Saving lives with zinc

University of Bergen scientists who have carried out large-scale studies in Nepal and India believe that zinc supplements can both treat and prevent diarrhoea. Their research project has produced such good results that the World Health Organisation (WHO) wants to bring zinc into the routine treatment of diarrhoea.

Research fellow Tor Strand of the University of Bergen's Centre for International Health has just spent two-and-a-half years in Nepal, studying the effects of zinc supplements on diarrhoea. This project, and other international studies of zinc, have produced such promising results that zinc may well become a standard treatment for diarrhoea in children all over the third world.

Serious health problem

Even though Strand has still to finish his doctorate, his research has aroused a great deal of international interest. He was recently invited by WHO to a meeting of scientists in India, at which international zinc researchers agreed to urge WHO to use zinc supplements in the routine treatment of diarrhoea in children in developing countries.

"What we still need to do is to work out dosage details - as well as which countries and age-groups should be included. One of the jobs of WHO is to advise countries as to how various illnesses should be treated. The organisation now wants to have zinc treatment included in its list of recommendations", says Strand.

Apart from special types of diarrhoea such as dysentery and cholera, no medicines are available to shorten the duration of this illness.

"For many years now, WHO has been advising treatment with what are known as oral rehydration fluids to avoid acute dehydration in cases of diarrhoea. This simply prevents the sick person from drying out. It turns out that 50% of all the children who die of diarrhoea die of long-term weakening of the system, malnutrition and of other infections which they catch because the diarrhoea episode lasts for such a long time", says Strand.

Every year, between two and four million children die of diarrhoea, more than 95% of them in developing countries. One of the worst-affected countries is Nepal. Research coordinator Halvor Sommerfelt started doing research on diarrhoea in cooperation with scientists in India. Nepal was later added to his study area. Sommerfelt and Strand believe that Nepalese and Indian children do no receive enough zinc, and in collaboration with Indian and Nepalese researchers they have shown that this is an important factor in prolonging the course of the disease.

"Children quickly get into a vicious circle. Most start off with insufficient zinc stores, and then they lose important nutrients such as zinc in their faeces when they get diarrhoea. This makes them more and more ill", says Strand.

Strengthening the immune system

"Unlike measles or tuberculosis, for example, which are caused by a single bacteria or virus, diarrhoea can be caused by a wide range of micro-organisms. This is what makes it difficult to develop a general anti-diarrhoea vaccine. Zinc supplements directly affect the ability of the individual to tackle the disease", says Strand.

Zinc occurs naturally in meat, milk products and certain grains. In many developing countries such foodstuffs are in short supply.

"Zinc is essential for the cell division process, which is a continuous process in human beings. Cell division is necessary for the normal functioning of the immune system, for the process of growth and to enable the skin and mucous membranes to act as barriers to infections. An extreme lack of zinc by itself can result in diarrhoea. It can also produce changes in the skin and reduce growth", says Strand.

"If the immune system is not functioning well enough, the body is unable to mobilise the white blood cells in the immune system and to heal wounds. Bacteria can easily enter the body via open wounds and mucous membranes. When bacteria get into a person who is suffering from zinc deficiency, the immune system is not strong enough to deal with them".

However, zinc supplements may act not only on people with low levels of zinc in their bodies.

"Zinc can strengthen the immune system. Studies in the USA have shown that it also helps people who are suffering from colds", says Strand.

From the clinic in Bhaktapur, Tor Strand gave the patients in his study either zinc or a placebo from white plastic bottles.

Thorough study

A total of 1800 children took part in the study in Nepal.

"In order to obtain reliable results, we divided the children into four groups. One group was given a placebo and another group zinc, while a third group received zinc plus vitamin A. The fourth group also received zinc, but these children were given it by their own mothers. This was in order to find out whether zinc works just as well when it is administered by mothers as by trained field workers", says Strand.

The white plastic bottles with either zinc or placebo were each marked with a number, and no-one knew which bottles actually held real zinc. The identities of the bottles were kept secret in in Copenhagen. A major operation was mounted in order to make the study as good as possible. The whole study was run from the University of Kathmandu.

"We had a staff of about 40 in Nepal, including doctors, other categories of health worker and computer operators. One group went to the homes of the children every day and put the medicine in their mouths. Another group went to their homes every fifth day to examine the children and to ask whether they had been ill or had had diarrhoea during the previous five days. In addition to these groups we had a control team who went out on randomly selected days to check that the others had done their jobs properly. We interviewed the mothers about the course of the disease, and blood samples were taken and laboratory analyses carried out at the hospital", says Strand.

"Every child was given a course of treatment that continued for a week after the diarrhoea episode had passed, and they were all followed up a month later. We examined children from six to 35 months of age. The results of the study all point clearly in the same direction: zinc hastens the cure of diarrhoea. This is good, because the longer the illness last the more likely a child is to die of it. The only side effect of zinc is that small children may throw it up. However, if we divide the dose into smaller portions, we can avoid this", says Strand.

Too cheap?

Strand emphasises that zinc is cheap.

"Of course, it is fine that a medicine is cheap, but paradoxically enough this in itself may slow down the widespread adoption of the new treatment. Doctors in Nepal are just as much under the influence of the pharmaceutical industry as Norwegian doctors. There is not a great deal of money to be earned on zinc, and people tend to have more faith in expensive medicines", claims Strand.

"Last year, Berit Sofie Hembre, a Bergen medical student, carried out a study of what Nepalese doctors gave children with diarrhoea. It turned out that there were far too many antibiotics in use; these seldom have any effect on diarrhoea, and using them inappropriately can increase antibacterial resistance in the future. Zinc is therefore a welcome alternative treatment, and its efficiency is now well documented", concludes Strand.