Fat Soluble Vitamins Flashcards
what is the two types of vitamin A
-retinol
-beta carotene
what is the main function of retinol in body cells?
-essential for growth and metabolism of all body cells
how is retinol used in the eye?
-required for the formation of rhodopsin it is a purple pigment found in the retina which is necessary for vision in reduced light
what is the main function of vitamin A in general?
-essential for maintenance of healthy skin and surface tissues e.g. the lining of the respiratory and digestive tracts
what are the 2 the main function of beta carotene?
-antioxidant in body tissues which remove free radicals which are the by products of metabolism
-a high intake may offer some protection against some forms of cancer and the removal of free radicals may also protect against CVD
what are four food sources of retinol?
-cod
-liver
-dairy products
-eggs
what are four food sources of beta carotene?
-carrots
-red peppers
-spinach
-mangoes
what type of foods offer retinol?
-animal and fish sources
what types of foods offer beta carotene?
-red/yellow/orange/green plant sources
a deficiency of vitamin A in children can cause what?
-reduced rate of growth
how can a deficiency of vitamin A effect eyesight?
-limited production of rhodopsin can result in night time blindness
-if the condition is not too serious and only a slight problem it can be reversed by increasing the intake of vitamin A
how can a deficiency of vitamin A affects the health of skin?
-a deficiency can affect resistance to infection is lowered due to poor condition of the mucous lining of the respiratory tract
what is the name of the condition than can occur due to an extremely low intake of vitamin A -
-xerophthalmia can occur as the tear glands become blocked and the cornea becomes dry and inflammed
are excessive intakes of vitamin A likely?
-no they are unlikely with a balanced diet
what is the term used to describe an over consumption of vitamins?
-hypervitaminosis
what are symptoms of hypervitaminosis of vitamin A ?
-drowsiness
-irritability
-skin and bone disorders
-enlarged liver
why are vitamin A levels during pregnancy recommended ?
-it can cause defects in the baby
over many years what can a large intake of vitamin A lead to?
-it can contribute to osteoporosis and makes bones more likely to fracture with increased age
what is another name for vitamin D?
cholecalciferol
what is the main function of vitamin D ?
-it is necessary for the growth and maintenance of bones and teeth
what is vitamin D used to help absorb?
-calcium from the intestine and for the uptake of calcium and phosphorus by the bones and teeth
how can vitamin D be formed ? how can this vary?
-formed in the skin n exposure to sunlight
-the amount can vary with latitude and the amount of time someone spends outside
what are four food sources of vitamin D ?
-cod liver oil
-eggs
-margarine
-dairy products
what is the only non food source of vitamin D ?
-sunlight
what is the disease in children that can result because of a deficiency of vitamin D? why is this disease developed?
-rickets
-a lack of vitamin D results in failure to absorb calcium and contributes to the softening of bones
-the bones bend under the weight of the body, bow legs are symptoms of rickets
what disease can result in adults due to a lack of vitamin D?
-osteomalacia which is a condition in which the bones become soft, weak and painful and fracture easily
-elderly people are more susceptible to this as they may be housebound or living in a nursing home and therefore have limited time outside
who might also be at a higher risk of having a deficiency of vitamin D ?
-individuals with intestinal problems which reduce the absorption of vitamin D e.g. coeliac disease may also become deficient
what can result with an over consumption of vitamin D
-too high an intake can result in excessive amounts of calcium being deposited in the soft tissues such as the kidneys and so excess vitamin D can result in kidney damage
what is another name for vitamin E ?
tocopherol
what is the function of vitamin E ?
-offers protection for lipids especially PUFAs against free radical damage
-protects against some types of cancer. Free radicals may also damage molecules inside the cell such as DNA and proteins, cells with damaged DNA are more prone to cancer
how does vitamin E act as an antioxidant?
-free radicals which are produced because of normal chemical reactions which can damage membranes.
-free radicals oxidize the lipids forming peroxides this can cause damage to cell membranes which can increase the risk of inflammatory such as rheumatoid arthritis
what are four food sources of vitamin E ?
-wheatgerm
-vegetable oils (vitamin E prevent rancidity by preventing oxidation of unsaturated fatty acids)
-nuts
-margarine
what are 4 symptoms of a deficiency of vitamin E ?
-slow wound healing
-lack of energy
-poor concentration
-muscle weakness
how are most likely to have a deficiency of vitamin E ?
-people who are unable to absorb and utilize vitamin E correctly however this is very rare
what happens as a result of an overconsumption of vitamin E?
-it have a low toxicity
-very high doses can lead to other fat soluble vitamins being effected e.g. prevents the absorption of vit A
-too high a consumption can also lead to a loss of appetite
what is another name for vitamin K ?
phylloquinone
what are the 3 main functions of vitamin K ?
-essential for blood clotting
-helps wounds to heal properly
-co-enzyme in the production of certain proteins that help to prevent osteoporosis
what are 4 food sources of vitamin K ?
-green leafy veg
-dairy products
-cereals
-red meat
how is vitamin K produced in the body?
-can be synthesized by gut bacteria in the large intestine
why is a deficiency of vitamin K rare?
-the vitamin is synthesized in the intestine and is also present in a normal diet
who is most likely to have a deficiency of vitamin K ?
-newborn up to 6 weeks and premature babies
-Vitamin K is routinely given to all newborn babies, this will assist with blood clotting and prevent the potentially fatal, Vitamin K deficiency Bleeding, VKDB, this is carried out by injection in hospital soon after birth
what is the effects of an overconsumption of vitamin K
-few toxic reactions to vitamin K have been identified
