MICRONUTRIENTS: VITAMINS & MINERALS
Core Topic 1: Fundamentals of Human
Nutrition
Micronutrients
Comprise of Vitamins and MineralsDo not provide energy, but are required to fulfil
functions in the body and promote good healthThe body can only synthesise vitamin DRequired in much smaller amounts than
macronutrients RDI is measured in milligrams (mg) or micrograms (ug)
1000 milligrams (mg) = 1 gram (g) 1000000 micrograms (μg) = 1 gram (g)
Deficiency diseases occur if there is a lack in the diet.
Vitamins
Identified in the 20th century Originally named alphabetically, but now
identified as chemical names. For example, Vitamin C is Ascorbic Acid.
Organic compounds (made by plants or animals).
Vitamins fall into two categories: Fat soluble Water soluble
Fat soluble Vitamins (A, D, E and K)
Fat soluble vitamins dissolve in fatA deficiency takes a long time to develop, because the
body is able to store significant amounts in the liver and adipose tissue.
Activity 1: Pairs who researched fat soluble vitamins will present their findings to two large groups. You must discuss:- The role of fat soluble vitamins, common food sources, effects of deficiency and excess and RDI
Water Soluble Vitamins (B group and C)
Water soluble vitamins dissolve in water and in turn they are easily transported away (urine, faeces and perspiration)
Not stored in the body; thus, must be replenished regularly.
Easily destroyed by light, oxygen, poor storage, food preparation and cooking.
Activity 2: Pairs who researched water soluble vitamins will present their findings to two large groups. You must discuss:- The role of fat soluble vitamins, common food sources, effects of deficiency and excess and RDI
Minerals
Inorganic elements derive from the soil and water.Minerals play a role in many chemical reactions
within the body and form the structure of hormones, enzymes, vitamins and bones.
Some minerals are required in large amounts: Calcium, Phosphorus, Iron, Sodium, Potassium,
Magnesium and Sulfur. Other minerals are required in smaller amounts
and are referred to as trace minerals: Iodine, Zinc, Copper, Cobalt, Manganese, Fluoride and
Selenium.
Calcium
The body requires calcium for: Strong bones and teeth with
help from phosphorus, vitamin C and Vitamin D
Normal blood clotting The transmission of
impulses along nerves Contractions and relaxation
of muscles
Calcium
Common Food Sources include: Milk and milk products Tofu Almonds Sesame seeds Most breads Dark green vegetables
including broccoli and bok choyseaweed
Calcium
Our bodies do not absorb calcium well if large amounts of protein, sodium or caffeine are consumed
The calcium absorbed into the intestine from food must be the same as the amount lost in urine, faeces and perspiration.
If sufficient calcium is not obtained from the diet, skeletal calcium will be reabsorbed causing bone loss and in the long term osteoporosis.
Only about 20% of the dietary calcium consumed is absorbed by the body.
NRVs for CalciumAge EAR
mg/per day
RDI mg/per
dayBoys/Girls14-18yrsMen19-50yrs>50yrsWomen19-50yrs>50yrsPregnancy & Lactation
1,050
8401,100
8401,100
840
1300
1,0001,300
1,0001,300
1,000
Iron
Iron is required by the body to: Form a part of haemoglobin,
which carries oxygen around the body.
Form a part of the myoglobin in the muscles, which makes the oxygen available for muscle contraction.
Essential part of some enzymes involved in the oxidation and utilisation of energy in cells.
Iron
Haem Iron Found in animal foods such as beef, chicken, fish
and offal meats including liver, brain and kidney. Non-Haem Iron
Derives from plant foods including beans and lentils.
The body absorbs between 2%-8% of the iron from plant sources.
Good vegetarian sources of non-haem iron include iron-fortified breakfast cereals, flours and grains.
Iron
When foods high in Vitamin C (citrus fruits, broccoli, pumpkin, cabbage) are consumed, the absorption rate of iron increases.
Meat will increase the absorption of Iron Soy proteins, Calcium and Phosphorus reduce the
absorption of Non-Haem Iron. Tea, coffee and wine reduce iron absorption by
binding the iron and carrying out of the body. Vitamin A helps release iron; thus, insufficient
Vitamin A may lead to an iron deficiency.
Iron
The most common deficiency across the world.
Deficiency will lead to decreased production of red blood cells; thus, leading to anaemia, chronic tiredness, irritability and decreased capacity to exercise.Q1: Who is at risk of an iron deficiency? Vegetarians Athletes People who eat small amounts of food
NRVs for SodiumAge EAR
mg/per day
RDI mg/per
dayBoys 14-18yrs
Girls 14-18yrsMen Women19-50yrs>50yrsPregnancy Lactation
8
8
6
8522
6.5
11
15
8
188
27
9
Sodium
Sodium controls fluids that enter and leave the body cells and help to control muscle contraction and relaxation.
Common food sources include: Salt Processed foods Snack foods
Sodium
Excess sodium intake may cause: High blood pressure (Hypertension) Fluid retention (Oedema) Kidney and heart failure Reduced absorption of calcium
Deficiency causes: Muscle cramps, vomiting and apathy Not common in Australia but high levels of physical
activity in intense heat can result in deficiency in the short term
RDI Less than 2300mg per day for teenagers and adults (2.3g)
Water
Water is essential to healthWater is required by the body to:
Transports nutrients to all of the cells Excretes waste Maintain the sodium and potassium balance Water acts as a shock absorber for your joints Lubricate parts in the body
Saliva allows food to slip easily through the gut Saliva also keeps your mouth moist and rinses your teeth;
thus, reducing tooth decay. Control your body temperature
Perspiration, or sweat can evaporate when it absorbs enough body heat; thus, keeping the body cool.
Water
Sources of water include: Meat contains 50%-60% Vegetables and fruit contain 95%
How much water? 6-8 glasses of water per day Hot weather or physical activities
increases the fluid requirements by the body.
Water is lost through: Sweating Breathing Faeces Urine
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