Chapter 9 Vitamins Introduction to Vitamins Review from chapter 1 o Except for water macronutrients are energy yielding o Needed in large amounts per body weight o Source of energy List the general functions of vitamins and minerals Micronutrients o Not energy yielding o Involved in metabolic processes o Not a source of energy but Assist in providing energy Categories of micronutrients o Vitamins Organic o Minerals Inorganic Types of Vitamins As they were discovered vitamins were assigned a letter o Vitamin A B C D E and K Researchers eventually realized that vitamin B wasn t a single vitamin therefore each vitamin was assigned a subscript o Vitamin B1 Vitamin B2 In addition vitamins were also categorized into two groups based on solubility o Water soluble o Fat soluble Water Soluble and Fat Soluble Vitamins Identify vitamins that are fat soluble and water soluble Fat soluble ADEK Fat Soluble Vitamins Fat Soluble Vitamins o Stored in the body for longer periods of time and in larger amounts o Stored in the liver and body s fat cells o If in high amounts Greater likelihood for adverse effects or toxicity Water Soluble Vitamins o Generally not stored in the body large quantities Greater chance of deficiencies o Less likely to have adverse effects if consumed in large amounts But adverse effects reported Vitamin A Occurs in nature in three different chemical forms Retinol Most active form of vitamin A and stored in the liver o Retinal o Retinoic acid List the functions of vitamin A Functions of vitamin A include o Integrity of epithelial cells o Bone growth o Reproduction cell membrane stability o o o o Gene regulation Vision Immune function Recommended Intakes for Vitamin A The RDA for vitamin A o 900 g per day for men o 700 g per day for women o Those with increased needs Women who are breast feeding Older tables and charts as well as supplements may list vitamin A recommendations in International Units IU instead of micrograms Food Sources of Vitamin A Discuss the differences between preformed vitamin A and provitamin A Identify dietary sources of preformed vitamin A and provitamin A Two forms of vitamin A found in foods o Preformed vitamin A Ready for use active form of vitamin A Found in animal based or fortified foods DIETARY SOURCES Ex Fortified milk cheese cream butter eggs liver o Pro vitamin A Converted to active form as needed by the body Ex beta carotene cannot function as vitamin A until activated Predominately plant based foods DIETARY SOURCES Ex Spinach dark green leafy vegetables and broccoli Also abundant in orange and red foods Apricots cantaloupe carrots sweet potatoes and pumpkins Functions of Vitamin A Describe the toxicity conditions associated with vitamin A Vitamin A is crucial to normal vision o Early stages of vitamin A deficiency o Night blindness o Reversible when start consuming vitamin A Vitamin A is also involved in the maintenance of healthy cornea tissue the outer layer of the eye o Short term vitamin A deficiency Cornea becomes dry and damaged o Long term vitamin A deficiency Xerophthalmia irreversible eye damage can occur Permanent loss of vision Functions of Vitamin A Immune o Vitamin A plays an important role in disease resistance particularly for children o Production of white blood cells Integrity of Epithelial cells o Found in the skin lungs and lining the gastrointestinal tract The process by which specialized cells develop that are capable of performing specific functions o Cell differentiation Functions of Vitamin A Gene regulation o Plays a role in whether genes are turned on or off o Therefore plays an indirect role in the regulation of metabolism through its influence on gene regulation Bone metabolism o Stimulates the bone cells that break down the inner part of bone Can lead to poor growth in children Vitamin A Toxicity Describe the toxicity conditions associated with vitamin A Vitamin A stored in the fat tissue and liver o Can be stored in the body for a long time Symptoms of Vitamin A toxicity include o o Liver defects Slight birth disease Should I Take Beta carotene as a Supplement Although preformed vitamin A is toxic if taken in large doses o Pro vitamin A as a form of B carotene is not known as being toxic in itself Research has suggested that beta carotene may help prevent heart disease and cancer however o Higher incidence of lung cancer Due to various studies health professionals do not recommend beta carotene supplementation for the general public Vitamin D Another name for vitamin D is cholecalciferol o In addition to being a vitamin it is also classified as a hormone and a steroid Discuss the role of vitamin D in relation to calcium Vitamin D plays a crucial role in the regulation of calcium metabolism and helps maintain blood calcium levels o It stimulates the cells of the small intestine to produce a calcium binding protein called calbindin Increases calcium absortion o Vitamin D also causes the bones to release calcium Maintain blood Recommended Intakes of Vitamin D The 2010 Dietary Guidelines for Americans sets the AI as such o For infants children adolescents and adults up to 70 years of age at 15 g vitamin D per day Discuss the reason for the increased vitamin D requirements in the elderly The requirement for vitamin increases as we age o For adults older than 70 the AI increases to 20 g per day o Why we need more Decreased ability to convert vitamin D into its active form active form enhances calcium As we get older decreased likelihood of adequate exposure to sunlight Food Sources for Vitamin D List the sources of vitamin D in the body In addition to sunlight food sources that contain good quantities of vitamin D include o Vitamin D fortified milk or margarine o Eating liver o Sardines salmon and shrimp o Cheeses and yogurts are not often fortified with vitamin D Making Your Own Vitamin D Outline the synthesis and activation of vitamin D in the body o The human body can make vitamin D as long as it has adequate exposure to sunlight o Cholesterol in the skin combines with ultraviolet rays o Converted into a precursor for Vitamin D o Makes it way to the kidneys o Eventually makes it way to the kidneys Converted to active from there Identify individuals at risk for inadequate vitamin D stores o Those who poor exposure to sunlight or UV rays may be at risk for vitamin D deficiency o Living far from equator o Wearing clothing over much of body using evidence found o Using sunblock o Cloud cover or smog Vitamin D