nutrients in food

There are many different kinds of nutrient in our diet.

Protein
This is an essential body-building food. Much of the structure of cells is protein. Muscles are mostly proteins as are enzymes and hormones. Meat, fish, egg white and milk contain lots of protein. A good source of protein for vegetarians is Soya beans. In many undeveloped countries there is not enough protein in the diet which can prevent normal growth and development.

Fat
Cell membranes are made of fats. Fat also provides a long term store of energy. It also acts as insulation in many animals. Meat, milk and egg yolk contain a lot of fat. Oils are liquid fats. Many plants produce oils such as sunflower oil and olive oil which is used in cooking and to make margarine. It is much healthier to eat plant oils than to eat animal fats, because animal fats are usually much higher in cholesterol, which can cause heart attacks.

Carbohydrate
Starch and sugar are the main types of carbohydrate in the diet. They provide a more immediate source of energy than fats (eg glucose that is used in respiration). The staple diet (the main source of energy) for any population is always starch. In Asia the staple diet is mostly rice; in Britain it is mostly bread (or other products made from wheat flour) or potatoes; in Italy it is pasta and in Central America it is traditionally mainly Maize. Anything sweet contains sugar, such as cakes, sweets etc. Although starch and sugars contain basically the same thing, it is better to eat mostly starch as too much sugar can upset the osmotic balance in your body. Any carbohydrate that is not used is converted into fat for storage.

Vitamins
These are essential chemicals that you need to eat in order for your body to function properly. Vitamin C is needed to help bind the cells together. Without you can get scurvy. Vitamin D is needed so that your body can deposit calcium correctly. A lack of vitamin D leads to Rickets, a disease where the bones lack strength, resulting in the legs bending. Good sources of vitamins are fruits, vegetables and milk.

Minerals
These are inorganic compounds. This means that they do not need to be made by a living thing. If you went to the moon you would find minerals, but you would not find any of the substances mentioned above. Calcium is an example of a mineral that is an important part of our bones and teeth. Iron is another mineral; in this case it is an important part of the haemoglobin in our blood. A good source of calcium is milk. Iron is particularly common in liver and spinach. Many vegetables provide smaller amounts of these vitamins.

Roughage (fibre)
Much of the food we eat cannot be digested and passes right through the gut and is egested in the faeces. Much of this is the cellulose in the cell walls of plants. However, this is still useful because it gives some solid substance to the half digested food in the intestine which makes digestion easier. Without roughage a person can get ulcers, colon cancer and can suffer from constipation. Most roughage is found in fruits and vegetables. Constipation is often the result of eating too much meat and not enough vegetables. Modern packaged foods are often lacking roughage.

A balanced diet includes all of these nutrients in the required amounts. It also includes water. They are not all required in large amounts. Only small amounts of vitamins and minerals are required, but they are still very important. Eating the wrong amounts of these nutrients can be a problem, leading to malnutrition. Eating too much is often as bad as eating too little. In many developed countries people suffer from obesity (being overweight) because they eat too much sugar and fatty foods in their diet. Other parts of the world are lacking one aspect of a balanced diet or they have too little food altogether. The world produces enough food for everyone, but it is often in the wrong places and there are difficulties in distributing it to everyone.

Foods with lots of carbohydrates or fats are high energy foods. If a person eats a lot of this they can put on weight, unless they do a lot of exercise. If you take in more energy than you use you put on weight. If you use more than you take in you lose weight. When someone is dieting they should lower the amounts of fatty foods that they eat and do a bit more exercise. This ensures that they stay healthy. Harsh diets are very bad for the body and can even lead to you putting on more weight in the long run.