Southland children who were at schools that got rid of the free milk programme in 1950 could have a 30 per cent higher risk of bowel cancer than those who had daily milk until 1967, a new study says.
The University of Otago research, recently published in the American Journal of Epidemiology, surveyed 562 New Zealanders between the ages of 30 and 69 who had developed colorectal cancer and 571 people of the same age who did not.
The study's co-author, Professor Brian Cox, said results showed those who had daily milk in schools had a 30 per cent lower risk of bowel cancer.
The risk was lowest in those who had drunk about 1200 bottles of milk during their school years.
Between 1937 and 1967, when the scheme was abolished, all New Zealand schoolchildren were given half a pint of full milk a day.
However, from 1950, many Southland schools opted out of the scheme after being given the option by the provincial education board.
For people who started school in Southland from 1951 to 1967, only 36 per cent had had school milk at least once. In other regions in the same period, 85 per cent of children had had milk, the study said.
If the results of the study held true, Southland schoolchildren from 1950 would have a 30 per cent higher risk of developing colorectal cancers, but more investigation was necessary before firm conclusions could be drawn, Prof Cox said.
The Otago-Southland region had a historically high rate of bowel cancer compared to the rest of the country, he said.
"We're still trying to work out why ... The school milk study doesn't fully explain that."
A British study had suggested increased calcium intake could actually increase the risk of bowel cancer, but Prof Cox said it had been less specific than the New Zealand study and used different methodology. New Zealand drinking water also contained less calcium compared to Britain, which could have an impact, he said.
It appeared higher calcium intake in youth resulted in fewer growths, called adenomas, forming on the intestinal walls, he said. Adenomas are seen as precursors to malignant cancer.
Dairy giant Fonterra announced a plan to reintroduce a daily portion of milk to 110 primary schools in Northland last week.
Prof Cox welcomed the plan, but said government help would be needed to keep it going.
"If it was run for a couple of years then stopped it's not going to achieve a lot," he said.
- © Fairfax NZ News
Your club information portal, post or view your sports fixtures, results and general information.
Check out what's on in your community or post an upcoming event.
Subscribe to a digital replica of The Southland Times.
Southland Times subscriber news and information.
Click here for information about advertising with The Southland Times.
Buy copies of photos featured in The Southland Times.