Cause and effect eg. processed food and children's development

(87 Posts)
jugglingjo Tue 08-Feb-11 07:20:35

I've just heard on the morning news that a new study suggests that young children with a bad diet including lots of processed food have been found to later develop to have lower IQ's than their peers.

Interesting. However I'm wondering if this could be a classic example of something I've suspected in research about development for some time.

That is, how sure can they or we be that this is really a causal relationship. Have the factors accompanying this poor diet really been taken sufficiently into account.

Things like socioeconomic class, poverty, struggling parents, and the things that may go with this package such as less stimulating experiences, less engaged parents, less communication between parents and children etc. etc.

Scientific research needs to be rigorous, and yet you hardly ever hear mention of the degree of causality that is being suggested. Or how accompanying factors have been considered.

A causal relationship is always just presumed.

At least by the media.

I think there are many things which affect our development more than diet. Though a good diet is very important for our health and well-being.

What do others think ? Especially about the science aspect ?

jugglingjo Tue 08-Feb-11 07:22:31

Sorry didn't mean to post in "conception", only on the talk boards.

Can anyone move to more suitable place?

Thanks smile

onimolap Tue 08-Feb-11 07:30:27

That it is plausible.

Fats are very important in the brain (structure and function). If your diet consists of food with poorer fats, I'm not at all surprised there's a measurable effect, especially in the formative years.

jugglingjo Tue 08-Feb-11 07:46:31


But what about the other effects?

Have they really been taken into account?
And if so, how was this done ?

In my work with children I've had lots of opportunities to see the importance of both communication and stimulating experiences in children's development.

I think there's an over emphasis on diet with regard to children's development, behaviour etc.

But more than the specifics of this research, my point is a general one.

Whenever you hear of research ( via the media) a causal relationship is always presumed.

With interesting research regarding people, lifestyles, and development, it just isn't that straight-forward !

onimolap Tue 08-Feb-11 07:55:04

Here's a link to the Telegraph's account. It was a study of 14,000 families, published in The Journal of Epidemiology and Community Health (anyone know what its standing is?), and it said potential confounders were excluded.

What annoys me is the headline, which says good diet boosts IQ. The study indicates nothing of the sort: it shows poor diet can inhibit it. Not the same thing at all.

jugglingjo Tue 08-Feb-11 08:13:04

Thanks onimolap. I look forward to reading your link when time allows. (School run beckons ! )

My suspicion is that "potential confounders" have been excluded without sufficient scientific rigour !

jugglingjo Tue 08-Feb-11 08:19:20

Have now read article and will consider.

Note though that there is very little consideration given to accompanying factors
(As is always the case !)

onimolap Tue 08-Feb-11 08:22:58

What we need is a subscriber to the JECH to tell us about it properly - the press reporting of the study is never going to give enough detail.

FreudianSlippery Tue 08-Feb-11 08:24:31

I would expect it is implicated, but it's something I've not devoted too much thought to. I just figure it's not good to have too much processed food anyway, due to physical health, so we keep it fairly (not totally) limited. A good rule of thumb is that if the ingredients list has too many items, or if they are random scientific gobbledegook, don't eat it much

onimolap Tue 08-Feb-11 10:15:46

Here's another link - to SKY, but there are links therein to the authors of the study (Avon longitudinal study, Bristol University).

Lancelottie Tue 08-Feb-11 10:25:12

You hardly ever hear of the confounding factors because that would be quite boring (pages and pages of very, very similar plots and statistics, I should think), but yes, in a properly carried out study, they should have been considered and probably were, otherwise the reviewers should have sent the researchers back to have a re-think.

Always a good question to ask, though!

I remember a study showing that 'manual-oral transmission of lead residue in soil' [or kids sticking mucky hands in mouths] was correlated with lower IQ, but the authors 'could not rule out the possibility of inverse correlation effects of IQ on manual-oral transmission pathways and frequency', which I took to mean that thick kids eat more mud...

Lancelottie Tue 08-Feb-11 10:25:45

sorry, 'inverse CAUSALITY', not correlation.

onimolap Tue 08-Feb-11 10:26:57

Lancelottie: love that example!

onimolap Tue 08-Feb-11 10:37:56

Found it!!!!

Ariesgirl Tue 08-Feb-11 10:47:51

I'm of the same opinion about all stuff regarding what is put in a child's mouth. That includes FF vs BF.

jugglingjo Tue 08-Feb-11 12:13:13

Great example Lancelottie.

Inverse causality looks like a distinct possibility on that one !

Anyone have any other examples of research which has given you a distinct hmm feeling of scepticism ? (sp?!)

jugglingjo Tue 08-Feb-11 12:35:55

Thanks for link onimolap -

Have just sent an email to kate northstone, one of the researchers, to let her know about our discussion, and something of my thoughts on this one !

Even though mine are now 9 and 11 perhaps we might keep pizza night to once a week !

Another thought though, have they included making allowances for breast-feeding, as this has been shown to have a positive effect on IQ, and could easily be a confounding factor here ?

Poppet45 Tue 08-Feb-11 13:35:40

Okay, OP do you know much about the use of statistics in science? ANOVA tests, Poisson distributions that sort ot thing? Basically there are dozens of carefully worked out mathematical formulae that are used in research papers during the analysis phase which allow researchers to tease out individual variables from a whole mass of data and check for correlations, causal relationships that sort of thing. They look like a foreign language but yes they mean that to a 95 per cent confidence interval, researchers can generally be sure that what they think is happening is happening. The problem is they are very dry, dusty, and hard going to read through so they don't make a newspaper article which has maybe 500 words to convey the whole story. However if you're interested, or still need to be convinced it's not all a big con, you might want to start reading about the use of biological statistics. Having had to do just that during my degree I would personally recommend you didn't

HelenMumsnet (MNHQ) Tue 08-Feb-11 14:37:29

Hello. We're going to move this thread to In the News - we're sure it'll get some more posts once it's there...

Hammy02 Tue 08-Feb-11 14:56:54

It is more likely that the type of parents that feed their children rubbish are less likely to encourage their children in their education, read to them every night etc. It is the same as the nonsense arguement that playing a musical instrument makes children achieve more academically. Noooo. Again, the type of parents that encourage their child to play an instrument will be the same types that encourage their children academically. Duh.

Chil1234 Tue 08-Feb-11 15:49:43

There's quite a well-known study that analysed the behaviour and development of two groups of prisoners.... one on standard prison food and the other on a much more nutritious diet. That showed quite a strong correlation between good nutrition and things like calmer behaviour. In the prison example, of course, it's a thoroughly controlled group and the effects were seen over a relatively short period. So external factors like poverty or upbringing could be eliminated.

Jamie Oliver's campaign seemed to suggest that children on a better diet were better equipped to concentrate at school. I don't think it's too big a leap to suggest that if better nutrition leads to better behaviour in adults and an improved ability to concentrate in children then a still-developing child is more likely to reach its intellectual potential

jugglingjo Tue 08-Feb-11 15:53:37

Hi Poppet, In answer to your question about how much I know about the use of statistics in science -

I know a fair amount as I have a degree in science (geology) from Bristol University (who are incidentally involved in this research) We learnt about and used statistics in my geology, geography and economics courses. Later I've used them during small research projects as a psychiatric nurse and early years teacher. My DH has a PhD in palaentology, and we have many friends involved in research. with my daughter I've taken part in two research projects at Cambridge University (as participants!)

So, I know more than many people - enough to be annoyed at the way science is reported in the media !
But less than experts such as yourself.
I understand about normal distributions etc.
That sort of level.
I've used a statistical method for comparing characteristics of two different populations.

I feel the media could assume a slightly higher level of scientific understanding in it's readership.
It could for example discuss what the main "confounding factors" were found to be. It could tell us what level of confidence was arrived at during the research.

There is often a lot of detail about the research methods, and too little devoted to the actual conclusions.

For example in the reporting of this research soome of the quoted comments were that a good diet is important because of the levels of obesity in children. But this research was actually nothing to do with that, seperate though related, issue.

Hammy - Great to see someone picking up on my wider point !
Exactly the sort of thing I mean ! wink

Loopynoo Tue 08-Feb-11 16:02:51

Hi all, below is the abstract of said article. Think it might help the discussion...

My own opinion? I think as with most things in life you get what you put in, and our DCs are no different, however a little bit of "bad" food ixed in wiht a healthy balanced diet is probably best and this article does little to change/influence what i feed DS. 1955.abstract?sid=58a861cf-c1b1-4090-8574-eb134b16 4d8e

Are dietary patterns in childhood associated with IQ at 8 years of age? A population-based cohort study


Little is known about the effects of overall diet in childhood and intelligence later in life.

The current study, based on the Avon Longitudinal Study of Parents and Children, uses data on children's diet reported by parents in food-frequency questionnaires at 3, 4, 7 and 8.5 years of age. Dietary patterns were identified using principal-components analysis and scores computed at each age. IQ was assessed using the Wechsler Intelligence Scale for Children at 8.5 years. Data on a number of confounders were collected, and complete data were available for 3966 children.

After adjustment, the ‘processed’ (high fat and sugar content) pattern of diet at 3 years of age was negatively associated with IQ assessed at 8.5 years of age—a 1 SD increase in dietary pattern score was associated with a 1.67 point decrease in IQ (95% CI &#8722;2.34 to &#8722;1.00; p<0.0001). The ‘health-conscious’ (salad, rice, pasta, fish, fruit) pattern at 8.5 years was positively associated with IQ: a 1 SD increase in pattern score led to a 1.20 point increase in IQ (95% CI 0.52 to 1.88; p=0.001).

There is evidence that a poor diet associated with high fat, sugar and processed food content in early childhood may be associated with small reductions in IQ in later childhood, while a healthy diet, associated with high intakes of nutrient rich foods described at about the time of IQ assessment may be associated with small increases in IQ.

jugglingjo Tue 08-Feb-11 16:51:26

This research just shouts to me that there are underlying reasons why some of the children are getting a much a better diet than others.

Call me skeptical, but I've yet to be convinced that these underlying factors have been given due consideration !

It's not exactly a controlled trial, is it ?

But, now this thread has been moved by MNHQ to "In the news" I hope people will feel free to discuss all aspects of this research.

How important do you feel the diet of young children is to their future development, intelligence, and well-being ?

Personally, as I've said, I think it's more important for our physical health, and that other things are more important factors in determining our intellectual, emotional, and social health etc.

jugglingjo Tue 08-Feb-11 17:20:25

An equally interesting possibility to consider,

- that what we do with our children and our level of engagement with them in the early years could be responsible for this variation of 5 points in their IQ rating by the age of 8. ( Probably more than 5 points, as we've been told that such confounding factors have been taken into account, so the original differences in IQ were probably greater )

Does anyone know of any further research along these lines ?

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