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There are six main groups of nutrients or food chemicals contained in food.
They are:
Dietary fibre is another important part of food. It is not considered a nutrient, but is necessary for food health. No one food contains all the nutrients needed, and so it is important that we have a balanced intake of a combination of foods. Eating the correct combination of foods in the appropriate amounts will give us a better chance of leading healthy lives. However, eating the wrong foods or following an unbalanced diet may lead to dietary problems that can cause sickness and lack of energy, and may even lead to death.
Carbohydrates are sugars, starches and fibre. The simplest forms of carbohydrates are sugars such as glucose, sucrose, dextrose, fructose and lactose. Starches are complex forms of carbohydrate that during the process of digestion are broken down to simple sugars. Fibre is a non-digestible form of carbohydrate found in grains, cereals, breads fruit and vegetables.
Carbohydrates are a major source of fuel and energy, and they allow protein used for growth and maintenance of body cells. The dietary fibre found in unrefined products is important for proper bowel function. The main sources of carbohydrates are breads, breakfast cereals, rice, pasta, lentils, fruit and vegetables. Smaller amounts can be found in milk and other dairy products.
Proteins are essential for growth and maintenance of a healthy body. They are the body's main building material. They are used to make new cells for muscle tissue, skin, hair, blood and so on. Their main functions are building, repairing and replacing cells.
Proteins are found in meat, poultry, fish, eggs, dairy products, lentils, nuts, breads and cereals.
The technical word for fats is lipids. They are the most concentrated source of energy found in the diet and are found in both animal and plant foods. Besides being a major source of energy, fats supply and help the absorption of fatty acids and fat soluble vitamins (A, D, E and K) which do not dissolve in water but do dissolve in lipids. Lipids are also used in the structure of all cells and nervous tissue.
Sources of fats are butter, margarine, vegetable oils, dripping, dairy products, fatty meats, chicken, egg yolks, nuts and seeds. Only very small amounts of fat are needed.
Vitamins are essential for the normal functioning of our bodies (metabolism), growth and development. They are needed in only very small amounts for normal growth and health. Each vitamin (named alphabetically) is made up differently and all have very specific jobs to do in the body. Vitamins act as regulators. They are essential for the release of energy within the body, for building tissue and for controlling how the body uses food.
Sources of vitamins are mainly fruit and vegetables, but specific vitamins can be found in other foods, such as milk, eggs, cereals, nuts, yeast, liver, fish and meat.
Minerals are inorganic substances (i.e. they don not contain carbon) required by the body for many metabolic processes. They form part of the structure of hormones, enzymes and vitamins. They are necessary for the correct functioning of the body. Like vitamins, they are needed in only very small amounts and do not provide energy. They help regulate water balance, muscle contraction and nerve function.
Minerals are found in all foods, so that eating a varied and balanced diet should provide the necessary amounts for good health.
Over two-thirds of our body weight is made up of water. It is needed for the functioning of every cell and organ in the body, for lubrication, temperature control and excretion. Approximately 1.5 to 2.5 litres of water is needed each day for good health. Water is found in all foods but we need to drink extra fluids to replace water lost by urine, moist exhaled air and perspiration.
