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Cat Nutrition

The cat’s natural diet provides it with the perfect balance of nutrients. For example, a raw adult domestic mouse comprises of approximately 56% protein and 24% fat.

A cat can easily swallow a mouse whole and will usually consume this prey in its entirety, including the bones. Bones in the mouse provide a 2:1 ratio of calcium to phosphorus for the maintenance of the cat’s skeleton. Besides, calcium and phosphorus, a mouse supplies all the essential vitamins and minerals required by the feline species.

Essential & Specialized Nutrient Requirements of the Feline

Protein provides amino acids, the building blocks of all body tissues, and enzymes, which support the body’s chemical reactions. The cat’s body can manufacture most amino acids, with the exception of taurine and arginine. Taurine deficiency leads to vision problems, (central retinal degeneration), heart failure (acute cardiomyopathy), reproductive problems, immune system dysfunction and blood clotting disorders. Taurine is destroyed by heat processes. One study found that an average of 52 percent of the taurine in raw meats was lost through baking and an average of 79 percent through boiling. As a result of heat processing, many commercial cat foods once had low levels of taurine which resulted in detrimental health for cats consuming them. Raw meat and organs are excellent sources of taurine. Heart is an especially rich source of this amino acid.

Arginine is the other essential amino acid cats require. Arginine is required for normal protein synthesis and as an essential component of the urea cycle. As a key urea cycle intermediate, arginine functions to convert large amounts of toxic ammonia to non-toxic urea that is excreted from the cat’s body. The generation of toxic ammonia results from the metabolism of high-protein meals and body protein stores. Therefore, an arginine deficiency can cause severe hyperammonemia (high blood ammonia levels) within several hours of consuming a single arginine-free meal, due to the disruption of the ammonia detoxification process. Clinical signs of hyperammonemia include vomiting, muscle spasms, incoordination, seizures, coma, and death. Arginine has important roles that include increasing endocrine activity, improving nitrogen retention, collagen deposition in wounds, enhancing T-cell function, and the growth of lymphocytes, one of the five kinds of white blood cells.

The sulfur-containing amino acids methionine and cysteine are required in higher amounts by cats than most other species especially during growth. Methionine and cystine are considered together because cystine can replace up to half of the methionine requirement of cats. Although these amino acids are present in high amounts in animal flesh, methionine tends to be the first “limiting” amino acid in many typical ingredients used in modern cat foods. A “limiting amino acid” is the essential amino acid found in the smallest quantity in the food. Clinical signs of methionine deficiency include poor hair growth and a crusting dermatitis at the junctions of the mouth and nose.

Fat is the cat’s most energy-dense nutrient, with more than twice the energy per gram than protein. It also carries the fat-soluble vitamins A, D, E and K. Animal fat contains essential fatty acids (EFAs) that cats cannot make, but are vital for health. Cats have a special need for one particular fatty acid, arachidonic acid, because they cannot synthesize it from the parent fatty acid, linoleic acid, as can dogs. The basis for this additional requirement is the low hepatic delta-6-desaturase (D6D) enzyme activity in cats. Arachidonic acid regulates skin growth, is necessary for proper blood clotting, and is needed for the gastrointestinal and reproductive systems to function properly. Arachidonic acid is abundant in animal fat, particularly fats surrounding internal organs and brain tissue.

Omega-3 fatty acids are also important for maintaining healthy skin and coat. These fatty acids are found in high concentrations in fish oils and certain plants. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are provided by including fish such as salmon, herring, mackerel, anchovies, and sardines or fish oil in the diet.

Eicosapentaenoic acid (EPA) is not currently considered essential in companion animal nutrition. Research suggests that this class of fatty acids may benefit pets during certain life stages or when suffering from certain diseases. Omega 3 fats play an important role in the production of powerful hormone-like substances called prostaglandins. Prostaglandins help regulate many important physiological functions including blood pressure, blood clotting, nerve transmission, the inflammatory and allergic responses, the functions of the kidneys and gastrointestinal tract, and the production of other hormones.

Docosahexaenoic acid (DHA) is the most abundant fatty acid in queen's milk and is important for normal eye and brain development. Experimental animals whose diets are low in DHA have been found to have smaller brains, reduced brain development, diminished visual acuity and delayed central nervous system development. DHA is found in animal organs such as brain and liver, and cold water fish.

Cats do not have an essential requirement for carbohydrates. In their natural habitat, cats consume prey high in protein with moderate amounts of fat and minimal amounts of carbohydrate thus, they are metabolically adapted for higher metabolism of proteins and lower utilization of starch (soluble or insoluble fiber) than omnivores. Although cats can use carbohydrates as a source of energy, they have limited ability to spare protein utilization by using carbohydrates instead. Nevertheless, commercial diets are formulated with a mixture of animal and plant-derived nutrients, especially dry foods that requires starch for the extrusion process to make kibble. Although cats eat these diets, the limitations of substituting animal-origin nutrients with plant-origin nutrients in cat foods are being increasingly realized. Recent research has shown that high-carbohydrate diets are to blame in most cases of feline diabetes. In fact, not only diabetes but many serious health problems in cats have a dietary factor. Some are actually caused by diet, and all are affected by it including: obesity, chronic vomiting, hepatic lipidosis, pancreatitis, arthritis, heart disease, allergies, inflammatory bowel disease, chronic renal failure, lower urinary tract disease, hyperthyroidism, viral conjunctivitis, skin and coat problems and cancer.

Cats lack salivary amylase, the enzyme responsible for initiating carbohydrate digestion. Many pet owners and pet food manufacturers insist on adding species-inappropriate vegetables or grains to a cat's diet claiming that they would eat them along with the stomach and intestines of their prey. However, this does not take into account that the amount of vegetable matter in the average bird or mouse is extremely small and often the stomach and the intestines are not even eaten. Additionally, cats have low activities of the salivary and pancreatic enzyme amylase and reduced activities of intestinal disaccharidases that break down carbohydrates in the small intestines.

All animals have a metabolic requirement for glucose. This requirement can be supplied either through endogenous synthesis (Endogenous synthesis refers to the synthesis of a compound by the body) of glucose or from carbohydrate food sources. Metabolic pathways in the liver and kidney use other nutrients to produce glucose through a process called gluconeogenesis. This glucose is then released into the bloodstream to be carried to the body’s tissues. Metabolically, the cat possesses several unique mechanisms for metabolizing carbohydrates. The cat can maintain normal blood glucose levels and health even when fed a carbohydrate-free diet. The capability is at least partly related to its different pattern of gluconeogenesis. In most animals, maximal gluconeogenesis for the maintenance of blood glucose levels occurs during meals, when carbohydrate is no longer available to tissues. Cats maintain a constant state of gluconeogenesis with a slightly increased rate immediately after eating. In addition, cats also appear to be able to produce glucose by at least one novel metabolic pathway that is not observed in other species. Because the cat’s body is limited in its ability to conserve amino acids and because a carnivorous diet contains little carbohydrate and large amounts of protein, the use of gluconeogenic amino acids for the maintenance of blood glucose levels is a distinct advantage to the cat.

There are two forms of fiber – insoluble and soluble. Soluble fiber keeps food in the stomach longer whereas insoluble fiber stimulates the bowel. Fiber is a natural part of the cat’s diet, coming from the fur, feathers and viscera of its prey. A variety of fiber sources such as beet pulp, chicory, rice bran, and psyllium are some of the fiber sources commonly used in prepared commercial cat diets, all poor substitutes when compared to nature’s model.

Fat Soluble Vitamins
Vitamins are organic compounds that take part in a wide range of physical and chemical processes in the cats’ body. Vitamin deficiencies can lead to widely ranging clinical abnormalities that reflect the diversity of their metabolic roles. The vitamins A, D, E and K, are soluble in fat.

Most animals can manufacture their own vitamin A but cats cannot because they lack the intestinal dioxygenase enzyme responsible for cleaving beta-carotene into two vitamin A molecules. As a result, the cat has a specific dietary requirement for preformed vitamin A, whereas other species can use carotenoids derived from plants. This unique dietary requirement can be traced to the evolutionary development of the cat as a strict carnivore with reliance on animal tissues rather than plant materials. Liver is a rich source of vitamin A. Although including beta-carotene in the diet cannot prevent the development of vitamin Deficiencies in Vitamin A lead to such problems as retinal degeneration, reproductive failure and various forms of dermatitis.

During exposure to sunlight 7-Dehydrocholesterol is produced in relatively large quantities in the skin of many vertebrate animals, including humans. Cats have insufficient 7-dehydrocholesterol in the skin to meet the metabolic need for vitamin D photosynthesis; therefore, they require a dietary source of vitamin D. Vitamin D is relatively abundant in animal liver and fats so the need for dermal production is minimal if a proper diet is fed.
Vitamin E acts as an "antioxidant". It protects vitamin A and essential fatty acids from oxidation in the body cells and prevents breakdown of body tissues. It is important for normal reproduction, muscle function, and disease resistance. In a cat, a deficiency of vitamin E can result in steatitis, the deposit of yellow-pigmented substances in the body fat which produces a painful inflammatory response. Affected cats develop sensitivity to being touched, reluctance to move, fever and loss of appetite. Prolonged consumption of excessively high levels of vitamin E can have depressing effect of other fat-soluble vitamins and may cause prolonged blood-clotting time.

Vitamin K promotes blood-clotting. A dietary deficiency of vitamin K has not been described in a cat.

Water Soluble Vitamins
The water-soluble vitamins include vitamin C and the B-complex family, and play many roles in health and metabolism. Cats require increased amounts of certain B vitamins, including thiamin, niacin, pyridoxine (B6), and, in some circumstances, cobalamin (B12). Cats do not convert the amino acid tryptophan to B vitamin niacin, which may be attributed to the consumption of high-protein, animal-based diets during its evolutionary development. The activity of the picolinate carboxylase enzyme is 30 to 50 times higher in cats than other animal species. This increased activity prevents the conversion of tryptophan to niacin. Animal tissues contain high levels of B vitamins as well as tryptophan and niacin. The regular consumption of a carnivorous diet provides adequate niacin. Niacin deficiencies can lead to loss of appetite and weight, inflamed gums, and hemorrhagic diarrhea.

Unlike humans, cats normally synthesize vitamin C from glucose, so there is no purpose in supplementing the diet unless there is a high metabolic need or inadequate synthesis. In some instances, supplementation may actually be harmful, because excessive ascorbic acid is excreted in the urine as oxalate. A high concentration of oxalate in the urine has the potential to contribute to the formation of calcium oxalate stones in the urinary tract. The cat's natural prey provides some vitamin C in entrails such as the spleen, lungs and thymus.

More than 18 mineral elements are believed to be essential for mammals. There are seven macrominerals or trace elements: calcium, phosphorus, sodium, magnesium, potassium, chloride, and sulfur. There are at least 11 trace elements: iron, zinc, copper, iodine, selenium, cobalt, molybdenum, fluorine, boron, and chromium.

Minerals are inorganic elements that are vital to life and are components of muscles, tissues and bones. Minerals play an important role in sustaining and regulating various chemical reactions and bodily functions, including acid-base balance, oxygen transport, nerve conduction and immunological responses. Some minerals act as antioxidants, which may help prevent diseases that are caused by the damaging effects of free radicals (i.e., autoimmune disease and diabetes). Various factors can interfere with mineral absorption and possibly result in a deficiency of that mineral, including aging, pregnancy, stress, disease and other nutrients or medications. Mineral composition - specifically the large particle size of many minerals - also may cause inadequate absorption in the gastrointestinal tract.

Whether a mineral is considered essential or not is based on its nutritional benefits. An element may be considered nutritionally beneficial if a low intake of that element has detrimental consequences (i.e., signs of deficiency).With a move toward disease prevention, an element also may be considered nutritionally beneficial if it has been found to reduce the risks of chronic diseases. Therefore, in reviewing minerals it is important to consider the primary goal of preventing nutrient deficiencies, as well as the secondary goal of reducing the risk of chronic diseases.

The Major Minerals

Calcium is the most common mineral found in the cat’s body. Calcium is found in bones and teeth, and about 1 percent is present in the blood, muscles and tissues. Functions of calcium include maintaining skeletal structure, mediating the constriction and dilation of blood vessels, conducting nerve impulses, muscle contraction and activating the blood-clotting cascade. Consequences of calcium deficiency include nutritional secondary hyperparathyroidism; loss of bone mineral content, which can lead to collapse and curvature of lumbar vertebrae and pelvic bones; bone pain, which can progress to pathological fractures.

There is a balance and movement between calcium in the bloodstream and calcium in the bone. When there is a deficiency of calcium in the blood, the body draws it out of the bone, causing the bone to be brittle, weakened and at risk for fractures. Another mechanism in which bone becomes weakened is through the remodeling process. Bone continuously is broken down (resorption) and replaced with new bone (formation). When bone resorption exceeds bone formation, bones become frail and weakened, increasing the risk of fractures and bone pain.

Chloride is an electrolyte present in the highest concentrations in cerebrospinal fluid and the gastrointestinal tract. It is responsible for controlling water and acid-base balance in the body. Sodium and potassium are other electrolytes that work with chloride in maintaining that balance. Additional functions of chloride include stimulating the liver to filter wastes, hair coat and teeth growth and producing the stomach acid necessary for digestion. Chloride deficiency may be caused by continuous vomiting and diarrhea or prolonged illness. Those conditions could lead to an acid-base imbalance in the body, which may present as nausea, vomiting, confusion and weakness.

Approximately 60 percent of magnesium in the body is present in bones and the skeleton, and the remaining is found in the muscle and in other tissues that are metabolically active including the brain, heart, liver, and kidney. Magnesium plays a role in bone growth, muscle relaxation, cellular energy production, conduction of nerve impulses and normal heart rhythm. Although magnesium deficiency is rare, certain conditions (i.e., gastrointestinal disorders, renal disorders and old age) can lead to depletion of magnesium.

Phosphorus is the second most essential mineral found in the body. It is a component of bone, and approximately 85 percent of the body’s phosphate is present in the bone in the form of calcium phosphate. The remaining percentage is present in the muscle and other soft tissues. Phosphorus is responsible for maintaining acid-base balance, oxygen delivery, energy production, kidney function and heart muscle contraction. Symptoms of low blood phosphorus levels (hypophosphatemia) include anemia, muscle weakness, bone pain and numbness of the extremities.

Potassium is an electrolyte responsible for controlling nerve impulse conduction, muscle contraction and heart function. Potassium is found in the muscle, kidney, and liver. Signs of deficiencies include anorexia; retarded growth; neurological disorders, including ataxia and severe muscle weakness.

Sodium, an electrolyte found in the body, is an essential mineral, which is consumed as sodium chloride—otherwise known as table salt. Similar to potassium and chloride, sodium is responsible for conduction of nerve impulses, muscle contraction, cardiac function and maintaining blood pressure. Initial symptoms of sodium deficiency include vomiting, muscle cramps, and confusion.

Sulfur is concentrated in muscles, skin and bones and aids in the secretion of bile from the liver, removing potentially toxic substances (i.e., cadmium, copper, mercury, arsenic, lead, and aluminum) from the body and making collagen.

The Trace Minerals

Although known as a toxic or poisonous element, arsenic has been identified as an essential trace mineral. Arsenic is believed to be involved in the metabolism of amino acids in the body, as well as other enzyme reactions.

The potential benefits of boron as an essential trace mineral only recently have been recognized. Boron aids in vitamin D metabolism, absorption, and utilization of calcium and development and maintenance of bone. It also promotes normal growth and development.

The primary role of chromium as an essential trace mineral is in the metabolism of glucose and enhancing the response of insulin receptors to insulin. Liver is considered to be rich in chromium.

Copper’s primary role is in the synthesis and use of hemoglobin, as well as the storage and metabolism of iron, maintenance of bone, strengthening of connective tissues (especially in the heart), enhancement of the immune system, skin pigmentation and production of neurotransmitters. Although copper deficiency is uncommon, the most common sign is anemia, in addition to low white blood cell count, loss of skin pigmentation, impaired growth, cardiovascular abnormalities, reduced weight gain and longer time to conceive.

Approximately 95 percent to 99 percent of the body’s total fluoride is present in bones and teeth. Calcium by itself won’t build a molecule of bone. To use calcium, the body has to have adequate supplies of at least 9 other minerals, and fluoride is one of those minerals.

Iodine is an essential mineral required in small amounts for the synthesis of thyroid hormones - thyroxine (T4) and triiodothyronine (T3) - that regulate growth and development, muscle function and functioning of the nervous and circulatory system. Approximately 75 percent of the body’s iodine is found in the thyroid gland, and the remaining iodine is distributed throughout the body. Iodine deficiency results in hypothyroidism and symptoms include lethargy, fatigue, sensitivity to cold, weight gain and dry skin and hair.

The two main sources of iron in the body, hemoglobin and myoglobin, are responsible for the storage and delivery of oxygen. The remaining iron is stored in the muscles, heart, liver, spleen and bone marrow. Iron deficiency occurs in various stages, beginning with depletion of iron stores and developing to decreased red blood cell formation and, ultimately, reduced hemoglobin production (iron deficiency anemia). Iron deficiency anemia is characterized by symptoms of fatigue, increased heart rate, rapid breathing, and increased susceptibility to infections.

Manganese is required by the body in small amounts for various enzyme reactions, which play a role in the breakdown of fats, protein and carbohydrates, strengthening of bone, nerve transmission, reproductive processes and the production of collagen. Although rarely seen, signs of manganese deficiency include impaired growth and reproductive function, impaired glucose tolerance, possible neurological disorders (i.e., seizures) and altered lipid metabolism.

Adequate levels of molybdenum are required by the body for various enzyme processes (i.e., protein formation, carbohydrate metabolism and utilization of iron), fetal development and formation of bones and teeth. Deficiency of molybdenum is extremely rare because the cat’s typical diet provides enough of this trace mineral to perform the necessary functions.

Studies have yet to determine an exact function of nickel in the body, and, therefore, a dietary reference intake has not been established. Highest concentrations of nickel in the body are found in the thyroid gland, adrenal glands and the lungs. Nickel may play a role in hormone production and activation of enzymes; with most of the information available from animal studies. Nickel deficiency has been linked to abnormal bone growth, poor absorption of iron and altered metabolism of calcium and vitamin B12.

Selenium works as an antioxidant, along with vitamin E, to prevent body tissues from the damaging effects of free radicals. Highest selenium concentrations are present in the kidneys, liver, spleen, pancreas and testes. Selenium is required for normal growth, development and thyroid function. The level of selenium in meat and organs may vary depending on the selenium content of the soil, the feedstuffs grown on that soil, and whether the feed animal has been supplemented with selenium. As a result, the actual contribution of selenium may be variable.

From animal studies, it appears that silicon plays a role in the formation of collagen, cartilage, and bone. Connective tissue and bone disorders are the most common signs of deficiency.

Vanadium is involved in a number of enzyme reactions and is most known for its ability to mimic the effects of insulin. The highest concentrations of vanadium in the body are present in the kidneys, spleen, liver, bone, testes and lungs. Vanadium may play a role in thyroid hormone metabolism and may have potential hypoglycemic and lipid-lowering effects. In animals, deficiency primarily caused decreased growth and thyroid function.

Zinc is found in high concentrations in the eyes, liver, and bones. Zinc is essential for immune system function, neurological responses (taste and smell sensations), reproductive health, wound healing and growth. Early signs of zinc deficiency include poor appetite, weight loss and slow healing of wounds developing to severe symptoms, such as hair loss, diarrhea, immunosuppression, reduced growth, impaired taste and impaired vision.

Other Trace Minerals
Although other trace minerals (i.e., aluminum, bromine, cadmium, cobalt, germanium, lead, lithium, rubidium, and tin) are present in small amounts in various tissues, there is limited evidence of their uses in the prevention or treatment of chronic disease.

Antioxidants and Zoochemicals
The use of oxygen in the body's normal processes creates chemicals known as free radicals. These have unpaired electrons and so they try to steal them from other molecules. These attacks damage the body's cells - a process called oxidation. In much the same way that air turns a cut apple brown, so oxidation damages the cell membranes, genetic material in cells (DNA), fatty acids and other body structures.

Free radicals can affect the rate at which the body ages, start cancers by damaging the DNA in cells, increase heart disease, produce cataracts and encourage degeneration of the lens of the eye that ultimately leads to blindness and contributes to inflammation of the joints, as in arthritis.

Antioxidants (AO) come to the rescue and neutralize free radicals. Although the body produces its own antioxidants to deal with free radicals produced each day as part of normal oxidation in the cells, an overload may leave the body's system unable to cope.

Early research centered on the antioxidant vitamins A, C and E also known as the ‘ACE’ vitamins and minerals such as copper, selenium, iron, manganese, and zinc. But in the last few years, researchers have discovered many, many more naturally occurring anti-oxidants which are not strictly nutrients from plants but zoochemicals derived from animals. Meat, organs, and fat found in the animal carcass include carnosine, glutathione, CoQ10, L-Carnitine, alpha-lipoic acid and conjugated linoleic acid (CLA).

Carnosine is a small molecule composed of the amino acids, histidine and alanine. It is found in relatively high concentrations in several body tissues; most notably in skeletal muscle, heart muscle, and brain. The exact biological role of carnosine is not completely understood, but numerous animal studies have demonstrated that it possesses strong and specific antioxidant properties, protects against radiation damage, contributes to the function of the heart, and wound healing. Carnosine has been suggested to be the water-soluble counterpart to vitamin E in protecting cell membranes from oxidative damage. Other suggested roles for carnosine include actions as a neurotransmitter (chemical messenger in the nervous system), modulator of enzyme activities, and chelator of heavy metals (i.e., a substance that binds heavy metals, possibly reducing their toxicity).

Alpha-Lipoic Acid
Alpha lipoic acid (ALA) is a sulphur-containing antioxidant, which occurs naturally, in small amounts, in muscle tissue (meat), kidney, and heart. Alpha lipoic acid (ALA) is readily soluble in water and fat, enabling it to exert an antioxidant effect in almost any part of the body, including the brain. At the cellular level, alpha lipoic acid (ALA) can act both as an antioxidant, capable of recycling other antioxidant nutrients such as vitamin C and vitamin E, and as a coenzyme for key metabolic enzymes involved in energy production. In addition to its role as an antioxidant, alpha lipoic acid (ALA) also raises the levels within cells of a substance called glutathione.

Due to its antioxidant properties, glutathione participates in a process which cells use to break down highly toxic peroxide and other high-energy, oxygen-rich compounds, in turn preventing them from destroying cell membranes, genetic materials (eg. DNA), and other cell constituents. Glutathione is also involved in repair of damaged DNA. It can bind carcinogens in the body, aiding in their removal via the urine or feces. It plays a role in immune function and can recycle vitamins C and E back to their active forms. Fresh muscle meat is an especially rich source.

Coenzyme Q10
Coenzyme Q10, or simply CoQ10 is a fat-soluble vitamin-like substance present in every cell of the body and serves as a coenzyme for several of the key enzymatic steps in the production of energy within the cell. It also functions as an antioxidant. It is naturally present in small amounts in a wide variety of foods but is particularly high in organ meats such as heart, liver and kidney. CoQ10 is also synthesized in all tissues and in healthy individuals normal levels are maintained both by CoQ10 intake and by the body's synthesis of CoQ10.

L-Carnitine is a water-soluble vitamin known as vitamin BT. Because of the close structural sameness it is often classed with amino acids. L-Carnitine is synthesized from the essential amino acids lysine and methionine, but enough vitamin B1 (thiamine) and B6 (pyridoxine) must be available. Unlike a true amino acid, it is not used in protein synthesis or as neurotransmitter, but is used for long-chain fatty acid transport and is required for entry of these long-chain fatty acids into the mitochondria of the cell, as well as for the removal of short-chain organic acids from the mitochondria, which frees the intra-mitochondrial coenzyme. It is therefore important for the energy supply within the cell, as well as muscles, assists in preventing fatty build-up in areas such as the heart, liver, and skeletal muscles. L-Carnitine is considered to be conditionally essential in the cat. Cats can synthesize L-carnitine within their bodies but in limited amounts.

Supplemental L-carnitine has been found to be beneficial for cats with certain cardiac diseases such as decreased cardiac arrhythmia and to improve heart rate. It is also recommended for weight loss in obese cats. Until recently, Pet food companies paid little attention to L-carnitine in commercial diets. Because L-carnitine is sensitive to heat, losses can occur quickly during the processing of dry and canned pet foods. Therefore, it is becoming increasingly common as an additive in pet diets. However, L-carnitine has always been present in the carnivore’s natural diet, mainly in muscle tissue (meat) and liver.

Conjugated Linoleic Acid (CLA)
"CLA" stands for "conjugated linoleic acid"—a fatty acid identified in the 1970s by Dr. Michael Pariza, researcher and director of the Food Research Institute at the University of Wisconsin, Madison. Pariza had been investigating the potential for carcinogenic effects in ground beef when he instead discovered a compound that could block the growth of tissues that support cancer. The active compound was identified as CLA—a form of linoleic acid with a differing arrangement of bonds within the molecule—hence the term "conjugated." Preliminary research suggests that CLA may not only suppress cancer cell development, but may also help reduce risk of heart disease, boost the immune system, and help build lean muscles in animals. CLA is a naturally occurring substance in the guts of ruminant or cud-chewing animals like cows, and is present in fats in the meat of animals, specifically those that are grass-fed.

Nutrient Synergy
Nutrients never occur as isolates in natural foods. They are integrally related with many other natural molecules that are required for their absorption, assimilation, and non-toxicity. Most often, supplemental vitamins, minerals, and antioxidants are only a part of the whole nutrient complex. Isolated and synthetic nutrients are unnatural, usually poorly absorbed, and missing known and unknown co-factor nutrients.

Although some isolated or synthetic nutrients can and do have some benefit, they are a vastly inferior way to obtain nutrients. In order for the body to absorb and utilize a synthetic or isolated nutrient it must reform them into organic complexes (as they are in whole foods). Only a small percentage is able to be re-formed into absorbable, usable matter. The remaining unusable portion either, at best, settles out in the tissues as harmful deposits, or taxes the liver and kidneys before it is excreted in the urine.

If an isolated or synthetic nutrient is an antioxidant, it may actually weaken the body's immune system. The body's white blood cells use free radicals to destroy foreign bacteria. Isolated or synthetic antioxidants may weaken the body's ability to do so. They can also interfere with the body's use of oxygen. Antioxidants in whole foods (in addition to being much more effective), do not interfere with the body's ability to use free radicals constructively or it's ability to use oxygen (they enhance both). Despite modern advances, the best source of nutrients, by far is natural food!