Fat soluable vitamins

Found as : Retinol - animal products (milk,cheese,egg yolk, oily fish) Beta Carotene -  plant foods (carrots, mangos, darker green = more BC)

Functions

Makes Rhodopsin  (purple) pigment in retin for night vesion/ dim light)  

Mucous Membranes -  cornea of eye, lining of respiratiory and digestive tracts moist and infection free

Health of skin - maintance

Growth - of all cells

Cancer - protects against it

Requirements -  men 700 ug, women 600ug, extra 100 during pregancy 

Deficiency - rare but signs are....

Retarded growth in children, night blindness;unable to synthesis rhodopsin, health of skin and resistance to infection is lowered due to poor mucous lining  of tracts, bacteria invasion causing permanent scaring to cornea of eye e.g xerophthaimia ; blocked tear glands.

Factors affecting absorption

• low protein/ fat intake affects metabolism and absorption
• acute infections lower concentration in blood

Effects on cooking and storage

• not affetced by cooking usually
• storage, retinol in fatty foods may be lost in oxidation

Excess

Toxicity when stored,hypervitaminosis = drowsines,iritabilityand skin disorders, pregnant women encouraged not to eat = birth defects, liver damage, bone damage

Occurs

Cholcalciferol (d3) ; natural for, from sunlight 

Ergocalciferol;(D2) synthetic form of vitamin, produced by action of light on yeast

Sources 

Naturally - animal foods e.g oily fish, liver , cheese, milk (content varies throughout the year in milk so not a good source ) , bfast cereals and margarine fortified.

Formed in skin when exposed to light, varies according to latitiude, time spent in sun, skin pigmentation.

Requirements 

Normal sunlight sufficent , 10ug frequired if housebound , over 65, pregnant or lactating 

Deficiency

• Skeletol deformity, unnatural limb posture, delayed ability to stand, knock kness, bow legs.
• Children - rickets
• adults - oesteomialacia (brittle bones)
• asian diets low as culture doesn't encourage skin exposure

Excess

• calcuim deposition in soft tissue e.g kidneys
• hypervitaminosis d - kidney damage

FAA and Bioavailability  cheap diet /lack of sunshine

Effects of cooking  unaffected / stable and insoluable in water

Function

• growth and maintance of bones and teeth

Properties 

powerful antioxidant, insol in water, stable in heat and acids, alcohol ,unstable in alkalis and uv light

Sources Wheat germ, veggie oils, nus, egg yolk, pulses, fruit and veg, soya beans (good source)

Functions

• natural antioxidant in cell membranes
• antioxidant, used rancidity by preventing oxidation of unsat fatty acids, which protects lipids against free radical damage as peroxide formation in cell membrane is prevented due to the obstruction of oidation, the risk of cell contents leaking is reduced.
• prevents against oxidation of vit a and c
• protects against some forms of cancer as free radicals damage against DNA and protien molecules in cells.
• prevent retrolental fibroplasia of premie babies, caused by action of oxygen on developing blood vessels in babies eyes.
• delays ageing and improves skin condition.

Requirements

• men; less than 4mg , women less than 3 mg, infants 0.4g per gram of PUFA

Deficiency 

• rare, fat sol viamins stored in liver, premies fed infant formula (high in PUFAs, low in vit e), people who absorb inadequately can develop nervous system problems.

Excess  non toxic to humans

EOC

• sensitive to oxidation, esp. in heat and alkali
• degration in frozen foods
• processing and refining flour
• cooking in fats; 70% - 90% loss
• boiling ; 30% loss
• Canning ; 80% loss

Properties -  fat sol, insol in water, heat stable, affected by irridation

Sources -  large amounts form green leafy veg, eggs, milk,wheat bran, fish oils. Synthesised by bacterial action in intestine , small store in liver.

Requirements -  adults 1ug per 1kg of body weight, infants; 10 ug

Deficiency

• haemorrhogic disease may develop in new borns who are prone to low reserves, breast milk and cows milk contain little, disease manifests through abnormal bleeding.
• mild deficiency leads to prolonges clotting time. severe means that blood will fail to clot and can lead to loss of life

Excess