yield no energy

assist enzymes to release energy

can only cure the disease caused by a deficiency 

of that vitamin

quantity provided by the food

Amount absorbed and used by the body

Inactive form of a vitamin

Must be converted to the active form

K,E,D,A

Occurs in fats and oils

absorbed the same as lipids

stored in liver & fatty tissues

Not readily excreted and can become toxic

Vitamin A

Retinolic Acid

Act as a hormone

Role in gene expression

regulates cell differentiation

maintains integrity of epithelial cells

Supports reproduction

major transport and storage form 

Active in vision

Maintains clear cornea

Participates in light detection

Plant derive precurosr

is in an extremely effective antioxidant

Protect other compounds from attack from oxygen

Free radicals can form from oxidation

age-related blindness

alzheimer's

Arthritis

calaracts

diabetes

kidney disease

one year's supply can be stored in the body

90% in the liver

Affects cell differentiation & maturation

Consequences: hardening of cornea, rough scaly, hard skin, drying and hardening of salivary glands, lumps of keratin around hair follicles, decreased immunity

Comes only from animal derived vitamin A or supplements

children are very vulnerable

RDA 700 ug for women and 900 ug for men

Multivitamins = 750-1000ug

Poses a tetratogenic effect 

Supplements 

Acne treatments

May weaken bones and contribute to osteoporosis

Measured in retinol activity equivalents (RAE)

Body makes 1 unit of retinol from 12 units of beta-carotene

Not converted to active form rapidly enough to be hazardous

can turn people bright yellow

builds up in fat beneath the skin

preformed found only in animal foods

Richest sources: liver, fish oil

Other foods:

milk, cheese, fortified cereals, butter (some), eggs (some)

Margarine & low fat & fat free milk are fortified with Vitamin A

bold dark orange color in fruits & vegeables 

dark green color in fruits and vegetables

white plant foods have none.

can be synthesized with help of sunlight.

liver manufactures a precursor that migrates to skin

sun's rays convert to second precursor

liver & kidneys produce active vitamin D

is a hormone.

Vitamin D's action

Target organs

Intestine, kidneys, bones

brain pancreas, skin, reproductive organs, many cancer cells.

Vitamin D's actions

Deficit implicated in

High bp

rheumatoid arthritis 

type 1diabetes

multiple sclerosis

Vitamin D's role in bones

role

makes calcium & phosphorus available in the blood that bathes the bones

Calcium & phosphorus

stimulates absorption from GI tract

Releases from bones to blood

Stimulates retention by the kidneys

Deficiency rickets, osteomalacia, osteoporosis 

Vitamin D Deficiency 

Symptoms

Same as those of calcium deficiency 

rickets in children

Adult rickets (Osteomalacia)

Risk factor for osteoporosis

Vitamin D toxicity 

Excess vitamin D :

enhances calcium absorption

produces high blood calcium

promotes return of bone calcium into the blood

Vitamin D toxicity

Excess calcium 

Can precipitate in soft tissues

*forms stones (kidney) 

*may harden blood vessels

In excess is most toxic of all vitamins

sun poses no toxicity risk

does cause premature wrinkling & risk of skin cancer

SPF 8 & above retard synthesis of vitamin D 

Need only about 10-20 mins of sun to make Vitamin D

Vitamin D & the sun

Factors limiting exposure

geographic location

season of the year

time of day

air pollution

clothing 

tall building

indoor living 

sunscreens 

Fat soluble antioxidant

Protects PUFA & other lipids from oxidation

Protects lungs

May offer protection from heart disease

Vitamin E Deficiency

Consequences

Erthrocyte hemolysis

Loss of muscle coordination & reflexes

Vitamin E

Associated with

Diseases causing fat malabsorption

Extremely low fat diets

Extremely high doses

Interfere with blood clotting action of vitamin K

Enhances anticoagulant medications

Research results are conflicting as to supplement safety

Tolerable Upper Level = 1,000 mg

RDA = 15 mg

Widespread in foods

Found in : margarine, salad dressings, shortening, wheat germ oil is rick in vitamin E.

Destroyed by heat processing & oxidation

Blood clotting

Synthesis of several bone proteins

can be synthesized by bacteria in intestine

deficiency is rare

Have a sterile digestive tract

single dose of vitamin K recommended at birth

Other vitamins other than KEDA, Easily absorbed, easily excreted, supplements can reach toxic levels