HEALTH: SECOND OPINION

TAP water has a poor public image in Britain. People complain about its taste, and from time to time stories circulate about the pollution of water sources by toxic chemicals, though in reality such incidents are rare. The manufacturers of bottled waters emphasise the purity of their products, taken from sources such as mountain springs fed by deep underground aquifers. Their campaigns have made the table-water market big business in both Europe and North America.

People who want to spend money on bottles of water are doing their bodies no harm, but the demonisation of water from the tap may not be good for children. In Britain now most children never drink plain tap water, and this may be harmful to their health.

Researchers at Southampton University have been studying the drinking habits of small children attending health centres and toddler groups. Their report in Archives of Disease in Childhood gives data on 105 children aged between two and seven. Three-quarters of the toddlers and half the infants never drank plain tap water.

By far the most popular drink was fruit squash, diluted with water. Blackcurrant concentrates were very popular. Mothers said their children drank squash rather than water because they preferred the taste. What this means, however, is that these children had developed a taste for sweet drinks.

Does this matter? Isn't drinking fruit squash rather than tap water one more indication that we live in an affluent society? The Southampton specialists are in no doubt that this trend is harmful, and for three reasons. First, most squashes, even when diluted, contain a lot of sugar, and children who drink squash thoughout the day may get as much as half their total energy intake from it. Squash may contain some useful vitamins, but it is not a good source of nutrients. Second, the high sugar content of many squashes carries a risk for children's teeth. And third, a toddler who drinks several bottles of squash each day will not be hungry at mealtimes.

The report describes a few children who seemed to have become ill as a result of drinking too much fruit-flavoured water. Four boys and four girls were referred to hospital because of poor appetite, poor behaviour at meals, poor weight gain and loose stools. When other possibilities had been ruled out the most likely explanation was that these children drank too much sugary fluid - as much as three pints a day in some cases.

How should parents recognise that their child's health may be being affected by drinking too much sweet fluid? One clue is reluctance to eat (breakfast is often an exception, because the child wakes up hungry). The child will have normal energy, but the stools will often be loose. Replacing fruit drinks with plain water will usually produce a marked improvement.

American paediatricians have reported similar concern, though there the main culprit seemed to be undiluted apple juice. A parent might think nothing could be healthier than fruit juice uncontaminated by additives. That may be true, but children will be better nourished if they get most of their energy from a mixed diet of solid foods, washed down with old- fashioned water.