One amazing benefit that breastfeeding provides for moms is a lower chance of breast cancer. According to studies, a woman’s risk of contracting this illness appears to decrease with the length of time she breastfeeds.
Overview
Breastfeeding has substantial health benefits to the mother, especially in lowering her risk of breast cancer, in addition to its well-established function in infant nutrition and development.
Breastfeeding has been repeatedly associated with a lower incidence of breast cancer; epidemiological evidence points to a dose-dependent association between the two: the longer a woman breastfeeds, the greater her chance of reducing the disease.
Breastfeeding induces hormonal changes, such as reduced ovulation, which lowers a woman’s exposure to estrogen, which are thought to have this protective impact.
Several biological mechanisms have been proposed as potential contributors, such as immune regulation during lactation, breast tissue differentiation, and the exfoliation of possibly damaged cells, which may aid in the prevention of cancer formation.
Biological Processes
Recent research indicates that one important reason behind breastfeeding’s protective effects may be epigenetics.2. Gene expression can be suppressed by DNA methylation, a process that adds a methyl group to DNA.2. FoxA1, a gene required for the development of healthy breast tissue, is one that is impacted by this process.2.
FoxA1 is frequently suppressed in breast cancer by hypermethylation.2. Mutations in the tumor suppressor gene BRCA-1, which aids in controlling FoxA1 methylation, may be the cause of this.2. When BRCA-1 isn’t working properly, FoxA1 gets hypermethylated, which raises the risk of breast cancer.2.
It seems that breastfeeding modifies this epigenetic composition.2. Lower levels of FoxA1 methylation have been observed in breastfeeding women; this phenomenon is comparable to the protective impact of a functioning BRCA-1 gene.2. Reducing pregnancy-associated plasma protein-A (PAPP-A) overexpression, a characteristic frequently seen in breast cancer, is another benefit of breastfeeding.2.
One unique BRCA-1 gene product called BRCA1-IRIS, which functions as an oncogene, is also involved in the development of breast cancer; the length of nursing appears to be a major modulator of this process.3. During pregnancy, IRIS is essential for the development of mammary cells. However, overexpression of it can contribute to aggressive breast malignancies, including triple-negative breast cancer (TNBC).
However, continuous breastfeeding encourages the removal of possibly malignant cells and decreases IRIS expression.3. On the other hand, inadequate nursing can promote the persistence of IRIS-overexpressing cells and raise the risk of cancer.3.
The immune system and hormone levels are impacted by lactation, which enhances this protective effect. Breastfeeding induces the production of prolactin, which inhibits the hormone estrogen, which is connected to hormone receptor-positive (HR-positive) breast cancer.
Furthermore, a powerful combination of modulators such as immune cells, antibodies (including SIgA), and cytokines are delivered by breast milk, which may enhance immune surveillance in breast tissue.1. For instance, it has been demonstrated that the oleic acid and alpha-lactalbumin present in breast milk cause tumor cells to undergo apoptosis.
The cyclical processes of breastfeeding and involution, which are marked by p53, c-myc, and BCL-xl gene expression and tissue remodeling, may also play a role in eradicating precancerous cells and preserving genomic integrity.
Evidence from epidemiology
There is a consistent link between breastfeeding and a lower risk of breast cancer, according to epidemiological research.
A combined review of data from 47 epidemiological studies across 30 nations found that the risk of breast cancer decreased by 7.0% with each birth and by 4.3% for every 12 months of nursing.4
Nonetheless, a different study found that parity raises the possibility of HR-negative. Nonetheless, compared to women who never breastfed, parous women who breastfed had a decreased risk of this kind of cancer.
Interestingly, nursing appears to have a protective impact in both developed and developing nations4. Disparities do, however, persist between ethnic groupings. Compared to non-Hispanic white women, black and Hispanic women have worse breast cancer death rates and are less likely to breastfeed.
For instance, compared to women of other races, black women—who are disproportionately impacted by aggressive forms of cancer—have a lower incidence of breastfeeding beginning (69.4%).7. This has been connected to the fact that about 70% of black moms return to work soon after giving birth since they are their families’ main source of income.
Effects of exclusive breastfeeding and duration
Breastfeeding has long been linked to a lower risk of breast cancer; longer breastfeeding periods seem to offer even more protection. A cumulative 6-month breastfeeding duration is associated with a considerable reduction in the incidence of breast cancer, according to the threshold effect seen in many studies.
Breast cancer risk may be increased by inappropriate breastfeeding methods or restrictions.9. These include stopping breastfeeding too soon, not nursing for the full six months as advised, and abrupt involution, which can result in ductal hyperplasia and increased inflammation—two conditions that raise the risk of breast cancer.
Effects of nursing on various forms of breast cancer
The effect of breastfeeding on the risk of developing a particular subtype of breast cancer varies. While giving birth seems to reduce the chance of HR-positive, even in the absence of breastfeeding, lactation doesn’t seem to provide any extra protection against it.
Nursing, however, has a strong protective effect against HR-negative, especially the aggressive TNBC.5,10
A 31% decreased risk of TNBC was seen in women who nursed for a minimum of a year. Among younger African-American women, this protective impact was even more prominent, with an 82% risk reduction seen in those who breastfed for six months or longer.
Implications for global health
Global policies, both present and future, that encourage breastfeeding as a preventative measure against breast cancer include complete policy packages, workplace support, and health recommendations.
Health groups recommend exclusive breastfeeding for six months, although the practice is not widely followed.11–13
The Global Breastfeeding Collective establishes policy initiatives with the goal of providing varied lactation support and aligned family leave by 2030.11–13 In order to reduce racial disparities in breastfeeding rates and promote breastfeeding-friendly surroundings, governments and the CDC strengthen programmatic support while highlighting the need for a coordinated strategy.
Obstacles and difficulties when nursing
Widespread breastfeeding failure is hampered by several issues. A barrier is created by the social stigma associated with it, especially in public places, which is frequently impacted by cultural norms and a lack of societal support.
Mothers are additionally hindered by limited workplace accommodations and training and assistance within healthcare systems.14
Women’s decisions can be influenced by deceptive information about the advantages of nursing, physical obstacles like discomfort or difficulties lactating, and psychological barriers.
A multimodal strategy centered on public information campaigns, workplace policies that have been improved, healthcare professional training, and community-based support structures is needed to get beyond these obstacles.