Chapter 9 The FatSoluble Vitamins FatSoluble Vitamins n

Chapter 9 The Fat-Soluble Vitamins

Fat-Soluble Vitamins n n n Vitamins A, D, E and K are fat-soluble vitamins. Fat-soluble vitamins require bile and dietary fat for absorption. Once absorbed, they are transported with fats through the lymphatic system in chylomicrons before entering the blood. Fat-soluble vitamins can be stored in body fat, meaning that intakes can vary without a risk of deficiency (as long as there average intakes over time). Because they can be stored in body fat, fat-soluble vitamins are not easily excreted. This increases the risk of toxicity with high intakes. Copyright 2010, John Wiley & Sons, Inc.

Absorption of Vitamins Copyright 2010, John Wiley & Sons, Inc.

Fat soluble vitamins require _____ and _____ for absorption into the mucosal cell. a) bile and lymph b) lymph and dietary fat c) lymph and chylomicrons d) bile and dietary fat Copyright 2010, John Wiley & Sons, Inc.

Since vitamin A and carotenoids are bound to proteins in foods, ______ is necessary to release them for absorption. Pepsin Bile Amylase Lactase Copyright 2010, John Wiley & Sons, Inc.

Vitamin A n n Vitamin A is found preformed, from animal products or supplements, or in precursor form, from plant foods, in the diet. Vitamin A plays a key role in q night vision q cell differentiation q growth regulation. Copyright 2010, John Wiley & Sons, Inc.

Vitamin A n n n Preformed vitamin A compounds are known as retinoids. In the diet, preformed Vit A is present as retinol bound to fatty acids. retin. Ol and retin. Al are interconverted in the body. Plants contain precursors to vitamin A known as carotenoids. Carotenoids can be converted into retinal in the intestinal mucosa and the liver. B carotene is not as well absorbed as preformed Vit A (about 12 mg dietary B carotene yeild 1 mg retinol). Copyright 2010, John Wiley & Sons, Inc.

The carotenoid with the most vitamin A activity is _____. a) Beta-carotene Zeaxanthin b) Lutein c) d) Lycopene Copyright 2010, John Wiley & Sons, Inc.

Vitamin A in the Diet Copyright 2010, John Wiley & Sons, Inc.

Beta-carotene is least plentiful in which food? yellow squash spinach yellow apples carrots Copyright 2010, John Wiley & Sons, Inc.

hypercarotenemia Large intake of carotenoids. Not toxic as the conversion to retinoids is limited. Caused by excess carotenoids stored in adipose tissue. http: //www. dermnetnz. org/systemic/img/carot-s. jpg Copyright 2010, John Wiley & Sons, Inc.

Vitamin A and the Visual Cycle Copyright 2010, John Wiley & Sons, Inc.

Keratomalacia from vit A deficiency http: //webeye. ophth. uiowa. edu/eyeforum/atlas/photos/8 healed-keratomalacia-with-buphthalmos. jpg Copyright 2010, John Wiley & Sons, Inc.

Vitamin A is stable except when exposed to: a) heat b) light c) lack of oxygen d) fat Copyright 2010, John Wiley & Sons, Inc.

Which form of vitamin A is involved in vision? carotenoids preformed vitamin A retinal retinoic acid Copyright 2010, John Wiley & Sons, Inc.

Vitamin A and Gene Expression Copyright 2010, John Wiley & Sons, Inc.

Cell differentiation, or the process by which a cell becomes more specialized, is most affected by which form of vitamin A? a) preformed vitamin A b) c) d) retinal retinoic acid retinol Copyright 2010, John Wiley & Sons, Inc.

Vitamin A Deficiency and Toxicity n n Vitamin A deficiency is a threat to the health, sight and lives of millions of children around the world. Vitamin A deficiency can be caused by insufficient intake of vitamin A, fat, protein or zinc. Preformed vitamin A can be toxic if taken in high amounts. Medications made from vitamin A, such as Retin A or Accutane, can cause serious side effects. Copyright 2010, John Wiley & Sons, Inc.

Vitamin D n n n Vitamin D is known as the “sunshine vitamin” because it can be produced in the skin by exposure to UV light. Only a few foods are natural sources of Vitamin D, including liver, fatty fish, fish oils and egg yolks. Vitamin D can be toxic at high levels, so there are strict limitations on the categories of foods that can be vitamin D-fortified. Copyright 2010, John Wiley & Sons, Inc.

Vitamin D's primary function in the body is to a) prevent anemia b) regulate calcium and phosphorus levels c) regulate iron levels in the body d) support night vision Copyright 2010, John Wiley & Sons, Inc.

Vitamin D n Vitamin D is important for q q q bone health normal functioning of the parathyroid gland regulation of the immune system. Copyright 2010, John Wiley & Sons, Inc.

Vitamin D Deficiency and Toxicity n When vitamin D is deficient, dietary calcium cannot be absorbed efficiently and there can be improper bone mineralization and abnormalities in bone structure. n In children, vitamin D deficiency can result in rickets; in adults, osteomalacia. n Oversupplementation of vitamin D can result in high blood and urine calcium concentrations, depositing of calcium in blood vessels and kidneys, cardiovascular damage and possibly death. Copyright 2010, John Wiley & Sons, Inc.

Vitamin D n Rickets is a syndrome characterized by bone deformities in children, and caused by vitamin D deficiency. Copyright 2010, John Wiley & Sons, Inc.

Osteomalacia n A vitamin D deficiency disease in adults which is characterized by weak (principally affects bone remodeling Low vitamin D levels have been found in 8% of women living in nursing homes, 6% of young women, and 1. 6% of elderly people living in the community in Omaha, Nebraska For people of south Asian (Indian subcontinent) descent living in the UK, 56% of elderly and 41% of the young have been found to have significantly lower levels of vitamin D than Caucasian controls. Copyright 2010, John Wiley & Sons, Inc. May coexist with osteopersosis

African Americans are at increased risk of vitamin D deficiency for all of the following reasons except: Darkly pigmented skin filters out more light. They spend less time in the sun than people of other ethnic origins. Milk consumption is low. Lactose intolerance is common. Copyright 2010, John Wiley & Sons, Inc.

Vitamin D in the Diet Copyright 2010, John Wiley & Sons, Inc.

Vit D What macronutrient is the base for Vit D? Copyright 2010, John Wiley & Sons, Inc.

Vitamin D from UV Light or the Diet Cholecalciferol is a form of vitamin D, also called vitamin D 3 or calciol. It is the unhydroxilated form of Vit D, formed right after 7 -dehydrocholesterol is struck by light Copyright 2010, John Wiley & Sons, Inc.

Vitamin E n n n Idenetified as the fat soluble component of grains important for fertility. Vitamin E is also called tocopherol. (Greek tos: childbirth and phero: to bring forth) Vitamin E has antioxidant properties. Alpha-tocopherol is the form of vitamin E absorbed by the human body. The other forms cannot be distrubuted. The supplement form contains 8 different isomers, only ½ of which are active in the body. Vitamin E absorption depends on normal fat absorption. Once absorbed, vitamin E is incorporated into chylomicrons. Copyright 2010, John Wiley & Sons, Inc.

Converting Vit E units (pg 403) To estimate alpha tocopherol in foods If values are given as mg alpha-Tes 1. 1. Mg x 0. 8= mg alpha tocopherol If values given in IUs 2. 1. 2. 3. First determine if the source is synthetic or natural IU natural alpha tocopherol x 0. 67=mg alpha tocopherol IU synthetic x 0. 47= mg alpha tocopherol Copyright 2010, John Wiley & Sons, Inc.

Vit E n Roles of vitamin E? q Antioxidant n q maintains the integrity of cell membranes n n n q Preserves lipids such as LDL and PUFAs Red Blood Cell: Vitamin E deficiency in newborns might result in hemolytic anemia. Lung cells Nervous system cells protects against some environmental pollutants. n Heavy metals (lead, mercury), toxins (carbon tetrachloride, benzene), pollutants (ozone). Copyright 2010, John Wiley & Sons, Inc.

In the liver, vitamin E is incorporated into _____ and from there distributed to other lipoproteins and delivered to cells. Chylomicrons VLDL HDL Copyright 2010, John Wiley & Sons, Inc.

Vitamin E in the Diet Copyright 2010, John Wiley & Sons, Inc.

Which is NOT considered a good source of vitamin E? a) peanuts b) soybean oil c) fortified breakfast cereals d) orange and yellow vegetables Copyright 2010, John Wiley & Sons, Inc.

Vitamin E is an Antioxidant Copyright 2010, John Wiley & Sons, Inc.

Vitamin K n n Vitamin K was named for koagulation, the Danish word for coagulation. Vitamin K is found in several forms, including phylloquinone and menaquinones. Abnormal blood coagulation is the major symptom of vitamin K deficiency. Vitamin K deficiency is very rare in the US. Copyright 2010, John Wiley & Sons, Inc.

Vitamin K in the Diet Copyright 2010, John Wiley & Sons, Inc.

A Summary of the Fat-Soluble Vitamins Copyright 2010, John Wiley & Sons, Inc.

Vitamin A toxicity occurs most frequently when large amounts of _____ is (are) ingested. a) b) c) carrot juice egg yolks polar bear liver d) vitamin A supplements Copyright 2010, John Wiley & Sons, Inc.

A Summary of the Fat-Soluble Vitamins Copyright 2010, John Wiley & Sons, Inc.

The recommended intake of vitamin E is expressed in: a) b) c) REs µg alpha-tocopherol equivalents d) mg alphatocopherol Copyright 2010, John Wiley & Sons, Inc.

Benefits and Risks of Fat-Soluble Vitamin Supplements Copyright 2010, John Wiley & Sons, Inc.

Trends in the modern diet have reduced the consumption of fruits and vegetables. This has reduced our intake of all of the following except vitamin ____. A D E K Copyright 2010, John Wiley & Sons, Inc.

A deficiency of vitamin A can result in a) beri b) goiter c) scurvy d) xerophthalmia Copyright 2010, John Wiley & Sons, Inc.

Which of the fat soluble vitamins can be synthesized by bacteria in the intestine? a) vitamin A b) vitamin D c) vitamin E d) vitamin K Copyright 2010, John Wiley & Sons, Inc.

Long term use of antibiotics may result in vitamin K deficiency because: a) antibiotics may interfere with absorption of the vitamin b) antibiotics use vitamin K to function properly c) antibiotics may change the bacterial flora in the gut, decreasing vitamin K production d) antibiotics may promote other vitamins which compete with vitamin K for absorptionc Copyright 2010, John Wiley & Sons, Inc.

Vitamin E's primary function in the body is: a) to act as an antioxidant b) to increase absorption of calcium in the small intestine c) to regulate acid-base balance d) to regulate phosphorus levels Copyright 2010, John Wiley & Sons, Inc.

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