Cat nutrition - focus on minerals
Although minerals constitute only 0.7% of a cat's body, they are very important in keeping it healthy. Together with vitamins and enzymes, minerals contribute to bone and cartilage formation, the normal function of muscle and nerve tissue, the acidic balance of the body, oxygen transport and the production of hormones. The minerals which are needed in the greatest amounts are calcium and phosphorus. Other important minerals are: Magnesium, Potassium, Sodium and Chloride. Minerals which are required in trace amounts are: Copper, Iron, Iodine, Manganese, Selenium and Zinc.
- The requirement for calcium is the highest of all minerals. It is an essential mineral involved in many body functions including bone formation, blood coagulation, muscle contraction and the transmission of nerve impulses. Calcium is present in large amounts in bone and dairy products but there is very little of this mineral in meat. In the past, many domestic cats had a poor diet and used to suffer from calcium deficiency. They developed a condition known as rickets, in which the bones become very thick and brittle. Nowadays calcium is added routinely to cat food, and calcium deficiency is very uncommon in cats.
- Phosphorus is the next mineral which a cat's body needs most. Phosphorus is plentiful in meat and therefore a phosphorus deficiency is very uncommon in cats. If anything, cats may suffer from too much phosphorus, which may lead to kidney damage. It has been shown that the most important thing is a proper calcium/phosphorous balance - a ratio of 1.2 parts of calcium for each part of phosphorus.
- Magnesium is important for the proper absorption of calcium, phosphorus, sodium and potassium and some vitamins eg. vitamin C and E. It is also required for building bones and protein. Magnesium is found in large quantities in milk and fish. The level of magnesium in the body can be affected by the level of calcium and phosphorus, since these two minerals inhibit magnesium absorption. Magnesium deficiency is very rare in cats.
- Potasium is mostly found within the cells and is required for a proper potasium/sodium balance. It is also necessary for the proper function of enzymes in muscles and nerves. Potassium is plentiful in most foods, so potassium deficiency is not normally caused by bad diet. However, cats may lose critical amounts of potassium due to chronic diarrhea and/or vomiting or as a consequence of kidney disease. Symptoms of potassium deficiency include loss of appetite, poor growth, weakness, nervous disorders and in severe cases, cardiac arrest.
- Sodium is important in maintaining the balance between fluid inside the cell and extracellular fluid. Together with chloride, sodium helps to carry nutrients to the cell. Sodium normally comes from sodium chloride (salt) and it is added to most foods. It is rare to have a sodium deficiency, but too much sodium may cause a cat severe dehydration. This is uncommon if cats have access to fresh water.
- Chloride works in conjunction with sodium. A cat's requirement for chlorate is approximately 1.5 that of sodium. As with sodium, chloride deficiency is rare unless the cat has specific health problems such as chronic diarrhea and/or vomiting.
- Copper is involved in many process in the body including the development of bone, connective tissue and collagen. It also aids the absorption of iron, development of hair pigment and acts as a general anti-oxidant. Copper is present in liver and fish. It is absorbed from the stomach and intestines and stored in the liver, brain and kidneys. Cats require approximately 5 mg of copper per 1 kg of food. Some vitamins, e.g. vitamin C can inhibit the absorption of copper, and high levels of calcium and phosphorus have the same effect. Some studies have shown that copper in dry food is more difficult for cats' bodies to absorb. Copper deficiencies or toxicity through excess is very rare in cats, but when present, copper deficiency can lead to anemia and bone deformation.
- Iron in combination with proteins and copper forms hemoglobin (the molecule in red blood cells that carries oxygen). Iron is needed continuously to provide hhemoglobin for newly produced red blood cells. Low level of iron will lead to the development of anemia. It is recommended that nursing cats get iron supplements. Cats require about 70 mg of iron for every 1kg of food. Foods high in iron are liver and fish but most commercial cat foods come with easy to absorb iron supplements.
- Iodine is important for the proper function of the thyroid gland. A deficiency of iodine causes a condition known as hypothyroidism (suboptimal production of thyroid hormone). Cats with this condition will have weight problems, and often lose their hair and become irritable. A cat requires approximately 0.35mg of iodine per kg of food. Iodine is found in fish and nowadays most pet foods are supplemented with iodine in the form of potassium, calcium or sodium iodine.
- This is important for the proper function of many proteins and carbohydrates, fertility and growth. Good sources of manganese are eggs, nuts and green vegetables - none of which are a cat's first food of choice. However, many pet food manufacturers also add manganese supplement to their products. Cats require 7 mgs of manganese for each kg of food eaten. The mineral is stored predominantly in the liver and to a lesser extent in the kidneys, pancreas, and bone. Manganese deficiency is rare, and if present it mainly affects kittens. Manganese-deficient cats are likely to be infertile, and may also suffer from stunted growth and some bone changes.
- Selenium is a trace element and as such is important in conjunction with vitamin E as an anti-oxidative agent. Meat is a good source of selenium especially since a cat requires only trace amounts (0.1 mg per kg). Selenium deficiency in cats is virtually unknown, but over-feeding with selenium for a prolonged time can have a toxic effect causing hair loss, lameness, anemia, and liver cirrhosis (a condition which manifests itself by the replacement of damaged cells with scar tissue resulting, in extreme cases, in liver failure).
- Zinc is now recognized as an essential mineral and the recommended dose for a cat is 75mg per kg of food. Meat and bone are both good sources of zinc. Zinc is important for healthy skin and hair, but also binds to some proteins (called metalloproteinases) which are involved in many immunological processes and are a vital part of the inflammatory processes (which prevent infection after injury). The absorption of zinc by the body is rather poor (estimated absorption is approximately 10-40%) that is why the the recommended dose is quite high.
The information supplied here is intended as a guideline only.