Plant-Based Diets Reduce Risk for Breast Cancer

Plant-Based Diets Reduce Risk for Breast Cancer

Plant-based diets reduce the risk for breast cancer in postmenopausal women, according to research presented at the annual meeting of the American Society for Nutrition. Those women who followed a healthful, plant-based diet of fruits, vegetables, legumes, and whole grains the longest had the least risk of cancer compared to those who ate less healthy foods or animal products. Those who followed lower quality diets increased their risk for breast cancer.

Now a new study suggests that regularly eating a diet high in the foods that help you stay at that healthy weight – fruits, vegetables and other plant foods – may by itself lower risk of breast cancer.

The link to lower risk was most pronounced for tumors that are not fueled by hormones. These breast cancers are less common, but more challenging to treat.

The study was published in The American Journal of Clinical Nutrition.

Going into the study, researchers looked to get away from individual foods and nutrients and focus on dietary pattern, which looks at the overall types of foods we regularly eat. Almost 100,000 women answered questionnaires about what they ate, along with genetic and other risk factors. Five dietary patterns emerged:

1)    plant based: lots of fruits and vegetables

2)    high-protein, high-fat: lots of meat, eggs, butter and fried foods

3)    high carbohydrate: lots of pasta, bread and convenience foods

4)    ethnic: lots of legumes, soy-based foods, rice and dark green leafy vegetables

5)    salad and wine: high in lettuce with low-fat dressing, fish, wine, coffee and tea

Over three quarters of the women ate some combination of these patterns (15 percent ate a single pattern). The researchers scored how much each woman’s diet fell into each pattern. The women were placed into groups of highest through lowest for the diets, depending upon whether they ate the most or least of that dietary pattern.

After 14 years, the pattern that emerged for overall breast cancer protection was the plant-based. Women who most ate a plant-based diet had a 15 percent lower risk compared to those who least ate this type of diet. Alcohol intake, a risk factor for breast cancer, slightly lowered the protective effect of the diet.

The risk reduction for the plant-based dietary pattern was strongest for tumors that do not have receptors for estrogen and progesterone (PR). These cancers do not respond as well to treatment.

Women in the highest plant-based diet group had a 34 percent reduced risk of ER negative/PR negative tumors, compared to those in the lowest group.

Many components of a plant-based diet could reduce breast cancer risk, the authors write. Plant foods’ fiber, nutrients and phytochemicals all have shown cancer-fighting properties. There are a few caveats with this study, such as that the women’s dietary pattern was based only on what they were eating at the start of the study. Yet this study follows others that look at the health benefits of what people are eating overall and disease risk. 

The study was funded by the National Cancer Institute and the California Breast Cancer Research Fund.



Shah S, Mahamat-Saleh Y, Ait-Hadad W, Varraso R, Boutron-Ruault MC, Laouali N. Adherence to Healthy and Unhealthy Plant-Based Diets and Risk of Breast Cancer Overall and by Hormone Receptor and Histologic Subtypes Among Postmenopausal Women. Abstract presented at: Nutrition 2022, annual meeting of the American Society for Nutrition; June 14-16, 2022; virtual conference.

Dietary patterns and breast cancer risk in the California Teachers Study cohort, The American Journal of Clinical Nutrition, Volume 98, Issue 6, December 2013, Pages 1524–1532,



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