In a landmark study published recently in the Journal of Nutritional Biochemistry, researchers from the University of Guelph in Ontario, Canada have proven that a diet rich in omega-3 fatty acids (healthy fats found in cold water fish, such as salmon, and in certain plant foods, such as walnuts) can inhibit the growth of breast cancer tumors by 30 percent, especially if started early in life.
While advocates of omega-3s have long believed that diet may significantly help in preventing cancer, epidemiological and experimental studies to back up such claims have been lacking, and human studies have been inconsistent - until now.
“It’s a significant finding,” said David Ma, a professor in Guelph’s Department of Human Health and Nutritional Sciences, and one of the study’s authors. “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 something else.”
Known as an expert on how fats influence health and disease, Ma believes the study will lead to more research on the benefits of healthy living, and on using diet to reduce cancer risk. “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,” Ma said. “So we’ve used modern genetic tools to address a classic nutritional question.”
The modern genetic tools used by Ma and his research team enabled them to genetically engineer mice that uniquely produce omega-3 fatty acids and develop aggressive mammary tumors. Then, Ma’s team compared those mice to other mice that were genetically engineered only to develop aggressive mammary tumors.
The results provided solid evidence that the mice producing omega-3s developed only two-thirds as many tumors - and any tumors they did develop were 30 percent smaller than those in the control mice.
"This model provides a purely genetic approach to investigate the effects of lifelong omega-3s exposure on breast cancer development. To our knowledge, no such approach has been used previously to investigate the role of omega-3s and breast cancer," said Ma. "The fact that a food nutrient can have a significant effect on tumor development and growth is remarkable, and has considerable implications in breast cancer prevention.”