write an essay, including the following: Introduction, Food sources, Physiological, Metabolic and Nutritional functions, Deficiency and excess effects, RDI and Bioavailability. The essay should
contain an introduction and a conclusion. Use sub headings as appropriate. The references must be cited in the text and listed alphabetically at the end of the essay. Use Harvard system of
referencing. References should be recent (published in the last 5 years), should be mostly from scientific journals, may include text book references (maximum of three) and internet references
(maximum of 2).
Note the following when considering the different aspects of your answer:
• Source includes information about where the vitamin is available naturally (e.g., carrots are a good source of vitamin A and beta carotene). Precursors are compounds that can be converted to
active vitamins also known as provitamins (e.g., precursor of vitamin D is 7-dehydrocholesterol)
• Chemical properties include structure of the vitamin and essential chemical properties such as stability, oxidation, antioxidants etc.
• Physiological properties include digestion, absorption, storage in the body
• Metabolic role includes the role of vitamin in various biochemical reactions in the body (e.g., component of co-enzyme in biochemical reaction)
• Deficiency symptoms relate to expression of symptoms when vitamins are deficient in the diet and or due to other physiological or biochemical complications (e.g., poor absorption due to
celiac disease).
• Diseases include development of disease conditions due to chronic deficiency of vitamins and aetiology refers to the cause of the disease (e.g., Rickets –vitamin deficiency in children)
• Toxicity relates to excess consumption and storage of vitamin in the body and its effect on the metabolic and physiological functions of the body (e.g., teratogenic- abnormal foetal
development and birth defects)
• Functions in the body include role of the vitamin (e.g., role of vitamin A in vision; role of vitamin K in blood clotting).
• Bioavailability include the rate and extent to which a vitamin is absorbed and utilised in the body
• Fortification is the addition of vitamins to a food, to correct or prevent a widespread vitamin deficiency, or to restore vitamin lost in processing
• Vitamin supplements – use of supplements, their effect, advantages, disadvantages, toxicity, safety limits, recommended intakes.
