The Universal Benefits of Breastfeeding

Health Letter, November 2016

By Azza AbuDagga, M.H.A., Ph.D.

“In all mammalian species the reproductive cycle comprises both pregnancy and breastfeeding: in the absence of the latter, none of these species, man included, could have survived.” — pediatrician Bo Vahlquist, 1981[1]

It is both conventional wisdom and long-held medical knowledge that breastfeeding is the optimal way to feed newborns and infants. For many years, the American Academy of Pediatrics has recommended exclusive breastfeeding for about the first 6 months of a baby’s life, followed by continued breastfeeding as other foods are introduced, with continuation of breastfeeding for one year or longer as mutually desired by the mother and her baby.[2]

Yet breastfeeding rates vary dramatically worldwide: Over 95 percent of mothers nurse their babies up to their first birthday in rural areas of sub-Saharan African countries, compared with less than 20 percent in most high-income countries.[3] According to the Centers for Disease Control and Prevention (CDC), four out of five American infants start to breastfeed after birth.[4] But only about half continue to breastfeed at 6 months and about a third at 12 months.

A two-article series[5],[6] published in The Lancet in January 2016 represents one of the most comprehensive analyses on breastfeeding to date. The series captured information from numerous systematic reviews of studies. The collective evidence summarized in the series affirms the benefits of breastfeeding for children, women and societies.

Benefits for children

The series cited multiple studies supporting the conclusion that breastfeeding is associated with reduced infant deaths throughout the world. Specifically, studies from low- and middle-income countries found that infants under 6 months who are not breastfed die at about four times the rate of those who receive breast milk. Another study showed that breastfeeding is associated with about a 50 percent reduction in deaths due to infectious diseases in children from 6 to 23 months of age.

Evidence from high-income countries linked breastfeeding to a 36 percent reduction in sudden infant deaths and a 58 percent decrease in necrotizing enterocolitis, a highly fatal condition that typically occurs in the first month of life and is characterized by severe damage to the intestinal tract.

The series estimated that if almost all mothers breastfeed their babies, 823,000 avoidable infant deaths (nearly 90 percent under 6 months of age) would be prevented every year across 75 low- and middle-income countries.

Overwhelming evidence demonstrates that breastfeeding has a protective effect against infections in infants. For example, breastfeeding can prevent about half of all diarrhea episodes and over 70 percent of diarrhea-related hospital admissions. Similarly, about a third of respiratory infections and nearly 60 percent of respiratory-infection-related hospital admissions can be avoided by breastfeeding.

Additional evidence from high-income countries indicates that breastfeeding can serve as an important protection against otitis media, a common infection of the middle ear, in children under 2. There is also evidence that suggests that breastfeeding may slightly reduce the risk of asthma. A review of several studies suggests that breastfeeding is associated with a 19 percent reduction in the incidence of childhood leukemia. Multiple studies show that breastfeeding is associated with a 68 percent reduction in improper alignment of the teeth.

Studies also show that children who are breastfed for longer periods have higher average intelligence levels than those who are breastfed for shorter periods or not breastfed at all; the longer the duration of breastfeeding, the higher the average intelligence levels.

In terms of benefits later in life, evidence compiled from multiple studies shows that children who are breastfed for longer periods are 26 percent less likely to be overweight or obese. This relationship seems to be consistent across income levels. Growing evidence also points to a possible association between breastfeeding and a decrease in the risk of Type 2 diabetes.

The only harmful effect related to breastfeeding noted by the series is an increase in tooth decay in children who are breastfed for more than 12 months, a side effect that can be avoided by improving oral hygiene.

Benefits for mothers

In addition to giving mothers the opportunity to bond with their newborns, breastfeeding promotes the release of the hormone oxytocin, which helps the uterus return to its normal size after delivery and reduces bleeding from the uterus. Exclusive or predominant breastfeeding has a well-recognized role in birth spacing (increasing time between pregnancies and allowing the woman’s body to rest), because the hormone prolactin, which is stimulated by nursing and increases milk production, also suppresses ovulation.

Research shows a clear association between breastfeeding and reduced maternal depression. Breastfeeding may also decrease maternal obesity: Evidence from a very large British study shows that a woman’s mean body mass index is 1 percent lower for every six months that she breastfeeds. Analysis of evidence from multiple studies suggests that breastfeeding is associated with a lower risk for Type 2 diabetes in women who breastfed for longer periods.

There is robust evidence linking lifetime breastfeeding time to reduced breast cancer risk: Every 12 months of breastfeeding are associated with a 6 percent reduction in the incidence for breast cancer. The series estimates that current rates of breastfeeding prevent almost 20,000 annual deaths related to breast cancer and that an additional 20,000 related deaths are preventable by increasing breastfeeding practices worldwide. Likewise, longer periods of breastfeeding have been linked to up to a 30 percent reduction in the risk of ovarian cancer.

Benefits for societies

Besides emphasizing that “breast is best” for the health of children and mothers, the series presents specific economic benefits that increased breastfeeding could bring to societies. For example, not breastfeeding is associated with approximately $300 billion in annual global economic losses related to preventable diseases and lost lives.[7] These economic losses could be avoided if near-universal breastfeeding rates are adopted, eliminating all or much of the $45 billion spent annually on breast milk substitutes across the globe. The series points to environmental harms due to formula feeding. For example, in the U.S., 550 million cans, 86,000 tons of metal and 364,000 tons of paper are wasted annually in the process of packaging breast milk substitutes.

The series points out that breastfeeding is one of the few positive health behaviors that are more widespread in poor than in rich countries. This indicates that the health inequalities between rich and poor children throughout the world would be even worse in the absence of breastfeeding.

Conclusion

The evidence presented in the Lancet series leaves no doubt that breastfeeding provides an opportunity for children to have a strong nutritional head start in life, which can translate into benefits for children, mothers, and society at large.

The reasons that lead some women to avoid or stop breastfeeding include factors related to the mother, child and family, as well as community and societal factors, such as lack of baby-friendly health care facilities and workplace settings. Therefore, the series calls for efforts across all these levels to educate women and their families about breastfeeding and to support their ability to breastfeed optimally.

One important effort for fostering breastfeeding among new mothers is to negate and counter the skilled marketing of the formula industry. To this effect, Public Citizen has been urging hospitals for years to end infant formula marketing,[8] because this marketing has a serious negative impact on breastfeeding rates.[9]

Advice for mothers to establish and sustain exclusive breastfeeding

  • Discuss breastfeeding plans with doctors or midwives during pregnancy and ask how you can learn about breastfeeding.
  • Inquire about the breastfeeding support practices and “baby-friendly” designation of the maternity facility you are considering for giving birth.
  • Learn how to maintain lactation, even in the case of separation from the baby soon after birth.
  • Initiate breastfeeding within the first hour after birth if possible, because the early period after delivery is critical for optimal breastfeeding.[10]
  • Breastfeed as demanded by your baby in order to maintain steady milk flow.
  • Give infants no food or drink other than breast milk, unless medically indicated, for the first six months of their lives.
  • If you are working, check your state laws regarding whether your employer is required to provide you a time and place to pump during business hours. (See the CDC website for specific recommendations regarding proper handling and storage of human milk and breastfeeding during travel.)

References

[1] Vahlquist B. Introduction. Contemporary Patterns of Breast-Feeding Report of the WHO Collaborative Study on Breast-Feeding. Geneva: World Health Organization; 1981.

[2] Eidelman AI, Schanler RJ, Johnston M, et al. Breastfeeding and the use of human milk. Pediatrics. 2012;129(3):e827-e841.

[3] Victora CG, Bahl R, D Barros AJ, et al. Breastfeeding in the 21st century: Epidemiology, mechanisms, and lifelong effect. Lancet. 2016;387(10017):475-490.

[4] Centers for Disease Control and Prevention. Breastfeeding Report Card: Progressing Toward National Breastfeeding Goals United States, 2016. https://www.cdc.gov/breastfeeding/pdf/2016breastfeedingreportcard.pdf. Accessed October 17, 2016.

[5] Victora CG, Bahl R, D Barros AJ, et al. Breastfeeding in the 21st century: Epidemiology, mechanisms, and lifelong effect. Lancet. 2016;387(10017):475-490.

[6] Rollins NC, Bhandari N, Hajeebhoy N, et al. Why invest, and what it will take to improve breastfeeding practices? Lancet. 2016;387(10017):491-504.

[7] Rollins NC, Bhandari N, Hajeebhoy N, et al. Why invest, and what it will take to improve breastfeeding practices? Lancet. 2016;387(10017):491-504. Strader K. Infant Formula Marketing in Public Hospitals: An Outdated and Unethical Practice. April 2016. www.citizen.org/sites/default/files/public-hospitals-infant-formula-marketing-report-april-2016.pdf. Accessed October 17, 2016.

[8] Strader K. Infant Formula Marketing in Public Hospitals: An Outdated and Unethical Practice. April 2016. www.citizen.org/sites/default/files/public-hospitals-infant-formula-marketing-report-april-2016.pdf. Accessed October 17, 2016.

[9] Piwoz EG, Huffman SL. The impact of marketing of breast-milk substitutes on WHO-recommended breastfeeding practices. Food Nutr Bull. 2015;36(4):373-386.

[10] Centers for Disease Control and Prevention. Breastfeeding Report Card: Progressing Toward National Breastfeeding Goals United States, 2016. https://www.cdc.gov/breastfeeding/pdf/2016breastfeedingreportcard.pdf. Accessed October 17, 2016.