Vitamins And Minerals

Vitamins and minerals are naturally occurring nutrients which, even though they are only needed in tiny amounts, are essential for life. Without them, the enzymes that regulate your metabolism would not function as well as they should.

Vitamins

There are 13 major vitamins that you either cannot synthesise (eg vitamin C) or which are only made in tiny amounts (eg vitamin D, vitamin B3) that are too small for most people’s needs. You therefore need to obtain adequate amounts of vitamins from your food – from the plants and animals that can synthesise them.

Vitamins are involved in all the body’s metabolic reactions from digestion, energy production and immunity to cell division, growth, tissue repair, hormone secretion and reproduction. They are involved in the transportation of oxygen and wastes in the circulation, vision, sensory perception and mental alertness.

How quickly low intakes of a particular vitamin lead to deficiency depends on how much is stored in your body, and how quickly your supplies run out. In general, you can store vitamins that are fat-soluble more easily (eg in your liver, in fat cells) than those that are water-soluble and easily flushed from your circulation into the urine.

The highly fat-soluble vitamins are vitamin A, vitamin D, vitamin E and vitamin K.

The water-soluble vitamins are vitamin C and the B group of vitamins (with the exception of vitamin B12 which can be stored in the liver). Because they are readily lost in the urine, water-soluble vitamins must be continually replenished from your diet.

Lack of water-soluble folic acid can develop quite quickly, for example, during times of increased need (eg pregnancy) or when intakes are low, while stores of the more fat-soluble vitamin B12 can take years for deficiency to progress to an insidious condition that tends to creep up on you, known as pernicious anaemia.

For more information on each vitamin visit my A-Z of vitamins menu and select the page you are interested in.

Minerals

The word mineral literally means ‘mined from the earth’. In nutritional terms, the word refers to inorganic elements that you need to obtain in relatively larger amounts of over 100mg per day (eg calcium, magnesium). Elements needed in smaller amounts are usually referred to as trace elements (eg iodine, zinc).

Around 20 minerals and trace elements are essential for human metabolism. Some act as antioxidants (eg selenium, manganese) while other have an important structural role in bones and teeth (eg calcium, phosphate). Others are essential for normal cell function and fluid balance (eg sodium, potassium). Many act as co-factors to speed enzyme reactions and keep your metabolism ticking over at the correct rate (eg copper, iodine, manganese). Iron is best known for its role in oxygen transport, while others are important for hormone balance (eg chromium, magnesium). Some trace elements such as boron, nickel, tin and vanadium are known to be essential for normal growth, although their exact roles are not yet fully understood.

Vitamins and minerals in food

In general, the level of minerals in food depends on the soil on which they were grown or reared. This is because plants can only absorb minerals from the soil from which they make their way up the food chain. In contrast, the vitamin content of food is generally similar whatever the source, as the plants and some animals synthesise these themselves. Mineral deficiency is more common than vitamin deficiency because minerals are needed in greater amounts for health, and because minerals are often lacking from the soil – either because they are depleted by agricultural practices, or because they were leached out of the soil during the last ice-age (eg selenium).

Vitamin and mineral deficiencies are especially common among people following restricted diets (eg for weight loss or due to food intolerances), those with reduced appetites (eg elderly), those with increased needs (eg growing teenagers, pregnant women) and in people eating vegetables grown in mineral-poor soils.

To help maximise your intake of vitamins and minerals:

Avoid processed, pre-packaged or convenience foods
Eat unrefined wholegrain products (eg cereals, wholewheat pasta, brown rice) rather than white versions
Eat at least five servings of fresh fruit and vegetables per day
Eat a handful of nuts and seeds per day (unsalted)
Eat oily fish at least once and preferably twice a week
Consider eating foods that are organically grown, especially fruit and vegetables
Eat fruit and vegetables raw or only lightly steamed where possible
Re-use juices from cooking vegetables (eg in sauces, soups or gravy) to reclaim lost nutrients.