After being diagnosed with breast cancer, many women make diet and other lifestyle changes to improve their health as they recover from treatment. Eating a healthy diet after being diagnosed can give you more energy as you recover and improve your quality of life.
Researchers have wondered if eating a healthy diet after being diagnosed improves survival. A study done by experts at the National Cancer Institute suggests that postmenopausal women who eat healthy after a breast cancer diagnosis are less likely to die from breast cancer or any other cause.
The research is part of the very large Women’s Health Initiative Clinical Trial and the Women’s Health Initiative Observational Study. Both studies are commonly called the WHI. Together, the two studies include information from more than 161,608 postmenopausal women who were ages 50 to 79 when they joined from 1993 to 1998. The WHI wants to find any links between health, diet, and lifestyle factors and health problems, such as cancer.
The study was published in the April 2014 issue of Cancer Epidemiology, Biomarkers & Prevention. Read the abstract of “Better Postdiagnosis Diet Quality Is Associated with Reduced Risk of Death among Postmenopausal Women with Invasive Breast Cancer in the Women’s Health Initiative.”
For this study, the researchers compared two groups of women who had been diagnosed with invasive breast cancer:
- 1,205 women in the WHI Dietary Modification Trial who changed their diets after being diagnosed
- 1,112 women in the WHI Observational Study who didn’t change their diets after being diagnosed
As part of the WHI, the women regularly fill out a survey on the foods they eat and how often they eat them. The researchers used information from food surveys completed:
- just before the women were diagnosed
- about 1.5 years after diagnosis
- once every 3 years for 9 years after that
The researchers figured out the quality of the women’s diets by assigning points to the foods they ate using the Healthy Eating Index, created by the U.S. Department of Agriculture. The Healthy Eating Index used the 2005 U.S. Dietary Guidelines for Americans as the basis for assigning points. According to the guidelines, a healthy diet includes:
- 4 servings of fruit
- 5 servings of vegetables
- 6 ounces of grains (three ounces should be whole grains)
- 5.5 ounces of meat or beans
- 3 cups of dairy
- no more than 6 teaspoons of oils
The guidelines also recommended that solid fats, alcohol, and sugar be eaten in moderation.
The Healthy Eating Index gives a score for eating certain types of foods. Scores range from 0 to 100 – a higher score means a better quality diet.
In this study, scores for diets were:
- 34-63 equaled a poor quality diet
- 63-77 equaled a mixed quality diet
- 78-100 equaled a high quality diet
Women in the poor quality diet group ate more calories, drank more alcohol, and exercised less than women in the better quality diet group.
Overall, 415 women died during the study:
- 188 died from breast cancer
- 227 died from other causes
Compared to women who ate a poor quality diet, women who ate a high quality diet:
- had a 26% lower risk of dying from any cause
- had a 42% lower risk of dying from something other than breast cancer
The researchers also looked to see if diet had an effect on survival rates for different types of breast cancer. They found:
- women diagnosed with estrogen-receptor-positive disease who ate a high quality diet had a 45% lower risk of dying from any cause compared to women who ate a poor quality diet
- diet quality appeared to have no effect on survival rates in women diagnosed with estrogen-receptor-negative disease
It’s not clear why diet quality didn’t have an effect on estrogen-receptor-negative breast cancer. The researchers suspect that because estrogen-receptor-positive breast cancer generally has a better prognosis than estrogen-receptor-negative breast cancer, survivors of estrogen-receptor-positive disease are more likely to die from something other than cancer. These other causes may be more affected by diet quality than breast cancer.
While these results are encouraging, it’s important to keep several things in mind:
- The study relied on the women accurately reporting what they ate and drank. Sometimes people don’t remember everything they eat and drink, which would affect the results of the study.
- The study didn’t look to see if women were following their breast cancer treatment plans completely. Stopping a treatment early would affect the study results.
- The study only looked at postmenopausal women diagnosed with breast cancer. The results can’t be applied to premenopausal women diagnosed with breast cancer.
If you’re a postmenopausal woman who’s been diagnosed with breast cancer, it makes sense to make healthy diet and lifestyle choices to keep your risk of recurrence as low as it can be and your overall health the best it can be, including:
- eating a diet low in added sugar and processed foods
- eating a diet rich in unprocessed, nutrient-dense foods (foods that have the most vitamins, minerals, and healthy compounds)
- exercising regularly at the highest intensity level you’re comfortable with
- avoiding alcohol
- not smoking
It also makes sense to stick to your treatment plan. Treatments such as chemotherapy and radiation therapy can require trips to the hospital or doctor’s office for several months. You also may need to take medicines for 5 or 10 years after surgery. You get the best results when you follow your plan completely and on schedule.
For tips on how to overcome common problems with following a treatment plan, visit the Breastcancer.org Staying on Track with Treatment pages.