Vitamin D

This vitamin is necessary for normal bone formation and for retention of calcium and phosphorus in the body. It also protects the teeth and bones against the effects of low calcium intake by making more effective use of calcium and phosphorus. Also called the sunshine vitamin, vitamin D is obtained from egg yolk, liver, tuna, and vitamin-D fortified milk. It is also manufactured in the body when sterols, which are commonly found in many foods, migrate to the skin and become irradiated. Vitamin D deficiency, or rickets, occurs only rarely in tropical climates where sunlight is abundant, but it was once common among children of other areas before the use of vitamin D-fortified milk. Rickets is characterized by deformities of the rib cage and skull and by bowlegs, due to failure of the body to absorb calcium and phosphorus. Because vitamin D is fat-soluble and stored in the body, excessive consumption can cause vitamin poisoning, kidney damage, lethargy, and loss of appetite.

Vitamin C

Vitamin C or ascorbic acid, a well-known vitamin is important in the formation and maintenance of collagen, the protein that supports many body structures and plays a major role in the formation of bones and teeth. It also enhances the absorption of iron from foods of vegetable origin. Scurvy is the classic manifestation of severe ascorbic acid deficiency. Its symptoms are due to loss of the cementing action of collagen and include hemorrhages, loosening of teeth, and cellular changes in the long bones of children. Assertions that massive doses of ascorbic acid prevent colds and influenza have not been borne out by carefully controlled experiments. In other experiments, however, ascorbic acid has been shown to prevent the formation of nitrosamines—compounds found to produce tumors in laboratory animals and possibly also in humans. Although unused ascorbic acid is quickly excreted in the urine, large and prolonged doses can result in the formation of bladder and kidney stones, interference with the effects of blood-thinning drugs, destruction of B12, and the loss of calcium from bones. Sources of vitamin C include citrus fruits, fresh strawberries, cantaloupe, pineapple, and guava. Good vegetable sources are broccoli, brussels sprouts, tomatoes, spinach, kale, green peppers, cabbage, and turnips.

The B Vitamins

Known also as vitamin B complex, these are fragile, water-soluble substances, several of which are particularly important to carbohydrate metabolism.

Vitamin B1
Thiamine, or vitamin B1, a colorless, crystalline substance, acts as a catalyst in carbohydrate metabolism, enabling pyruvic acid to be absorbed and carbohydrates to release their energy. Thiamine also plays a role in the synthesis of nerve-regulating substances. Deficiency in thiamine causes beriberi, which is characterized by muscular weakness, swelling of the heart, and leg cramps and may, in severe cases, lead to heart failure and death. Foods richest in thiamine are pork, organ meats (liver, heart, and kidney), brewer's yeast, lean meats, eggs, leafy green vegetables, whole or enriched cereals, wheat germ, berries, nuts, and legumes. Milling of cereal removes those portions of the grain richest in thiamine; consequently, white flour and polished white rice may be lacking in the vitamin. Widespread enrichment of flour and cereal products has largely eliminated the risk of thiamine deficiency, although it still occurs today in nutritionally deficient alcoholics.

Vitamin B2
Riboflavin, or vitamin B2, like thiamine, serves as a coenzyme—one that must combine with a portion of another enzyme to be effective—in the metabolism of carbohydrates, fats, and, especially, respiratory proteins. It also serves in the maintenance of mucous membranes. Riboflavin deficiency may be complicated by a deficiency of other B vitamins; its symptoms, which are not as definite as those of a lack of thiamine, are skin lesions, especially around the nose and lips, and sensitivity to light. The best sources of riboflavin are liver, milk, meat, dark green vegetables, whole grain and enriched cereals, pasta, bread, and mushrooms.

Vitamin B3
Niacin, also known as nicotinic acid and vitamin B3, also works as a coenzyme in the release of energy from nutrients. A deficiency of niacin causes pellagra, the first symptom of which is a sunburnlike eruption that breaks out where the skin is exposed to sunlight. Later symptoms are a red and swollen tongue, diarrhea, mental confusion, irritability, and, when the central nervous system is affected, depression and mental disturbances. The best sources of niacin are liver, poultry, meat, canned tuna and salmon, whole grain and enriched cereals, dried beans and peas, and nuts. The body also makes niacin from the amino acid tryptophan. In large amounts it reduces levels of cholesterol in the blood, and it has been used extensively in preventing and treating arteriosclerosis. Large doses over long periods cause liver damage.

Vitamin B6
Pyridoxine, or vitamin B6, is necessary for the absorption and metabolism of amino acids. It also plays roles in the use of fats in the body and in the formation of red blood cells. Pyridoxine deficiency is characterized by skin disorders, cracks at the mouth corners, smooth tongue, convulsions, dizziness, nausea, anemia, and kidney stones. The best sources of pyridoxine are whole (but not enriched) grains, cereals, bread, liver, avocadoes, spinach, green beans, and bananas. Pyridoxine is needed in proportion to the amount of protein consumed.

Vitamin B12
Cobalamin, or vitamin B12, one of the most recently isolated vitamins, is necessary in minute amounts for the formation of nucleoproteins, proteins, and red blood cells, and for the functioning of the nervous system. Cobalamin deficiency is often due to the inability of the stomach to produce glycoprotein, which aids in the absorption of this vitamin. Pernicious anemia results, with its characteristic symptoms of ineffective production of red blood cells, faulty myelin (nerve sheath) synthesis, and loss of epithelium (membrane lining) of the intestinal tract. Cobalamin is obtained only from animal sources—liver, kidneys, meat, fish, eggs, and milk. Vegetarians are advised to take vitamin B12 supplements.

Other B Vitamins
Folic acid, or folacin, is a coenzyme needed for forming body protein and hemoglobin. Recent investigations show that folic acid deficiency may be responsible for neural tube defects, a type of birth defect that results in severe brain or neurological disorders. Folic acid is effective in the treatment of certain anemias and sprue. Dietary sources are organ meats, leafy green vegetables, legumes, nuts, whole grains, and brewer's yeast. Folic acid is lost in foods stored at room temperature and during cooking. Unlike other water-soluble vitamins, folic acid is stored in the liver and need not be consumed daily.

Pantothenic acid, another B vitamin, plays a still-undefined role in the metabolism of proteins, carbohydrates, and fats. It is abundant in many foods and is manufactured by intestinal bacteria as well.

Biotin, a B vitamin that is also synthesized by intestinal bacteria and widespread in foods, plays a role in the formation of fatty acids and the release of energy from carbohydrates. Its deficiency in humans is unknown.

Vitamin A

Vitamin A is a pale yellow primary alcohol derived from carotene. It affects the formation and maintenance of skin, mucous membranes, bones, and teeth; vision; and reproduction. An early deficiency symptom is night blindness (difficulty in adapting to darkness); other symptoms are excessive skin dryness; lack of mucous membrane secretion, causing susceptibility to bacterial invasion; and dryness of the eyes due to a malfunctioning of the tear glands,

The body obtains vitamin A in two ways. One is by manufacturing it from carotene, a vitamin precursor found in such vegetables as carrots, broccoli, squash, spinach, kale, and sweet potatoes. The other is by absorbing ready-made vitamin A from plant-eating organisms. In animal form, vitamin A is found in milk, butter, cheese, egg yolk, liver, and fish-liver oil. Excess vitamin A can interfere with growth, stop menstruation, damage red blood corpuscles, and cause skin rashes, headaches, nausea, and jaundice.

Undulant Fever

Undulant Fever, also known as brucellosis, infectious disease caused by various species of bacteria of the genus Brucella, transmitted to humans from lower animals, especially cattle, hogs, and goats. Human beings acquire the disease through contact with infected animals or by drinking their raw milk. The disease has been known as Malta fever, Bang's disease, Mediterranean fever, rock fever, and goat fever. In animals the disease generally can cause partial sterility, decreased milk supply, and abortion of a fetus. In humans undulant fever assumes acute and chronic forms. The acute form is characterized by weakness, chills, and high night fevers and often results in central nervous system disorders, painful joints, and miscarriage.

Chronic undulant fever is difficult to diagnose, as the symptoms are exceedingly varied and vague. A diagnostic blood agglutination test is available. As a rule human beings suffering from undulant fever respond favorably to the administration of broad-spectrum antibiotics. The pasteurization of milk is essential to the control of undulant fever.

Ulcerative Colitis

Ulcerative Colitis, a chronic disease of unknown cause in which the lining of the colon and rectum becomes severely inflamed and eventually wears away, forming shallow sores known as ulcers. Frequently the colon is permanently damaged. Ulcerative colitis, together with a related condition called Crohn’s disease, are generally referred to as inflammatory bowel diseases (IBDs).

Most people with ulcerative colitis have inflammation in their descending colon, the section of the large intestine stretching from the left side of the abdomen to the pelvis, and in the sigmoid colon, the section of the intestine that is joined to the rectum. Some people have inflammation and ulceration in all of the large intestine. The disease does not affect the small intestine.

Most people have only mild or moderate forms of the disease, with symptoms that include rectal bleeding, diarrhea, and feces that contains mucus, all of which are easily controlled with medication. People with a more severe form of the disease have extensive diarrhea, stomach pain, and fever, and they also tend to suffer from such problems as arthritis, liver problems, and leg ulcers. Patients with ulcerative colitis involving the whole colon that has lasted for more than ten years are at major risk for cancer.

Tumor

Tumor, broadly interpreted, any abnormal local increase in size of a tissue or organ. Medical research at the microscopic level, however, has made clear that swelling can be due either to the infiltration of cells from another part of the body or to the proliferation of cells originating within the affected site itself; only the latter circumstance is called a tumor.

Tumors are classified as either benign or malignant, although the benign-malignant distinction is not universally useful. The most important property rendering a tumor malignant is the ability to invade nearby or distant tissues; this spread to distant tissues is called metastasis, and it usually occurs by means of the blood or lymph vessels. Some so-called benign tumors can kill without metastasizing. Chief among these are brain tumors called gliomas, which can grow large enough to exert substantial pressure on nearby brain structures and destroy respiratory function. A liver tumor can kill by destroying the vital functions of that organ, even without metastasis. Cells in malignant tumors are also sometimes said to have lost their characteristic function, but blood cells form tumors, called myelomas, in which the cells retain the ability to form antibodies. Tumors of the uterus, called hydatidiform moles, are benign, but they can be forerunners of the cancer called choriocarcinoma. The clearest cases of benign tumors are skin moles and warts.