The trend is marked in middle-aged women who ate a 'war diet', in which rationing limited calorie intake, at some time in their youth. Studies from Norway, the Netherlands and Scotland show a reduction in risk of between 10 and 30 per cent, according to Professor Peter Boyle, director of the division of epidemiology and statistics at the European Institute of Oncology in Milan.
Professor Boyle, who conducted the Scottish study, said the findings gave a strong clue to the causes of the disease, which affects 135,000 European women each year. 'There is mounting evidence that women on a restricted diet at or around the time of puberty have less breast cancer as they come through life. This time, around puberty and just after, is perhaps of vital importance for breast cancer, and the wartime cohort are particularly interesting,' he said.
Scientists do not know if a low-calorie diet has a direct effect on factors involved in the development of breast cancer, or an indirect one through its influence on hormones and menstruation. Women on restricted diets often have irregular periods or none at all. A diet low in fat may also be significant, although studies on its role in breast cancer have produced conflicting findings.
The countries that were studied all introduced some form of rationing during the Second World War. Britain's wartime diet was generally acknowledged to be 'the best ever', according to Professor Gordon McVie, scientific director of the Cancer Research Campaign. Available food was more evenly distributed. Families which had suffered during the Depression benefited from this, and from the improvement in income when the war created employment.
Rationing improved the quality of diet for many families. From 1940, meat, sugar and dairy products were rationed, so that everyone had a share; bread was made with 'national flour' which contained 80 per cent of whole grain.
Extra vitamins A and D were added to margarine, and from 1941 children and pregnant women were given orange juice and cod liver oil to provide vitamins A, C, and D - vitamins A and C are important constituents of an 'anti-cancer' diet.Reuse content