Importance of minerals: Iron and calcium

Although they are required in small portions, minerals form an extremely important part of a nutritious diet. In this article, we shine a spotlight on iron and calcium.

Minerals as a food group

Minerals are inorganic elements present in the soil and water. These are absorbed by plants and enter our bodies when we consume these plants. Similarly, animals also obtain minerals from eating plants.

Minerals as a food are classified under micro-nutrients along with vitamins. Essentially we need a small quantity, hence they are also known as trace elements. Minerals cannot be created by the human body and nutritious food is the main source of minerals. Therefore, it’s imperative that we consume a balanced diet from which we get all the different types of minerals. Dietary supplements like multi-vitamin pills also provide minerals.

Importance of minerals

Although minerals are required only in small quantities, they play a very important role in the healthy functioning of the body. Minerals are necessary as they:

  • Are needed for growth and development
  • Are important for absorption of other nutrients
  • Boost immunity. Zinc is a good example of this
  • Help in bone, teeth and kidney health, among others
  • Regulate vital body functions

The essential minerals

The most important minerals needed by the body are listed below:

  1. Iron
  2. Calcium
  3. Zinc
  4. Potassium
  5. Magnesium
  6. Selenium
  7. Chromium
  8. Phosphorous
  9. Sodium
  10. Copper
  11. Iodine
  12. Fluorine


Iron is a very important micronutrient in our nutrition. Adults have 3-4 grams of iron in the body, most of which is circulating in the blood, while the rest is stored in the liver, spleen and kidney for emergencies. Haemoglobin, which is a constituent of red blood cells, contains 3.34 mg per gram of haemoglobin.

Functions of iron: Iron is required for brain development and function, formation of haemoglobin, muscle strength and regulation of body temperature. At a cellular level, iron acts as an oxygen carrier, transporting oxygen to all the cells. Lack of iron affects the immune system, whereas excessive iron can cause nausea, increased risk of infections and liver damage.

Sources of iron: Non-vegetarian sources of iron like meat, poultry, liver and fish are rich in haem-iron which is better absorbed than non-haem iron. The latter is present in vegetarian sources like cereals, green leafy vegetables, jaggery, nuts, oilseeds, dry fruits and legumes. The absorption of vegetarian sources is limited due to other substances which interfere with iron absorption. Certain foods like milk, eggs and tea also inhibit iron absorption.

Deficiency of iron: Iron deficiency anaemia is a major public health problem in a developing country like India.


Another important element for the human body is calcium. Adults have 1200 grams of calcium on an average, most of which is found in the bones.

Functions of calcium: Calcium is responsible for the formation of bones and teeth, functioning of the heart and muscle contraction. Low calcium and vitamin D levels lead to rickets in children and osteomalacia in adults.

Sources of calcium: The best available sources of calcium are milk and milk products (curd, buttermilk, cheese and cottage cheese), eggs and fish. Other cheap sources are green leafy vegetables, cereals and millets, although absorption of calcium from these foods is poor due to other compounds. Fruits like custard apple also contain this important micronutrient.

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