The benefits of breastfeeding to a young infant’s health are well-documented (though sometimes debated), and the American Academy of Pediatrics (AAP) recommends that babies be breastfed for the first year of life if possible. Are there any health benefits to the child for breastfeeding beyond a year? I am curious about this as my daughter approaches her first birthday.
Photo credit: Santiago Fernánde. via Wikimedia Commons
It is also important to point out that breastfeeding research conducted in developing countries does not tell us anything about outcomes in the U.S. and other developed countries. There is real evidence that extended breastfeeding benefits children in the developing world, where young children are challenged by malnutrition and greater exposure to infectious diseases, which is why the World Health Organization recommends breastfeeding for two years. My child has access to balanced nutrition and clean water, so whether she nurses beyond a year is less likely to affect her health.
These caveats aside, is there any research to support extended breastfeeding for the sake of my child’s health?
The AAP policy statement on breastfeeding doesn’t discuss breastfeeding beyond a year so didn’t provide any leads. Next, I checked the policy of the American Academy of Family Physicians (AAFP). On nursing beyond infancy, the AAFP position paper states,
“As recommended by the WHO, breastfeeding should ideally continue beyond infancy… It has been estimated that a natural weaning age for humans is between two and seven years [2]. Family physicians should be knowledgeable regarding the ongoing benefits to the child of extended breastfeeding, including continued immune protection [3], better social adjustment [4], and having a sustainable food source in times of emergency.” And on weaning a child due to a subsequent pregnancy, they state: “If the child is younger than two years, the child is at increased risk of illness if weaned [no citation].”
Let’s look at the research cited by the AAFP:
Should I wean my child at the “natural age”?
Katherine Dettwyler is an anthropologist at the University of Delaware. The reference of her work in the AAFP statement is for a book chapter that she wrote [2], but you can also read a summary of her research on her personal webpage. Dettwyler reviewed research on weaning in non-human primates and extrapolated from those observations to determine that the “natural” age of weaning of humans should be 2.5-7 years.
While I appreciate this anthropological perspective, I think it is inappropriate for the AAFP to make recommendations to humans based on what monkeys do. The monkeys do what they do because it probably does benefit their offspring, but this is not evidence that extended breastfeeding will benefit my child. And early human societies probably did breastfeed their children beyond a year. Let’s say that you were a mother raising a baby in a hunter-gatherer society. In your world, you don’t have a safe way to store food, so you have periods of relative feast and relative famine. Your food supply on a given day depends on the success of the most recent hunt and the seasonal availability of wild plant foods. Babies and toddlers don’t cope well with intermittent food supply. They need to eat often to support their rapid rate of growth and development. Of course you would breastfeed as long as possible so that you could provide your child with a reliable source of nutrients. This would allow you, the mother, to store calories and nutrients when food was abundant and later mobilize them to breast milk so that your child could continue to eat even when food was scarce. This is a brilliant evolutionary advantage of mammalian lactation, but it doesn’t really apply in today’s developed societies, where most children have ready access to more than enough calories and nutrients.
Does extended breastfeeding give my child immune protection?
The AAFP cites a 1983 study [3], which shows that concentrations of IgA, lactoferrin, and lysozyme are similar between 12 and 24 months of lactation. However, this was a tiny cross-sectional study, involving just 15 milk samples. And though it tells us is that breast milk still has immunological proteins in the second year of breastfeeding – we don’t know if breastfed toddlers are actually less likely to get sick.
Will my child have better social adjustment if I breastfeed longer?
To support their statement that extended breastfeeding leads to better social adjustment, the AAFP cites a prospective study of 1024 New Zealand kids enrolled at birth and studied for 8 years [4]. The study looked at correlations between duration of breastfeeding and conduct disorders, which were assessed by both the children’s teachers and their mothers. Once the data were adjusted for confounding variables such as family income or disruptions such as divorce, there was a small but significant correlation between longer breastfeeding and better conduct scores, as assessed by the mothers. In other words, the mothers that breastfed their children longer thought a bit more highly of their children, but mothers can be sort of biased, don’t you think? There was little relationship between breastfeeding and the teachers’ scores. The authors conclude, “Certainly, the results provide no support for the view that prolonged breastfeeding makes a major impact on subsequent social adjustment.” I agree – there are lots of ways to influence your child’s behavior in elementary school, but based on this study, breastfeeding is unlikely to help much.
Is breast milk a good food source in times of emergency?
Yes! I’m comfortable saying this even without any science to back it up. If we are ever victims of an earthquake or some other natural disaster, I can imagine it would be very useful to be lactating so that I know I have a ready-made clean source of food and water for my child. However, I probably won’t make my decision based on this unlikely event.
Is my child at increased risk for illness if weaned before 2 years?
Although the AAFP makes this statement, they don’t provide any research to back it up. I looked through countless other studies as well, and I couldn’t find anything to support this statement. So as far as we know, your child will be just fine if you wean before 2 years.
Needless to say, I’m disappointed in the AAFP. I whole-heartedly respect the mission of promoting breastfeeding and believe mothers should be supported if they want to continue breastfeeding beyond a year, but you shouldn’t have to stretch the truth about scientific studies to do so. Most women would read the AAFP’s policy statement and conclude that there is scientific evidence that their kids will be healthier and better-behaved if they breastfeed to two years. Women deserve to have accurate information with which to make their choices. You can tell them that they might enjoy breastfeeding their toddler and there is no rush to wean. You can even say that there may be health benefits, but there isn’t enough research to say for sure. Just don’t cite scientific evidence where there is none. Based on the research cited by the AAFP, there is no scientific evidence that it will compromise a child’s health to wean at a year.
I did read many more studies than these few cited by the AAFP, but this post has already gone on too long. I’ll let you know what data I did find and my own decision about breastfeeding beyond a year in uncoming posts. If anyone has run across a study that looked at breastfeeding beyond a year in the developed world, please pass it on!
What do you think? Does the end justify the means? Is it fair for the AAFP to stretch the scientific evidence to encourage women to breastfeed longer?
REFERENCES
1. CDC, Breastfeeding Report Card – United States, 2011. 2011.
2. Dettwyler, K.A. A Time to Wean, in Breastfeeding: Biocultural Perspectives, D.K. Stuart-Macadam P, Editor. 1995, Aldine De Gruyter: New York, NY. p. 39-73.
3. Goldman, A.S., R.M. Goldblum, and C. Garza. Immunologic components in human milk during the second year of lactation. Acta Paediatr Scand. 72(3): p. 461-2. 1983.
4. Fergusson, D.M., L.J. Horwood, and F.T. Shannon. Breastfeeding and subsequent social adjustment in six- to eight-year-old children. J Child Psychol Psychiatry. 28(3): p. 379-86. 1987.
Interesting, I am glad you thought to look into the benefits of extended breastfeeding! I have been so focused on other aspects of nursing, that I never stopped ti think about this end of it! You may be interested in my post about nursing… http://raisingnaturalkids.com/2011/10/16/returning-respect-back-to-the-breast/
Thanks for reading and for the link! I admit that I have some hesitations about nursing an older child in public, and I’ve been thinking a lot about why that is. I’ll write more about my personal feelings on this soon. And I also admit that I started to feel sort of silly about scouring all the scientific literature for health benefits (when there is so little research on this topic) because I realized that I didn’t care that much what the research says. I can think of many other benefits to nursing beyond a year, and so what if they haven’t been studied? I know, how very scientific of me:)
No, misstating the science is wrong no matter who does it. I think it adds to the problem we have in our society of people picking and choosing what scientific results to “believe in”.
That said- I breastfed my oldest until she was 23 months old. I quit because I was three months pregnant and breastfeeding was exacerbating morning sickness. Also- I figured it was time to let me body concentrate on nourishing the baby inside me, instead of the toddler on the outside.
I am now in the process of weaning my second child. She turned 2 at the beginning of the month.
Why have a breastfed for the second year? Because I like it and my daughter likes it.
Also, having breastmilk on hand makes treating pink eye sooo much easier and faster, and pink eye incidence seems to peak in 1-2 year olds in our day care. I’m not sure if I would have kept going just for that reason, but it sure came in handy a few times.
Why am I weaning now? It just feels like it is the right time to me.
When you say it made treating pink eye easier – do you mean that you applied breast milk around the eye? I’ve heard of that use before but thankfully haven’t had reason to try it yet. Another health benefit (that I don’t think as been studied) but that I have heard plenty of anecdotal evidence for: sick toddlers will likely still nurse (though they may not feel like eating or drinking other fluids), which can help them stay hydrated and nourished through a cold or the flu.
Yep. You squirt some breastmilk in the eye and it clears up pink eye. It is faster than the commercial drops and stings less (I know, because I’ve used it on myself).
My theory is that the natural killer cells in the breastmilk are doing the job.
It was certainly easier to get my toddler getting over a stomach bug to nurse than to do anything else. Also, you can let them have breastmilk almost immediately after they throw up (and in our case, it usually stayed down), making it easier to keep them hydrated.
It’s good stuff, that breast milk.
We seem to have a lot in common;) I did a presentation on this topic a couple for years ago. I also found it very difficult to find relevant published data. Here is one North American study:
J Pediatr Gastroenterol Nutr. 1984 Nov;3(5):713-20.
Breast milk volume and composition during late lactation (7-20 months).
Dewey KG, Finley DA, Lönnerdal B.
http://www.ncbi.nlm.nih.gov/pubmed/6502372
I would love to hear your thoughts! In general, I think extended breastfeeding is not a high priority for research funding:( It is difficult to even get a consistent definition of ‘extended breastfeeding’.
Hi again Jayda! So nice to have your comments here! I checked this article, and it provides some data on breast milk volume and composition. Of course breast milk is a nutritious food for toddlers, but it doesn’t provide any evidence that BM is better than other foods or cow’s milk nutrient-wise. I might work up a comparison between late lactation human milk and cow’s milk though, just to see how they stack up ml by ml. And I completely agree that extended breastfeeding is not a high priority for research funding. It is even hard to find studies that compare BF for 6 months vs a year. And maybe that’s OK, because there are other research questions that are perhaps more pressing, but having some evidence for benefit might help normalize extended breastfeeding in our culture should women choose to continue nursing.
Another likely important variable that adds to the challenge of this sort of research is the variation in proportion of calories provided and number of nursing sessions per day. Maybe it makes a difference if a child is breastfeed on demand vs once per day? I did the latter after one year, enjoying bedtime nursing until 2 years 5 months. Of course, I fit into every category you list as those most likely to extend nursing….
On the other hand, physical contact is so important that maybe there would be no difference if you could control for cuddle time regardless of nursing activity?
Yes! There is so much variation in the amount of milk provided. I have seen some studies, for example, that show that nursing >6x/day past 8-9 months really put breastfed babies at high risk for iron deficiency, so I think it is possible to breastfeed an older infant or toddler too much, to the point of displacing nutrients that you can’t get enough of through breast milk. 1-2 feedings (or snackings) per day would be totally different.
Snuggle time is a HUGE confounding factor in breastfeeding research. This is one of the major critiques of the research showing cognitive benefits of breastfeeding period. Who’s to say that a formula-fed baby who was cuddled a lot wouldn’t get the same benefits? Of course, I am guilty of checking my email on my phone while BF, so it isn’t always quality cuddle time:)
THANK YOU. I have long had concerns about the studies that show smarter, healthier breastfed babies. I do support breastfeeding mothers – but I have real difficulty with all this “science” that’s performed without controlling for variables.
I breastfed my son for 13 months,the choice to wean was made for me by accident (I cut my finger, requiring stitches and antibiotics) but it was pretty clear he was more ready for it than I was. I’d imagine this varies from woman to woman and child to child.
Per Jen’s response – I’ve often wondered if the differences between breast and bottle have more to do with physical contact and the mother’s attention than with the actual milk, but you’re right – how do you measure that? I remember my son used to stuff his little hand in my mouth if I tried to have a conversation while he was nursing.
MH – Thanks for reading and for your comments! I feel like breastfeeding is such a sensitive topic these days. I was nervous about posting this article, because I fully support breastfeeding and extended breastfeeding, but I think we have to really honor each woman’s right to choose how to feed her baby. I’ve heard so many stories of women who couldn’t or even didn’t want to breastfeed and were subsequently racked by guilt about it, and I think that just detracts from the joy of raising a baby. So I just feel like we all deserve to know what the science really says or doesn’t say and make our own choices without having the research spun at us all the time. I don’t think many women are breastfeeding beyond a year just because they’d feel guilty about weaning, but I bet it happens in some circles.
My daughter naturally stopped at 18 months so I’m convinced she didn’t need it anymore. Interesting post, thanks
wow. i’m pretty disgusted by the AAP on this one. another way to phrase your question might be, “is it okay to lie to patients? pretend we know things we just feel might be true?” um, NO.
i’ve been studying the history of american health care this year, and this is a shameful return to (continuation of?) the age-old pattern of defining health via morality instead of science.
I agree, Bionic. (Thought this is about the AAFP, not the AAP.) No matter how good their intentions are, medical organizations have a responsibility to give doctors and patients accurate information. The doctors part is important too. Most family practitioners aren’t going to go read all the breastfeeding literature for themselves – they’re going to count on the AAFP to give them accurate information so that they can make the best recommendations for their patients. I just hate to think of mothers who aren’t enjoying breastfeeding continuing to do it beyond a year because they think their child is going to suffer if they wean.
I’ve been thinking about this question in light of the AAP’s television recommendations, which I wrote about last week. They don’t really have enough data to say that a little TV is really going to hurt kids under two, but they still “discourage” TV for that age group, because that was their best interpretation of the data we have. However, they clearly state the limitations of those data in their policy statement and go on to recommend more research. The problem then becomes how their policy statement is perceived in the media, but I at least think the AAP was honest in their own statement. Although it may seem like a subtle difference, to me it is huge.
oops — i’ll remember to give blame where it’s due!
yes the AAP statement — as opposed to its reception by the popular press — is a good model of how to handle a grey area better.
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Okay, so a year late! Just came across your blog.
I think the biggest scientific thing here that’s missing is the milk composition. IF we are not meant to extend beyond a year, our breastmilk would not continue to change in composition to meet our child’s needs. Is that not true?
I know we do have clean water, access to balanced nutrition, and less risk of malnutrition. However, there are a lot of things going on in the growth of a baby, too, that your body seem to be so aware of. The milk adapts to that growth. The composition never seems to stay the same month by month, nor is it ever the same for each baby. It is uniquely for that baby. I’d continue to reap the benefits of that, if I could.
But I also see the advantages in weaning. The baby usually also seems to know when it’s time to stop.
Hi! Thanks for stopping by and for leaving your comment/question. I guess the answer depends on what you mean by “meant to extend [BFing] beyond a year.” We as a species probably evolved breastfeeding for a few years, as Dettwyler suggests with her anthropological data. Our breast milk may have evolved to help meet the changing nutrient requirements of our growing kiddos, but we can’t be sure about that. For example, I think it is fairly universal that babies start eating solid foods as their teeth start to come in, but what those foods would be would vary around the world. Our breast milk could not have evolved to be the perfect complement to all traditional diets around the world – these could range from plants, insects, game meat, grain crops, seal blubber, fish – you get the picture. And whether it is a great complement to a today’s Western diet is not a given either (I’m not saying it isn’t – it is probably one of the higher quality foods in most toddler diets, mine included!).
Milk composition changes across the lactation are fascinating, and they occur in all species. We extend the lactation of modern day dairy cows by milking them beyond the age at which their calves would naturally wean. (As a side note, if you’ve ever watched a mama cow trying to fend off her adolescent calf butting aggressively at her udder – you know that this is not calf-led weaning!) Their milk composition changes as the lactation wears on, but that doesn’t mean that their calves are at a disadvantage because they aren’t still nursing. Their calves may be happily munching on grass or alfalfa or grain and doing just fine.
The point is that there just isn’t evidence that kids are missing out nutritionally or immunologically if they wean at a year, at least not in developed countries. In developing countries, outcomes are sometimes worse in kids that breastfeed for longer, probably in part because this might be occurring in poorer families with other challenges, but having breast milk displace other foods, such as those rich in iron, is probably part of the picture. And there may well be benefits of breastfeeding beyond a year in developed countries – it honestly hasn’t been studied well. But without studies, I don’t think it is OK for a medical organization to make a recommendation for something that to me, should really be a personal parenting choice. That said, it has been my choice to continue to nurse my toddler, not out of a desire to meet an arbitrary recommendation, but because we both still enjoy it.
My 1 yr old son has diary allergies so I have decided to nurse him beyond the 1 year mark. You could include this point in your article because extended breastfeeding is very beneficial to toddlers who cannot consume cows milk products.
Thank you for this wonderful post. As a biologist that critically reviews scientific literature and sincerely values objectivity, I have been seriously investigating the details of breastfeeding in recent weeks (our first child is on the way shortly). I have found precious little information supporting extended breastfeeding and actually a couple of studies suggesting extended breastfeeding (in developed nations) may leave children deprived of other critical nutrients attained through varied diets past ~six mos. of age and may even lead to a reluctance in accepting other foods as you pass through the toddler years (leading to unintended impaired growth, malnourishment, and added parenting difficulties). I really do appreciate this cogent and well-researched post. Your in-depth investigations significantly add to the legitimacy of your review and are greatly appreciated. I wish folks took the time to do what you did more often (with all subjects, from A to Z).
Great blog….there’s some stuff looking at morbidity and mortality in young children who have been weaned (or not) that might be worth looking at…all developing country contexts but that’s where you find enough children breastfeeding past infancy to look at! The relevance to developed country contexts is not clear, you would not expect to see huge differences in infection rates between weaned and breastfeeding children but in individual cases there are no doubt situations where breastfeeding makes a difference. However, the difference in breast cancer rates between women that breastfeed each child for years vs those who breastfeed for months is large! Briend A, Bari A 1989, Breastfeeding improves survival, but not nutritional status, of 12-3 months old children in rural Bangladesh. Eur J Clin Nutr 43: 603–608. Feachem RG, Koblinsky MA 1984, Interventions for the control of diarrhoeal diseases among young children: promotion of breast-feeding. Bull World Health Organ 62: 271–291. Lepage P, Munyakazi C, Hennart P 1981, Breastfeeding and hospital mortality in children in Rwanda. Lancet 2: 409–411. Molbak K, Gottschau A, Aaby P, Hojlyng N, Ingholt L, da Silva AP 1994, Prolonged breast feeding, diarrhoeal disease, and survival of children in Guinea-Bissau. BMJ 308: 1403–1406. WHO Collaborative Study Team on the Role of Breastfeeding on the Prevention of Infant Mortality 2000, Effect of breastfeeding on infant and child mortality due to infectious diseases in less developed countries: a pooled analysis. Lancet 3: 41–4. World Health Organization 1998, Complementary Feeding of Young Children in Developing Counties: a Review of Current Scientific Knowledge World Health Organization, Geneva.
As a pregnant woman, I plan to breast feed for at least 2 years…. for my own benefit. Years of breastfeeding are inversely correlated with Breast Cancer rates. Researchers found a real drop-off in cancer rates among mothers who breastfed for at least 2 years.
If this is my only baby, I want to make sure I have the lowest possible risk of breast cancer; and I have never seen a comment like this on a breast/formula/weaning discussion.
It’s a great point, and I’m happy that you brought it up since i didn’t address it in this post. The AAFP doesn’t list it as a reason to encourage women to breastfeed for 2 years. But yes, if you only have one child, this would be a reason to keep going. My understanding is that the 2 years is cumulative – it doesn’t have to come from one lactation. And I’m curious if breastfeeding one child for two years would really have the same effect on breast cancer risk as breastfeeding 4 for 6 months each. For me, lactating during that second year meant feeding just a couple of times per day and probably making just a few ounces of milk. Definitely lower intensity physiologically than the first 6 months of lactation. I should look closer at the cancer data, but given the rates of breastfeeding over the last few decades, especially of breastfeeding past 1 year, I would guess that most of the cancer data comes from women with several shorter lactations.
I just recently weaned my daughter, shortly after her second birthday. I can tell you that I really enjoyed this second year of breastfeeding. That was enough of a reason to me to keep breastfeeding, but it is a personal thing and I completely understand if other moms feel differently.
And we can’t ignore the benefits of breastfeeding amenorreah. I think the cancer reducing benefits of breastfeeding are two fold
1) the breast tissue is ‘doing it’s job’ (possibly diminishing impacts after 6-8 months)
and 2) the breast tissue is protected from hormonal surges relating to menstruation.
Thanks for your reply!
There’s only one study that I am aware of that has looked at the impact of a decent length of breastfeeding on risk of breast cancer.
Zheng, T., L. Duan, et al. (2000). “Lactation reduces breast cancer risk in Shandong Province, China.” American Journal of Epidemiology. 152(12): 1129-1135.
Results from studies of western populations investigating lactation and breast cancer risk have been inconsistent. To examine this issue, the authors conducted a hospital-based case-control study in Shandong Province, China, in 1997-1999. A total of 404 cases and an equal number of controls were included. Detailed information regarding lactation, menstruation, and reproduction was collected through in-person interview. The authors found a significant inverse association between duration of lactation and breast cancer risk. For women who breastfed for more than 24 months per child, the odds ratio was 0.46 (95% confidence interval (CI): 0.27, 0.78) when compared with those who breastfed for 1-6 months per child. A significantly reduced risk of breast cancer was also found for those whose lifetime duration of lactation totaled 73-108 months (odds ratio = 0.47, 95% CI: 0.23, 0.95) and for those who breastfed for > or =109 months (odds ratio = 0.24, 95% CI: 0.11, 0.53). The test for trend was statistically significant for both mean duration of lactation per child (p = 0.02) and lifetime duration of lactation (p = 0.00). Further stratification by menopausal status resulted in the same conclusion. These data suggest that prolonged lactation reduces breast cancer risk.
Thank you, Karleen, I’m happy to know about this study! I will be interested in looking at it closer. And wow, I’m impressed with those >109 month breastfeeding moms!
Two words: lactational amenorrhea, haha. No, seriously though, I do know that exclusive breastfeeding followed by “delayed introduction of solids (at 6+ months)” and continuing with extended breastfeeding plus TOTAL pacification at the breast has kept my cycles at bay so we can more easily space our children about 3 years apart. I am at 13 months breastfeeding and we are hoping to go to 2 years at least, not just for this reason but because of other health reasons for myself (like the decreased breast cancer rates listed above). Another reason we have continued is simply because we don’t plan on introducing cow’s milk for dietary reasons. We just plan on using (my) human milk until he decides to wean himself naturally. Oh and boob juice is incredible when you have a sick little one (especially when they can’t keep food down). I’d extend breastfeeding for this reason alone!
I also catch milk and donate, so while the AAFP might be stretching their “benefits”, there certainly are many others.
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