Fat Soluble Vitamins Water Soluble Vitamins The Vitamins.

Fat Soluble VitaminsWater Soluble Vitamins

The Vitamins

Objectives

Vitamins are micronutrients Very small amounts are needed by the body (>1 gm) Very small amounts are contained in foods.

Vitamins are essential. The roles they play in the body are very important. Most vitamins are obtained from the foods we eat. Some are made by bacteria in the intestine One is made in the skin

There is no perfect food that contains all the vitamins in the right amount.

Characteristics of Vitamins

Objectives

Vitamins are non-energy producing They do not contain kcalories. They are involved in extracting energy

from the macronutrients. Some vitamins in foods are

precursors. Vitamins are classified according

to how soluble they are in fat or water.

Characteristics of Vitamins

Fat Soluble Vitamins vs. Water Soluble Vitamins

Variety is the Key

Vitamins are

derived from

a variety of

foods.

Vitamin A, D, E, K

Fat Soluble Vitamins

Objectives

After reading Chapter 6, completing a concept map and class discussion, you will be able to:

Identify fat soluble vitamins Distinguish fat soluble vs water soluble Identify food sources for Vitamins A,D,E,K Identify toxicity levels for Vitamins A,D,E,K Describe one major role for Vitamins A,D,E,K

Objectives

Fat Soluble Vitamins: Characteristics Essential Organic Structure Non-energy Producing Micronutrients Stability Bioavailability Toxicity

“More is Better”

Vitamin Misconception

Toxicity Toxicity is rare but it is a possibility. Toxicity is very rarely associated with

food. Toxicity results from overuse of

supplements.

Vitamin Concept MapVitamin Concept Map

Vitamin

FUNCTIONS

Other Facts

Food Sources

Vitamin A

FunctionsFunctions SOURCESSOURCES

Vitamin A

OtherOther FactsFacts

Other names Preformed Vitamin A – retinyl esters

Retinol, Retinal, Retinoic acid Sources: animal foods, fortified foods,

pharmaceutical supplements Provitamin A - Precursors=carotenoids

Beta-carotene and other carotenoids Sources: plant foods

Vitamin A

2001 RDA Men: 900 g RAE/day Women: 700 g RAE/day RAE=Retinol Activity Equivalents

1 microgram of retinol 12 micrograms of beta-carotene 24 micrograms of other precursor carotenoid

Upper level for adults: 3000 g/day

Vitamin A

Chief functions in the body Vision Maintenance of cornea, epithelial

cells, mucous membranes, skin Bone and tooth growth Reproduction Immunity Antioxidant effect of beta-carotene

Vitamin A

Vitamin A in Vision

Function in protein synthesis and cell differentiation

Vitamin A

Night blindness Xerosis (corneal drying) Bitot’s spots Karatomalacia Xerophtalmia Hyperkaratosis Impaired immunity

Vitamin A Deficiency

Keratinization Vitamin A

deficiency symptom

Vitamin A Deficiency

Toxicity from provitamin A impossible Conversion of carotenoids to retinal highly

regulated by the body Homeostatic mechanisms control tightly

Toxicity from preformed A inevitable Efficient absorption and hepatic storage of A Storage continues until pathologic condition

develops; liver stores ~80% of body reserves

Vitamin A Toxicity

Large % of population in developed nations have intakes of preformed vitamin A higher than the RDA 75% of people may be routinely ingesting

more than RDA Some studies suggest that as little as

twice the RDA intake may contribute to subclinical Vitamin A toxicity

Vitamin A Toxicity

Occurs when adults ingest >100x RDA of preformed Vitamin A for a period of hours or several days.

Occurs when children ingest >20x RDA of preformed Vitamin A for same period.

Less of a problem than chronic toxicity

Acute Toxicity

Acute toxicity symptoms Blurred vision Nausea, vomiting, vertigo Increase of pressure inside skull,

mimicking brain tumor Headaches

Acute Toxicity

Occurs when adults ingest >25,000 IU preformed Vitamin A for >6 years >100,000 IU preformed A for >6 months

Wide individual variabilty Children particularly sensitive to daily

intakes of 1500 IU/kg body weight. Elderly at significantly greater risk

Chronic Toxicity

Chronic toxicity symptoms Increased activity of osteoclasts

causing reduced bone density Liver abnormalities Birth defects

Chronic Toxicity

Vitamin A & Macular Degeneration

Studies in the elderly suggest that the use of large doses of certain vitamins and minerals are beneficial in the prevention of macular degeneration

Some evidence exists that improvement in existing damage may be seen

Vitamin/

Mineral

Amount % DV

A 14,320 IU 286

C 235 mg 371

E 200 IU 667

Zinc 348 mg 232

Copper 0.8 mg 40

Vitamin A & Macular Degeneration

WARNING

Vitamin A directs the process of borrowing and redepositing calcium in the bone

Too much preformed Vitamin A (retinol) can promote fractures.

Use Vitamin A in form of beta-carotene, a pre-curser form which does not increase fractures

Vitamin A & Macular Degeneration

Beta-carotene Dark leafy green

vegetables, spinach, broccoli

Deep orange veggies Carrots, pumpkin,

squash, sweet potato Deep orange fruits

Apricots, cantaloupe

Vitamin A Sources

Retinol Fortified milk, butter

cheese, cream Fortified margarine Eggs Liver

Vitamin A Sources

Copyright 2005 Wadsworth Group, a division of Thomson LearningCopyright 2005 Wadsworth Group, a division of Thomson Learning

Vitamin D

FunctionsFunctions SOURCESSOURCES

Vitamin D

OtherOther FactsFacts

Other names Calciferol 1,25-dihyroxy vitamin D (calcitriol) Animal version: vitamin D3 or

cholecalciferol Plant version: vitamin D2 or ergocalciferol Precursor is the body’s own cholesterol

Vitamin D

1997 adequate intake (AI) 19-50 years: 5 g/day 51-70 years: 10 g/day more than 70 years: 15 g/day

Upper level for adults: 50 g/day

Vitamin D

Chief functions in the body Mineralization of bones

raises blood calcium and phosphorus by increasing absorption from digestive tract

withdrawing calcium from bones stimulating retention by kidneys)

Vitamin D

Calcium and phosphorous absorption Without D only 10-15% dietary calcium

absorbed With D absorption increased to 30-40% Without D about 60% phosphorous

absorbed With D absorption increased to ~80%

Vitamin D

Recent research indicates Vitamin D has a role in the prevention of Heart disease Type-1 Diabetes Multiple Sclerosis Rheumatoid Arthritis Crohn’s Disease Certain Cancers

Vitamin D

Nonskeletal functions of Vitamin D Brain, prostate, breast, colon tissues and

immune cells have Vitamin D receptors and respond to 1,25-dihydroxyvitamin D (the active form of D)

1,25-dihydroxyvitamin D controls more than 200 genes

Potent immunomodulator

Vitamin D

Deficiency Rickets

Inadequate calcification Misshapen, deformed

Lax muscles with spasm Osteomalacia

Loss of calcium Soft, deformed bones Pain, weakness

Vitamin D

Toxicity – Hypervitaminosis D Elevated blood calcium Calcification of soft tissues (blood

vessels, kidneys, heart, lungs, tissues around joints)

Thought to be the most frequently occurring vitamin toxicity but………..

Vitamin D

The Sunshine Vitamin Approximately 90% of

Vitamin D requirement obtained from sun

UV light from sun hits skin, triggers synthesis

Activated in liver and kidneys

Vitamin D

Fortified Milk Margarine Butter Cereal

Veal, Beef Egg yolk Fatty fish (salmon, sardines, herring)

Vitamin D Sources

Vitamin E

SOURCESSOURCESFunctionsFunctions

Vitamin E

OtherOther FactsFacts

Other name: alpha-tocopherol 2000 RDA

Adults: 15 mg/day Upper level for adults: 1000

mg/day Easily destroyed by heat and

oxygen

Vitamin E

Chief function in the body Antioxidant

stabilization of cell membranes, regulation of oxidation reactions, protection of polyunsaturated fatty

acids and vitamin A

Vitamin E

Vitamin E: Antioxidant

Polyunsaturated plant oils Margarine Salad dressing

Leafy green vegetables Wheat germ Whole grains Egg yolks Nuts and seeds

Vitamin E Sources

Vitamin K

FunctionsFunctions SOURCESSOURCES

Vitamin K

OtherOther FactsFacts

Other names Phylloquinone Manaquinone Menadione Naphthoquinone

2001 AI Men: 120 g/day Women: 90 g/day

Vitamin K

Family of vitamins Naturally found in primarily two forms

K1 and K2

K3 simpler form; synthetically created

Identified by German scientists Required for normal blood clotting

Named “K” for German word for “clot” No Tolerable Upper Limit

Vitamin K

Bacteria in intestines produce ~75% of Vitamin K absorbed by body daily

Vitamin K not stored in body Vitamin K needs to be supplied

daily Absorption dependent on healthy

liver and gall bladder

Vitamin K

K1 produced by plants we eat K2 produced by bacteria in intestine;

converted from K1

K2 more potent (15x); more active; and wider range of activities Better absorbed; longer biological activity Predominant form found in body tissues Used preferentially by all tissues but liver

Vitamin K

Chief functions in the body Synthesis of blood-clotting proteins

and bone proteins that regulate blood calcium

Vitamin K

Synthesis of bone proteins that regulate blood calcium; prevent bone loss

Integration of calcium into bones Prevent calcium deposition in blood

vessels (vascular calcification) Maintain blood vessel elasticity

Vitamin K: Other Functions

Bisphosponates – osteoporosis drugs K improves utilization of these drugs

Wafarin - anticoagulants As little as 1 mg/day can interfere

with anticoagulant activity of drug

Vitamin K and Medication

Bacterial synthesis in GI tract

Leafy green vegetables

Cruciferous vegetables

Liver Milk

Vitamin K Sources

Vitamin K1 produced by plants and algae Broccoli, kale, chard; plant oils like canola

and soybean Hydrogenated soybean oil has ineffective K

Vitamin K2 produced by bacteria in gut Food Sources: fermented soybean (Natto);

dairy products, egg yolk

Vitamin K Sources

ObjectivesAntioxidants

ObjectivesAntioxidants

Objectives

After reading Chapter 6, completing a concept map and class discussion, you will be able to:

Identify fat soluble vitamins Distinguish fat soluble vs water soluble Identify food sources for Vitamins A,D,E,K Identify toxicity levels for Vitamins A,D,E,K Describe one major role for Vitamins A,D,E,K

Objectives

ObjectivesFat Soluble Vitamins