Breast cancer is the most common cancer in women worldwide, and is the second most common cancer overall. Studies show that one in eight women will develop breast cancer during their lifetime, and it is estimated that aside from non-modifiable risk factors, 30-50% of breast cancers can be prevented by a healthy diet.
 
In a recent clinical trial, researchers assessed a mouse model of breast cancer, and found that dietary exposure to a healthier lipid profile, with a greater prominence of omega-3 fatty acids, significantly mitigated breast cancer outcomes in a mouse model.
 
Preceding epidemiological evidence suggests that populations with greater intakes of omega-3s seem to have a reduced incidence of breast cancer, whereas Western populations with a high intake of omega-6 fatty acids, such as linoleic acid, have a higher incidence of breast cancer.
 
In the animal trial, the mice were assigned to one of five diets, each of which was prominent in one type of omega-3 or omega-6 fatty acids. Starting at 10 weeks of age, tumor volume in the mice was calculated, and tumor measurements were taken three times per week when a new tumor was detected, until termination at 20 weeks of age.
 
It was found that tumor onset was significantly earlier in the safflower-fed mice enriched in omega-6 fatty acids, whereas mice with high omega-3 diets had the greatest extension of tumor latency. Mice whose fat intake came primarily from flaxseed oil had an intermediate tumor latency.
 
With respect to tumor outcomes, it was clear that mice fed saturated fatty acids, plant-derived omega-3 fatty acids, and monounsaturated fatty acids each had the poorest outcomes – mice that were fed a diet with a high profile in marine-derived omega-3s had the best tumor outcomes, the researchers said.
 
“For simplicity, dietary studies often are a comparison of two different diets, which gives rise to a ‘good vs. bad’ dietary conclusion,” the researchers said. “By comparing all the major families of fatty acids together using enriched oils, this study was able to provide a relativistic view of their influence on breast cancer outcomes. In conclusion, marine-derived n-3 PUFA best mitigates breast cancer outcomes compared to other dietary fatty acids examined in this study. [Monounsaturated fatty acids], [Saturated fatty acids], and plant-derived n-3 PUFA performed similarly and n-6 PUFA fed mice had the poorest breast cancer outcomes. Overall, these findings highlight the need to carefully consider the type of fatty acid in dietary lifestyle interventions for the prevention of breast cancer.”