Is there an advantage to delaying solids?

In 2001, the Word Health Organization recommended that babies be exclusively breastfed for 6 months, after which they should gradually be offered complementary foods until the majority of their diet consists of solid foods at around a year old. This replaced their earlier recommendation of exclusive breastfeeding for 4-6 months, after it was shown that babies nursed exclusively for the whole 6 months had fewer episodes of gastrointestinal disease, and their mothers benefited from greater weight loss postpartum and better birth control due to lactational amenorrhea. While also universally adopted by various national health organizations, some researchers maintain the evidence for this change was insufficient, doubting the capability of breastmilk to adequately nourish some infants until the age of 6 months in developed countries, where infectious disease is of relatively lesser concern (see here and here). These concerns are somewhat diminished by the recommendations to supplement all babies with vitamin D and iron, however.

However, it seems to be popular among the AP/NP set to delay the introduction of solid foods even past the six-month mark, some even past the first year. There seem to be multiple reasons for this:

* The idea that if breastmilk is the “perfect food” for babies, it will continue to be so even past 6 months. Solid food is described by some as an assault on the babies’ “virgin gut” – previously touched only by breastmilk.

We’ve discussed why this is fallacious here; in addition and in line with this thinking, AP/NP sites often encourage mothers not to supplement their breastfed babies with iron and vitamin D, despite the evidence that breastfed babies are prone to deficiencies of both compared to formula-fed ones.

Apparently, some ‘alternative’ sources (I’ve read of women referring to Mendelsohn’s book as a resource, for example, or taking the advice of their favorite ND) claim that all babies can subsist upon breastmilk alone for at least 12 months. Given that some breastfed babies are already demonstrating deficiencies in iron and zinc by 6 months, this makes little sense.

* The concept of ‘baby led weaning, which states that babies should not be fed until they are able to sit up and show interest in picking up finger foods and stuffing them in their own mouths. The idea, as far as I understand it, is that purees were necessary only in the days when babies were fed at very young ages and had spoonfuls of food thrust down their gullets, and when the baby’s motor coordination enables her to get her own food ensures that her chewing apparatus will also be sufficiently developed to handle regular table food.

Alas, it does not always seem to be the case that babies acquire motor skills and hand-eye coordination in exact accordance with their dietary needs. Also, many babies, even when starting solids older, seem to need the interim stage of pureed food before they acquire the skill of chewing. Not to mention that babies can easily bite off more than they can chew and choke in the process (my younger son was especially adept at that. Sometimes I wonder how he managed to make it through his first year and a half). And of course, for all the lip service paid to the process being “baby led”, if a baby clearly indicates he wants solid food by 4 or 5 months, even to the point of grabbing food, other rationales are used not to give him his ‘natural’ wish.

*The claim that delaying solids prevents sensitization to foods and consequently, allergies and autoimmune diseases. The original reasoning for this was the finding that babies until the age of 4-6 months have an ‘open’ or ‘leaky gut’ – meaning that the mucosal cell layer lining the intestinal tract of a young baby is permeable to protein-containing fluids. Over time, tight junctions appear between the intestinal cells, creating an impermeable barrier. The initial permeability of the intestine enables babies to receive various nutrients available in colostrum and early breastmilk; however, if allergenic proteins are introduced at this time, the thought was that these proteins could easily reach the baby’s blood stream and sensitize the immune system, causing future allergic reactions like eczema, asthma, celiac disease and various other specific manifestations of food allergy, and autoimmune diseases such as type 1 diabetes. The The American College of Asthma, Allergy, & Immunology still recommends very gradual and late introduction of potential allergens into babies’ diet, and complete avoidance of these allergens for years in babies who are at high risk for food allergies (even in utero).

However, newer research is coming to light that shows that delaying exposure to food allergens can be every bit as bad – i.e, there is an optimal window period during which it is best to introduce potential food allergens. This is a spinoff of the hygiene hypothesis, if you will – that a bit of early exposure may actually prevent sensitization to a given foodstuff.

In a recent study from Germany, delaying introduction to solid foods past 4 or 6 months wasn’t associated with fewer allergies at age 6. On the contrary, later introduction of solids was associated with more food allergies.

Regarding specific allergens, it seems that introducing cows’ milk products late (beyond 9 months) was associated with an increased incidence of eczema and recurrent wheezing, and delaying other foods beyond 7 months – also with allergies to inhaled substances at age 2. With regard to gluten (wheat protein), it seems that the optimal time for introduction of gluten-containing foods is between 3-7 months, both with regard to the development of celiac disease in susceptible infants and type 1 diabetes. Also important is that the babies were breastfeeding at the time the new foods were introduced.

Another study currently under way is examining early exposure to peanuts and the risk of developing peanut allergy later in life. This was prompted by the observation that children here in Israel, who eat a peanut-based snack called Bamba by the bagful as a weaning food (its consistency is airy and slightly softer than a large Rice Krispie, making it ideal for kids to hold and eat), have a significantly lower incidence of peanut allergies than their American and British Jewish counterparts. I don’t know if the association is causal and I resisted all attempts – and there were many! – to push Bamba on my own kids by well-meaning passersby until they were a year old, but we do seem to have a lot fewer peanut-allergic kids here (though such children do exist). The results of this study should be apparent by 2013.

In short, it may very well be that parents who delay introduction of solids beyond a certain point (7-9 months) may not be doing their babies any favors with regard to either acquiring the skills of eating, optimal nutrition or allergy/autoimmune disease prevention. In fact, it may be that introducing solids a bit earlier than the WHO currently recommends (at 4-6 months rather than 6, as was originally recommended) might be better.

As a result, the European Society for Pediatric Gastroenterology, Hepatology and Nutrition is now recommending that:

Exclusive or full breast-feeding for about 6 months is a desirable goal. Complementary feeding (ie, solid foods and liquids other than breast milk or infant formula and follow-on formula should not be introduced before 17 weeks and not later than 26 weeks. There is no convincing scientific evidence that avoidance or delayed introduction of potentially allergenic foods, such as fish and eggs, reduces allergies, either in infants considered at increased risk for the development of allergy or in those not considered to be at increased risk.

(If you click on no other link, please click on that position paper – it’s very comprehensive and deserves a read, IMO.)

DISCLAIMER: I recommend you always listen to your chosen pediatrician/allergist, especially if a child already has a food allergy, regardless of what I present here.

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19 Responses

  1. My pediatrician recommends waiting until 6 months, but he doesn’t spout any of the “leaky gut” stuff or recommend waiting longer than 6 months. He told me something along the lines of, “Currently, we think waiting until 6 months is the optimal way to avoid food allergies. That may change in a few years, though, you never know.” 🙂

    I had to wonder about the women who delay solids until a year. Granted, they tend to be the type who cosleep and just expect their babies to wake multiple times every night, so that might be part of it.

    In the last week, my daughter has started waking at 1am to feed (previously she’s been sleeping from 8:30-4:30 or so) so I’ve been trying to feed her more solids in the evening hoping that it will help her sleep through the night. She likes the flavor, but isn’t interested in more than a couple of bites. I’m okay with feeding her when she’s hungry, but it would be nice to avoid the nighttime wakenings whenever possible! 🙂

  2. I found this blog yesterday while following a series of links on the MMR vaccine, and if I try telling you how much I love it I will sound like a fawning sycophant. Debunking dogmas is one of my all-time favourite hobbies. Since I almost never get time to indulge in it, these days, reading articles by other people debunking dogmas is a very good substitute. You’ve written the blog that I’ve dreamed of someday having the time and energy to write. I foresee many happy hours reading through your archives. Thank you for this.

    With regard to this particular blog post, I did write a post some while back on the topics of the WHO guidance to wait until six months for solids and on claims being made for baby-led weaning. It’s at , if you’re interested.

  3. Ooops, that link didn’t come out – WordPress must automatically delete anything between pointy brackets. The link was supposed to be

  4. Thank you so much for posting this along with sensible data to back it up!

    Unfortunately, my son HATES solid foods, both in pureed form and finger food. He’s 8 months old and you have to do a song and dance to get 1/2 a container in him a sitting, and you get MAX 2 sittings a day.

    I often wonder if it’s because we spent his first 6 months spraying nasty ass Zantac into him, now he’s afraid of anything but a bottle or a boob. He gets a cherrio in his hands, it gets near his mouth and he flips a bit, screams.

    Man, I hope that changes.

  5. Two things, one’s a question and one’s a comment.

    The comment: Despite the AP/NP idea that babies should be able to determine on their own when they’re ready to eat solids and that “purees” aren’t necessary, it’s pretty common worldwide for a baby’s first non-milk food to be solids that have been chewed first by one of his parents. Food is pre-chewed for baby. That’s basically what a blender does anyway.

    The question: Do any of the recommendations take the child’s weight into account? My son is almost 15 weeks and over 16 pounds already. Would his size have any influence on whether he tried solids closer to 4 months or 6 months in terms of physiological readiness?

  6. Thanks for another informative post.
    I have an unrelated breastfeeding question. How come in the US quality of mother’s does not seem to be taken into consideration? see here for instance:
    I find it hard to believe.
    I have a strong suspicion that I was squirting vitamin water because my dd’s weight and height shot up after we started solids. (I don’t eat a low fat diet). My mom said that in the old country they had mothers pump some milk and look at the color to determine its content. Yellow=fatty, blueish=not fatty. My dd didn’t take bottle, so I didn’t pump much, but I believe my milk was bluish.

  7. Sarah V. is reading my blog! And she likes it!

    *faints dead away*

    I guess that means we can now start a mutual admiration society 🙂 . You are soooo blogrolled, lady!

    Your post about pureed food is great, and I pretty much agree that starting solids at 4 months vs. 6 months is no biggie . If I had to quibble, it would be about using KellyMom as a resource (very biased, and the source she uses to support her argument – Piscane A et al – has no iron-supplemented control group. Studies that do, show a greater incidence of iron deficiency anemia among breastfed infants).

  8. Daisy – I was going to mention that point (about feeding pre-chewed food in primitive societies) as well, but it got lost in the post’s editing. Though many of those societies are also feeding said pre-chewed food to their babies from a very, very young age.

    About the baby’s size being an indicator of when to start solids – I would think it’s more a matter of whether your baby is acting satisfied on your milk (barring temporary growth spurts) and is gaining weight at an acceptable rate, than how he measures in absolute terms on the growth charts. I can tell you my eldest was clearly not satisfied by either breastmilk or supplementary formula by 4 months, and it’s not because he was a huge baby. Not surprisingly, he took to the Beech-Nut sweet potato puree my mother-in-law bought for him (and gave us to feed; she isn’t that pushy!) like a fish to water…

    K. – the Babble article isn’t wrong, to the best of my knowledge. It takes a very malnourished mother to make ‘skim’ breastmilk . Insufficient weight gain at that age (2 weeks) can most commonly be attributed to either low milk volume (either underproduction, or the baby has a problem getting the milk out of the breast) or less commonly – the baby not getting enough of the fatty hindmilk. The color (blue vs. yellow) can vary with Mom’s dietary intake of other substances, not necessarily with the fat content, and the fat content can also change throughout the day. So looking at the color, especially from one single pumping, isn’t a reliable guide to what your baby is actually getting.

  9. Thanks for the explanation.

  10. Yay! I’m blogrolled! 😉

    You sound as though you know me from somewhere – is that so? Or did you just read my blog after I posted that comment?

    Ooops on the use of Kellymom as a reference. You are absolutely right about her bias, and I knew about it, as well, so should have known better than to do that. I might edit the post accordingly, if I ever get round to it.

  11. From a cursory reading of your website, you’re obviously the Sarah V. who duelled with Hathor the Cow on her own blog a while back regarding infant sleep/CIO. We seem to have been thinking along similar lines on this as well (though you, apparently, expressed those thoughts a full year and a half before I did!)

    It was an exercise in futility given this is Hathor we’re talking about…but I am still in awe 🙂 .

  12. I have to agree to a point on purees–they’re not AS necessary when you begin at 6 months as opposed to 4. I went to mashing things up with a fork within a couple of weeks. There’s also some evidence (sorry, probably read it in the Guardian or smoething!) that delaying second stage foods too long can result in difficulty.

    My experience was that waiting for signs of readiness was much more helpful than a date. I waited until she wanted it (happened a little after 6 months–3rd time I tried) and it went a lot more smoothly than my friends who started pushing it at 4 months. I’d watch them trying to shove pureed banana into obviously uninterested babies and thought they’d be saving everyone a lot of trouble by not bothering. If she had wanted it before 6 months I would happily have given it to her, but she didn’t. She was chugging down immense amounts of formula (6 225ml bottles) right before she weaned but she would spit anything else out.

    I thought BLW was a great idea because I’m lazy, but my kid wasn’t having it. She begged for food off a spoon, but wouldn’t pick it up until she was nearly a year old. So I think the “BLW is the only way” method is nonsense.

  13. Alexis – IME, many if not most kids first starting out on solids still need purees initially. Many ‘graduate’ to finger foods very fast, however. And there some kids who take a great deal of offense to purees as well – I had a 9-month-old girl in my office last month whose father claimed she needed a speech therapy evaluation because he was told by her daycare she was ‘orally defensive’ as she was very hard to feed. All the while, the little girl was sitting on Daddy’s lap, munching contentedly on a piece of Bamba! 😆

    I’ve heard about the ‘window period’ theory of starting solids as well, but can’t really find any support for it in the literature. I can tell you that as a medical student, I encountered a couple of 2 year olds who’d recently immigrated from Ethiopia. Their diet up until then had consisted almost solely of breastmilk and cows’ milk straight from the udder. Not only were they extremely malnourished, they also had no idea how to deal with solid food and needed professional help to learn how to chew. I admit this is a very extreme example, however.

    I usually tell mothers that the the kid’s “job” between 6-12 months is to learn how to ingest swallowed food and gradually make it into the lion’s share of his diet. As long as the parents keep offering and the kid keeps sampling even a drop, the potential allergen issue is dealt with and the kid learns about various consistencies of food on his own timeline.

  14. Oh yes – I’m sorry if I wasn’t clear. I certainly wasn’t giving finger foods at 7 months! Just that she spent much less time on very smooth purees than a lot of the children I saw who started earlier, and went to more textured foods fairly quickly. Mashed up with a fork, as opposed to blitzed or sieved.

  15. My baby’s first food besides breast milk was toast. . .Toast that probably had something evil like peanut butter on it. . . Toast that belonged to one of my other children. . . Toast that he scavenged off the kitchen floor. He’s a third child.

    OK. I got that off my chest.

  16. Glad you liked the post on CIO! Yes, I knew it wouldn’t make a blind bit of difference to Hathor, but there was always the remote chance it would make one of her fans think twice. More realistically, given that any guilt-ridden parent can find this stuff on the ‘Net, I wanted to be sure the other side was out there as well.

    Yes, I love doing this sort of thing – taking some bit of propaganda and debunking it. I have a list of things I want to write on that line, but just no time at all to do it. Maybe once the kids are in school….

  17. I am really enjoying your blog and I want to link to a few articles here on Rational Moms.

    Just had to comment here because I wanted to introduce solids at four months but our pediatrician advised against it. We just started this week! I found it tough to wait, because my son is so big. By now I might have gotten a little bit of a break from nursing so much!

    But we do trust our doctor, and I make decisions based on her advice.

  18. Julie,

    Feel free to link to anything you like.

    As I pointed out, this is fairly new info; I also have a handout that refers to the first 6 months as being solids-free. It’s just nice to know that it’s not the end of the world if you do start a bit earlier.

  19. I’m a total AP / SUPER CRUNCHY mom and I agree wholeheartedly with your post. I think that waiting that long to start solids is ridiculous and neglectful. Babies usually show obvious signs of wanting solids way before that. It’s one of the couple issues I have with my “parenting niche” that just bug the crap out of me (the other is the fact that I willingly had a planned C Section for my own mental health, apparently that makes me evil).

    Thank you for this post!

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