A Quick Guide to Minerals in the Diet: Mineral Salts From The Soil Provide Us With Essential Nutrients

A Quick Guide to Minerals in the Diet: Mineral Salts From The Soil Provide Us With Essential Nutrients

The mineral elements that occur most abundantly in food are carbon, hydrogen, oxygen and nitrogen, and these find their way into carbohydrates, fats and proteins, with only the latter containing nitrogen.

Phosphorus is also present in various forms in nucleic acids and ATP and sulphur is found in some proteins. All these are classed as macronutrients, but there are at least another 25 micronutrients present in foods, often in minute amounts as trace elements. These find their way into our bodies, but not all nutrients (e.g. iron & calcium) are readily absorbed and only about 16 micronutrients have been shown to be essential to life. Some are present merely as contaminants (e.g. mercury, lead), while others are present (e.g. tin, aluminium) but have uncertain biological roles (1).

When a body is examined at post mortem, it is possible to analyse the tissues for chemical elements and the list of ingredients looks something like this:

  • oxygen 65%
  • carbon 18%
  • hydrogen 10%
  • nitrogen 3%
  • calcium 1.5%
  • phosphorus 1%
  • potassium 0.35%
  • sulphur 0.25%
  • sodium 0.15%
  • chlorine 0.15%
  • magnesium 0.05%
  • iron 0.004%
  • iodine 0.00004%
  • traces of copper, manganese, zinc, fluorine, molybdenum, silicon, boron, cobalt, chromium, nickel, selenium, strontium and vanadium,
  • Other elements are present, but only as contaminants – including mercury, aluminium, cadmium, lead and tin, all of which are potentially toxic to the body.

Imagine a well built (but otherwise healthy) person weighing 100kg or 15.7 stone, then the above percentages can be read as weights in kg for each of the elements. The body of this person would have approx. 65kg of oxygen,18kg of carbon, 1.5kg of calcium, 1kg of phosphorus etc. This shopping list for elements found in the human body is somewhat misleading, because these elements are usually combined with each other forming compounds taking part in biochemical reactions. For example, approximately 70% of the human body consists of water, at least 15% is fat and 12% is protein (2). It must be remembered that the human body is greater than the sum of all its parts.

How are Minerals Different to Vitamins?

Mineral elements are inorganic molecules, with low molecular masses, soluble in water and obtainable in solution from plants via the water they absorb from the soil. They are needed in variable amounts from approximately two micrograms for vanadium to 3.5g per day for potassium. Their functions fall into three broad categories:

  1. Physiological roles in the heart and circulatory system, muscles and nervous system (e.g. potassium, sodium, calcium, iron, copper and magnesium).
  2. Protective and defence roles in the immune system (e.g. iron, zinc and selenium).
  3. Structural roles in the skeleton (e.g. calcium, magnesium, phosphates, fluoride and strontium).

Vitamins, on the other hand, are organic high molecular mass compounds, with variable solubility and precise functions. They represent compounds which the body has lost the ability to manufacture for itself, and as such they stand as imperfections of our metabolism, largely unrelated to each other biochemically or structurally, but otherwise essential to man (3).

Chasing vitamins in food is not that difficult but finding minerals is much easier, because the answer lies in the soil. By increasing our intake of fruit and vegetables and sticking to this regime, we acquire all the necessary minerals within a balanced diet. The “five a day” guideline from the Food Standards Agency in the UK is currently followed by only 14% of adults, with middle-aged individuals reaching four portions of fruit and vegetables per day, so don’t worry about how to cook the turkey, goose, duck or chicken this Christmas – get busy with those sprouts and parsnips!

Categories: Diet, Health, Nutrition