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