Kids Research Express

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 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, interfere

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

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, 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-

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

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 functio