Minerals (AQA GCSE Food Preparation & Nutrition): Revision Note

Minerals

• In our body, a mineral is a naturally occurring element that helps with a wide variety of functions

• As a micronutrient, minerals only need to be consumed in small amounts in the diet to maintain a healthy level

• Some examples of the main minerals consumed in our diet are:

  • calcium

  • iron

  • sodium (salt)

  • fluoride

  • iodine

  • phosphorus

Calcium

• The main function of calcium in the body is to aid with increasing strength in our bones and teeth

  • Other roles include helping to control muscle contractions and aiding with blood clotting

• Dairy products such as milk, cheese, and yoghurt are rich in calcium. It can also be found in:

  • nuts, soya beans and tofu

  • oily fish

  • green, leafy vegetables

  • bread and fortified cereals

• Having a deficiency of calcium in the diet can lead to weak, brittle bones that are prone to breaking

  • rickets is a condition where bone development in children is stunted and can lead to bone deformities during development

  • osteoporosis tends to happen more in older people because it involves bones weakening over time. This is a common condition in elderly people but can occur at any age

• Consuming an excess of calcium can cause digestive issues like stomach pain and diarrhoea

• Dietary reference values state that an average adult should consume 700 milligrams (mg) of calcium per day

  • Young children with smaller bodies do not need as much - around 450-550 mg per day

  • teenagers during adolescence should consume more calcium to account for increased bone growth - around 1,000-800 mg per day with differences between males and females

Examples of calcium-rich foods

Myriams-Fotos, via Pixabay (opens in a new tab)

Iron

• Iron is an important mineral found in red blood cells

• The iron binds to the oxygen when it enters the body in the lungs and carries it around the body to respiring tissues

• Red meat, such as beef, is very rich in iron and this iron can be easily absorbed into the blood. Other sources of iron include:

  • beans and nuts

  • dried fruit and green, leafy vegetables such as spinach

  • liver and eggs

  • fortified cereals and bread

• Non-meat products contain a form of iron that is more difficult to absorb called non-haem iron

  • consuming vitamin C makes it easier to absorb iron during digestion

• Vegans and vegetarians must pay careful attention to their diets to ensure they do not become deficient in iron

• Anaemia is a condition caused by having a deficiency of iron in the diet

  • iron carries oxygen to respiring cells that are releasing energy. Without iron, there is less oxygen being delivered to the cells and less energy available to the body

  • this can result in tiredness and dizziness

  • reduced respiration and lack of available energy can also result in an increased heart rate and shortness of breath during exercise

• Consuming an excess amount of iron can lead to digestive issues like constipation, nausea and stomach pain

• Dietary reference values for iron vary between adult males and females because females lose blood during menstruation so new red blood cells containing iron need to be produced to replace those that are lost

  • females require around 14.8 mg of iron per day, whereas males only require 8.7 mg of iron per day

  • adolescent males who are growing rapidly require slightly more - around 11.3 mg per day

  • post-menopausal females who no longer menstruate require the same quantity of iron as males

Examples of an iron-rich food

Alpha from Melbourne, Australia, CC BY-SA 2.0, via Wikimedia Commons (opens in a new tab)

Sodium (salt)

• Sodium is a mineral found in table salt

• Salt in the blood helps to regulate the water balance between the cells and the blood (due to osmosis)

  • sodium also plays a role in the passage of nerve impulses, muscle contraction, and respiration

• Salt is found in many foods, including:

  • bacon and cheese

  • processed foods like tinned foods and ready meals

  • savoury snacks like salted nuts and crisps

• Salt is often found in high levels in many foods as it is used as a common seasoning to increase flavour

• Consuming too much salt can be detrimental to health. It can increase blood pressure, which in turn increases the risk of heart attacks and strokes

• A deficiency of sodium can lead to muscle cramps and in extreme cases can cause kidney failure, liver disease and heart failure

• Dietary reference values for sodium state that adults should not consume more than 6 grams of salt per day

Fluoride

• Fluoride is an important mineral to prevent tooth decay and improve the strength of the enamel of the teeth - this is why it is often found in toothpaste and mouthwash products, as well as in food

  • it can also be used to increase bone strength

• Fluoride is often artificially added to tap water and this can vary in quantity between regions, however, it can also be found in natural mineral water

  • it can also be found in bony fish like sardines, seafood and in tea

• A deficiency of fluoride can lead to increased risk of tooth decay

• Excess fluoride in the diet can cause staining and 'pitting' in tooth enamel and in extreme cases can lead to a condition called skeletal fluorosis that causes bone deformities

• Dietary reference values for fluoride state that adults should consume around 3-4 mg of fluoride per day

Tap water contains fluoride image

Olga Lioncat, via Pexels (opens in a new tab)

Iodine

• Iodine is a mineral used to create a hormone called thyroxine, which helps to regulate the rate of metabolism in the body

• Iodine can be found in red meat, fish caught from the ocean and saltwater shellfish, cereals and grains, as well as products produced from those grains, such as bread

• A deficiency of iodine is rare. If it does occur it can lead to reduced quantities of thyroxine, which can lead to development problems in children and reduced IQ

  • iodine deficiency can also lead to a swollen thyroid, causing a lump to appear in the front of the neck called a goitre

• Excess iodine can increase quantities of thyroxine in the blood, leading to weight gain

• Dietary reference values for iodine are that adults should consume around 140 micrograms (mcg) per day, with children consuming slightly less

Phosphorus

• Similarly to calcium, phosphorus is also found in bones and teeth and helps to improve strength

  • it also helps us to release the energy stored in our food

• Phosphorus can be found in many foods including red meat, dairy products, fish, bread, oats, beans and lentils

• A deficiency of phosphorus can lead to bone pain, fragile bones, stiff joints and fatigue

• Excess phosphorus can lead to diarrhoea and stomach pain and can increase the risk of bone fractures

• Dietary reference values for phosphorus are that adults need around 550 mg of phosphorus per day