Food is often classified as:
- Carbohydrate, including Fibre
- Protein
- Fat
- Vitamins and Minerals
Carbohydrates are substances that contain carbon, hydrogen and oxygen. They are used in the body to produce energy. They include sugars and starches. Carbohydrates are usually obtained from plant sources. They are broken down in the body to form glucose, and any that is not immediately required in stored in the liver and muscles as glycogen. Plants use carbohydrates to build structures and store any excess as starch, whereas, animals use protein.to build structures and store any excess as fat.
Plants make carbohydrates from sunlight, water, chlorophyll, and carbon dioxide. We obtain them from plants, for example:
- cereals
- starchy roots
- legumes (pulses)
- vegetables and Fruits
- sugars, preserves and syrups
Carbohydrates are mainly used by the body to produce energy. Where there is a lack of energy, we might think of carbohydrates. The energy in the body is used for:
- External activities (behaviour), such as work, sport, leisure - that is any movement of the body.
- Internal activities including breathing, pumping blood, digestion and the activities of the immune system.
None-digestible carbohydrate (Fibre)
Fibre, or roughage, refers to the non-digestible carbohydrates in vegetables and to a lesser extent in fruit. Fibre may actually be 'fibrous', as in celery, or may be a powder, or, when mixed with water in the intestines, a jelly. Fibre provides:
- Bulk
- Lubrication, and
- Nutrition for friendly bacteria in the colon.
When fibre is combined with water, it swells up and provides bulk to the digestive system. This makes it easier for food to pass through the intestines. Food also passes through the digestive system faster, so that waste products are retained for less time in the body.
Some fibre has the effect of lubricating the contents of the intestines and, therefore, makes the food pass through easily and in a timely manner. The benefits here are the same as for bulk.
In addition, friendly bacteria in the colon feed on fibre and they are therefore nourished by it. By helping these friendly bacteria, we enable them to help us to digest food. Also, by giving them support, they are more able to exclude other, less friendly bacteria, from our colons.
Fibre is, therefore, necessary for a healthy and efficient digestive system.
Proteins are composed, like carbohydrates, of carbon, oxygen, and hydrogen, but with nitrogen. They may also contain sulphur and phosphorus. They are complex molecules composed of amino acids.
Proteins are used by the body to:
- enable growth, development and repair.
- build structures such as muscles, tissues and organs, including the heart, lungs, digestive organs.
- enzymes, such as those required for digestion.
- hormones, such as those for the endocrine glands.
Proteins, therefore, are needed not only for obvious body structures, such as muscles, but also for the immune and digestive systems, etc.
Complete proteins are obtained from meat, fish and dairy products including eggs. Proteins can also be obtained from certain combinations of foods, for example, cereals and beans.
Fats are substances that are not soluble in water. They are composed of fatty acids and glycerol. Fats are also called lipids.
Sources of fat include animal meat, fish, and vegetable oils. Fats are used by the body:
- In every cell structure.
- Especially to build nerves and brain. The brain is 40% fat.
- To insulate the body.
- To produce sex hormones and adrenal cortex hormone
- To produce cholesterol (essential for cell membranes and bile salts, for example).
- To absorb certain vitamins (A, D, E, and K).
- To store energy.
Fats have got themselves a bad name in recent times, yet they are an essential food. That is, the body requires its intake of fat every day for health and, especially, well being. Like the other groups of food, when the body does not get the fat it needs, then illness results.
Vitamins are substances that are required in the diet for health and wellbeing. They are often grouped as fat-soluble or water-soluble. Fat-soluble vitamins are vitamins A, D, E and K. Water-soluble vitamins include vitamins C and B.
Minerals are non-organic substances that are required in the diet. While only small amounts of minerals are required in our diet, they are critical in building bones and teeth, regulating heartbeat and transporting oxygen from the lungs to the tissues.
Vitamins and minerals occur in a variety of foods. That is, by eating a variety of foods, you can get the necessary vitamins and minerals you need for health.
Deficiencies and excesses in any of these groups of foods produce illness and lowered wellbeing.
Western diets are especially deficient in the minerals calcium and iron and in the Omega 3 fatty acids.
Calcium is obtained from, for example, milk and from eating canned salmon including the bones (salmon also contains Omega 3 fatty acids). Iron is often obtained from meat, especially liver.
Lacto-vegeterians can get their calcium from milk, and vegans (who do not eat any animal products) can get their calcium from fortified soy milk. To obtain your calcium requirements from non-animal sources, you would have to eat a very large amount of vegetables or fruits.
