Let’s Talk About Poo


Let’s start as we mean to go on – tackling the issues no-one wants to talk about – with one of the commonest but least glamorous subjects in paediatrics: constipation.

Children with constipation visit GP’s, general paediatric outpatient clinics and specialist gastroenterology services up and down the country every day. The condition causes pain and misery for huge numbers of kids who really should just “poo and go” without a second thought or backward glance into the toilet bowl. Kids have more important things to be doing than worrying about poo.

Sadly, guidance produced by the National Institute for Clinical Excellence (NICE) in May 2010 (1) states that around 5-30% of the child population is affected by constipation, depending on the criteria used for diagnosis. In more than one third of these cases the problem will become chronic. The guideline states:

The exact cause of constipation is not fully understood but factors that may contribute include pain, fever, dehydration, dietary and fluid intake, psychological issues, toilet training, medicines and familial history of constipation. Constipation is referred to as ‘idiopathic’ if it cannot be explained by anatomical or physiological abnormalities.

[N.B. In a few cases constipation can be due to an abnormality of the nervous or endocrine (hormonal) systems and these should always be excluded by an appropriate medical practitioner.]

Section 1.5 of the guideline deals with dietary and lifestyle factors influencing the management of constipation once it has occurred:

1.5 Diet and lifestyle

1.5.1 Do not use dietary interventions alone as first-line treatment for idiopathic constipation.

1.5.2 Treat constipation with laxatives and a combination of […] behavioural interventions [and] dietary modifications to ensure a balanced diet and sufficient fluids are consumed.

1.5.3 Advise parents and children and young people (if appropriate) that a balanced diet should include […] adequate fluid intake [and] adequate fibre.

1.5.4 Provide children and young people with idiopathic constipation and their families with written information about diet and fluid intake.

1.5.5 In children with idiopathic constipation, start a cows’ milk exclusion diet only on the advice of the relevant specialist services.

1.5.6 Advise daily physical activity that is tailored to the child or young person’s stage of development and individual ability as part of ongoing maintenance in children and young people with idiopathic constipation.

Why is diet given such a low priority, both in relation to the possible causes of constipation and its treatment? After all, what goes in is what comes out. Why do experienced doctors believe that idiopathic constipation can be managed, but is likely to remain a chronic problem for the sufferer? Why do they feel that once laxatives have failed there is little else to be done?

In particular, why should a cow’s milk exclusion diet only be recommended by “relevant specialist services”? Who are “relevant specialist services” anyway? Paediatric dieticians perhaps, who are generally of the opinion that dairy products are necessary for optimum growth and development, particularly for “strong bones and teeth” (more on that later); or maybe paediatricians, who generally have little or no training in nutrition?

Arguably, “relevant specialist services” could refer to anyone who has read and understood the relevant literature. So let’s begin with the primary paper cited by NICE:

In 1998, 65 italian children with chronic idiopathic constipation were, after two weeks off all medication, given either cow’s milk or soya milk for two weeks, followed by a week off, followed by the other milk for a further two weeks. Those receiving soya milk were also asked to exclude all cow’s milk-based products from the diet for that period of time. Neither the number of bowel movements, nor the hardness of the stool, changed significantly for any of the participants during cow’s milk phase. However, during the soya milk phase, 44 of the 65 participants showed a response, defined as eight or more bowel movements during the two week period. For these 44 children, there was a significant increase in stool frequency and all 44 experienced a reduction in pain and/or difficulty passing stool. These 44 children remained on soya milk for one month after the crossover trial was completed, and then received a two week long challenge with either cow’s milk or soya milk. No adverse reactions were noted in either group, however in all those receiving cow’s milk there was a recurrence of constipation after 5-10 days. Reintroduction of soya milk again resulted in resolution of symptoms in all cases. After 8-12 months on a cow’s milk free diet, cow’s milk was reintroduced in 15 children, and all of them showed a recurrence of symptoms within 5-10 days.

There are some criticisms of this study. Although stated to be double-blind, this was in reality unlikely to have been possible. Soya milk and cow’s milk do taste different. The study was carried out at a centre specialising in food allergies, and there was a higher incidence of associated symptoms suggestive of cow’s milk allergy (wheeze, runny nose or rash) in those that responded (11 of the 44). However this may simply indicate that cow’s milk allergy is likely to be an important causal factor in the development of constipation in a proportion of children.

These are impressive, if preliminary, results. So why, having noted them, does NICE still not recommend a routine trial of a dairy-free diet for all children presenting with chronic constipation? Does it consider that the elimination of cow’s milk from the diet constitutes such a nutritional risk that it must only be carried out under the direction of a specialist?

The answer is probably yes, given the widely held belief that dairy products are necessary for children’s health. The fact that more than 70% of the world’s population consume no dairy after weaning (2) and have perfectly strong bones and teeth should hint at a problem here, as should the observation that it is the countries with the highest intakes of dairy products (and therefore of calcium) that also have the highest rates of hip fracture (a marker for osteoporosis – again, more on this later). That said, for those who still consider that high calcium intakes, equivalent to those found in dairy-heavy diets, are necessary for children, all major supermarket chains now stock soya milks and other dairy substitutes fortified with calcium and vitamins.

The problems we are left with then are those of behaviour change and education: not easy nuts to crack, especially in a busy clinic with 10-20 minute slots per patient. Far too many children in this country eat a diet consisting primarily of chicken nuggets, fish fingers, sausages, chips, mash, white bread (ham or cheese sandwiches, toast and butter), coco-pops, squash, fizzy drinks, crisps, sweets and so on. So where do you begin? There is a commonly held belief that exclusion diets of any sort are too difficult for most people, and for some people that may be true – certainly with the level of support the NHS is able to provide. For optimal health and calcium intake, instead of dairy we should all be eating lots and lots of green vegetables (and figs and almonds…) (3), but the reality is that that may be hard for many parents of fussy young children – used to food that is either brown or white – to manage.

References:

1. http://guidance.nice.org.uk/CG99 Accessed on 2nd November 2012.

2. http://www.vegetarian.org.uk//white-lies Accessed on 2nd November 2012.

3. http://www.diseaseproof.com/archives/children-avoiding-cows-milk-may-alleviate-chronic-constipation-in-children.html Accessed on 2nd November 2012.

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