Micronutrients

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Micronutrients
Extension
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Learning objectives

• To understand the importance of micronutrients.
• To recognise the difference between water soluble
  and fat soluble vitamins, major minerals and
  trace minerals.
• To know the functions and sources of the
  micronutrients.
• To know the problems caused by malnutrition.
• To understand some interactions between nutrients.

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Micronutrients

• Micronutrients are needed in much smaller
  amounts than the macronutrients.
• In general vitamins are needed to regulate the
  maintenance and growth of the body, and to
  control metabolic reactions in cells.
• Most vitamins are provided to the body by the
  diet, however, the body can make vitamin D,
  vitamin K and niacin.

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Vitamin A (retinol, carotene)

• Vitamin A is fat soluble vitamin needed for the
  normal structure and functioning of the skin and
  body linings, e.g. in the lungs.
• This vitamin also helps with vision in dim
  light, as well a keeping the immune system
  healthy.

Found in two forms, retinol in foods from animal
sources and carotenoids from plant
sources. Vitamin A retinol is found in liver,
whole milk, Vitamin A carotenoids are found in
dark green leafy vegetables, carrots and orange
coloured fruits.
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Too much or too little?

• Deficiency leads to poor vision in dim light or
  night blindness. In severe deficiency it can lead
  to total blindness.
• Vitamin A is stored in the liver and too much
  vitamin A can be toxic.
• Consuming too much vitamin A whilst being
  pregnant has been linked with birth defects.

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Vitamin D (Cholecalciferol)

• Vitamin D is needed for the absorption of
  calcium and phosphorous from foods, to keep bones
  healthy.
• Recent research also suggests that vitamin D
  enhances immune function and improves muscle
  strength.
• Vitamin D is found in the diet as well as being
  made by the action of ultra violet rays on the
  skin.

Vitamin D occurs naturally in some animal
products, including fish liver oils, oily fish,
egg yolk, and butter. Cereals, margarine and low
fat spreads are also fortified with vitamin D.
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Vitamin D deficiency

• Deficiency in vitamin D leads to rickets and the
  formation of soft bones. Bones in the legs may
  bend due to body weight.
• Osteomalacia may also occur in the older
  adults, as pain and muscular weakness.
• Vitamin D can be stored by the body and so too
  much will result in the body absorbing too much
  calcium.
• Young children, housebound older adults, and
  people who practice religions where their skin
  must be covered, may be at risk of deficiency.

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Vitamin E (Tocopherol)

• Vitamin E is a group of similar molecules with
  common properties and functions.
• Vitamin E acts as an antioxidant and protects
  cells in the body against damage.

Vitamin E is mainly found in vegetable oils,
nuts, seeds and wheat germ.
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Deficiency and excess of vitamin E

• A deficiency in this vitamin is rare because it
  is so widely available in the diet.
• In very rare cases neurological disabilities
  such as lost reflexes have developed.
• There are no recorded adverse reactions to large
  doses of vitamin E.

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Vitamin K

• Vitamin K is needed for normal clotting of blood
  and is
• also required for normal bone structure.
• Infants are given vitamin K at birth.
• Vitamin K is also produced by the bacteria in the
  gut.

Vitamin K is found in green leafy vegetables e.g.
broccoli, lettuce, cabbage, spinach and meat and
dairy products.
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Too much or too little?

• Deficiency of vitamin K is rare in adults, but
  is sometimes seen in new born babies.

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Thiamin (B1)

• Thiamin is needed for the release of energy from
  carbohydrate. It is also involved in the nervous
  sytem and the heart.
• Thiamin cannot be made or stored in the body, so
  it is necessary to obtain this from the diet.

Thiamin is mainly found in whole grains, nuts,
meat (especially pork), fruit and vegetables and
fortified cereals.
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Thiamin deficiency

• Thiamin deficiency can lead to the development
  of the condition called Beri-beri. This leads to
  symptoms such as fatigue, weakness of the legs
  and anorexia.
• Alcohol can prevent absorption of this vitamin
  causing Wernick-Korsakoff syndrome (a
  neurological disorder characterised by numb
  limbs, confusion, vision changes and lack of
  co-ordination).

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Riboflavin (B2)

• Riboflavin is needed for normal growth and the
  release of energy from carbohydrate, protein and
  fat.
• It is also involved in the transport and
  metabolism of iron in the body and is needed for
  the normal structure and function of skin and
  body linings.

Riboflavin is found in milk, eggs, rice,
fortified breakfast cereals, liver, legumes,
mushrooms and green vegetables.
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Too much or too little?

• The tongue, lips and skin become affected when
  the body is low in riboflavin.
• Over nutrition of this vitamin is rare.

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Niacin (B3)

• Niacin is important for releasing energy from
  food, and is important for the normal structure
  of the skin and body linings.
• Niacin also maintains the health of the nervous
  and digestive system.

Niacin can be found in meat, wheat and maize
flour, eggs, dairy products and yeast.
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Too much or too little?

• A deficiency in niacin can lead to pellagra
  including the development of
• dermatitis
• dementia
• diarrhoea.
• Over nutrition is rare.

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Vitamin B12

• Vitamin B12 is needed for the formation of red
  blood
• cells and synthesising fatty acids in the myelin
  of nerve
• tissue.
• Vitamin B12 also helps to release energy from
  food.

Vitamin B12 is found in meat, fish, cheese, eggs,
yeasts extract and fortified breakfast cereals.
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Deficiency of vitamin B12

• Deficiency of vitamin B12 can lead to
  megaloblastic anaemia.
• It can also lead to some neurological problems.
• Vegetarians and vegans are often at risk of
  malnutrition.

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Folate (Folic acid)

• Folate describes a group of molecules with
  common properties and functions. Folic acid is
  the most stable form of folate.
• It is important for the formation of healthy red
  blood cells. It is also needed for the nervous
  system and specifically for the development of
  the nervous system in unborn babies. It can
  reduce the risk of neural tube defects in a
  foetus, e.g. spina bifida.

Good sources of folate include yeast extract,
green leafy vegetables and fortified cereals.
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Deficiency of folate

• Deficiency of folate can lead to megaloblastic
  anaemia where the red blood cells become
  enlarged.
• Women planning on becoming pregnant are
  recommended to increase their intake of folate to
  prevent neural tube defects in the foetus. It is
  recommended that these women take a supplement
  because it is difficult to achieve such high
  levels of folate through diet alone.

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Vitamin C (Ascorbic acid)

• Ascorbic acid is needed for the normal structure
  and function of body tissues, e.g. collagen.
• It also acts as an antioxidant that protects the
  body from free radicals.

Sources of ascorbic acid include fresh fruits,
especially citrus fruits and berries, green
vegetables, peppers and tomatoes. Vitamin C is
also found in potatoes (especially in new
potatoes).
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Too much or too little?

• Scurvy can result from lack of vitamin C. It
  tends to occur in infants and the older adults.
• Scurvy leads to spots on the skin, bleeding gums
  and loose or loss of teeth.
• Over nutrition of ascorbic acid is rare.

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Minerals

• Minerals are inorganic substances needed by the
  body for many different functions.
• These are needed in different amounts in large
  (major minerals) and small (trace minerals)
  amounts.

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Calcium (Ca)

• Calcium is important for the formation and
  maintenance of strong bones and teeth, as well as
  the functioning of nervous and muscles.
• It is also involved in blood clotting.

Sources of calcium can be found in milk, cheese
and other dairy products, green leafy vegetables,
soft edible bones in fish, calcium enriched soya
bean products and bread.
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Too much or too little?

• Rickets (develops in children) and Osteomalcacia
  (develops in adults) may both develop, but this
  will not be due to calcium deficiency alone.
• Tetany may also develop, where muscles contract
  rigidly.
• Too much calcium can lead to deposits in the
  body, eventually causing death.

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Iron (Fe)

• Iron is needed for needed for the formation of
  haemoglobin in red blood cells which transport
  oxygen around the body.
• It is also required for normal metabolism and
  for removing unwanted substances from the body.
• The immune system also requires iron.

Haem iron is present in animal sources (including
eggs) in the form of haemoglobin. Non haem iron
is present in plant sources such as beans, nuts,
dried fruits, wholegrains, soya bean flour and
dark green leafy vegetables.
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Too much or too little?

• A lack of iron will lead to anaemia. The
• symptoms of this are
• feeling of tiredness
• lacking in energy
• general weakness
• poor concentration.
• Too much iron in the diet will lead to
  constipation,
• nausea and vomiting.

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Phosphorus (P)

• Phosphorus is essential for the structure bones
  and teeth, for the structure of cell membranes
  and for energy metabolism.

Phosphorus is found in all foods.
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Potassium (K)

• Potassium is found in body fluids and is
  essential for water and electrolyte balance and
  normal functioning of cells, including nerves.

Potassium is present in all foods, but found
richly in fruit (dried fruits, bananas, berry
fruits), leafy green vegetables (e.g. broccoli
and spinach) meat, nuts, seeds and pulses.
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Sodium (Na)

• Sodium helps to regulate body water content and
  electrolyte balance, and is involved in energy
  utilisation and nerve function.

Sodium is present in very small amounts in raw
foods. It is often added as salt during
processing, preparation, preservation and
serving. High salt processed foods are bacon,
cheese, yeast extract and smoked fish.
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Too much or too little?

• Consuming too much sodium can lead to hardening
  of the artery walls and high blood pressure or
  hypertension.
• Consuming too little sodium can be caused by
  excessive vomiting, diarrhoea and is accompanied
  by a loss of water from the body.

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Fluoride (F)

• Fluoride helps with the formation of strong
  teeth and protects against dental decay (caries).
• This is a trace element, therefore only a small
  amount of this mineral is required for good
  health.

Fluoride can be found in drinking water and in
small amounts in tea and saltwater fish. Some
areas choose to have fluoride added to the
drinking water.
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Too much or too little?

• Excess fluoride in the diet can lead to mottling
  or discolouration of teeth.

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Nutrient interactions

• Some nutrients work together in the body
  completing different functions.
• For example
• the vitamins A,C and E
• calcium phosphorus and fluoride
• iron and vitamin C
• carbohydrates and B vitamins.

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Anti-oxidants

• Vitamins A, C and E all create anti-oxidant
  activities in the body. These work on protecting
  the body from free radicals.
• Free radicals are atoms or groups of atoms with
  an unpaired or spare electron. Cells within the
  body may function poorly or cease to function as
  a result of free radicals acting on the DNA
  structure of cells.

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Calcium, phosphorus and fluoride

• Together, these nutrients help teeth and bones
  to harden.
• Vitamin D controls the amount of calcium
  available. Less vitamin D means less available
  calcium.

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Iron and Vitamin C

• Vitamin C will increase the bodys absorption of
  non haem iron (non meat sources of iron).
• This is particularly important for vegetarians
  and vegans.

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Carbohydrates and Vitamins B

• For the body to use the energy contained in
  carbohydrates there are two B vitamins that help
  in the production of energy.
• These are
• riboflavin
• thiamin.

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Review of the learning objectives

• To understand the importance of micronutrients.
• To recognise the difference between water soluble
  and fat soluble vitamins, major minerals and
  trace minerals.
• To know the functions and sources of the
  micronutrients.
• To know the problems caused by malnutrition.
• To understand some interactions between nutrients.

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For more information visit www.nutrition.org.u
k www.foodafactoflife.org.uk