KEY POINTS:
Love it or loathe it, those warm half pints of milk a generation of Kiwis were forced to swig at school may prove beneficial against developing bowel cancer decades later.
Otago University associate professor Brian Cox thinks so and is embarking on a survey of 1000 people to
investigate the link between the school milk programme and a reduced risk of developing bowel cancer.
Work by Professor Cox, director of the Hugh Adam cancer epidemiology unit, found the risk of developing bowel cancer among men and women born between 1941 and 1956 was 60 per cent lower than for previous generations.
"The generations before then all had a similar risk for a very, very long time and then, suddenly, you've got this dramatic reduction.
"It quite clearly shows that something quite profound happened in terms of the upbringing of that generation before they reached 25 which determined their risk of bowel cancer as adults."
Professor Cox believes the answer may lie in the fact that this group grew up during the time when all schoolchildren between 7 and 12 received a free half pint of full cream milk each school day.
Studies have shown that supplementing the adult diet with calcium supplements reduces the occurrence of certain types of bowel cancer and the free milk would have provided about 75 per cent of the daily calcium requirement of a child.
"We took somewhat of a leap and wondered whether calcium in childhood might alter one's adult risk of bowel cancer."
Professor Cox said there might be other factors involved but the milk theory was chosen to be tested first because many people would have memories - good and bad - of the school milk programme, which ran from 1937 to 1967.
"I remember some kids throwing up when the milk was too warm. There were other kids who would try and drink three half-pint bottles like they thought it was beer or something."
Professor Cox and colleague Dr Mary Jane Sneyd now plan to test the theory with the survey of people aged 25 to 69, some of whom have bowel cancer.
Through questionnaires, participants will be asked about their school milk consumption and other aspects of their diet.
The study, which was made possible through one of 23 grants totalling $553,000 from the Genesis Oncology Trust this summer, is to be completed this year.
New Zealand has one of the highest rates of bowel cancer in the world. In 2002, 2588 cases were diagnosed and there were 1135 deaths.
Milk monitor
* The school milk programme ran from 1937 to 1967.
* All children aged between 7 and 12 received a free half pint of full cream milk each school day.
* The risk of developing bowel cancer among those born between 1941 and 1956 has been found to be 60 per cent lower than in previous generations.
* Studies have shown that supplementing the adult diet with calcium reduces the occurrence of certain types of bowel cancer.
* The free school milk would have provided about 75 per cent of a child's daily calcium requirement.