Calcium, Iron and Potassium Why Do We Need Them?

Alongside vitamins, there are various minerals our body needs to function effectively. There are many that we must eat as part of a healthy, balanced diet, so they can help to build strong bones, support our oxygen-carrying capacity and convert food into energy. Let’s focus on calcium, iron, and potassium and why the human body needs them.


Calcium is the most abundant mineral in the body and is essential for building and maintaining strong teeth and bones, blood clotting and enabling our muscles to contract. Almost all of the calcium, around 99%, in your body is found in your teeth and bones.

If your diet lacks calcium it can cause your bones to become weak, leading to a condition called osteomalacia in adults. In children, low calcium can cause rickets which is characterised by bone deformities.

Sources of calcium

There are plenty of food sources available which are rich in calcium, including:

  • Dairy products like milk, cheese, and yoghurt
  • Soya beans
  • Broccoli
  • Okra
  • Cabbage
  • Nuts
  • Tofu
  • Sardines and pilchards if the bones are eaten, too


What is it?

Iron is an important element in the production of red blood cells. The main function of red blood cells is to carry oxygen around the body and, specifically, a protein called haemoglobin is responsible for this function. Haemoglobin gives these cells their distinctive red colour and iron is an essential part of this protein.

It is easy to become low in iron, especially if you do not eat many iron-rich foods. Women of childbearing age are at risk of low iron, particularly because of the blood loss during the menstrual cycle. Vegans are also at a greater risk of iron deficiency because plant sources of iron are absorbed poorly compared to meat sources. If the deficiency is severe, it can lead to anaemia, causing shortness of breath and extreme tiredness.

Iron-rich food sources

There are two types of iron available in the diet, haem iron and non-haem iron. Haem iron is found mostly in animal sources whereas non-haem iron is present in plant-based foods.

Foods rich in iron include:

  • Beef liver
  • Beef
  • Chicken
  • Oysters
  • Sardines
  • Spinach
  • Green peas
  • Cashew nuts
  • Lentils
  • Fortified cereals and bread

Symptoms of iron deficiency anaemia:

  • Tiredness
  • Pale skin
  • Heart palpitations
  • Shortness of breath


What is it?

Potassium is an essential mineral which is also an electrolyte. That means it helps to conduct electrical impulses in the body and helps to regulate:

  • Water balance
  • Blood pressure
  • Nerve impulses
  • Muscle contractions
  • pH

Your kidneys regulate potassium levels and remove large amounts by excreting it via urine. High levels of potassium can lead to health problems so it’s important to eat a balanced diet.

Potassium-rich food sources

  • bananas
  • cantaloupe and honeydew melons
  • apricots
  • sweet potatoes
  • mushrooms
  • cooked spinach
  • cucumbers


Calcium, iron, and potassium are examples of essential minerals that the human body needs to function efficiently. Low levels of any of these can lead to adverse health issues. However, by eating a healthy, balanced diet should ensure you get all of the essential vitamins and minerals the body needs.


NHS. (2017). Calcium. Available at:

NHS. (2017). Iron. Available at:

NHS. (2018). Iron Deficiency Anaemia. Available at:

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