Breastfeeding Lowers Your Risk of Breast Cancer

The benefits may extend to mothers and children

Breastfeeding is healthy for your baby and a wonderful way to bond with them. It has also been shown to lower a woman's risk of breast cancer due to its positive effects on hormones, damaged cells, and genes that either fuel or help protect one from the disease.

Furthermore, breastfed babies may have a reduced risk of childhood illnesses as well as certain cancers later in life.

Statistics and Theories

A 2017 report issued by the American Insitute for Cancer Research (AICF) and the World Cancer Research Fund (WCRF) concluded that five months of breastfeeding is associated with a significant 2% drop in the risk of breast cancer. The AICR/WCRF panel drew these conclusions from 13 studies involving 11,610 women.

The panel offered several theories as to why this occurs. Some of the studies contended that, by delaying menstruation, breastfeeding reduces the lifetime exposure to estrogen and, in turn, the risk of estrogen-receptor-positive breast cancer.

Others hypothesized that breastfeeding rids the body of genetically damaged breast cells that are more likely to become cancerous. It is also possible that breastfeeding alters the expression of genes in breast cells and makes them more resistant to cancerous mutations.

Some studies have also suggested that breastfeeding protects against hormone receptor-negative breast cancers, including an aggressive type known as triple-negative breast cancer.

Duration of Breastfeeding

The choice to breastfeeding is a very personal one, but there is some evidence that doing so for one-and-a-half to two years may reduce your risk of breast cancer regardless of your age or menopausal status.

This is supported in part by research in which women in lower-income countries⁠—⁠who almost invariably breastfeed longer⁠—had lower rates of breast cancer as well as nominally reduced rates of ovarian cancer and type 2 diabetes.

Based on these findings, the researchers postulated that increasing the rate and duration of breastfeeding in all countries, regardless of income, could prevent as many as 20,000 deaths from breast cancer each year.

Children may also benefit. According to a study published in JAMA Pediatrics, children who are breastfed for six months or longer appear to have a lower risk of childhood leukemia. They also have a reduced risk of infection, malocclusion of the teeth, and diabetes than non-breastfed babies.

Application and Limitations

Despite the positive findings, breastfeeding should not be considered a form of cancer prevention. Even if you have several pregnancies and breastfeed each baby, you may still get breast cancer. Simply having breast tissue puts you at risk.

To this end, it is important to perform a monthly breast self-exam to check for changes in your breasts and to have annual mammograms to look for lumps and lesions you may not be able to feel.

Irrespective of cancer risk, the World Health Organization recommends that women breastfeed exclusively for a minimum of six months before introducing solid foods.

A Word From Verywell

While there are established health benefits of breastfeeding, how you choose to feed your child depends on several important factors. The best choice is the one you feel is right for both you and your baby.

Breastfeeding challenges are more common than you may think and can derail the best efforts of even the most committed-to-nursing moms. Be kind to yourself as you navigate the best path forward.

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Article Sources

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  1. World Cancer Research Fund, American Institute for Cancer Research. Diet, nutrition, physical activity and breast Cancer. Updated 2018.

  2. Islami F, Liu Y, Jemal A, et al. Breastfeeding and breast cancer risk by receptor status-a systematic review and meta-analysis. Ann Oncol. 2015;26(12):2398-407. doi:10.1093/annonc/mdv379

  3. Victora CG, Bahl R, Barros AJ, et al. Breastfeeding in the 21st century: epidemiology, mechanisms, and lifelong effect. Lancet. 2016 Jan 30;387(10017):475-90. doi:10.1016/S0140-6736(15)01024-7

  4. Amitay EL, Keinan-Boker L. Breastfeeding and childhood leukemia incidence: a meta-analysis and systematic review. JAMA Pediatr. 2015;169(6):e151025. doi:10.1001/jamapediatrics.2015.1025

  5. World Health Organization. Exclusive breastfeeding for six months best for babies everywhere. January 15, 2011.