THE Chinese race has multiplied over the centuries without a diet based on dairy products. But in both Hong Kong and China, calcium-rich milk is now being portrayed as important for growth and for strong bones and teeth.
Dr Sophie Leung is concerned too much emphasis is being put on milk in children's diets without an understanding of how much is needed and that those over two are drinking too much full-cream milk.
She has commissioned research by a post-graduate student at Chinese University, working with a team from the Zhongshan University of Medical Sciences, Guangzhou, to find out more about calcium in the Chinese diet.
The findings suggest Chinese children absorb calcium more efficiently and therefore might not need as much as Caucasians. The study compared schoolchildren in Jiangmen, Guangdong with those in Hong Kong and data available on children in the West. Over 260 children aged eight took part.
''We have found Westerners might have 800mg of calcium a day compared with about 300mg among the mainland Chinese. This is a big difference. But the efficiency of calcium absorption among the Chinese is double that of the Caucasians.
''If they eat 100mg of calcium, they absorb 60mg, compared with 30mg in the West,'' she said.
Reasons for the different absorption rates could be that habitually low calcium intake had brought adaptability among ethnic Chinese or that the higher protein and phosphate levels in the Western diet could impair absorption.
Warren Lee, who has carried out the research as part of his PhD, said absorption among the Hong Kong children with high calcium intake was still more efficient than those in the United States, at 55 per cent, compared with 35 to 40 per cent among Caucasian children in the US. The rate among children with low calcium intake in Jiangmen was 63 per cent.
Using the same children, Mr Lee has also been studying calcium supplementation. One group has received a 300mg supplement a day - equal to a glass of milk - over 18 months. ''We have found that those in the study had an increase in bone density but they had no significant increase in height. I compared the data with studies in the US. The rate of bone acquisition was no different from children given higher doses, of 700mg or 800mg, in America.'' One of the best sources of calcium is dried small fish, a traditional Chinese food. Only 13 grams provides 100mg of calcium.Tofu is also good, 67gm providing 100mg. For milk, 85gms provides 100mg.
According to Larry Eisentrager, chief operation officer of Nestle Dairy Farm, per capita milk consumption in Hong Kong was still only one-eighth that of the United States. ''Milk is one of the best sources of calcium and one of the most readily available,'' he said.
He added that at 3.5 per cent, the fat content of milk was low, even compared with lean meat. He thought the increased consumption of snack foods was more likely to explain the increased fat content in children's diets. But Dr Leung said 3.5 per cent fatcontent of milk was still too high for children over two.