Extra fruit, veg may not affect breast cancer outcomes

By Stephen Daniells

- Last updated on GMT

Related tags: Breast cancer, Nutrition

Doubling the five-a-day recommendations for fruit and vegetable
consumption does not provide any extra protection against the
recurrence of breast cancer, says a new study.

The research, published in the Journal of the American Medical Association​, included 3,088 women who were previously treated for early stage breast cancer, and found that adopting a diet very high in vegetables, fruit and fibre and low in fat did not have a lower risk of breast cancer recurrence, compared to women who followed a diet of five or more servings a day of fruit and vegetables. Lead researcher Marcia Stefanick from the Stanford Prevention Research Center said however that this was not evidence that fruit and vegetables conferred no benefits. "I would certainly hope that people don't interpret these results as evidence that eating a lot of vegetables doesn't make a difference in breast cancer,"​ she said. "What it shows is that getting more than the recommended amounts doesn't change the recurrence rate for women who have already completed treatment for early-stage breast cancer."​ The "five-a-day" message is well known, but applying this does not seem to be filtering down into everyday life. Recent studies have indicated that consumers in both Europe and the US are failing to meet recommendations from the WHO to eat 400 grams of fruit and vegetables a day. The randomized controlled trial suggests that women divided the women into two groups: the intervention group (1,537 women) was advised to eat a diet with daily targets of five vegetable servings plus 473 ml (16 oz) of vegetable juice, three fruit servings, 30 grams of fibre, and 15 percent to 20 percent of energy intake from fat; the comparison group (1,551 women) was advised to stick to the "five-a-day" dietary guidelines. During an average of 7.3 years of follow-up, the researchers documented breast cancer events in 256 participants (16.7 per cent) in the intervention group and 262 participants (16.9 per cent) in the comparison group, with breast cancer recurrence and mortality rates nearly identical for both groups of women. One hundred and fifty five women (10.1 per cent) in the intervention group and 160 women (10.3 per cent) in the comparison group died from breast cancer. More than 80 percent of all deaths were due to breast cancer. "In conclusion, during [an average] 7.3-year follow-up, we found no evidence that adoption of a dietary pattern very high in vegetables, fruit, and fibre and low in fat vs. a 5-a-day fruit and vegetable diet prevents breast cancer recurrence or death among women with previously treated early stage breast cancer,"​ wrote the authors. In an accompanying editorial, Susan Gapstur and Seema Khan from Northwestern University wrote than a number of questions still need to be examined regarding diet and cancer risk. "Several issues remain to be addressed regarding the effects of dietary interventions on breast cancer prognosis. It is becoming increasingly clear that evaluating dietary effects is complex and requires careful monitoring to ensure adherence to the intervention goals so that any hypothesized effect can be detected,"​ they wrote. "In addition, studies assessing whether breast cancer prognosis would be improved with interventions that focus on the complex components of energy balance (i.e., physical activity and energy intake) appear warranted. "Unfortunately, available data do not support best practice dietary recommendations to improve long-term prognosis for early stage breast cancer survivors,"​ they concluded. Every year, over one million women are diagnosed with breast cancer worldwide, with the highest incidences in the US and the Netherlands. China has the lowest incidence and mortality rate of the disease. Source: Journal of the American Medical Association​ Volume 298, Number 3, Pages 289-298 "Influence of a Diet Very High in Vegetables, Fruit, and Fiber and Low in Fat on Prognosis Following Treatment for Breast Cancer - The Women's Healthy Eating and Living (WHEL) Randomized Trial" ​Authors: J.P. Pierce, L. Natarajan, B.J. Caan, B.A. Parker, E.R. Greenberg, S.W. Flatt, C.L. Rock, S. Kealey, W.K. Al-Delaimy, W.A. Bardwell, R.W. Carlson, J.A. Emond, S. Faerber, E.B. Gold, R.A. Hajek, K. Hollenbach, L.A. Jones, N. Karanja, L. Madlensky, J. Marshall, V.A. Newman, C. Ritenbaugh, C.A. Thomson, L. Wasserman, M.L. Stefanick Editorial: Journal of the American Medical Association​ Volume 298, Number 3, Pages 335-336 "Fat, Fruits, Vegetables, and Breast Cancer Survivorship" ​Authors: S.M. Gapstur, S. Khan

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