Vitamins PDF

Vitamins Vitamins are organic compounds that are essential in small amounts for body processes. Vitamins themselves do not provide energy. They enable the body to use the energy provided by carbohydrates, fats, and proteins. Classification of Vitamins: Vitamins are commonly grouped...

Vitamins Vitamins are organic compounds that are essential in small amounts for body processes. Vitamins themselves do not provide energy. They enable the body to use the energy provided by carbohydrates, fats, and proteins. Classification of Vitamins: Vitamins are commonly grouped according to solubility. A, D, E, and K are fat-soluble, and B complex and C are water-soluble.  Vitamins Fat-Soluble (4) Water-Soluble (9) Vitamin A Vitamin B complex includes: Vitamin D Vitamin (B1) Vitamin B12 (cobalamin) Vitamin E Vitamin (B2) Folate Vitamin K Niacin Biotin Vitamin B6 Pantothenic acid Vitamin C (ascorbic acid)  Vitamin A: The amount of vitamin A consumed by humans is very important. A severe increase in this vitamin or severe deficiency leads to serious problems. Vitamin A is found in many forms in foods, for example retinol. Vitamin A consists of two basic dietary forms: preformed vitamin A, also called retinol, which is the active form of vitamin A; and carotenoids, the inactive form of vitamin A, which are found in plants. More than 600 plant pigments are found in nature, 50 of which are provitamin A such as beta-carotene.  Functions of Vitamin A. 1- Vitamin A is a family of fat-soluble compounds that play an important role in vision, bone growth, reproduction, and cell division. 2- Vitamin A helps regulate the immune system, which helps fight infections. 3- Vitamin A has been labeled as an antioxidant when, in fact, provitamin A (carotenoids) is the part of the family that functions as an antioxidant. Antioxidants protect cells from free radicals. 4- Helps to manufacture sex hormones and growth processes. 5- Affects protein synthesis and growth of bones and teeth. 6- It increases body immunity and prevents cancer and helps in the manufacture of red blood cells. 7- Skin and cellular health.  Food Sources: Vitamin A comes from animal sources, such as eggs, meat, fortified milk, cheese, cream, liver, kidney, cod, and fish oil. However, all of these sources, except for skim milk that has been fortified with Vitamin A, are high in saturated fat and cholesterol. - Cod liver oil - Eggs. - Fortified breakfast cereals. -Fortified skim milk. - Orange and yellow vegetables and fruits. - Other sources of beta-carotene such as broccoli, spinach, and most dark green, leafy vegetables. 1- Signs of a deficiency of vitamin A include night blindness. 2- Dry skin and increased susceptibility to infections. 3- Avitaminosis A can result in blindness or xerophthalmia (serious eye disease characterized by dry mucous membranes of the eye, caused by a deficiency of vitamin A). 4- Lack of vitamin A is the leading cause of blindness in the world and led to (the accidents). 5- People in poor rural areas, as well as elderly people, also people with liver disease and people suffer from AIDS, are often at risk of vitamin A deficiency.  Recommended daily allowance (Vitamin A): Life stage group RDA μg/day Infants 0–6 months 400 7–12 months 500 Children 1–3 years 300 4–8 years 400 Males 9–13 years 600 14–18 years 900 19 – >70 years 900 Females 9–13 years 600 14–18 years 700 19 – >70 years 700 Pregnancy 50 years 770 Lactation 50 years 1300 Hypervitaminosis A. The use of a single vitamin supplement should be preventing, because an excess of vitamin A can have serious consequences. Signs of hypervitaminosis A may include birth defects, hair loss, dry skin, headaches, nausea, dryness of mucous membranes, liver damage, and bone and joint pain. In general, these symptoms tend to disappear when excessive intake is discontinued.  Vitamin D: Vitamin D present in two forms- D2 (ergocalciferol) and D3 (cholecalciferol). Each is formed from a provitamin when exposed to ultraviolet light. They are equally effective in human nutrition, but D3 is the one that is formed in humans from cholesterol in the skin. D2 is formed in plants.  Vitamin D is heat-stable and not easily oxidized, so it is not harmed by storage, food processing, or cooking. One scientist recommended that people should expose their hands, faces and muscles to the sun twice to three times a week to get 30 to 50 percent of the sun they need for the process. On the other hand, the person must be exposed to sunlight for 10 to 15 minutes to complete the process. People with dark skin need a period of exposure to the sun more than light skin, but the period is not specified.  Functions of Vitamin D. 1- The major function of vitamin D is the promotion of calcium and phosphorus absorption in the body. 2- Helps in calcium deposition in the bones. 3- Regulation of calcium and phosphorous in the bones, teeth, and cartilage in children and maintenance of healthy bones and teeth in adults. Vitami n D plays an essential regulatory role in the following bodily functions 4- Maintenance of blood calcium and phosphorus levels 5- Reduces the development of certain cancer cells, such as occurring in the skin, bone and breast cancer cells. 6- Vitamin D is absorbed in the intestines and is chemically changed in the liver and kidneys. Excess amounts of vitamin D are stored in the liver and in adipose tissue. Sources of vitamin D: The best source of vitamin D is sunlight, which changes a provitamin to vitamin D3 in humans. The amount of vitamin D that is formed depends on the individual’s pigmentation (coloring matter in the skin) and the amount of sunlight available. Very few foods in nature contain vitamin D. The flesh of fatty fish (such as salmon, tuna, and mackerel) and fish liver oils are among the best sources. Small amounts of vitamin D are found in beef liver, cheese, and egg yolks. Vitamin D in these foods is primarily in the form of vitamin D3. Some mushrooms provide vitamin D2 in variable amounts. Mushrooms with enhanced levels of vitamin D2 from being exposed to ultraviolet light under controlled conditions are also available. Dietary reference intakes for Vitamin D: Age group RDA (IU) Infants 0–6 months 400 Infants 7–12 months 400 Children 1–3 years 600 Children 4–8 years 600 Children and Adults 9–70 years 600 Adults > 70 years 800 Pregnancy & Lactation 600  Deficiency of vitamin D: The deficiency of vitamin D inhibits the absorption of calcium and phosphorus in the small intestine and results in poor bone and tooth formation. Young children suffering vitamin D deficiency may develop rickets, which causes malformed bones and pain, and their teeth may be poorly formed. Adults lacking sufficient vitamin D may develop osteomalacia and softening of bones. A deficiency of vitamin D contributes to osteoporosis.  Hypervitaminosis D Hypervitaminosis D is usually due to taking more than the recommended daily value of vitamin D. If you take a multivitamin, look at the amount of vitamin D in it. Some prescription medications used to treat high blood pressure and heart diseases can cause an increase in vitamin D in the blood. Estrogen therapy, taking antacids for a long time can also cause elevated levels of vitamin D. Excessive amounts of vitamin D in the body can cause calcium levels in the blood to rise. This can lead to a condition called hypercalcemia (too much calcium in your blood). Hypervitaminosis D must be avoided because it can cause, fatigue, loss of appetite, weight loss, excessive thirst, excessive urination, dehydration, constipation, high blood pressure, deposits of calcium and phosphorus in soft tissues, kidney and heart damage, and bone weakness.  Vitamin E: Vitamin E consists of two groups of chemical compounds. They are the tocopherols and the tocotrienols. There are four types of tocopherols: alpha, beta, delta, and gamma. The most biologically active of these is alpha-tocopherol.  Functions of Vitamin E. 1- Vitamin E is an antioxidant. It is aided in this process by vitamin C and the mineral selenium. It is carried in the blood by lipoproteins. 2- When the amount of vitamin E in the blood is low, the red blood cells become vulnerable to a higher-than-normal rate of hemolysis. 3- Vitamin E has been found helpful in the prevention of hemolytic anemia among premature infants. 4- Enhance the immune system. 5- Because of its antioxidant properties, it is commonly used in commercial food products to retard spoilage.  Requirements of Vitamin E: Research indicates that the vitamin E requirement increases if the amount of polyunsaturated fatty acids in the diet increases. Life Stage Group RDA (mg/d) Adequate Intake (AI) mg/d 0- 6 months 4 7 – 12 months 5 1-3 year 6 4-8 year 7 9-13 year 11 14-18 year 15 > 18 year 15 Pregnancy ≤18 year 15 19-50 year 15 Lactation ≤18 year 19 19-50 year 19  Sources of vitamin E: 1- Vegetable oils made from corn, soybean, safflower, and cottonseed and products made from them, such as margarine, are the best sources of vitamin E. 2- Wheat germ, nuts, and green leafy vegetables also are good sources. 3- Animal foods, fruits, and most vegetables are poor sources. 4- The richest food sources of vitamin E are almonds, sunflower seeds, and edible vegetable oils, which contain varying proportions of alpha, beta, delta, and gamma tocopherols or tocotrienols  Hypervitaminosis of Vitamin E: 1- Although vitamin E appears to be relatively nontoxic, it is a fat-soluble vitamin, and the excess is stored in adipose tissue. Consequently, it would seem advisable to avoid long-term mega doses of vitamin E. 2- The lethal dose LD50, or the toxic dose required to kill 50% of experimental rats or mice, is 4000 mg of vitamin E per kg. Vitamin E can act as an anticoagulant, increasing the risk of bleeding. 3- Hypervitaminosis E may also counteract vitamin K, leading to a vitamin K deficiency. 4- In high doses, vitamin E has prooxidant properties, possibly causing oxidation which may damage cells and increase the risk of cancer or mortality. 5- Long-term use of high doses may cause nausea, diarrhea or vision deficiencies.  Vitamin K: Vitamin K is made up of several compounds that are essential to blood clotting. Vitamin K1, commonly called phylloquinone, is found in dietary sources, especially green leafy vegetables such as spinach and in animal tissue.  Vitamin K2, called menaquinone, is synthesized in the intestine by bacteria and is also found in animal tissue. In addition, there is a synthetic vitamin K, called menadione. Vitamin K is destroyed by light and alkalies.  Vitamin K is absorbed like fats, mainly from the small intestine and slightly from the colon. Its absorption requires a normal flow of bile from the liver, and it is improved when there is fat in the diet. 1- Vitamin K is essential for the formation of prothrombin, which permits the proper clotting of the blood. It may be given to newborns immediately after birth because human milk contains little vitamin K and the intestines of newborns contain few bacteria. With insufficient vitamin K, newborns may be in danger of intracranial hemorrhage (bleeding within the head). 2- Vitamin K may be given to patients who suffer from faulty fat absorption; to patients after extensive antibiotic therapy (ingestion of antibiotic drugs to combat infection) because these drugs destroy the bacteria in the intestines; as an antidote for an overdose of anticoagulant; or to treat cases of hemorrhage.  Sources of Vitamin K. The best dietary sources of vitamin K are green leafy vegetables such as broccoli, cabbage, spinach, and kale. Dairy products, eggs, meats, fruits, and cereals also contain some vitamin K. Cow’s milk is a much better source of vitamin K than human milk. The synthesis of vitamin K by bacteria in the small intestine does not provide a sufficient supply by itself. It must be supplemented by dietary sources. Requirements of Vitamin K. Vitamin K is measured in micrograms. The adequate intake “AI” for vitamin K is 120 μg for men and 90 μg for women. This is not increased during pregnancy or lactation. Infants up to 6 months should have 2.0 μg a day. Those between 6 months and 1 year should receive 2.5 μg a day. Vitamin K must be ingested daily. What is absorbed today will be utilized immediately with very little storage in the liver. Hypervitaminosis. Ingestion of excessive amounts of synthetic vitamin K can be toxic and can cause a form of anemia. Deficiency of Vitamin K. The only major sign of a deficiency of vitamin K is defective blood coagulation. This increases clotting time, making the client more prone to hemorrhage. Human deficiency may be caused by faulty fat metabolism, antacids, antibiotic therapy, inadequate diet, or anticoagulants.