fat) of cell membranes of organs and tissues in the body. In general, the higher the fat content in a diet, the more vitamin E is required to counteract the normal oxidation processes and metabolism of fat. Vitamin E is found in wheat germ, corn oils, soybean oil, sunflower oils, and cottonseed oils. Most animal food sources (such as egg yolk and dairy products) supply very limited amounts of vitamin E. The liver has large amounts of vitamin E, but it is also found in most all tissues of the body.
Vitamin K’s most important function is to help blood clot.Vitamin K is required for production of four clotting factors (prothrombin and clotting factors VII, IX, and X) in the liver.Vitamin K is found in leafy green vegetables such as spinach, kale, cabbage, and cauliflower. Liver, egg, and certain fish meals also contain vitamin K, but at lower levels. Certain forms of vitamin K are synthesized by bacteria in the large intestine, and this contributes to at least some, if not all, of the daily requirement for dogs. Dogs with intestinal problems or those treated with certain antibiotics will have lower bacterial counts in the large intestine – these dogs may have an increased need for supplements of vitamin K.
Vitamin B-complex consist of thiamin, riboflavin, niacin, pyridoxine, pantothenic acid, biotin, folic acid, cobalamin, and choline. All nine act as coenzymes (chemical “helpers” for chemical reactions to occur) for energy metabolism and tissue synthesis. Folic acid, cobalamin, and choline are particularly important for growth, cell maintenance, and blood cell production. The other five are important in energy metabolism.
Humans, guinea pigs, and a few other species can not make Vitamin C. Deficiencies of vitamin C in these species result in a condition called scurvy which causes impaired wound healing, capillary bleeding, anemia, and abnormal bone formation. Dogs, on the other hand, can produce vitamin C, and do not have a daily requirement for it. Dogs produce vitamin C in the liver from glucose and galactose metabolism. Some breeders and performance dog owners add vitamin C to their dog’s diets because they believe it prevents certain developmental bone and skeletal problems. Some others supplement their dogs with vitamin C during growth, stress, and illness dogs because they believe the dog doesn’t produce sufficient vitamin C or their dog may have a higher requirement for it. Currently there is little research proving supplemental vitamin C is beneficial for any of these situations. However, daily use of moderate doses (500-1,000 mg) is probably not harmful.
Beta-carotene – Boost to the Immune System It is well known that stress affects the immune system. Performance dogs experience more stress than most dogs and may have a higher risk of contracting various illnesses. So anything that may stimulate the immune system to work better for the performance dog should be considered. Beta-carotene is one vitamin that my help to do just that. Beta-carotene is in the family of carotenoids. Carotenoids are the dark red pigments that provide orange or deep yellow color to many plants and vegetables such as carrots or corn. Even green vegetables contain carotenoids, but their color is masked by the deep green color of chlorophyll. Dogs can not make beta-carotene, so it must be eaten or taken as a supplement. Until recently, the role of beta-carotene and the immune system of dogs was poorly understood. In fact, it wasn’t even known how well beta-carotene was absorbed by dogs’ intestinal tract. Research now indicates dogs supplemented with it absorb and use it well. Also dogs supplemented with beta-carotene over long periods had better absorption than those dogs supplemented only once. Dogs have an enzyme in their intestine that converts beta-carotene into an active form of vitamin A. That is why beta-carotene is called a precursor to vitamin A. Vitamin A is extremely important to produce and maintain healthy skin and membranes lining the respiratory and intestinal tract. The skin and lining of the respiratory and intestinal tract are important first lines of defense against foreign bacteria and viruses. So dogs fed diets with beta-carotene may have stronger immune systems than those who are not. Beta-carotene also has been shown to significantly increase the functioning of B and Tlymphocytes, cells that play an important role in combating infection. Dogs supplemented with beta-carotene have significantly higher levels of antibodies (by producing B cells) than dogs fed diets without beta-carotene. So beta-carotene may be one of the keys to helping dogs stay healthy and competitive longer.
Because Calcium and Phosphorus work hand-in-hand, they will be discussed together. Calcium and phosphorus are important components of bone and teeth. Both are critical for skeletal integrity, and both can be reabsorbed from bone and transported by the blood to other sites in the body when needed. Hormones and other body chemicals help keep the balance between the two. The recommended ratio of calcium to phosphorus for dogs is between 1.2:1 to 1.4:1. By supplementing calcium, this ratio will become unbalanced, throwing regulating systems in the body off while creating problems especially for young dogs. In young, quickly growing puppies, supplementing calcium alters the calcium to phosphorus ratio and developmental skeletal problems such as osteochondrosis, hypertrophic osteodysptrophy, hip dysplasia, and panosteitis can occur. Some breeders believe that large breed puppies require more calcium than smaller breed puppies, and supplement it during the growing phase. When this is done, not only is the ratio altered, but also the absolute levels of calcium increases creating many developmental skeletal problems. Commercial dog foods are required to have the proper ratio and recommended levels of calcium and phosphorus. If you are feeding a homemade or combination diet, determining what the ratio of calcium to phosphorus is and the absolute amount of calcium is difficult to assess. Ideally homemade and combination diets should be sent to a nutrition laboratory (university or independent nutrition lab) on a regular basis to analyze the content of these and other minerals. If this isn’t done regularly, it is possible to cause developmental skeletal problems especially in growing large breed dogs. Many general multi-vitamin and mineral supplements made for dogs may have high levels calcium (since it generally is a very cheap mineral and frequently is used as a filler) without regard to the ratio of calcium to phosphorus. By supplementing dogs with many of these products, both the ratio of calcium and absolute amounts may alter the delicate balance between these two minerals creating health problems. Calcium is found in high levels in diary products and vegetables. Grains, meat, and organ tissues have smaller levels of calcium. Phosphorus is found in a large variety of meat foods such as fish, poultry, beef, and organ meats.
Cobalt is part of vitamin B12 and is found in diary products and fish.
Copper and iron are two minerals that have a synergistic relationship. Copper must be present for iron to be absorbed from the intestine and transportation to body tissues. Copper is also important in the production of hemoglobin. Copper is stored in the liver which is why organ meats, such as liver, provide a high amount of copper in a diet.
Thyroid hormones such as thyroxine and tri-iodothyronine contain the mineral iodine. Animals with a deficiency of iodine have enlarged thyroid glands and a deficiency of thyroid hormones. Growing animals with iodine deficiencies can have poor growth, skeletal deformities, skin abnormalities, as well as neurologic disorders. Iodine is found in meats such as fish, beef, and liver, so a dietary deficiency of iodine is unusual in dogs.
Iron can be found in just about any cell of the dog’s body, but the highest concentration is in red blood cells as hemoglobin and myoglobin. Hemoglobin helps transport oxygen from the lungs to the tissues through the bloodstream. Meat by-products such as liver and kidney are the richest in iron. Other types of meats, eggs, fish, whole grains, and vegetables also contain iron.
Magnesium is important to provide structure to the skeleton and for proper nerve impulses and muscle contractions. It is found in foods such as grains, vegetables, and diary products.
Manganese plays an important role in normal cell functions such as metabolic reactions and regulation of nutrient metabolism. It also is important for reproduction and normal bone growth. Whole grains and vegetables are good sources of manganese. Meat and other animal based products contain very little manganese.
Selenium is an important part of an antioxidant enzyme that protects cell membranes. Good dietary sources of selenium include fish, meats, and grains. Because selenium is so abundantly found in most foods dogs eat, supplementation is rarely needed and, in fact, supplementation can be toxic.
Sulfur is used for the synthesis of cartilage, insulin and heparin (an anticoagulant). It is an important component of sulfurcontaining amino acids such as methionine and cystine. It is found in most meats.
Zinc is important for normal fat, protein, and carbohydrate metabolism. It also plays an important role in the synthesis of RNA and DNA, the genetic building blocks of cells. Meats, organs, milk, egg yolks all contain zinc. Some vegetables also contain zinc, however dogs absorb zinc more readily from meat and eggs. It is critical to ensure you are feeding your dog a balanced diet when considering vitamins and minerals. More is not always better, and in fact, can create serious medical problems. Feeding a high quality, premium dog food is one way to ensure the basic vitamin and mineral needs for your dog are being met. Look for those diets that promote vitamin packages to build and maintain a health immune system. If feeding a homemade or combination diet, assuring the proper balances of vitamins and mineral will be trickier. Regular evaluation of your diet at a nutritional lab can help determine if the proper ratios certain minerals are present, or that the vitamins are in high enough quality for absorption.