The long-awaited results of the Women's Healthy and Eating Lifestyle Study were published today in JAMA. This large, randomized, multi-center study studied the effect of a low-fat diet that was also very high in vegetables, fruits, and fiber on the occurrence of additional breast cancer events and over-all survival for early-stage breast cancer patients after therapy was completed.
The short answer is that no substantial difference was found for subsequent breast cancer events or overall survival between the two groups (the intensive diet intervention groups versus the control group). Both groups had a nearly identical rates for breast cancer events during the mean follow-up of 7.3 years (16.7% for the diet group vs. 16.9% for the control group). A nearly identical rate for all-cause death was also seen between the two groups (10.1% for the diet group and 10.3% for the control group) with >80% of all deaths due to breast cancer in both groups. Various subgroup analyses (hormone status, tumor size, age, etc, etc) also showed very few differences between the diet and control groups.
It is important to point out that ~75% of all study participants in both the diet and the control group had already changed their diet before the study started by increasing their intake of fruits and vegetables to ~7 servings/day. However, there did not appear to be an advantage to the few women in the diet group who started at less than 5/day to increasing to 9+/day.
The full article in JAMA is available to read by clicking on the title of this posting.
Take home points:
(1) This is no time to throw out the baby with the bathwater. Keep those healthy lifestyle habits that you are working on for cancer survivorship, cancer prevention, and overall good health!
(2) The data from the control arm of this study (posted on 7/15) clearly showed a 50% reduction in the subgroup of women who did consume at least 5 servings/day of fruits and vegetables plus briskly walked the equivalent of 30 minutes/day for 6 days/week, even in obese women.
(3) Previous data published from the Iowa Women's Health Study have showed significant decreased incidence in primary cancer diagnoses in those women who achieved higher number of cancer prevention lifestyle goals.
(4) The Nurses Health Study has shown a 50% decrease in breast cancer recurrence in those women who briskly walked at least 3 hours/week, and these data showed the most benefit to those women who were initially overweight or obese.
(1) I am not changing one thing about what I eat or how I exercise.
(2) I have never felt guilt about not reaching my daily goals of 9+ servings of fruits and vegetables or walking an hour/day.
(3) We have a more defined window of what may be "enough" to achieve optimal outcomes, however, most good science (like this study) usually raises more questions than it answers.
(4) However, I will repeat one of my recommendations from 7/15:
If you are a cancer survivor and have lost significant weight during therapy and/or also have medical conditions such as diabetes, overweight/obesity, multiple food allergies, GI disorders or symptoms as a few examples, I highly recommend seeking the expertise of a Registered Dietitian (RD) at your cancer treatment facility who can assess your overall nutritional and lifestyle requirements to design a plan that meets your individual nutritional needs to improve your overall health.
Science keeps marching on, one step at a time. I extend my deep gratitude and heart-felt thanks to all the women who volunteered to be a part of the WHEL study, all the health care professionals who conducted the study, and the funders of this valuable and much-needed research (The Walton Family Foundation and NCI).
Diana Dyer, MS, RD