Continued from Part 1 - Starting Solids - The Facts Behind Today's Media Hype
Please note the term weaning in this article is used in the typical UK sense of starting solids and beginning the transition to weaned (which may ultimately take years) rather than the more often US meaning of "stopping breastfeeding".
"The evidence does not suggest an adverse effect of exclusive breastfeeding for 6 months on infant growth on an overall population basis, i.e. on average."
The above recommendation was endorsed by the Scientific Advisory Committee on Nutrition (SACN) when in September 2001SACN agreed that:
"There was sufficient scientific evidence that exclusive breastfeeding for 6 months is nutritionally adequate but that due to current practices in the UK there should be some flexibility in the advice."
The Department of Health added to this:
"Although there is no evidence to suggest that giving a baby solid food before six months has any health advantage, it is important to manage infants individually so that any deficit in growth and development is identified and managed appropriately. All infants are individuals and will require a flexible approach to optimise their nutritional needs".
In short what the body of evidence suggests is that solids should not be introduced before 4 months (or 17 weeks to be precise) - this is very clear (1). After this point studies considering outcome become more conflicting when examining risks.
Take gastroenteritis - some indicate increased rates in those receiving solids before six months, whilst others suggest little significant statistical difference between 4-6 months in developed countries. Note this data is only applicable to introducing foods, not breastmilk substitutes. (2,3)
Regarding other health issues WHO state:
"The evidence does not demonstrate a protective effect against respiratory tract infection (including otitis media) or atopic disease, in infants exclusively breastfed for 6 months compared to infants exclusive breastfed for 4–6 months"However data from the 2006 National Health and Nutrition Examination Survey showed that:
"US infants who were exclusively breast fed for more than six months had lower risk of pneumonia and recurrent otitis media than those breast fed for four to six months."These are just a couple of examples selected from a large body of evidence, but as you can see it quickly becomes confusing. There are likely to be a number of reasons for this; firstly the definition of "exclusive breastfeeding" varies from study to study. The WHO review states::
"Because the definition of “exclusive breastfeeding” in studies in the systematic review often included infants who were predominantly breastfed, the term is used here to include both true exclusive breastfeeding and predominant breastfeeding, as defined by WHO."This suggests that should studies examine infants exclusively breastfed in the true sense, the results would be more compelling.
Secondly a not insignificant percentage of the studies are observational and so bias must be carefully evaluated, thirdly study parameters may differ eg an often cited study regarding solids and gastroenteritis is the Belarus PROBIT, however this studies exclusive feeding to three months or six months - not four or five (10). Another consideration is that infants are unlikely to all mature at an exact pace, with gut development happening somewhere between 4-6 months for most infants and thus some were ready and some weren't.
"Most of the body’s systems are maturing and growing rapidly at 4-6 months and the timing and rate of weaning should take account of considerable individual variation." (1)
An issue often raised is iron, however when birth and mother's nutrition are typical - there is nothing to suggest a baby should need supplementation pre solid readiness - and some discussion that doing so may be harmful.
"The data on iron status were conflicting but suggests that there may be a need for iron supplementation where newborn babies have suboptimal levels." (2)
Dewey found risks of iron deficiency increased in infants with a birth weight lower than 3kg who are exclusively breastfed for six months (5); however anaemia in the mother and routine early clamping of the umbilical cord are also predisposing factors (6). Ted Grainer PhD has an interesting discussion paper here, warning that we should ensure infants are indeed deficient before supplementing infants younger than 6 months, otherwise it may lead to reduced growth or increased susceptibility to infection.
A guideline has to be a simple message that can easily be understood and implemented by as much of the population as possible. As the majority of infants are weaned following a parent led approach, recommending a six month weaning guideline prevents those who are not ready being exposed to solids early, whist providing adequate nutrition for the vast majority; thus is a practical choice for a guideline.
Ultimately there is no compelling evidence to suggest any benefits to routinely introducing solids pre six months and some evidence suggesting potential risks during the 4-6 month period; making it more about why to introduce solids than why not.
As we discussed in part 1 many do not understand why a guideline exists, nor the detailed evidence behind it – pushing the guideline to six months has reduced the amount of infants receiving solids before four months.
What is gut maturity?
As discussed in this blog entry, at birth an infant has what is often called an “open gut” to allow immunological properties in breastmilk to slip easily into baby's bloodstream. In very simple terms, "good bacteria" actively works to destroy any harmful pathogens, and also coats these gut spaces to prevent germs accessing this ,route.
By around six months these spaces have closed in preparation for the introduction of solids. However we also know that once something else is introduced into the gut other than breastmilk,the protective coating is destroyed and the number of potentially harmful pathogens increases.
Therefore if the gut is still “open”, both good and bad have direct entry to the bloodstream which can potentially increase risks of infection.
Department of Health Recommendations.
"At about six months babies are ready to be moved onto a mixed diet.
Try giving solid foods when your baby:
• wants to chew and is putting toys and other objects in their mouth
• and starting solids will not make your baby more likely to sleep through the night again.
Weaning is also easier at six months. If your baby seems hungrier at any time before six months, they nay be having a growth spurt, and extra breast or formula milk will be enough to meet their needs. Ask your health visitor for advice, especially if your baby was premature. Solid foods should never be introduced before four months."The NHS weaning leaflet states:
"By six months, your baby will be developing the skills to sit up, hold objects and put them to his or her mouth, and will show signs of being interested in the food you and your family are eating.
When to start:
At about six months babies can easily be moved onto a mixed diet. Try giving solid foods when your baby:
1. Can sit up
2. Shows interest in solid food
3. Picks up food and puts it in his or her mouth
4. Wants to chew and may have teeth"
Readiness for solids & physical development:
What is interesting is as the information within the guidelines above suggests, several studies including those involved in forming the guideline, indicate readiness to eat is about a lot more than just “gut closure”.
Baby develops the skills to not only pick up food, but also bring it to their mouth (as per their “grabbing accurately” point) they need to have lost the tongue thrust reflex for any of that food to make it into the mouth.
Baby then needs to process and chew the food (as per the “wants to chew” point) and finally move food to the back of the mouth and swallow. This is actually a pretty complex set of skills! “External readiness” appears to develop in tandem with gut development – so by the time baby can pick up food and eat it, they are ready to digest.
"Using the available information on the development of infant's immunologic, gastrointestinal and oral motor function, the expert review team concluded that the probable age of readiness for most full term infants to discontinue exclusive breastfeeding and begin complementary foods appears to be near six months or perhaps a little beyond. They also felt that there is probable convergence of such readiness across the several relevant developmental processes."The same paper also states:
"Unique needs or feeding behaviours of individual infants may indicate a need for introduction of complementary foods as early as 4 months of age, whereas other infants may not be ready to accept other foods until approximately 8 months of age." (7)Note this paper suggests some infants may be nearer eight months - a point to remember for later.
"Weaning should not start before neuromuscular coordination has developed sufficiently to allow the infant to eat solids. The majority of infants should not be given solid foods before the age of four months, and a mixed diet should be offered by the age of six months”. (1)However on a practical basis, practitioners understood this policy to mean that infants should be introduced to solids food at 4 months! In reality the researchers found most infants were somewhere between 4-8 months when developmentally ready for more.
Ready to help themselves?
What many parents are not aware of is that the Department of Health Infant Feeding Recommendation also states:
"Parents should be advised of the risks associated with weaning before the neuromuscular co-ordination has developed sufficiently to allow the infant to eat solids. Solid foods should not be offered before four months (COMA) However, if an infant is showing signs of being ready to start solid foods before six months, for example, sitting up, taking an interest in what the rest of the family is eating, picking up, and tasting finger foods then they should be encouraged."It would logically also seem to make sense that development of the gut would keep up with physical skills - if baby could pick up and consume food developed before gut maturity, this would require an adult to constantly prevent the child accessing food
If we buy into the concept that baby is often meant to be held close in slings and suchlike, this often makes an interesting time when it comes to food. I chatted to some mums about this recently online:
“The guideline is ok providing you can get your toddlers to understand it! At 5 months, R simply helped herself to her sister’s plate of rice cakes! She had a lick and a taste before throwing the food and moving on to something else. The next night however she literally dived head first into her sister’s meal and had a good chew on some broccoli. What has been interesting to watch is how slowly she’s starting solids compared to her puree weaned sister. She has licked, squidged, chewed and spat out and seems to be following a clear pattern of progressing skills."Of course the guideline can seem to cause as much concern the other way:
"L is my first daughter following two boys and had no interest at solids at seven months (unlike the boys who both dived in with gusto). I was quite worried and spoke to my Health Visitor who suggested breastfeeding her less often to try and encourage her to eat, but that just resulted in lots of crying and no more eating. I then borrowed "My Child Won't Eat" from the Analytical Armadillo and after a chat began to see food in a different light. I felt more relaxed once I stopped preparing special meals that were always just tipped on the floor and instead just shared what the rest of the family were eating, more confident she would eat when she needed to and was ready.. A couple of weeks later she started tasting bits and now has a great diet, her favourites are what I always considered "adult foods" before, spices, herbs, salads and even olives!"
Something else to consider is the all the when to start solids research is based on infants spoon fed purees. An approach which most often follows a parent led decision to start solids.
Something else to consider is the all the when to start solids research is based on infants spoon fed purees. An approach which most often follows a parent led decision to start solids.
The parent assesses readiness and takes over the process of moving food to the infants mouth. The food being nearly liquid may be consumed earlier and almost certainly in much larger amounts than infants self feeding. Parents base this decision of readiness, sometimes on false signs such as “increased waking” which may have been due to a developmental spurt or early teething, or baby demanding larger volumes of milk. This leads to some infants receiving solids way before there are external signs of physical readiness and indeed perhaps before the gut closes. This may also be important in the allergy debate as the amount of a food consumed seems to also be influential (as covered in part 1)
Self feeding - Baby led
Self feeding - Baby led
Gill Rapley introduced to the mainstream, something mums have been doing for years “baby led weaning”. This is allowing infants to continue self regulating their own intake by self feeding. Baby chooses when to start eating, and what to start with - parents simply make a range of foods accessible eg no salt, no sugar and rich in iron, zinc and B vits and baby helps themselves. You can also find more resources at Gill's site.
Due to increase popularity of this method, more research is becoming available which is positive.
In a study entitled "Is baby-led weaning feasible? When do babies first reach out for and eat finger foods?" Researchers found out of 602 infants, 56% had reached out for food before age 6 months, but 6% were still not reaching for food at age 8 months
“Baby-led weaning is probably feasible for a majority of infants, but could lead to nutritional problems for infants who are relatively developmentally delayed.” (due to them not reaching out for finger foods at 8 months)" (8)But remember the point from the study earlier that found some infants could be eight months before developmentally ready? (7)
This author assumes it may lead to nutritional problems - but if indeed the external skills and gut do indeed develop in tandem, not reaching could indicate an open gut and potentially increase infection risks? If nutritional status is compromised, would supplements make for a better choice? Furthermore as there are studies suggesting breastmilk is nutritionally adequate to meet the needs of some infants until closer to nine months - could it also be possible that those infants not reaching at 8 months are at an earlier stage of development and do not yet need complimentary nutrition? This should surely all be explored...
A 2010 study found:
"A controlling maternal feeding style has been shown to have a negative impact on child eating style and weight in children over the age of 12 months. Seven hundred and two mothers with an infant aged 6-12 months provided information regarding weaning approach alongside completing the Child Feeding Questionnaire. Mothers following a baby-led feeding style reported significantly lower levels of restriction, pressure to eat, monitoring and concern over child weight compared to mothers following a standard weaning response. No association was seen between weaning style and infant weight or perceived size. A baby-led weaning style was associated with a maternal feeding style which is low in control. This could potentially have a positive impact upon later child weight and eating style." (9)Lastly in 2011 a descriptive study investigating the use and nature of baby-led weaning reported:
Mums also often note the difference in amount consumed, Those self feeding gradually increase amounts as skills develop - whereas those spoon fed puree are suceptible to consume larger volumes more quickly (displaing breastmilk) and are more likely to suffer constipation. This may be because mum can feed baby much quicker than baby can feed themselves, meaning by the time baby realises they are full they have potentially already overeaten.
Gill Rapley conducted some small scale research and found:
“The babies who participated in the research were allowed to begin at four months. But they were not able to feed themselves before six months. Some of the younger babies picked food up and took it to their mouths; some even chewed it, but none swallowed it. Their own development decided for them when the time was right. Part of the reason for this study was to show (based on a theory of self-feeding) that babies are not ready for solid food before six months. It seems that we have spent all these years working out that six months is the right age and babies have known it all along!”I have to confess that my own experiences from supporting mothers have seen some infants eat (evidence in nappy!) before six months. However all have also been advanced in other areas – perhaps crawling or bum shuffling, grabbing with accuracy and comparable to six month olds developmentally.
Perhaps it’s not at all about nutrition.
Despite several papers suggesting infants are around six months before being developmentally ready to eat solids, the study showed around half had reached for food by this age. Therefore perhaps the squidging, exploring, mushing, bashing and licking before food becomes more important nutritionally, is all part of the same developmental continuum?
Think of just what a sensorial experience food is; hot, cold, hard, squidgy, rough, smooth. Think of the range of smells, tastes - it's a sensory party!
What is introduced may also influence outcome...
As discussed in this blog post, what we introduce is also significant. Whilst breastmilk alone is suitable until six months, this doesn’t therefore mean a few bits of fruit and veg are “extras” - solids displace breastmilk. What's more there is also evidence that solids reduces the bioavailability of iron from breastmilk - so if we are shifting from exclusive feeding, it makes sense to ensure the foods replacing the breastmilk are nutritious, calorific and aren’t going to increase risks of deficiencies such as iron.
There is no clear rationale for limiting diet to veg or fruits – if the gut has closed (which we are waiting for anyway before introducing solids) the theory of food proteins passing into the blood stream and triggering allergy wouldn’t appear to hold.
Do I advocate early weaning – absolutely not I advocate the 6 month guideline. Do I think that alongside keeping this guideline in mind we should also use an element of instinct and common sense; absolutely. If mums don’t try and second guess when baby is ready for solids, but simply waits and watches her infant. A plastic spoon and bowl whilst others are eating will no longer pacify – instead he will attempt to get food and watch you intently frantically chewing along, many become very vocal in their frustration of not getting food if they want it. If weaning is to be puree on a spoon, waiting until six months would appear the most sensible approach - followed by feeding slowly and carefully watching baby's cues, with plenty of time for baby to enjoy the sensorial element via touch.
Dr Jack Newman states:
"The best time to start solids is when the baby is showing interest in starting. Some babies will become very interested in the food on their parents’ plates as early as four months of age. By five or six months of age, most babies will be reaching and trying to grab food that parents have on their plates. When the baby is starting to reach for food, grabs it and tries to put it into his mouth, this seems a reasonable time to start letting him eat. There really is no reason to start on a specific date (four months, or six months). Go by the baby’s cues"Summary:
- The curent recommendation is to introduce solids around 6 months. (WHO, Department of Health)
- There are no reasons to routinely introduce solids earlier than six months, and potentially health implications of doing so. (WHO, Department of Health, SACN)
- Solids should not be introduced before four months (SACN)
- If an infant is showing signs of being ready to start solid foods after four months and before six months, for example, sitting up, taking an interest in what the rest of the family is eating, picking up, and tasting finger foods then they should be encouraged. (Department of Health)
- Readiness varies depending on the infant and is typically between 4-8 months - however for parents who have decided to wean using a puree it may be sensible to wait until 6 months to ensure they do not overfeed baby and displace essential nutrients in breastmilk (7)
- Susceptible infants may need iron supplementation earlier, however status should be confirmed as there may be risks to supplementing an infant with normal levels. (WHO, Department of Health, SACN)
- As solid food influences iron absorption from breastmilk, first foods offered when baby is showing signs of readiness should be nutritious, high in easy to absorb iron and other essential vitamins and minerals. (COMA, SACN)
Formula or Solids? If baby isn't gaining weight as expected, appears ever hungry but isn't showing signs of readiness, plus what about formula fed infants? coming up in part 3!
1. COMA 199423.
2. Kramer MS, Kakuma R. Optimal duration of exclusive breastfeeding. Cochrane Database of Systematic Reviews 2002, Issue 1.
3. Arch Dis Child 2009;94:148-150
4. Promotion of Breastfeeding Intervention Trial (PROBIT): a randomized trial in the Republic of Belarus. JAMA. 2001 Jan 24-31;285(4):413-20
5. Dewey et al 1998
6. Mercer, 2002
7. Developmental Readiness of Normal Full Term Infants to Progress from Exclusive Breastfeeding to the Introduction of Complementary Foods" Naylor and Morrow, 2001