Guide to micronutrients

Vitamins
Vitamins are essential for survival. They are organic (carbon-based) and can be broken down and altered by our bodies.

There are two types of vitamin: fat soluble and water soluble. Vitamins A, D, E and K are the fat soluble vitamins. These tend to circulate in the blood and any excess is stored in fatty tissue. This means that they are available whenever you need them and don’t need to be eaten everyday. On the other hand, it can be easier to ‘overdose’ on these vitamins.

Vitamin A: Our eyes, skin and immune system all benefit from vitamin A. It exists in two forms: in meat, as retinol; and in plants, in compounds called carotenoids. Good sources are meat, dairy products, cod liver oil, and orange coloured vegetables such as sweet potato, apricots and carrots. Pregnant women should avoid retinol-rich foods such as pâté and liver as they can be toxic to the foetus.

Vitamin D: An unusual vitamin, as the majority of vitamin D in the body comes not from food, but from sunlight. Vitamin D is made when UV rays hit the skin and is then used to help absorb calcium and maintain bone. This isn’t an excuse to start sun-worshipping though! It only takes around 10 minutes of sun on your face, arms and hands three times a week to get all the vitamin D you need. However, it is also found in some foods such as eggs, fish and fortified milk and spreads.

Vitamin E: An antioxidant, protecting the body’s cells from the toxic effects of oxidation. It also has a part to play in immunity. You can find vitamin E in green vegetables, whole grains, eggs, nuts, seeds and plant oils.

Vitamin K: Crucial for blood clotting. It is found in some foods such as cabbage and milk, but is also made by gut bacteria. Newborns (who have a sterile gut) are given vitamin K at birth as common practice.

The B vitamins and vitamin C are the water soluble vitamins. These circulate freely around the body, but are not stored – any excess is excreted in your urine. This means that they are less likely to reach toxic levels, but equally, you need to eat them regularly to create a ‘pool’ that your body can utilise as it needs.

Vitamins B: A group of eight vitamins (thiamin, riboflavin, niacin, vitamin B₆, vitamin B₁₂, folate, biotin and pantothenic acid) that help release energy and maintain the nervous system. They are found in milk and milk products, green leafy vegetables, yeast extract, whole grains and meat. Vitamin B₁₂ is only found in animal products – so vegans may want to consider B₁₂ supplements.

Vitamin C: Probably the best known of all vitamins – vitamin C boosts the immune system and helps with wound healing. Find it in fruits and vegetables such as citrus fruit, peppers, kiwi fruit and strawberries.

Minerals: Minerals are inorganic elements – they can’t be changed or destroyed. Unlike vitamins, not all minerals are essential to life. But here are some of the most important:

Calcium: Around 99% of the calcium in the human body is in the teeth and bones, however it also has a role in muscle contraction. Calcium can help prevent osteoporosis. Low-fat dairy products are a good source, but it can also be found in green leafy vegetables and legumes.

Iron: Helps carry oxygen around the body and is involved in releasing energy. If you have a low iron intake, you may find that you are tired and unmotivated. Iron deficiency can also lead to anaemia. Iron can be found in red meat, green leafy vegetables and dried fruit.

Sodium: Plentiful in the UK diet; in fact, most of us could do with cutting our sodium intake. Sodium is mostly consumed as sodium chloride – a compound also known as ‘salt’. It’s recommended that we aim for less than 6g of salt a day.

Zinc: Used in thousands of processes in the body, especially as part of the immune system. Meat, eggs, shellfish and green leafy vegetables are good sources.

Potassium: This helps maintain fluid balance in our cells and is crucial to the nervous system. Found mostly in fruit and vegetables.

Selenium: A trace mineral that acts as an antioxidant. It is found in the soil and is passed through the food chain. Seafood, meat, grains and Brazil nuts all contain selenium.