Susan E. McCann, PhD, RD
Susan E. McCann, PhD, RD, member and professor of oncology, division of cancer prevention and control, Roswell Park Comprehensive Cancer Institute, Buffalo, New York.
We already know that plant-rich diets are rich in health benefits, but I am always pleased to see research supporting the evidence as to when and why it matters, since it serves to reinforce the fact that enhancing wellness can measurably improve our health, even in the face of disease. A recent study demonstrated that lignans, a class of chemicals in such foods as seeds, whole grains, fruits and vegetables, may contribute to survival in women with breast cancer. Researchers from Roswell Park Comprehensive Cancer Institute in Buffalo, New York, asked 1,122 women who had been diagnosed with breast cancer between 1996 and 2001 to answer a questionnaire concerning their intake of more than 100 foods. The results showed that post-menopausal patients who ate a high-lignan diet were about 70% less likely to die from the cancer. Curiously, lignan intake didn’t make a difference in survival among pre-menopausal women.
Susan E. McCann, PhD, RD, in the division of cancer prevention and control, was the lead study author. She acknowledged there are several possible alternate explanations for the difference in survival between pre- and post-menopausal women — for instance, in younger women, breast cancer often is especially aggressive. Also, the fact that there were fewer of these younger, pre-menopausal women in the study may have affected the statistical significance of the results. Then again, she says, the younger women reported eating fewer lignans — and perhaps this is what made the difference in survival odds. Previous studies have shown lignans inhibit tumor growth by preventing fresh blood vessels from forming in them and interfering with growth factors that help fuel them.
But might a high-lignan intake help prevent cancer from developing in the first place? Interestingly, several small studies have shown this may help protect pre-menopausal women against breast cancer, but Dr. McCann says that the findings overall are inconsistent. For example, she did a study that showed lignans seemed to help protect women with genetic susceptibility to breast cancer, which some other studies replicated… and others did not. Dr. McCann is now conducting new research to investigate further what properties of lignans contribute to their cancer-fighting effectiveness.
A wide variety of foods contain lignans. Flax seeds are rich in them, but lignans are present as well in wheat, oats, barley and rye, fruit (especially berries), legumes, seeds (pumpkin and sesame, for example), a wide variety of vegetables, tea and even coffee, which after all starts out as a bean. Dr. McCann says that researchers are currently investigating more about the question of lignan intake and cancer, but in the meantime, you can pick from any number of reasons to eat lots of lignans — in addition to possible cancer protection, doing so will make it easier to maintain a normal weight, keep diabetes under control and help protect against a host of other chronic diseases.