Micro Minerals

Minerals and trace elements are inorganic substances required by our bodies in very small amounts and are classed as micronutrients. These elements become available to us when we consume plant and animal products which themselves have absorbed the minerals from the soil, rock or water in/on which they grow/graze. Some are essential and must be included in the diet, for example calcium, phosphorous, magnesium, sodium, chloride, potassium, iron, iodine, zinc and selenium. They support a large range of physiological functions (see Table 1), including:

Regulation of fluid balance in the body
Supporting the structural composition of bones and teeth
The transfer of nerve impulses
Acting as enzyme co-factors (something that is essential for an enzyme to work)
Growth and reproduction

Depending on requirements, minerals are needed in macro (>100mg per day), micro (1-100mg per day) or trace (<1mg per day) amounts and they have established Dietary Reference Values (see the post Nutritional Needs). A varied diet of naturally occurring foods should contain a plentiful supply of minerals without the need to take supplements. However, deficiencies may arise due to:

An inadequate diet, e.g. local soil and plants lack specific minerals
An improper diet, e.g. an excess of processed food
Reduced ability to absorb one or more nutrients

Deficiency of iron and iodine is a global problem, whilst zinc and selenium deficiencies are an issue in specific populations.

Table 1: Minerals (not an exhaustive list – see the link below for additional info)

Mineral	Functions and bioavailability	Sourced from
Calcium	The most abundant mineral in the human body Important for bone growth and health, the average adult skeleton contains around 1kg of calcium Acts as an enzyme co-factor Supports blood clotting, muscle contraction and transmission of nerve impulses Vitamin D is involved in the regulation of calcium levels in the blood Oxalates and phytates may disrupt absorption of calcium from the digestive tract, e.g. tea and cocoa	Dairy produce Dark green leafy vegetables Fortified food, e.g. breakfast cereal
Phosphorous	Along with calcium, phosphorous is important for bone growth and health A component of cell membranes (phospholipids) and DNA Involved in energy production from food Vitamin D is needed for the regulation of phosphorous levels in the blood	Dairy produce Meat Seafood Nuts and seeds
Magnesium	Important for bone development and health Acts as an enzyme co-factor	Seafood Wholegrain foods Leafy green vegetables Legumes Nuts and seeds
Sodium and Chloride (Salt)	Sodium and chloride are key regulators of fluid balance, e.g. maintaining blood volume and blood pressure Sodium supports nerve function and muscle contraction Chloride is needed to produce hydrochloric acid in the stomach and optimum functioning of the immune system Sodium and chloride are generally found together in food - processed foods tend to contain greater quantities of salt than natural foods Excessive salt consumption can lead to high blood pressure The daily reference intake for salt for an average adult is <6g	Meat Dairy produce Seafood
Potassium	A key regulator of fluid balance working in conjunction with sodium and chloride The balance of potassium within and outside cells is critical for effective transmission of nerve impulses and muscle contraction Acts as an enzyme co-factor	Legumes Potatoes Seafood Dates and raisins Bananas
Iron	Intake is tightly regulated by the small intestine Required for the transport of oxygen in the blood Acts as an enzyme co-factor Haem iron has greater bioavailability than non-haem iron The bioavailability of non-haem iron can be enhanced when sources of vitamin C are consumed at the same time Phytates and polyphenols may disrupt absorption of iron from the digestive tract, e.g tea, coffee and red wine Iron deficiency is the most common nutritional deficiency in the world and supplementation may be required if iron status cannot be maintained by diet	Non-haem iron is found in: Dark green leafy vegetables Mushrooms Legumes Haem iron is found in proteins such as: Beef Poultry Shellfish Liver
Iodine	Required to produce the thyroid hormones which regulate growth, metabolism and reproduction Levels are regulated by the kidneys Substances found in cassava, cabbage, cauliflower, Brussel sprouts and soybeans known as goitrogens, may compromise the body's ability to use iodine; particularly if dysfunction of the thyroid gland is pre-existing 1 billion+ people worldwide, mainly in Africa and Asia, are thought to be at risk from iodine deficiency Deficiencies range from goitre (swelling of the thyroid gland in the neck) to congenital hypothyroidism (cretinism)	Marine seafood and seaweed Dairy produce Iodised table salt
Zinc	Intake is tightly regulated by the small intestine Acts as an enzyme co-factor Needed for growth, immune function, gene expression and protein synthesis An important antioxidant Plant-based diets high in phytates (beans, seeds nuts, grains) inhibit zinc absorption Impaired immune function as a consequence of zinc deficiency can make children in developing countries acutely susceptible to infections such as diarrhoea, pneumonia and malaria	Shellfish Meat Liver Dairy produce Legumes Chocolate
Selenium	Used in the body to make proteins An important antioxidant Enhances the immune response Levels are regulated by the kidneys Selenium deficiency in the soil in parts of China causes Keshan disease In the UK selenium supplements are added to animal foods and fertilisers	Nuts - particularly Brazil nuts Seafood Meats

1, 2

Additional information on the minerals documented above, as well as some not covered here, including recommended intakes and the effects of deficiency and toxicity, can be found on the NHS web pages by following this link

References

McGuire, M. and Beerman, K.A. (2013). Nutritional Sciences From Fundamentals to Food. 3rd ed. US: Cengage Learning
Lanham-New, S.A., ed., Hill, T.R., ed., Gallagher, A.M., ed., Vorster, H.H., ed. (2020). Introduction to Human Nutrition. 3rd ed. UK: Wiley Blackwell, pp. 280-338

About The Author

Jane

Leave a Comment Cancel Reply

Ts & Cs / Privacy

Categories

Recent Posts

Gallery