Starting Solids - The Facts Behind Today's Media Hype

Part 1

So - most people by now will have heard today's news, if not here's a brief summary:

"Relying purely on breastfeeding for the first six months might not be best for babies, experts in the UK have warned.  The team said breastfed babies may benefit from being given solid food earlier."

"They suggest later weaning may increase food allergies and iron deficiency levels, but other experts backed the existing guidance."

Current advice suggests weaning (insert - from WHO and the Department Of Health) should occur at six months, but the UCL team say it could happen as early as four.

The feedback I'm getting from mums already is that many people with a young infant coming up to solids age will now be absolutely bewildered about when they should be thinking about solids!

Before I get on to the paper that fuelled today's news - let's start with a few facts we should bear in mind:

• The paper states three of the four authors "have performed consultancy work and/or received research funding from companies manufacturing infant formulas and baby foods within the past three years".
• The recommendation not to wean until six months has substantially cut the numbers of women who introduced solids before four months – from 85% in 2000 to 51% in 2005.  This is massively significant in terms of health implications as the evidence against introducing solids before 17 weeks is extremely strong.
• The recommendation not to wean until six months is also going to have impacted significantly on the profits of baby food companies.  As more parents follow the guideline for six months, less are buying baby food from four to six months...
• Why are non breastfed infants not discussed?  When are they supposed to introduce solids?  I guess this is far less likely to be of interest because most formula fed infants receive solids pre 6 months.  Whilst the DOH guidelines state 6 months for both breast and formula fed, there is no big focus on "6 months exclusive formula feeding" and so profits from this group are likely to remain far more stable.  Ironically as the non breastfed infant's gut matures more slowly than that of a breastfed infant due to lack of human growth factors, and as non breastfed infants are not exposed to new flavours via breastmilk, starting solids is likely to be just as significant (if not more) to non breasted infants and an area that really should receive more focus in terms of health impact.

What does the paper actually say?

The paper is entitled "Six months of exclusive breast feeding: how good is the evidence? and despite the media coverage of this, says far less than you may think.  It notes that the DOH guidelines are based on the WHO paper, which found:

No deficits have been demonstrated in growth among infants from either developing or developed countries who are exclusively breastfed for 6 months. 

But says the science was not fully evaluated by the DOH and calls for a reappraisal of the evidence.

They raise several concerns they feel warrant further investigation (as other studies contradict the ones quoted - it's not cut and dry and needs further evaluation)

Window for introducing new tastes

The discussion is all quite vague, from the paper:

There are also relatively unexplored concerns about the potential for prolonged exclusive breast feeding to reduce the window for introducing new tastes. Bitter tastes, in particular, may be important in the later acceptance of green leafy vegetables, which may potentially affect later food preferences with influence on health outcomes such as obesity

Perhaps this is relatively unexplored because we know babies are exposed to different flavours via breastmilk and so experience a wide range of tastes?

I asked Gill Rapley - Ex-health visitor, Ex midwife, Ex NCT breastfeeding counsellor, Ex lactation consultant and Baby Led Weaning proponent what she thought of this comment:

This is pure speculation and scare-mongering. Two counter-arguments spring to mind:

- Breastfed babies get a variety of flavours in their mother's milk and are known to be more receptive to a range of tastes once solids are introduced. They do not need experience of the food itself beforehand to be able to enjoy it at 6 months. (However, this may not be so for formula-fed babies.)

-The evidence for a 'window of opportunity' for the introduction of tastes is largely based on the observation that babies of 6 months and older tend to refuse new flavours. What these studies actually show is that they refuse new flavours offered on a spoon. No one has questioned the fact that the method of feeding used (in all the available research) happens to be spoon-feeding, simply because no one realised that there was an alternative way of offering solid foods to babies. In fact, in research terms, the feeding method is an important variable, whose significance has not been formally tested. As we know, the mass of anecdotal evidence from BLW parents suggests that babies who are allowed to feed themselves rapidly acquire a liking for a wide range of foods, including those with a bitter taste, such as broccoli.

Insufficient Iron

From the paper:

More recent data from 2007 raise further concerns on whether six months’ exclusive breast feeding would reliably meet iron requirements. US infants exclusively breastfed for six months, versus four to five months, were more likely to develop anaemia and low serum ferritin, which is of concern given irreversible long term adverse effects on motor, mental, and social development after iron deficiency.(20) (21) (22) Such risks might be reduced by improving iron status in pregnancy, delaying umbilical cord clamping, and supplementing infants at risk (for example, those with low birth weight).

So I dug out the studies they quoted (20-22)

Only one examines iron levels and infant feeding (20) The others are about the effects of severe anaemia.  The study examines 2268 infants, which sounds pretty impressing - until you discover only 136 were breastfed exclusively for six months.  Furthermore it's 6 months or more, so some may have been exclusively fed longer than 6 months which is often advised at the moment for high risk infants.  They found solids at 4-6 months instead of 6 months + reduced the risk of anaemia, low serum ferritin but not low hemoglobin and concluded:

Young children in the United States fully breastfed for 6 months may be at increased risk of iron deficiency. Adequate iron may not be provided by typical complementary infant foods.

It adjusted for birth weight and demographic, but no mention of other factors ie prematurity

This small study also contradicts the finding of numerous other studies.  For example a 2008 study found:

Full-term babies who are exclusively breastfed are not at heightened risk of low iron stores by the age of 6 months, even if their mothers were iron-deficient during pregnancy

Breast milk is low in iron, but infants can absorb it much more easily than they absorb the iron in fortified formula. Healthy full-term infants are also born with enough iron stores to make deficiency unlikely in the first 6 months.

Read more here

The evidence does seem to be particularly conflicting regarding iron, probably due to all the factors that can influence baby's store; such as type of birth, time of cord clamping and potentially mother's levels.  I fail to see however the connection with the starting solids debate, if an infant is low in iron they can have a supplement?  Cultural beliefs in the UK mean the first foods many infants receive are low in iron eg carrots, apples and we know introducing solids reduces the bioavailability of iron from breastmilk - therefore encouraging early weaning may increase risks of iron deficiency.

Coeliac disease

From the paper:

A more recent study in infants at risk (with a first degree relative with type 1 diabetes or carriage of certain HLA types), showed that introduction of gluten before three months and after six months was associated with increased risk of biopsy proven coeliac disease(26) and islet cell autoantibodies(27) . This finding suggests that gluten may best be introduced during a critical window of three to six months. In the same cohort, introduction of wheat after six months predicted increased risk of wheat allergy at age four years.(28)

Hmmm well it's an interesting interpretation of the studies.  The first they quote (26) has no mention of exclusive breastfeeding and purely examines the introduction of solids.  It also (significantly) is studying a group of "at risk" infants.  Those introduced to solids in the first 3 months had a five fold risk, and children not exposed to gluten until seven months or later were at a slightly increased risk compared to those who received it at 4-6 months. This difference was only marginally significant, however. 

When examining just the 25 children with biopsy-proven celiac disease, initial exposure to gluten in the first 3 months or at 7 months and later, significantly increased the risk compared with exposure at 4 to 6 months.  But it doesn't say how many of the 25 children with CDA were exclusively breastfed.  They also note that CDA rates are much lower in Finland (that consumes small amounts of Gluten) compared to Sweden which consumes far more.

They conclude:

The results of the present study provide for the first time convincing evidence that the time-honored, widespread recommendation to introduce gluten at the normal time into the diet of infants born to at-risk parents is indeed correct.

The second study they quote (27) is also examining high risk infants and has very similar findings to (26) again no mention or separation of feeding method.

The third study (28) is of 1612 children, four of whom developed detectable wheat-specific immunoglobulin. All four were first exposed to cereal grains after 6 months AND a first-degree relative with asthma, eczema, or hives was also independently associated with an increased risk of wheat-allergy development.   Four children doesn't seem very compelling evidence, and at least some of the four must have had another risk factor mentioned in order for them to associate it! Again no mention of feeding method. Feeding method is extremely significant as a study by Lvarsson found:

The risk of celiac disease was reduced in children aged <2 y if they were still being breast-fed when dietary gluten was introduced. This effect was even more pronounced in infants who continued to be breast-fed after dietary gluten was introduced.  The risk was greater when gluten was introduced in the diet in large amounts  than when introduced in small or medium amounts.  American Journal of linical Nutrition, Vol. 75, No. 5, 914-921, May 2002.

Allergy

The authors note that allergy and intolerance is still on the increase despite later weaning and conversely peanut allergy is low in cultures that wean with peanuts.  They go on to say:

The development of immune tolerance to an antigen may require repeated exposure, perhaps during a critical early window, and perhaps modulated by other dietary factors including breast feeding. A 2008 review(24) found an increased risk of allergy if solids were introduced before three to four months. After four months, the evidence was weak, but suggested an increased risk with delayed introduction of certain allergens

I can't access the review (24) but I have read before that links with allergy prevention were less compelling after 17 weeks - I don't think the WHO dispute this either.

In response to today's media coverage - a couple of leading organisations have released a statement:

UNICEF
Baby Milk Action
NHS

What actually is the Department of Health Guideline?
From the DOH:

At about six months babies are ready to be moved onto a mixed diet.
Try giving solid foods when your baby:

• can sit up
• wants to chew and is putting toys and other objects in their mouth
• reaches and grabs accurately.

It is normal for babies aged three to five months to begin waking in the night when they have previously and starting solids will not make your baby more likely to sleep through the night again.

Health experts agree that around six months is the best age for introducing solids. Before this, your baby’s digestive system is still developing and weaning too soon may increase the risk of infections and allergies. Weaning is also easier at six months. If your baby seems hungrier at any time before six months, they may be having a growth spurt, and extra breast or formula milk will be enough to meet their needs.

If you decide to wean at any time before six months, there are some foods that should be avoided as they may cause allergies or make your baby ill. These include wheat-based foods and other foods containing gluten (e.g. bread, rusks, some breakfast cereals), eggs, fish, shell fish, nuts, seeds and soft and unpasteurised cheeses. Ask your health visitor for advice, especially if your baby was premature.

Solid foods should never be introduced before four months. Here

and:

The World Health Organization(WHO) recommends that infants are fed exclusively on breastmilk until the age of 6 months and then breastfed alongside food for as long as the mother and baby are happy. Evidence suggests that as well as providing all the energy and nutrients that the child needs in its first few months of life, breastmilk promotes sensory and cognitive development. It leads to slower, healthier weight gain, reducing the chance of later obesity. It provides greater protection from infectious and chronic disease.

Babies breastfed for a minimum of 6months are less likely to experience colic, constipation, sickness/vomiting, diarrhoea, chest infections and thrush. Breastfeeding has also been shown to reduce the risk of ovarian and breast cancer in mothers. 

How do guidelines influence parents?
 
Parents who feel baby is happy and content are likely to follow the guidelines; those who feel concerned their baby is ready earlier, can speak to their Health Professional about earlier weaning; the HP can then judge each case on the individual child and signs of readiness.  The truth is that many parents are often unsure why the guidelines exist and also what risks studies suggest are involved at different ages (which I will discuss more in part two) therefore people often wean a couple of weeks prior to the guideline feeling it is close enough.  As mentioned above the recommendation not to wean until six months has substantially cut the numbers of women who introduced solids before four months – from 85% in 2000 to 51% in 2005.

Part 2 - Can babies be ready before six months and how will I know?