Rosalee M. Brown
The evidence is not clear, but there are drug trials which have been shown to reduce the risk of recurrent breast cancer in women. The results from the Breast Cancer Prevention Trial have also shown that women at high risk for breast cancer, who take the drug tamoxifen, lowered their risk by 45 per cent.
There are other available prevention measures which include preventative mastectomy and early detection through breast self-examination and routine mammograms.
What of nutrition
There are inconclusive studies and sometimes even conflicting ones regarding the role of nutrition in breast cancer prevention. The Women's Healthy Eating and Living study states that a "diet high in fruits, vegetables and fibre and somewhat lower in fat did not protect early-stage breast cancer survivors from further breast cancer, nor did it help them live longer than women in a comparison group'.
These findings contradict at least one other large study of diet and breast cancer risk. JAMA 2007 Jul 18;298(3): 289-98). Results from the Women's Intervention Nutrition study, a large randomised clinical trial reported in 2005, suggested that a low-fat diet helps prevent breast cancer recurrence in postmenopausal women, especially those whose cancers don't respond to oestrogen.
Another study, Low-fat Diet May Reduce Risk of Recurrence by Chlebowski et al, concluded that a low-fat diet may reduce the risk of breast cancer recurrence in postmenopausal women. However, in the Women's Health Initiative, completed in 2006, researchers found only a slight, statistically insignificant reduction in breast cancer risk among women 50 to 79 who lowered their total fat intake.
Factors at play
It is very difficult to study people's diet because, for example, someone who reduces his or her fat intake may also reduce his or her animal protein intake. The same individual may also increase his or her fruit and vegetable intake. So, there are many factors at play which make it difficult to isolate positive or negative effect.
Although particular foods and nutrients have not been identified as preventative weapons in the fight against breast cancer, there is evidence for the role of diet and a healthy lifestyle in other cancer prevention. The American Cancer Society advises people to reduce cancer risk through exercising, limiting alcohol use, maintaining a healthy weight (as overweight in postmenopausal women has been linked to breast cancer), breastfeeding and avoiding postmenopausal hormone replacement therapy.
Standard nutritional guidelines holds - food has a synergistic effect on health; consume a diet from the six food groups; consume more whole plant-based foods and less processed foods; consume a little animal fat and consume large amounts of fruits and vegetables of all colours.
Rosalee M. Brown is a registered dietitian/nutritionist who operates Integrated Nutrition and Health Services; email firstname.lastname@example.org.