Nutrition: From Science to You Second Edition Chapter 9 Lecture © 2014 Pearson Education, Inc. Fat-Soluble Vitamins

DO NOW Joe has noticed a rash recently on his skin and there’s blood in his spit when he brushes his teeth. There are a couple of cuts on his legs that have been there for a long time as well. What foods would you suggest that he start eating more of to help with these symptoms? © 2014 Pearson Education, Inc.

What Is Vitamin A? A family of fat-soluble retinoids (retinol, retinal, retinoic acid) –Preformed vitamin A is found primarily in animal foods. –Some plants contain provitamin A compounds, which are converted to retinol in your body. Carotenoids, including beta-carotene, are pigments that give color to carrots, butternut squash, and cantaloupe.

© 2014 Pearson Education, Inc. Functions of Vitamin A Participates in –Vision –Protein synthesis and cell differentiation –Reproduction –Bone health –A healthy immune system May help fight cancer –Carotenoids are antioxidants.

© 2014 Pearson Education, Inc. Food Sources of Vitamin A

© 2014 Pearson Education, Inc. Too Much Vitamin A Excessive amounts of preformed vitamin A can accumulate to toxic levels. –Toxic levels are generally a result of overconsumption of vitamin A in supplements. –Hypervitaminosis A can lead to liver damage and even death. Overconsumption –During pregnancy can cause birth defects in the face, skull, and CNS of the child –Can potentially result in osteoporosis and bone fractures in adults

© 2014 Pearson Education, Inc. Too Much Vitamin A (Cont'd) Carotenoids in foods are not toxic. –Do not pose serious health problems –Excess carotenoids can cause carotenodermia. Overconsuming beta-carotene supplements –May increase lung cancer risk

© 2014 Pearson Education, Inc. Too Little Vitamin A Chronic vitamin A deficiency causes night blindness. Prolonged vitamin A deficiency leads to xerophthalmia (inability to make tears). –Leading cause of preventable blindness in children, mostly in developing countries Deficiency can lead to keratinization of epithelial tissues. –Epithelial cells don't secrete mucus. –Cells are unable to function properly, promoting infection.

© 2014 Pearson Education, Inc. What Is Vitamin D? Called the "sunshine vitamin" Derived from a reaction between ultraviolet rays and a form of cholesterol in the skin –Exposure to sunlight can synthesize all of the body's vitamin D needs. Considered a conditionally essential nutrient Considered a prohormone Found in two forms –Cholecalciferol (vitamin D 3 ): Produced in the skin and found in animal foods –Ergocalciferol (vitamin D 2 ): Found in plants and dietary supplements

© 2014 Pearson Education, Inc. Metabolic Functions of Vitamin D Bone growth May prevent some cancers May prevent diabetes –Type 2 diabetes is associated with low blood vitamin D levels. Potentially helps reduce risk of some autoimmune disorders May regulate blood pressure

© 2014 Pearson Education, Inc. Daily Needs—Vitamin D Sun exposure cannot meet everyone's vitamin D needs. –The skin pigment melanin and use of suncreens reduce vitamin D production. –Sunlight intensity during winter in some locations is not sufficient to make enough vitamin D.

© 2014 Pearson Education, Inc. Food Sources of Vitamin D

© 2014 Pearson Education, Inc. Too Much Vitamin D A high intake can cause loss of appetite, nausea, vomiting, and constipation. Overuse of supplements may lead to hypervitaminosis D. Hypercalcemia –Can cause damaging calcium deposits in kidneys, lungs, blood vessels, and heart –Can affect the nervous system and cause severe depression Too-high levels are extremely rarely caused by food intake or overexposure to the sun.

© 2014 Pearson Education, Inc. Too Little Vitamin D Rickets: Vitamin D deficiency disease in children –Bones aren't adequately mineralized with calcium and phosphorus, causing them to weaken, leading to bowed legs. –On the rise in the United States due to decreased milk consumption, fear of skin cancer from sun exposure, and air pollution Other vitamin D deficiency disorders –Osteomalacia: Adult equivalent of rickets –Osteoporosis –Muscle weakness and pain

© 2014 Pearson Education, Inc. Metabolic Functions of Vitamin E Acts as a powerful antioxidant –Protects cell membranes; prevents oxidation of LDL cholesterol Acts as an anticoagulant, inhibiting formation of harmful clots inside bloodstream No evidence supporting a role in prevention of cancer or other diseases has been conclusively identified.

© 2014 Pearson Education, Inc. Food Sources of Vitamin E

© 2014 Pearson Education, Inc. Too Much and Too Little Vitamin E Too much –No known risk of consuming too much vitamin E from natural food sources Overconsumption of synthetic form in dietary supplements and fortified foods can increase risk of a hemorrhage Too little –Rare –Chronic deficiency of vitamin E can cause nerve problems, muscle weakness, and free radical damage to cell membranes.

© 2014 Pearson Education, Inc. Metabolic Functions of Vitamin K Ten percent of vitamin K is produced by bacteria in the colon. Promotes blood clotting Promotes strong bones

© 2014 Pearson Education, Inc. Food Sources of Vitamin K

© 2014 Pearson Education, Inc. Too Much or Too Little Vitamin K Too much –No known adverse effects –Individuals taking anticoagulant medications should keep vitamin K intake consistent. Changes in intake can increase or decrease drug effectiveness. Too little –Infants are born with too little vitamin K. –Deficiency severe enough to affect blood clotting is extremely rare. –May be a cause of hip fracture in older men and women

© 2014 Pearson Education, Inc. What Are Vitamins? Tasteless, organic compounds Required in small amounts Functions –Regulate metabolism –Help convert energy in fat, carbohydrate, and protein into ATP –Promote growth and reproduction Deficiencies can result in potentially serious symptoms.

© 2014 Pearson Education, Inc. Vitamins Were Discovered about One Hundred Years Ago Diseases related to deficiency and foods that helped cure them were recognized long before the vitamin was discovered. In the eighteenth century, acid in citrus fruit was noted to cure the symptoms of scurvy in British sailors. In the early 1900s, scientists discovered that thiamin and vitamin D cured beriberi and rickets. Scientists are now focusing on prevention of disease with vitamin research.

© 2014 Pearson Education, Inc. Vitamins Were Discovered about One Hundred Years Ago (Cont'd) Each new vitamin was given a temporary name when it was discovered. The naming of vitamins follows the letters of the alphabet, starting with A; we are now at the letter K. –A, B, C, D, E, and K –Vitamins F, G, and H were dropped. The nomenclature changed when vitamin B was found to have several functions. –Subscripts were added for each new isolated role.

© 2014 Pearson Education, Inc. There Are Criteria for Designating Vitamins Cannot be synthesized in ample amounts in the body Chronic deficiency is likely to cause physical symptoms. Symptoms will disappear once the vitamin level in the body is restored. –Deficiency can cause permanent damage. 13 compounds meet the above criteria.

© 2014 Pearson Education, Inc. All Vitamins Are Organic, but Differ in Structure and Function All vitamins contain carbon, hydrogen, and oxygen. –Some vitamins contain nitrogen and sulfur. The chemical structure of each vitamin is unique. Each vitamin is a singular unit. Vitamins are absorbed intact. Vitamins perform numerous essential functions. Some vitamins have more than one role in metabolism.

© 2014 Pearson Education, Inc.

Vitamins Found Widely in the Food Groups

© 2014 Pearson Education, Inc. Some Foods Are Fortified with Vitamins Fortified foods – addition of nutrients by manufacturers to –Enhance the nutrient quality of food –Prevent or correct dietary deficiencies –Ensure adequate intake for some individuals Enrichment is a form of fortification. Fortification can contribute to health risks. –Lead to vitamin excess –Displace nutrient-rich foods

© 2014 Pearson Education, Inc. Vitamins Are Popular Dietary Supplements Supplements… –Are not a substitute for healthy eating –Can cause bad side effects –Are not regulated

© 2014 Pearson Education, Inc. Vitamins Are Popular Dietary Supplements (Cont'd) May be helpful for some individuals –Pregnant and lactating women –Older individuals who need vitamin B 12 –Individuals who lack dietary vitamin D or sun exposure –Individuals on low-kilocalorie diets –Strict vegetarians –Individuals with food allergies or lactose intolerance –Individuals who abuse alcohol –Individuals who are food insecure –Breast-fed infants

DOL Compare and contrast the functions and food sources of the following four vitamins: –Vitamin D –Folate/Folic Acid –Niacin/B3 –Vitamin C © 2014 Pearson Education, Inc.