What are nutrients?

Food provides a range of different nutrients. Some nutrients provide energy, while others are essential for growth and maintenance of the body. 

Carbohydrate, protein and fat are macronutrients that we need to eat in relatively large amounts in the diet as they provide our bodies with energy and also the building blocks for growth and maintenance of a healthy body. Vitamins and minerals are micronutrients which are only needed in small amounts, but are essential to keep us healthy. There are also some food components that are not strictly ‘nutrients’ but are important for health, such as water and fibre.
Most people should be able to get all the nutrients they need by eating a healthy, varied diet, although there are a few exceptions. For example, women thinking about having a baby are recommended to take a folic acid supplement to prevent deformities such as spina bifida developing in their baby. Carry on reading to find out the main functions and food sources of the nutrients in our diet.

Nutrient	Function	Sources
Carbohydrate	Provides energy for the body.	All starchy foods, such as bread, rice, potatoes, pasta, cereals and cereal products; fruit and starchy vegetables, milk and milk products, sugar, preserves and confectionery.
Protein	Provides amino acids (building blocks) that we can’t make ourselves. Needed for growth, development and repair of the body. Also provides energy.	Meat, fish, eggs, dairy foods, cereal products such as bread, soya products, nuts and pulses.
Fat Micronutrients Water-soluble vitamins Water-soluble vitamins cannot be stored in our bodies and are readily excreted. These include vitamin B1, vitamin B2, vitamin B3, vitamin B6, vitamin B12, folate and vitamin C. Nutrient Function Sources Vitamin B1  (Thiamin) Helps to release energy from carbohydrate. It is also involved in the nervous system and the heart. Whole grains, nuts, meat (especially pork), fruit and vegetables and fortified breakfast cereals. Vitamin B2  (Riboflavin) Helps to release energy from food and is needed for the normal structure and functioning of the skin and body linings. Milk and milk products, eggs, rice, fortified breakfast cereals, liver, pulses, mushrooms and green vegetables Vitamin B3  (Niacin) Helps to release energy from food, and is important for the normal structure of the skin and body linings. It also keeps the digestive and nervous systems healthy. Meat, wheat and maize flour, eggs, milk and milk products and yeast. Vitamin B6 Helps to release energy from protein, and helps to form haemoglobin in blood (the substance which carries oxygen around our bodies). Poultry, white fish, milk and milk products, eggs, whole grains, soya beans, peanuts and some vegetables. Vitamin B12 Important for making red blood cells and to keep the nervous system healthy. Also helps to release energy from food. Meat, fish, milk and milk products, cheese, eggs, yeast extract and fortified breakfast cereals. Folate/ Folic acid Needed for the formation of healthy red blood cells. It is also needed for the nervous system and specifically for the development of the nervous system in unborn babies. Green leafy vegetables, wholegrain products, liver, nuts, peas, oranges, bananas and fortified breakfast cereals. Vitamin C Acts as an antioxidant and is important for the normal structure and functioning of body tissues. It also helps the body to absorb iron from non-meat sources such as vegetables, as well as assisting the healing process.                                                                                                               Fruit especially citrus fruits and berries; green vegetables, peppers and tomatoes. Also found in potatoes. Fat-soluble vitamins Fat-soluble vitamins are absorbed through the gut with the help of fat. These include vitamin A, vitamin D, vitamin E and vitamin K. Nutrient Function Sources Vitamin A Important for the normal structure and functioning of the skin and body linings, e.g. in lungs. It also helps with vision in dim light as well as keeping the immune system healthy. Liver, whole milk, cheese, butter, spreads, carrots, dark green leafy vegtables and orange-coloured fruits, e.g. mangoes and apricots. Vitamin D Needed for the absorption of calcium and phosphorus from foods, to keep bones healthy. Recent research also suggests that vitamin D enhances immune function and improves muscle strength. Oily fish, eggs, meat, fortified cereals and spreads. Most is obtained through the action of sunlight on our skin during the summer months. Vitamin E Acts as an  antioxidant and protects the cells in our bodies against damage.     Vegetable and seed oils and spreads, nuts and seeds. Vitamin K Needed for the normal clotting of blood and is required for normal bone structure.                  Green leafy vegetables, meat and dairy products.

Minerals

There are certain minerals we need to keep our bodies healthy. These include calcium, fluoride, iodine, iron, magnesium, phosphorous, potassium, selenium, sodium and zinc. Nutrient Function Sources Calcium Important for the formation and maintenance of strong bones and teeth, as well as the functioning of nerves and muscles. It is also involved in blood clotting. Milk and milk products, cheese and other dairy products, some green leafy vegetables such as broccoli, fortified soya bean products, canned fish (if containing bones that are soft and can be consumed) and bread. For more information on the dietary sources of calcium click here. Fluoride Helps with the formation of strong teeth and protects against dental decay (caries). Fluoridated water, tea, fish and toothpaste. Iodine Needed to make thyroid hormones, which control many metabolic processes, and keep our bodies healthy. Milk and milk products, sea fish, shellfish, seaweed and iodine-fortified foods, such as some salt. Iron Required for making red blood cells, which transport oxygen around the body. Also needed for normal metabolism and the functioning of enzymes that remove unwanted substances from the body. Liver, red meat, pulses, nuts, eggs, dried fruits, poultry, fish, whole grains and dark green leafy vegetables. Magnesium Helps to release energy from food and to maintain water balance. It is also important for the formation of strong muscles, bones and teeth. Found widely in foods, particularly green leafy vegetables, nuts, bread, fish, meat, milk and milk products. Phosphorous Needed for the formation of healthy bones and teeth, and for the release of energy from food. Red meat, milk and milk products, fish, poultry, bread, rice and oats. Potassium Controls water balance in our bodies and helps maintain a healthy blood pressure. It is also involved in the normal functioning of nerves. Fruit (especially bananas), vegetables, meat, fish, shellfish, milk and milk products, nuts, seeds and pulses. Sodium Helps regulate the water content in the body and the balance of electrolytes. Also involved in the use of energy, as well as the functioning of the central nervous system. Very small amounts in raw foods. Often added during processing, preparation, preservation and serving. Currently intakes of sodium are too high and so although some sodium is essential, most people need to reduce their intake substantially. Selenium An important component of the body’s defence system that protects our bodies against damage. It is also necessary for the use of iodine in thyroid hormone production, as well as the normal functioning of the reproductive system. Brazil nuts, bread, fish, meat and eggs. Zinc Helps to release energy from food. Needed for cell division, growth and tissue repair. Also necessary for normal reproductive development, the immune system and healing of wounds. Non-nutrients Water and fibre are non-nutrients, but are important substances that we need to include in our diets to stay healthy. Non-nutrient Function Sources Water Not a nutrient in the classical sense, but is essential for our bodies to work properly, for example for regulating body temperature, cushioning the joints, controlling blood pressure and keeping the body in balance. All drinks including water, milk, and juices. We actually get roughly 20% of our water requirements from the food we eat. Water-rich foods include fruit and vegetables, soups, stews and sauces. Fibre Not a nutrient, but improves the movement of the gut contents and helps prevent constipation. Some types of fibre also help lower blood cholesterol and glucose levels. Cereals, beans, pulses, lentils, fruit and vegetables. Meat, milk and milk products, cheese, eggs, shellfish, wholegrain cereals, nuts and pulses.

Provides essential fatty acids (that we can’t make ourselves but need in small amounts), as well as energy. It also carries important fat-soluble vitamins and is important for their absorption.

Fats and oils, meat and meat products, dairy foods, oily fish, nuts, cakes, biscuits, pastry products, crisps and other snacks, chocolate.