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Vitamins (Fat Soluble) Hallo, I hope that you all had a good week. Shall we carry on getting acquainted with the way our bodies function? Let's see what vitamins are all about. ( extracts are from the "Life Science" course ) Vitamins are organic compounds, which the body needs to function normally. They cannot be manufactured by the body ( with few exceptions ); therefore, they must be supplied by food. In their absence, disease will develop. The first vitamin was discovered in 1897 by a Dutch biologist named Eijkman. He found that when bran was removed from rice, people consuming the refined rice developed Beriberi, a serious disease. This finding directed Eijkman and other scientists to chemically analyze rice for the substance which, when not present in adequate amounts, resulted in the development of Beriberi. Thiamine, named B1 was discovered to be the mystery substance. Vitamins do not function alone or in a vacuum within the body. Vitamins work together: for instance, production of energy by the body when food is burned in the cells depends not only on vitamin B1, but also on vitamins B2 and niacin. Vitamins work together with all other nutrients such as fats, carbohydrates and proteins. Vitamins are only one small part of the metabolic machinery of the body. Vitamins can be categorized according to their properties. The 2 basic grouping of vitamins are the fat-soluble vitamins ( A, D, E, K ) and the water-soluble vitamins ( C, and the b-complex vitamins ) Certain common characteristics distinguish the fat-soluble vitamins from the water-soluble vitamins: 1) Fat-soluble vitamins are absorbed into the body as fat and with the fat and are soluble in fat solvent, whether water-soluble vitamins are soluble in water. 2) Fat-soluble vitamins are excreted mainly by the fecal pathway, whereas water-soluble vitamins are excreted via the urinary pathway. VITAMIN A: Was discovered in 1913. Vitamin A is relatively stable to heat but is destroyed by ultraviolet radiation ( sunlight ) Most dietary vitamin A is in the form of carotene, the yellow pigment of plants. About ½ the carotene consumed is converted into vitamin A in the body and the other ½ is utilized as a hydrocarbon. If the diet is devoid of fat, or if too little bile is secreted by the liver, or if too little thyroid hormone is secreted, there will be poor absorption of vitamin A in the intestine. This vitamin is stored in the liver. The body needs Vitamin A to maintain normal vision in dim light, for the synthesis of mucus ( secretion used to maintain the health of membranes lining the eyes, mouth and gastrointestinal, respiratory and genitourinary tracts ) Vitamin A is also needed for normal skeletal and tooth development, for formation of sperm, for the normal progression of the reproductive cycle of the female, for formation of the adrenal hormone cortisone from cholesterol, and for maintenance of the stability of all membranes. Male adults need 5000 Ius, female adults 4000 Ius, pregnant or lactating females 5000 Ius and infants about 1/10 th of the adult requirement, per day. ( Infants needs are easily supplies by breast milk ) A deficiency of Vitamin A is rare in the western world and is usually only seen in chronic diarrhea from colitis and other such diseases, liver disease or use of mineral oil. A deficient person manifests night blindness and degeneration of membranes. VITAMIN D : Was chemically isolated in food in 1930. Chemically, vitamin D is very stable. Neither heat nor oxygen will destroy this substance. It is produced when the skin or flesh of animals is exposed to the sunlight. The body needs vitamin D to maintain normal calcium and phosphorus metabolism in the body and to maintain the health of bones and teeth. With adequate D, the body is able to regulate the absorption of calcium and phosphorus from the intestines and the amount of phosphorus eliminated through the kidneys. Men, women and children require approximately 400 IUs of vitamin D per day. In summer the body produces excess vitamin D and stores it in the liver and draws upon the stores in winter in order to maintain normal vitamin D metabolism. Clothing prevents formation of D in the skin with sunlight exposure, and window glass, fog & smog may also interfere. In the warm months ½ hour exposure per day should suffice. A deficiency of vitamin D will result in rickets in infants and osteomalacia in adults. The body can not maintain normal bone structure when too little vitamin D is present. VITAMIN E: Vitamin E was isolated in 1936. It is a relatively stable vitamin but will break down on exposures to ultraviolet light and when exposed to rancid fats, lead or iron. Bile salts are needed for absorption . Most Vitamin E is stored in muscle and fat tissue. The body uses vitamin E mainly as an antioxidant. It chemically combines with oxygen. And, as a result of this, other organic compounds are not destroyed by oxygen. The amount of vitamin E needed for normal body function is about 15 IUs per day. Fortunately, one of the richest sources of E in nature is in unsaturated fats ( oils from nuts & seeds ) This vitamin is also found in fruits, vegetables, sprouted grain and sprouted legumes. When E is in extremely short supply, disease in many areas of the body results. There is a breakdown of the reproductive system, muscular system, nervous system and vascular ( blood vessels ) system. VITAMIN K: Vitamin K was discovered in 1935, by a doctor in Scandinavia. Vitamin K is easily destroyed by light but is stable to heat. Vitamin K is a vitamin that does not need to be supplied by food. Bacteria which live in the human intestine are fully capable of producing the vitamin K needed for normal functioning of the blood clotting process. It is absorbed with fat and as fat and therefore requires the presence of bile salts. The liver produces certain organic compounds needed for the blood clotting process. Vitamin k is needed by the liver for the production of these compounds. A dietary requirement has never been set for vitamin K because it is supplied by intestinal bacteria. Dietary sources of K is found in kale and green leafy vegetables, cabbage & cauliflower. A deficiency of vitamin K results in failure of the blood clotting system, resulting in hemorrhage. Shall we leave the water-soluble vitamins for next week? Until then, stay warm, The crazy Nut team