A lifelong diet rich in omega-3 fatty acids can inhibit
growth of breast cancer tumours by 30%, according to new research from the
University of Guelph.
The study, published recently in the Journal of Nutritional
Biochemistry, is believed to be the first to provide unequivocal evidence that
omega-3s reduce cancer risk.
“It’s a significant finding,” said David Ma, a professor in
Guelph’s Department of Human Health and Nutritional Sciences, and one of the
“We show that lifelong exposure to omega-3s has a beneficial
role in disease prevention – in this case, breast cancer prevention. What’s
important is that we have proven that omega-3s are the driving force and not
Breast cancer causes
Breast cancer remains the most common form of cancer in
women worldwide and is the second leading cause of female cancer deaths.
Advocates have long believed diet may significantly help in
preventing cancer. But epidemiological and experimental studies to back up such
claims have been lacking, and human studies have been inconsistent, Ma said.
“There are inherent challenges in conducting and measuring
diet in such studies, and it has hindered our ability to firmly establish
linkages between dietary nutrients and cancer risk,” he said.
“So we’ve used modern genetic tools to address a classic
How the study was
For their study, the researchers created a novel transgenic
mouse that both produces omega-3 fatty acids and develops aggressive mammary
tumours. The team compared those animals to mice genetically engineered only to
develop the same tumours.
“This model provides a purely genetic approach to
investigate the effects of lifelong omega-3s exposure on breast cancer
development,” Ma said.
“To our knowledge, no such approach has been used previously
to investigate the role of omega-3s and breast cancer.”
Mice producing omega-3s developed only two-thirds as many
tumours – and tumours were also 30% – as compared to the control mice.
“The difference can be solely attributed to the presence of
omega-3s in the transgenic mice – that’s significant,” Ma said.
“The fact that a food nutrient can have a significant effect
on tumour development and growth is remarkable and has considerable implications
in breast cancer prevention.”
Known as an expert in how fats influence health and disease,
Ma hopes the study leads to more research on using diet to reduce cancer risk
and on the benefits of healthy living.
“Prevention is an area of growing importance. We are working
to build a better planet, and that includes better lifestyle and diet,” he
“The long-term consequences of reducing disease incidence
can have a tremendous effect on the health-care system.”
The study also involved lead author Mira MacLennan, a former
U of G graduate student who is now studying medicine at Dalhousie University; U
of G pathobiology professor Geoffrey Wood; former Guelph graduate students
Shannon Clarke and Kate Perez; William Muller from McGill University; and Jing
Kang from Harvard Medical School.
Funding for this research came from the Canadian Breast
Cancer Research Alliance/Canadian Institutes of Health Research, the Canada
Foundation for Innovation and the Ontario Research Fund.