Health Guide Info

For people in normal health, the precise basal metabolic rate is linked to age, weight, the outside temperature, the working of the endocrine glands (which produce the body's hormones), and the shape of the body.

Whatever a person's individual energy requirement, this energy must be provided by food. Extra food, beyond the body's needs, does not supply extra energy. It generally, forms fat, leading to excess weight - which can result in ill health.

In addition to eating the right quantity of food, the body also needs the right type of food. It requires essential raw materials - such as carbohydrates, fats, proteins, vitamins and minerals. It also needs fibre (roughage obtained from foods of plant origin) and fluid, which are essential aids in the regulation of bodily functions.

Broadly speaking, carbohydrates (contained in sugar and starchy foods) and fats (in fat meat and dairy products) are the chief energy providing fuels in food. Proteins, in food such as meat, eggs and cheese, provide raw materials for the continuous repair and replacement of body tissues. Vitamins are needed to maintain the health of various organs and tissues, and minerals are essential components of blood, bone and teeth.

Fats and carbohydrates should be taken together; otherwise the fats will be incompletely burned up, forming waste products which can cause headache and lost of appetite. An example of a good carbohydrate/fat combination is bread and butter.

Foods vary in their nutritional value because of their different composition and combination of nutrients. They can be divided into five basic groups:

Milk
Meat
Fish
Cheese
Eggs and Vegetable Protein; Vegetables and Fruit; Bread and Cereals; Oils and Fats (mainly butter and table margarine)

A diet that includes foods from each of these groups in roughly the correct proportions will supply all the nutrients the body needs.

A protein molecule is made up of smaller units called amino acids. There are 22 different ones in animal protein, contained in various kinds of meat. Eight of these amino acids - all essential to life -cannot be made in the body by building them from simpler chemicals. These, the so-called essential amino acids, have to be provided directly by proteins in the diet.

The usefulness to the body of a particular protein is called its biological value. The value is generally highest for an animal protein, such as that in meat, cheese and eggs, and lowest for a vegetable protein, such as that in nuts and cereals. Some comparatively poor sources of proteins - for instance, bread or potatoes - may lack one or more of the essential amino acids. But in a mixture of them - bread and potatoes - the deficiencies in one are supplied by components in the other.

In most countries the chief sources of food energy are fats and carbohydrates. In Western countries much of the carbohydrate used in pastries, a biscuit, cakes and white bread is refined. Refining entails the reduction or elimination of some essential vitamins and minerals, and also a reduction of bulk and roughage, and may be the cause of the 'disease of civilization', such as constipation and the intestinal disorder diverticular disease.

Weight for weight, fat provides nearly twice as many kilojoules as does carbohydrate, and it is extremely satisfying. When food is scarce, as in wartime, people miss fats as much as they do proteins. Milk, butter, vegetable oils and animal fat, including suet, are all appetizing sources of fats.

There are at least 17 organic substances called vitamins. Most of them are needed to promote chemical reactions in the body. The actual amount of vitamins in any food is miniscule, but the quantities needed in the diet are also extremely small. For example, a person could be healthy on less then 30g of thiamine (vitamin B1) in a lifetime, provided micro-scopic amount were taken regularly.

Vitamin A is needed for child growth and for healthy vision; it protects the surface of the eye and the lining of the throat and bronchial tubes.

Vitamin D, partly provided by the action of sunlight on skin, is needed for the formation of healthy bones.

Thiamine (Vitamin B1) is needed for the steady release of energy from carbohydrates within the body.

Riboflavin (Vitamin B2) and Niacin (Vitamin B3) also assist in the production of energy.

Vitamin C is essential for healthy growth and repair of tissues.

The absence of vitamins from the diet can lead to various deficiency diseases.

For example, lack of Vitamin A can lead to eye disorders, bad skin and decreased resistance to infection; long term deficiency can lead to blindness. Too little thiamine (Vitamin B1) may lead to loss appetite, fatigue, nervous irritability and a type of neuritis. Lack of Vitamin C can cause scurvy, while a deficiency of Vitamin D can cause rickets, a bone disease in children.

Among the minerals the body needs are:
1. Iron (a vital constituent of the blood)
2. Calcium and Phosphorus(needed for bones, teeth)
3. Iodine(used by thyroid gland in regulating the rate of chemical reactions in the body)
4. Potassium(needed in body cells)

All foods are derived from the soil and sea. Their chemical composition is influenced by the underlying rocks, which contain complex mineral salts. It is these mineral salts that ultimately pass into our food. Because food supplies are taken from such a wide variety of agricultural sources today they are seldom deficient in minerals.

The body requires minute quantities of other element - sometimes called trace elements - such as magnesium, copper, cobalt, zinc, manganese and molybdenum.

The body contains less than a gram of the last five, but would not function without them as hey are essential in the manufacture of enzymes, the catalysts which trigger off chemical reactions in the body. There is usually more than enough of these trace elements in the average diet.