There are a great many Web sites and studies out there that talk about the benefits of breastfeeding. Like much of the stuff on the Web, they have been written at different stages in time, may or may not have been updated, may be based on science or may be based on what someone heard from their neighbour. In short, you can't believe everything you read online.
Breast is best.
Or is it?
All of the major health authorities in the world say that it is. The American Academy of Pediatrics, Health Canada, the World Health Organization, and others are all on the bandwagon. But it has become fashionable of late to claim that breastfeeding isn't really all that beneficial. That the benefits are all overblown.
When I set out to sort through the mess, to find the truth, I started initially collecting bibliographies and lists of studies that I was going to try to scour through at some point if I had time. Not for myself. But to provide a voice of reason in the face of the naysayers.
Fortunately, a number of people that I know and a number of authorities on the topic pointed me to one wonderful study. The über-study of all über-studies. It is called Breastfeeding and Maternal and Infant Health Outcomes in Developed Countries (April 2007) and it was prepared by a team of investigators at the Tufts-New England Medical Center Evidence-Based Practice Center in Boston. This is what was included:
We screened over 9,000 abstracts. Forty-three primary studies on infant health outcomes, 43 primary studies on maternal health outcomes, and 29 systematic reviews or metaanalyses that covered approximately 400 individual studies were included in this review.
Not only is the methodology sound and the research extensive, but as the title indicates, this study is about health outcomes in developed countries. That means that we can put to rest the claims that breast is only best if you don't have access to clean water or enough money to buy formula.
So what are the real scientific benefits of breastfeeding?
I have summarized them below. If you want to see the full details on the number of studies that contributed to each finding, the degree of accuracy, and the quality of the studies, then read the full paper. This is intended only as a summary of the major conclusions.
The benefits to the child
There are a number of health benefits to the breastfed child, some of them are significant and others are less significant.For full term infants the benefits include:
- Acute otitis media (middle ear infections): Babies that were ever breastfed had a 23 percent lower incidence of acute otitis media than exclusively formula fed babies.
- Atopic dermatitis (type of eczema): In families with a history of atopy, exclusive breastfeeding for at least 3 months was found to have a 42 percent reduction in atopic dermatitis compared with breastfeeding for less than 3 months.
- Gastrointestinal infections: Infants who were breastfeeding had a 64 percent reduction in the risk of non-specific gastroenteritis compared with infants who were not breastfeeding.
- Lower respiratory tract diseases: There is a 72 percent reduction in the risk of hospitalization due to lower respiratory tract diseases in infants less than 1 year of age who were exclusively breastfed for 4 months or more.
- Asthma: Breastfeeding for at least 3 months was associated with a 27 percent reduction in the risk of asthma for those without a family history of asthma and a 40 percent reduction for those with a family history of asthma.
- Type 1 Diabetes: Breastfeeding for at least 3 months results in between a 19 and 27 percent reduction in incidence of childhood Type 1 Diabetes compared with breastfeeding for less than 3 months (findings confirmed through multiple studies, but some cause for caution in interpreting results).
- Type 2 Diabetes: Found a 39 percent reduction in risk of Type 2 diabetes later in life for people that were breastfed as infants (some cause for caution in interpreting results).
- Childhood Leukemia: Breastfeeding for at least 6 months associated with 19 percent decrease in risk of childhood acute lymphocytic leukemia and a 15 percent decrease in the risk of acute myelogenous leukemia.
- Sudden Infant Death Syndrome (SIDS): The meta-analysis found that breastfeeding was associated with a 36 percent reduction in the risk of SIDS compared to not breastfeeding. Another study completed since the meta-anlaysis was done found a 50 percent reduction in the risk of SIDS as a result of breastfeeding.
In the past, other claims have been made about the benefits of breastfeeding. However this study determined that some of those benefits were based on other factors that may be associated with a greater incidence of breastfeeding. This includes cognitive development (IQ), which is more likely to be tied to maternal intelligence, socioeconomic status and home environment. It also includes the obesity issue. People who were breastfed are less likely to be obese as adults, but it is not clear whether this is due to breastfeeding or other factors (e.g. being part of a series of healthy choices that a family makes). The risk of cardiovascular disease also does not appear to be lower in breastfed infants than in formula fed infants.
The benefits to the mother
Often people only talk about the benefits to the baby, but forget to talk about the benefits to the mother. Women that are having trouble breastfeeding and considering giving up should think about not only their child's health, but also their own health and weigh the short-term issues they are having with breastfeeding against the longer term potential health benefits. Those benefits include:
- Maternal type 2 diabetes: In women with no history of gestational diabetes, each additional year of breastfeeding resulted in a 4 to 12 percent reduction in the risk of maternal type 2 diabetes (only nurses included in these studies though, so interpreting results for general population must be done with care).
- Breast cancer: A reduction of risk of contracting breast cancer of 4.3 percent for each year of breastfeeding (one study) or 28 percent for 12 or more months of breastfeeding (another study). Another study that I reported on in Save Yourself, Save Our Health Care System, found that if women in Canada breastfed for at least 16 months over their lifetime, we could cut the breast cancer rate from 6 percent of women to 3 percent of women.
- Ovarian cancer: Breastfeeding results in a 21 percent decrease in the risk of ovarian cancer.
Like with the benefits to the infant, there were some frequently reported benefits to the mother that cannot be scientifically proven. One example is weight loss, where there is no clear evidence that breastfeeding mothers shed the weight more easily than formula feeding moms (but we can eat more chocolate bars!). Another example is osteoporosis, where there is no clear benefit from breastfeeding. Postpartum depression is a tricky area, since it is hard to determine cause-effect i.e. did women stop breastfeeding because they had PPD or did they have PPD because they stopped breastfeeding?
When she wrote The Case Against Breastfeeding, Hanna Rosin claimed to have plowed through the studies on breastfeeding and found that the benefits were scant at best. Unfortunately, a lot of people read her article and I have seen her claim now stated over and over again as a fact. The truth is that Hanna Rosin only read a select few studies on breastfeeding, in particular those that would support her claim that perhaps the benefits were scant. She did not do a comprehensive review of the literature on breastfeeding like the one that I cited above.
In my post on the Economics of Breastfeeding: A Cost-Benefit Analysis and the follow-up to that post, I mentioned a study called Maternal Employment, Breastfeeding, and Health: Evidence from Maternity Leave Mandates that claimed that "increased breastfeeding duration has had no effect on overall physical or psychological health outcomes of either children or mothers". That seemed like a very loaded statement that contradicted much of what I had read elsewhere, so I dug into it. A better way to phrase their result would have been this:
- Extending maternity leave rights in Canada led to women taking 3 to 3.5 months longer off of work on average.
- Most women in Canada breastfed both before and after the change in maternity leave policies.
- Despite most women initiating breastfeeding, both before and after the change in maternity leave policies few women in Canada met the recommended duration of breastfeeding.
- The change in maternity leave policies resulted in women breastfeeding for, on average, 1 month longer than they did before the leave policy was changed.
- It also resulted in an average increase of 1.5 months in the length of exclusive breastfeeding.
- This increase in the length of breastfeeding did not show improvements to the physical or psychological health of either children or mothers using data collected about mother/baby pairs for which the children were aged 7 to 12 months old and 13 to 24 months old at the time
Basically, this doesn't look at the difference between formula feeding versus breastfeeding. It doesn't look at significant increases in the length of breastfeeding. It doesn't look at long-term results of breastfeeding on the child or the mother's health.
While I support continued research on this topic, we need to be careful how the results are thrown around and be more specific about what was actually found.
Does this mean that breast is only?
Breast is not just best. In fact, breastfeeding should be the standard, the default. However, that doesn't mean it is right or even possible for everyone all of the time. So breast is not only. Stay tuned for my next post on the issue of choice and options in infant feeding.