Fish consumption has previously been associated with reduced risk of some of the most common cancers, such as breast, prostate, and colon, but cancers of the lymph and hematopoietic system are not typically thought to be associated with diet.
Yet there is some previous evidence that fish consumption is associated with reduced risk of these cancers. Researchers from the University of Western Australia and CancerCare Manitoba in Canada had previously found people in fish-related occupations to have less risk of these diseases.
Their new investigation, published in the April issue of Cancer Epidemiology Biomarkers & Prevention (vol 13, 532-537), compared incidence of leukaemia, multiple myeloma, and non-Hodgkin's lymphoma in a population of more than 6,800 Canadians with fish consumption, reflected in a food frequency questionnaire.
After adjusting for age, sex, smoking, BMI, and proxy status, people who consumed greater proportions of their total energy intake from fresh fish had a significantly lower risk of each of the three types of cancer, and there was a significant dose-response for risk of leukemia and non-hodgkins lymphoma, they report.
Those in the highest quartile for percentage of fat intake from fish were at lowest risk: risk of all lymph and blood system cancers were reduced by 37 per cent and 34 per cent for proportion of dietary fat and energy from fish, respectively. The risk reduction was even greater for leukemia (45 per cent).
"These findings suggest that a diet high in fish may be protective against lymphohematopoietic cancers and confirm the reduced risk among fish workers," conclude the researchers.
Non-Hodgkin's lymphoma is the seventh most common cancer in men, and the sixth most common cancer in women in the UK. Leukaemia accounts for 2 per cent of all cancers but one third of all child cancers, according to Cancer Research UK.