Lecture 26: VITAMINS AND MINERALS Flashcards
How can we know if we get enough vitamins and minerals from the food we eat?
Clinical examination, anthropometry, biochemical tests or dietary assessment
What is involved in clinical examination?
Looking for symptoms - hair, skin, eyes, energy
What is involved in anthropometry?
Energy balance/growth - height, weight, BMI, % body fat
What is involved in biochemical tests?
Blood, urine, hair sample
What is involved in a dietary assessment?
- Measure what you eat (diary, recall, questionnaire, history)
- Convert foods into nutrients (food composition database)
- Compare with nutrient reference values
What may be sampled?
Individuals, groups or national (NZ adult nutrition survey 08/09)
What are vitamins?
Essential, individual, organic molecules
Do vitamins provide energy?
No, not when broken down but they do help in metabolism
What happens if vitamins are absent or low in diet?
Symptoms of deficiency may appear
How much vitamins are required in the diet?
Small amount (milligrams or micrograms)
What is bioavailability?
The amount absorbed and used which is different for different vitamins
What are the fat soluble vitamins?
A,D,E,K
What are the water soluble vitamins?
C, B vitamins (x8)
What vitamins do we need more of?
Water soluble because the fat soluble vitamins are stored
What is fortification?
Addition of vitamins to other food in order to increase intake
Does the NZ diet have enough of all vitamins?
Typically yes for all vitamins except vitamins D as it isn’t fortified
What are vitamins and minerals important for?
Acting as cofactors and coenzymes
What is other roles of vitamins and minerals?
Structural, antioxidants, DNA/RNA
What doe B vitamins do?
Act as coenzymes in metabolic processes which provide energy
What is niacin?
Vitamin B3 = nicotinic acid and nicotinamide
What are the sources of niacin in the diet?
Meats, liver, milk, fish, legumes, wheat
What is the function of niacin?
Nicotinamide adenine dinucleotide (NAD and NADP)
How many enzymes depend on NAD and NADP?
Over 200 to carry out oxidation and reduction reactions
What is NAD and NADP involved in?
Synthesis and breakdown of carbohydrates, lipids and amino acids
What is niacin deficiency?
Pallegra (dermatitis, diarrhoea, dementia, death)
What are minerals?
Essential, non-organic elements
Do minerals provide energy?
No
What happens if minerals are absent or low in the diet?
Symptoms of deficiency may appear
How much minerals are required in the diet?
Small amounts (milligrams or micrograms)
What mineral has high bioavailability?
Iron for use in haem group of haemoglobin
What minerals do the NZ diet lack?
Calcium (especially in women) and selenium is thought to be low because of low levels in soil but isn’t too much of a problem. All others are adequate
What is the role of minerals?
Cofactors (transfer of electrons in oxidation reduction reactions)
What are other roles of minerals?
Structural role (hydroxyapatite crystal: Ca5(PO4)3(OH)), key constituent of molecules, nerve impulse and muscle contraction, fluid and electrolyte balance
What are the roles of individual minerals?
They have multiple
What are the roles of individual trace elements?
Some have multiple roles but molybdenum, iodine and fluoride have specific
What is the role of molybdenum?
Cofactor for enzymes
What is the role of iodine?
Thyroid hormones
What is the role of fluoride?
Dental caries
What is magnesium a cofactor for?
More than 300 enzymes in a myriad of cellular processes- chelates to ATP (kinases), enzymes requiring water acts as a carrier, lipid and carbohydrate metabolism (glycolysis, glucose homeostasis, insulin action)
What are functions of magnesium?
Stabilises proteins, nucleic acids and membranes, an electrolyte, bone metabolism and remodelling, nerve impulse and muscle contraction
