Milk cutback setting off bone disease timebomb

By MATHEW DEARNALEY

Parents who cut back on milk in the home - often replacing it with cheaper soft-drinks - are putting their children at risk from bone-wasting disease.

Nutritionists preparing the Health Ministry's first national survey to assess the dietary health of children are concerned that milk now sells rfor about $1.65c a litre while the same money can often buy 1.5 litres of cola or other soft-drinks.

Consumption of biscuits and other sugary snack foods (often at the expense of fruit and vegetables) will also come under scrutiny.

The survey will start in June and will take a year to complete. About 5000 children aged from one to 14 years will be involved, and the results will hopefully provide less depressing news for parents than the most recent official British survey.

Half the surveyed British youngsters, aged from four to 18, did not eat citrus fruits, leafy green vegetables or eggs in a seven-day survey period.

But a pilot study of 333 children for the ministry survey has found that, although most children receive enough iron in their diet, many lack enough calcium essential for developing healthy bones and teeth.

This could cause long-term health problems. Bone mass developed in youngsters between nine and 20 is critical to preventing osteoporosis later in life, yet more teenagers internationally are drinking fizzy drinks and cordials at the very time calcium intake is most important.

Calcium is continuously excreted in urine and sweat, but encouraging regular exercise is also important for achieving peak bone mass.

Milk products remain the major calcium source in the New Zealand diet, but sardines are also rich in the mineral. Smaller amounts are found in eggs, green leafy vegetables, legumes, nuts and wholegrains.

If parents are concerned about increasing fat levels in their children's diet, there is a wide range of low-fat milk. Calcium-rich varieties are generally more expensive that the standard product.

The ministry says there is no evidence that soy foods harm youngsters, but the calcium absorption rate of non-fortified soy milk can be reduced by up to 20 per cent because of substances called phytates.

Phytates in plant foods such as grains and bran also inhibit the absorption of iron, which, perversely, gives white bread a nutritional tick as it has the bran removed.

Evidence suggests children with iron deficiencies have trouble learning and concentrating.

The ministry says vitamin C increases iron absorption by three to four times when taken in the same meal, and the potential benefits of an adequate fibre intake in childhood outweigh the risks.

The pilot study involved a random selection of children from Auckland, Shannon and Feilding, and the ministry says its findings cannot be interpreted as valid for all New Zealand youngsters.

Massey University nutritionist Dr Clare Wall is concerned that a separate study, of infants aged six to 24 months in Auckland, is finding iron deficiencies in about 20 per cent.

Although full-term infants are born with enough iron to last six months, she says that deficiencies in babies in the second half of their first year can be difficult to reverse.