Vitamins and Minerals Chapter 18

History of Vitamins Deficiency disease = a disease caused by a lack of a specific nutrient (ex. Scurvy) Vitamins = complex organic substances vital to life –Have been known to scientists for a long time, however they did not have the equipment or knowledge needed to fully understand them –In the 1880s, Japanese navy’s surgeons found that adding meat and vegetables to the sailors’ diet seemed to prevent beriberi = a disease of the nervous system that causes partial paralysis, weakness, mental confusion, and death. –In 1915, vitamins were recognized as a class of nutrients. Since then a dozen more vitamins necessary to humans have been identified, ending with vitamin B12 in 1948

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Function of Vitamins Vitamins perform specific functions in the body by working with compounds called enzymes Enzymes speed up reactions that would otherwise proceed too slowly to sustain cell life Enzymes include two parts, a protein molecules and a coenzyme If you don’t get enough of a certain vitamin, the enzyme that needs that vitamin as its coenzyme gradually slows its work (cell continue to function, but less efficiently and the organs and tissues they make up begin to die)

The Structure of Vitamins Vitamin molecules are single, self- contained units Each vitamin has its own structure, but with similar basic components »Six-sided ring that includes carbon or carbon and nitrogen atoms, joined by a variety of single or double bonds »Attached hydrogen atoms »Attached hydrocarbons, which are compounds of hydrogen and carbon atoms (they include one carbon and up to three hydrogen atoms)

Water-Soluble Vitamins Water-soluble vitamins = dissolve in water Circulate freely in the blood and cell fluids Water-soluble vitamins are quickly absorbed from the small intestine, and excess amounts are excreted in urine Need to be consumed daily Total of 9 water-soluble vitamins

9 Water-Soluble Vitamins Thiamin or vit. B1 Needed to metabolize carbohydrates Transmitting high-speed impulses in the nervous system Found in peas, pork, peanuts and wheat germ Thiamin is easily destroyed by oxidation Riboflavin or vit. B2 Important for growth Needed to metabolize protein and for tissue repair Found in both animal and vegetable foods including broccoli, beef liver, asparagus and milk It helps form red blood cells and release energy from glucose Also helps make another B vitamin, niacin Riboflavin is vulnerable to high pH and breaks down under light

9 Water-Soluble Vitamins Niacin Crucial for the release of energy from carbohydrates, fats, and protein Also needed for forming deoxyribonucleic acid,, better known as DNA Very little is lost during food processing, because it resists light, heat, oxidation, acids and bases Found in dry peas and beans, peanut butter, liver, chicken and fish Vitamin C Nutrient is found in citrus fruits, broccoli, bell peppers, potatoes, tomatoes and cabbage Helps prevent cell damage Promote iron absorption Helps the body heal wounds and resist infection Megadoses = excessively large amounts (people say taking vitamin C in a large dose will cure a cold) »Massive doses can cause kidney stones and diarrhea Vitamin C is stable in the presence of acids, but is destroyed by oxidation, light, heat and bases

9 Water-Soluble Vitamins Vitamin B6 Helps your body use carbohydrates and proteins Nervous system healthy and helps your body make nonessential amino acids Found in poultry, whole grains, and legumes Vitamin B12 You body can use carbohydrates, fats, and proteins better Works with folate to help build red blood cells and form genetic material Only animal products supply this vitamin

9 Water-Soluble Vitamins Folacin (folate or folic acid) Helps prevent birth defects of the brain and spinal cord Pantothenic acid Helps the body release energy from carbohydrates, fats, and proteins and helps produce cholesterol Promotes a healthy nervous system as well as growth Found in meat, poultry, fish, eggs, legumes, milk and whole-grain foods Biotin Helps your body use carbohydrates, fats, and proteins Found in green, leafy vegetables, whole-grain products, liver and egg yolks

Fat-Soluble Vitamins Fat-Soluble vitamins = dissolve in lipids, rather than water They occur in the fats and oils of food, fat- soluble vitamins usually carried in the blood in lipoproteins They are stored in the body until needed –Advantage in preventing deficiency, but also potentially dangerous in overdoses.

4 Fat-Soluble Vitamins Vitamin A (retinol) Found in animal products, such as liver, butter, egg yolk and cheese Used mostly to maintain healthy skin and mucous membranes which cells secrete protective mucus in the walls of the respiratory and digestive system Normal vision, development of bones The liver can store up to a year’s supply of vitamin A Taking megadoses of vitamin A