Vitamins Flashcards

Question

What is the DRV for Vitamin E?

Answer 1

4 mg a day for men 3 mg a day for women

Answer 2

Vitamin K, the generic name for a family of compounds with a common chemical structure of 2-methyl-1,4-naphthoquinone, is a fat-soluble vitamin that is naturally present in some foods and is available as a dietary supplement Includes phylloquinone (vitamin K1) and a series of menaquinones (vitamin K2). Menaquinones have unsaturated isoprenyl side chains and are designated as MK-4 through MK-13, based on the length of their side chain. Almost all menaquinones, particularly the long-chain menaquinones, are also produced by bacteria in the human gut

Answer 3

Vitamin K functions as a coenzyme for vitamin K-dependent carboxylase, an enzyme required for the synthesis of proteins involved in haemostasis (blood clotting) and bone metabolism and other diverse physiological functions.

Answer 4

Like dietary lipids ingested vitamin K is incorporated into mixed micelles via the action of bile and pancreatic enzymes, and it is absorbed by enterocytes of the small intestine. From there, vitamin K is incorporated into chylomicrons, secreted into the lymphatic capillaries, transported to the liver, and repackaged into very low-density lipoprotein

Answer 5

Compared to the other fat-soluble vitamins, very small amounts of vitamin K circulate in the blood. Vitamin K is rapidly metabolised and excreted. The body retains about 30-40% per oral physiological dose. About 20% is excreted in the urine and 40% to 50% in the faeces via bile.

Answer 6

Bleeding and haemorrhage due to significant increases in prothrombin time (blood clotting). Because vitamin K is required for the carboxylation of osteocalcin in bone, vitamin K deficiency could also reduce bone mineralisation and contribute to osteoporosis. Vitamin K deficiency can occur during the first few weeks of infancy due to low placental transfer of phylloquinone, low clotting factor levels, and low vitamin K content of breast milk.

Answer 7

Tomatoes Died fruits - apricots, raisins Nuts - chestnuts, walnuts, almonds Broccolis Spinach Courgette

Answer 8

Adults needs approximately 1 microgram a day of Vitamin K for each Kg of they body weight

Answer 9

Not stored (apart from B12) Enter the body freely, absorbed directly into blood stream, dissolves in intra and extra cellular fluids and is therefore transported in free form Higher turnover in the body with little storage Excrete it easily in urine, generally not harmful but in high doses can be Mainly coenzymes in energy metabolism Prone to leaching from food, more sensitive to heat

Answer 10

Vitamin B: Function: Enzyme co-factor Deficiency: Varies depending on the B vitamin Vitamin C: Function: Collagen synthesis, Enzyme co-factors, Antioxidant Deficiency: Scurvy, Impaired wound healing, Subcutaneous haemorrhage

Answer 11

Ascorbic acid (L-ascorbic acid is a white, odourless and stable solid, slightly soluble in ethanol, insoluble in organic solvents and soluble in water) It can be synthesised in plants and most animal species From D-glucose and D-galactose But cannot be synthesised by humans Or primates, guinea pigs, fruit eating bats, certain birds and many fish since they lack the final enzyme in the synthesis of the Vitamin C

Answer 12

Structure Potent reducing agent Antioxidant agent Acidic forming Exists in two isomers (mirror – image isomers L and D)

Answer 13

Plays a role in the regeneration of vitamin E Enhances iron absorption Vitamin C is required for collagen synthesis Vitamin C is a cofactor for the enzymes (coenzyme) in the hydroxylation of proline and lysine in collagen synthesis Hydroxylated proline and lysine are essential to produce normal collagen Hydroxyproline forms the backbone for the triple helical structure of collagen molecules (tropocollagen) Hydroxylysine is required for the cross linking of collagen (which increases the strength and elasticity of collagen)

Answer 14

Readily absorbed in small intestine Energy dependant absorption (ATP) 70 to 90% of average intake absorbed (30-200mg) Absorption decreased to 20% with a single 5g dose and to 6% with a single 12g dose Bioavailability from food and supplements is similar Transported unbound in plasma High concentrations found in intracellular fluid Maintained by ATP driven uptake mechanism

Answer 15

Studies show that the body is saturated with vitamin C at 20mg/kg body weight on average Normal plasma levels of vitamin range from 4 -15mg per litre This level can be maintained with a daily intake of between 60 and 100mg vitamin C by most people At levels greater than 200mg/day virtually all excess vitamin C is excreted in urine within 24 hours

Answer 16

Vitamin C is not stored in the body for long When vitamin C free/low diet consumed there is a 3% loss per day (approximately) On a usual intake about 50% of vitamin C is excreted in the urine as oxalic acid Ascorbic acid, dehydroascorbic acid and other metabolites make up the remainder When intake greatly exceeds requirement most of excess treated as unmetabolised vitamin C

Answer 17

Scurvy Impaired wound healing Loss of teeth die to damaged gums (bleeding gums) Subcutaneous haemorrhage (bleeding from capillaries) Failure or proper cartilage and bone formation

Answer 18

Fruits - oranges, mango, lemon, strawberries Vegetables - onion. spinach, coriander, tomato, parsley

Answer 19

9–13 years: Males: 45 mg Females:45 mg 14–18 years Males:75 mg Females: 65 mg 19+ years Males: 90 mg Females: 75 mg