Too few vitamins and too little fibre
There is a disease called beriberi. When a person gets this disease their nerves do not work properly and their muscles become weak. They find it painful and exhausting to walk and in time the disease may cause the heart to stop. In the late nineteenth century it was thought that this fatal disease was caused by a certain germ or microbe. At that time there was a doctor working in Indonesia who tried to find it. He was a Dutchman called Christiaan Eijkman.

The doctor was not having any success in his investigations and one day he looked out of the window and had a surprise. There was a flock of hens living in the hospital grounds and usually the doctor paid little attention to them. On this day he saw that the hens were staggering about like his patients. He concluded that they had beriberi. Eijkman decided to test the hens to see if they had the germ that he could not find in his patients. He looked without success. While he was making his investigations a strange thing happened. The hens began walking normally again. They had recovered from the disease.

Eijkman decided that perhaps the person who looked after the hens could provide an answer. He discovered that the hens were fed by the hospital cook. He discovered that a short time ago a cook worked at the hospital who fed the hens on a special mixture of foods which kept them healthy. This cook then decided that he would feed the hens on the same food as the hospital patients. The main food of the patients was polished rice so the hens received it too. Polished rice has its dark outer skin removed to make it look more attractive. After a while the cook left the hospital and the new cook stopped feeding the hens on polished rice and gave them their healthy food mixture.

Eijkman then checked the times when the hens were fed by the two cooks. He found that the hens developed beriberi when they were fed on the polished rice and recovered when the new cook fed them on their healthy food mixture. The doctor concluded that beriberi was not caused by a germ after all but by a lack of something in the diet. That 'something' was later discovered by other scientists. Today it is known as vitamin B1 or thiamin. It is found in the skin of the rice. If the patients had eaten unpolished rice instead of polished rice they would not have suffered from beriberi.

This true story shows a chance observation by a scientist can lead to a discovery. It also shows that not all diseases are caused by germs. Some are caused by a lack of certain substances in the food.

How did vitamins get their names?
The word vitamin comes from two words. They are vital and amine. At the time when it was discovered that certain substances in food could stop diseases, scientists had also discovered a group of chemicals called amines. They thought these substances in food were amines and as they were considered the substances vital for a healthy life they made up the name 'vitamin'. When the first vitamin was discovered it was given the first letter of the alphabet. The second vitamin was named after the second letter of the alphabet and so on. Later it was discovered that there was more than one vitamin B so they were called vitamin B1 and vitamin B2. When the chemicals that formed the vitamins were discovered it was found that they were not amines after all but the name vitamin has stayed. Today the vitamins on packets of food may be shown either as a letter or the name of the chemical it is made from. Vitamin A is also called retinol, vitamin B1 is also called thiamin, vitamin B2 is called riboflavin. Some B vitamins, such as niacin, are simply known by a name and not a number. Vitamin C is called ascorbic acid and vitamin D is called cholecalciferol.

How is the body affected if the diet lacks vitamin A?
A condition called night blindness develops. The eyes are able to see well enough in daylight but when it starts to go dark they can see lights but cannot pick out dim shapes. Everything would look black away from street lights. Vitamin A also helps growth and helps form the moist membranes in the nose to keep out germs. A lack of vitamin A can help germs attack the body.

Which foods are rich in vitamin A?
Butter, liver, cod liver oil, milk, tomatoes, carrots and apricots. Vitamin A dissolves in fat and can be stored in the body. The human liver can store up to two years supply of vitamin A so if the diet is lacking in vitamin A for a short time the body may not suffer.

How is the body affected by a lack of B vitamins?
If the diet lacks thiamin, beriberi may develop. If the diet lacks riboflavin, skin disorders may develop. If the diet lacks niacin, disorders of the skin, digestive system or nervous system may develop.

Which foods are rich in vitamin B?
Bread, milk, kidney and liver.

How is the body affected by a lack of vitamin C?
A condition called scurvy develops. At first skin cells collect in the holes from which hairs grow. As the disease develops, wounds take longer to heal, and blood vessels develop leaks which result in blood escaping into the joints, gums and under the skin. There may be a massive and fatal bleeding inside the body.

Which foods are rich in vitamin C?
Blackcurrant and the citrus fruits - oranges, lemons and limes are major sources of vitamin C. Tomatoes, potatoes, cabbages and sprouts also provide vitamin C.

How is the body affected by a lack of vitamin D?
A lack of vitamin D in the diet results in the disease called rickets. Vitamin D helps the body to take up calcium to build up bones. If it is lacking from the diet weak bones are formed. The main load-bearing bones of the body are the leg bones. If the diet is lacking in vitamin D these bones bend and the person becomes bow-legged. If rickets is detected at an early stage it can be cured by increasing the amount of vitamin D in the diet.

Which foods are rich in vitamin D?
Butter, margarine, cod liver oil, eggs, milk, cheese and oily fish such as sardines and pilchards.

Why is fibre important if it is not digested?
When food is digested it becomes soft and dissolves. Fibre is not digested and so remains firm throughout its trip through the body and gives the food some bulk. The food is moved along the digestive system by muscles in the gut wall. The fibre pushes on the gut wall and makes the muscles push back and move the food. The fibre also makes the lining of the gut produce a slime called mucus which helps the food slide along. During the digestion of food some harmful substances can be produced. If the muscles do not work properly they can cause pockets to develop inside the gut in which the harmful substances can collect and possibly cause damage. The fibre keeps the muscles working properly so the pockets do not develop and the harmful substances are released from the body with the undigested food.