Introduction
One of the biggest decisions that a new or expecting parent will make is deciding whether or not to breastfeed their child. If the child is breastfed, The American Academy of Pediatrics (AAP) recommends that infants be breastfed exclusively for the first 6 months and encouraged for at least 12 months or longer. (Neumours, 2017). Experts believe that breast milk is the best nourishment for children but for many women breastfeeding is not possible. When deciding whether to breastfeed or formula feed, the decision normally lies on lifestyle, comfort, and medical situations. For the women who are unable to breastfeed, formula is a healthy alternative, which provides babies with the necessary nutrients to grow and develop properly.
Breast milk is naturally the first nourishment for infants. Years ago, formula was not an option for nourishment and women with breast milk would sometimes feed other children whose mother’s did not produce milk. Studies have also shown that breastfeeding creates a bond between the mother and child due to the hormone secretion. Breastfeeding as a lifestyle choice, it is crucial in low-income countries. Many families are forced to breastfeed because of financial difficulties as opposed to choosing an option based on understanding. Although breastfeeding is not exclusive to families that are low income, it is statically shown that children in low-income homes are breastfed for longer than those that are in higher income homes. In the study titled Breastfeeding in the 21st century: epidemiology, mechanisms, and lifelong effect by Dr. Cesar Victoria and colleagues, their research shows how important breastfeeding is for all women and children, regardless of where they live and their income. Appropriate breastfeeding practices prevent child morbidity due to diarrhea, respiratory infections, and otitis media. In places where infectious diseases are common causes of death, breastfeeding protects infants from infection. Even when considering high-income populations, breastfeeding lowers mortality from causes such as necrotising, enterocolitis, and sudden infant death syndrome. (Victoria, 2016).
Although most differences between breastfed and formula fed infants decreases by age, studying the differences in the consumption of the two can lead to important revelations in biomarkers of infant nutrition. The adolescent period is very crucial for establishing healthy lifestyle choices that will prevail into adulthood. The consumption of breast milk shows advantages in lower risk of infection, higher childhood cognitive development, and lower risk obesity. Breastfeeding is also believed to be correlated to lipidomic levels, DNA methylation and gene expression, calprotectin levels, and Leptin levels. In this paper, the potential advantages and disadvantages of breastfeeding will be discussed and reviewed using previous research.
Body
When considering breast milk in the aspects of history, it can be considered to be the first nourishment for babies. This is exactly how Trisha Gura describes it in her review article entitled Nature’s First Functional Food. Breast milk abounds with complex carbohydrates called oligosaccharides that humans cannot digest but beneficial bacteria thrive on. These oligosaccharides were discovered fifty years ago and due to the lack of technology, scientists were unable to advance in their research and lost interest in the milk-microbe connections. Breastfeeding helps the baby fight against infections due to the macrophages and stem cells for regeneration and hundreds of thousands of bioactive molecules. Some of these bioactive molecules are fat-like and other protein-like. (Gura 2016).
When considering Formula as an alternative, it is created to have almost the same structure as breast milk. Their lipid structure mostly consists of triglycerides (TG). In Phillipa Prentice’s research titled Lipidomic Analyses, Breast- and Formula-Feeding, and Growth in Infants, the affects of being exclusively breastfed or formula fed was studied. The differences were seen within the early feeding pattern that reflects the lipid composition. There may also be additional effects of infant nutrition on early fat metabolism. (Prentice, 2015). Their results indicated that breast fed children had lower short chain unsaturated phosphatidylcholines (PC) but higher long chain polyunsaturated fatty acid containing PC. At 3 months, PCs contributed to 35% of the total lipid signal. The majority is seen to be medium and long chain fatty acids. When comparing breastfed infants with formula fed infants, the breastfed infants had less short chain unsaturated PC but higher long chain polyunsaturated fatty acid containing PC. (Prentice, 2015). This is correlated to previous research that cholesterol and lipoprotein levels in breast and formula milk cause differences in early physiology and metabolism. This shows that breastfed children have higher cholesterol and low-density lipoproteins than formula fed but lower high-density lipoproteins. Higher omega 3- and 6- fatty acids have also been reported among breastfed children. The results were obtained by dried blood spot sample, which provided a lipidomic profiling. The differences between breastfed and formula fed infants decreased with age. The lipid differences between breastfed and formula fed infants leads to the conclusion that breast milk intake lowers the risk of infection, higher childhood cognitive development and a lower obesity risk. It is yet to be understood what constitutes as healthy or normal lipidomic profiles but the consumption of breast milk shows advantages in lower risk of infection, higher childhood cognitive development, and lower risk obesity.
On the other hand, when considering the affects on DNA methylation in the offspring, Epigenetic mechanisms have been suggested as potential mediators of the effects of early-life exposures on later health outcomes. Breastfeeding is known to have short-term health benefits opposed to formula feeding but because these benefits lessen with time, there is evidence that the early exposure may continue over time and cause some kind of mark on the organism. DNA methylation occurs in cytosine-guanine dinucleotides in genomic regions called CpG islands. (Hartwig, 2017). The study titled Breastfeeding effects on DNA methylation in the offspring by Fernando Hartwig and colleagues, observed two groups of 16 female rats each. One group received breast milk and the other received a high carbohydrate formula. Half the animals in each group were given standard laboratory rodent diet at postnatal day 16. The other half was given standard food at day 24. (Hartwig, 2017). The results obtained show that breastfeeding might be negatively associated with promoter methylation of LEP, CDKN2A, and Slc2a4. It is positively associated with Nyp. LEP encodes an anorexigenic hormone. CDKN2A is involved in tumor suppression. Slc2a4 genes encode an insulin-related glucose transporter. It is positively associated with the promoter methylation of the Nyp. Nyp encodes an orexigenic neuropeptide gene. Higher gene expression levels of LEP and Slc2a4 genes and lower levels of the Npy genes gives evidence that breastfeeding might protect against obesity and diabetes. Because CDKN2A has important tumor suppressing roles, breastfeeding has the potential to protect against cancers. (Hartwig 2017). The study suggests that breastfeeding influences DNA methylation, but in conclusion more studies are needed to observe the long-term associations between breastfeeding and epigenetics.
Previous research over many years has shown that breastfed infants gain less weight during the neonatal period than those that are formula fed. This leads to the investigation of whether or not breastfeeding protects against rapid weight gain and obesity. In the study Breastfeeding duration and its relation to weight gain, eating behaviors and positive maternal feeding practices in infancy by Samantha Rogers, their research shows that a longer duration of breastfeeding is associated with slower weight gain from 1 to 6 and 1 to 12 months and lower weight at 6 and 12 months. These results show that infants that are breastfed longer are seen to eat solid food more slowly at 12 months. This shows that breastfeeding may influence slower eating styles, which enhances this response in early childhood. The research however did not find a relationship between breastfeeding and the duration of food enjoyment, food response, fussiness, or desire to drink. (Rogers 2017). When considering whether or not breastfeeding is correlated to obesity, further research must be done analyzing breastfeeding helps infants develop obesity-protective eating behaviors.
When considering the impact of intestinal behavior that breastfeeding may have on the first several months of life. The study by Masoumeh Asgarshirazi titled Comparison of Fecal Calprotectin in Exclusively Breastfed and Formula or Mixed Fed Infants in the First Six Months of Life, looks into the microflora in fecal matter. Microflora is seen to have major effects on the composition and functional differentiation of the immune cells. Calprotectin is a 36.5 kDA calcium and zinc binding protein complex from the s100 protein family, which constitutes about 60% of soluble cytsol proteins in human neutrophils. Calprotectin is known to have bactericidal and fungicidal properties, and various data suggest that it may also be involved in the regulation of the inflammatory process. When considering the correlation of calprotectin to fecal matter, it is associated with the degree of disease activity in inflammatory bowel disease in adults. The study involved sixty infants, 37 boys and 23 girls between the birth weights of 2500-4000 g. The infants were split into two groups, which were similar in sex, GI problems, and delivery route. 28 of the infants were exclusively breastfed while 32 were formula fed. The median stool calprotectin in exclusively breastfed infants was 312 μg/g in the first month and 210.5 μg/g in the sixth month. While in formula fed infants these quantities were 110 μg/g in the first month and 93.5 μg/g in the sixth month. There was no significant difference seen between male and female infants. (Asgarshirazi, 2016). Infants who were exclusively breastfed were found to have higher levels of calprotectin. When considering the levels correlated to time, there were higher levels of calprotectin in the first month of life when compared with the sixth. This is most likely due to immaturity of the gut barrier from inflammatory response. This is contrary to the benefits associated with breastfeeding. Calprotectin may have negative affects on growth and represents issues with inflammatory bowel responses. The research evidence shows that the correlation between calprotectin and breastfeeding may be a sign of enhanced mucosal immune maturity. (Asgarshirazi, 2016).
Leptin is produced in the human placenta and plays a crucial role in fetal and neonatal growth. When providing critical growth factors for a newborn child, the placenta replaces many functions of the mammary gland. In the study titled Leptin Expression in Human Mammary Epithelial Cells and Breast Milk by Susan Smith-Kirwin and colleagues propose that leptin is secreted by mammary epithelial cells in milk fat globules, this then goes into the lipid portion of the breast milk. RT/PCR analysis of RNA from the mammary gland revealed levels of leptin mRNA in comparison to adipose tissue. Levels of beta-casein were seen in the mammary gland but not in the adipose tissue RNA. Beta-casein is a marker of mammary epithelial cell differentiation. It was concluded through the results that leptin is present or associated with milk fat globules of breast milk. Breast milk had the highest amount of leptin but when considering whole and skim milk, there are higher levels of leptin in whole milk because they are associated with milk fat globules which partition into the lipid of the whole milk. (Smith-Kirwin, 1998). Thus nursed infants were found to have higher leptin concentrations. Leptin is separated in vesicles that are not detectable by radioimmunoassay. Leptin most likely becomes correlated with the milk fat globule when processed through the Golgi apparatus. The association of leptin with milk fat globules results in the protection of leptin degradation of leptin by the infant digestive tract. Because leptin concentrations in the mother and newborn are independent, placental leptin has been linked to regulate fetal growth and development.
Overweight status is defined by being exceeding the 95th percentile for age and sex when considering national data. Research suggests that breastfeeding is correlated to lowering the risk of obesity in adolescence. In the study titled Risk of overweight among adolescents who were breastfed as infants by MW Gillman, the extent to which weight is associated with breast or formula feeding and the duration of formula feeding was observed. A survey of 8186 girls and 7155 boys between the ages of 9 and 14 were studied by their diet, activity, and growth. (Gillman, 2001). When considering infants who were formula fed, girls from ages 9-14 were 5% overweight and boys 9%. The infants who were breastfed were a confidence interval of 0.78 for girls and 0.80 in boys at the same age group. (Gillman, 2001). This indicates that infants who were breastfed more than formula fed are less likely to be overweight during childhood and adolescence.
Conclusion
In conclusion when considering infants that are breastfed and formula fed, the benefits outweigh the disadvantages in breast milk. When deciding whether to breastfeed or formula feed, the decision normally lies on lifestyle, comfort, and medical situations. For women that cannot breastfeed, formula is a healthy alternative to breast milk because it is composed of primarily the same components of breast milk to mimic the natural composition. The consumption of breast milk shows advantages in lower risk of infection, higher childhood cognitive development, and lower risk obesity. When researching the differences in infants that were breastfed and formula fed, the differences are mostly short term. The only long-term correlation that can be seen is the link to adolescent obesity when infants are not breastfed.
When considering the affect breastfeeding has on DNA methylation, the main beneficial outcome of breastfeeding over formula feeding is the increased expression of CDKN2A, which has important tumor suppressing roles. This leads to the conclusion that breastfeeding has the potential to protect against cancers. The results of lipidomic analysis show that breastfed infants had less short chain unsaturated PC but higher long chain polyunsaturated fatty acid containing PC. This data shows that breast milk intake lowers the risk of infection, higher childhood cognitive development and a lower obesity risk. Leptin plays a large role in neonatal and fetal growth. The analysis of leptin levels in whole, skim, and breast milk show that leptin levels are highest in breast milk and lowest in skim milk. This evidences that milk fat globules of leptin are protected in the infant’s digestive system to ensure fetal growth and development.
In the many articles reviewed, only one showed a disadvantage to breastfeeding as opposed to formula feeding. The one disadvantage found in breast milk is the higher presence of calprotectin. Calprotectin is linked to inflammatory bowl disorders. Although breast milk and formula have similar compositions, breast milk contains many immunogenic components that help reduce cancer risks. Although breast milk may be more beneficial for children, the decision whether or not to breastfeed a child is up to the parents of the child.