vitamins

Function:

• essential for upkeep of nerves
• aids the oxidation of nutrients + releases energy from the body (a complx compound containing thiamin acts as a co-enzyme for two reaactions in the sequence of breaking down glucose)

Sources:

• cereal grains
• white flour (added by law)
• meat (bacon, ham + pork)
• potatoes

Deficiencies:

• glucose is only partially oxidised - pyruvic acid builds up in the bloods resulting in muscle weakness, heart palptations + degeneration of nerves
• Berberi:high alcohol intake requirements
  • wet beriberi - suffer from oedema (fluid in tissues) which can cause serious brain damage + neurological changes.  eventually a confusional state leading to wernicke-korsakoff syndrome
  • dry beriberi - excessive fatigue, inability to walk far distances, breathlessness, mood changes

Excess:

• intake above 3g/day is toxic

Bioavailabilty + absorption:

• absorption inhibited by alcohol + presence of thiaminases, found in some fish
• decomposes in high temperatures

Function:

• Forms part of the enzyme system involved in oxidation of glucose + release energy from body cells
• Essential for upkeep of tissues

Sources

• cheese
• liver
• kidney
• eggs

Deficiences

• affects mouth, eyes + skin
• Anaemia

Excess:

• excessives intakes are poorly absorbed

Bioavailability + absorption:

• sensitive to light
• absorption occurs readily from the small intestine
• overall loss from cooking is small

Function:

• forms part of the enzyme system in the oxidation of glucose + releases energy
• prevents pellegra

Sources:

• Yeast
• milk
• fish
• pulse vegetables
• cereals
• white flour (added by law)

Deficiencies:

• pellegra - symptoms: diarrhoea, dermatitis + dementia.  gastrointestinal tract may be inflammed causing heartburn, indegestion + abdominal pain

Excess:

• high doses may cause flushing + fall in blood pressure

Bioavailability + absorption:

• alcohol inhibits metabolism of niacin
• sleeping pills + food processing destroy it

Function:

• Aids many enzyme systems especailly protein synthesis.  involved in the metabolism of amino acids
• benefit women taking oral contraceptives or suffering from pre-menstrual syndrome
• plays a role in fat metabolism + glycogen metabolism (in muscles)
• factor to reduce homocysteine levels

Sources:

• Liver
• Whole milk
• Meat
• Peanuts
• Bananas
• Salmon

Deficiencies:

• Anaemia
• Smooth tongue
• Dermatitis
• Nervous/muscular system signs - headaches, fatigue, numbness + irritability

Excess:

• large doses can be harmful (>50mg/day)
  

Absorption + bioavailabilty:

• elderly have poorer rates of absorption + metabolism

Function:

• involved in more than one enzyme system + needed together with folic acid for red blood cell formation
• needed for the metabolism of fatty acids
• needed to release folate from its methyl form

Sources:

• foods of animal origin
• liver
• milk
• meat
• fish
• eggs
• added to breakfast cereals

Deficencies:

• causes pernicious anaemia
• failure of cell division - main sign is meglobalstic anaemia
• involves damage of nerve fibres with gradual loss of sensory and motor function
• the modest redcation will cause an elevation of plamsa homocysteine - may be a risk factor of CHD + dementia

Excess:

• no harmful effects

Absorption + bioavailabilty

• excess amounts of vit.c can interfere with availabilty

Function:

• used in megaloblastic anaemia treatment
• important nutrient at conception
• reduces risk of neural tube defects in unborn child - taken at least 12 weeks before and after conception

Sources:

• Liver
• Green leafy vegetables
• nuts
• pulse vegetables

Deficiencies:

• affects rapdily dividing cells (red blood cells)
• red blood cell formation results in megaloblastic anaemia - cells are immature + larger than normal
• white blood cell formation is also affected  - depression in immune system
• low intake at conception + early pregnancy may be linked with neural tube defects (spina bifida) in babies

Excess:

• may mask B12 deficiency + development of neuropathy

Absorption + bioavailabilty:

• readily lost during most cooking processes + destroyed by heat
• smoking interferes with absorption
• commonly used drugs (aspirin + contraceptive pill) interfere with metabolism

Function:

• antioxidant - reacts with free radicals + deactivates them before damage to lipids + proteins
• aids iron absorption from intestine by reeducing ferric iron to ferrous form
• formation of collagen - main protein of connective tissue
• aids wound healing
• cofactor for a number of hydroxylation reactions
• promotes immune system

Sources:

• fresh fruit + veg - citrus

Deficiencies:

• cannot be stored in body so regular intake is essential
• can cause scurvy - bruising, gums become black + spongy, anaemia due to poor iron absorption

Excess:

• higher intake is associated with lower disease risk

Absorption+ bioavailability:

• destruction is accelerated by exposure to light, alkali, oxygen, enzymes + heat
• destroyed readily during cooking
• readily oxidised