The week began with the extremely welcome news that the LEAP study, which had been on-going on at Guys’s and St Thomas’ Evelina Hospital for the last 5 years, has come up with exactly the results that we had all hoped that it would: that eating peanuts from an early age is likely to protect against peanut allergy.
And now researchers in Sweden tell us that using a dishwasher may actually increase the likelihood of suffering from allergy. What on earth will Friday bring?…
The LEAP research was inspired by a 2008 observational study, also led by Dr George du Toit, one of the lead authors in the LEAP research. This study compared 5,000 Jewish schoolchildren in Israel with 5,000 Jewish school children in the UK. And it found that the incidence of peanut allergy among the children brought up in Israel, who ate peanut in significant quantities from a very early age, worked out at 0.17% while the incidence among the British schoolchildren, whose parents had been advised to avoid peanut consumption by both mother and child, during pregnancy, breastfeeding and infancy, was 1.85%.
But, as Drs Gruchalla and Sampson point out in an editorial in this week’s New England Journal of Medicine, the 2008 study was only observational, so ‘data from controlled studies was needed to provide reliable clinical guidance’. And now we have that data. At 5 years of age, the prevalence of peanut allergy amongst the group of atopic children in the LEAP study who avoided peanuts was 13.7%; in the group who consumed peanuts from around 6 months onwards the prevalence was 1.9%. (For the full research report see the NEJM here.)
Of course the research raises almost as many questions as it answers. Should the guidelines on early ingestion of peanut be changed immediately? If so, how much should the children eat? Will tolerance persist if the children stop eating the peanuts? Could the LEAP study findings also apply to other allergens – eggs? milk? other nuts? None the less, some degree of clarity will be very welcome to those parents of at-risk, atopic infants for whom guidance on whether they should avoid or consume peanuts has, up till now, been at best foggy and at worst non existent.
And will it also focus attention on routes of sensitisation? How does one become allergic to a peanut, or to anything else? If the very process of eating something prevents one becoming allergic to it, which would appear to be the conclusion to be drawn from the LEAP study, can one be sensitised to an ‘allergen’ by another route?
How is it, for example, that a child can have a serious, maybe anaphylactic reaction to a peanut when it has never eaten one? Can sensitisation occur via the skin? So could an eczematous child be sensitised to peanut by the peanut oils on which a number of eczema creams and emollients are based? If so, could the proteins be absorbed through the skin or only into blood stream if the skin was broken? And if so, and if such absorption did sensitise the child to peanut (or any other allergen), why is the body’s reaction so different to the allergen when it is absorbed through the skin rather than through the stomach?….
Meanwhile, what of the dishwasher?
Well, researchers in Sweden, quoting the hygiene hypothesis which suggests that ‘microbial exposure during early life induces immunologic tolerance via immune stimulation, and hence reduces the risk of allergy development’ have been comparing the allergic status of children whose family use a dishwasher with those who wash by hand. And they have found that allergic disease is less common in families who was by hand than those who use a dishwasher, suggesting that ‘a less-efficient dishwashing method may induce tolerance via increased microbial exposure’.
Mind you, they do also note that ‘the risk was further reduced in a dose-response pattern if the children were also served fermented food and if the family bought food directly from farms’ so one does have to wonder whether other aspects of the family’s lifestyle might not have been as important as the dishwasher. (See here for the full report.)
Of course, in some quarters the hygiene hypothesis has now been has now been superseded by the micro biome hypothesis anyway – that it is not our exposure to external bugs that influences the chances of us developing allergies but the health of our population of internal bugs. But then it could be argued that a super clean plate could actively hinder a good bug from making its way via our fish fingers to join its fellow good bugs in our guts…. Time to log out, I think…
Yes I heard that about dishwashers. Why do you think that is? Less germs when washed in the dishwasher? Exposed to more when washing up? I do a bit of both, probably more hand washing because with only two of us it takes us ages to fill the dishwasher and I end up getting stuff back out to wash it before it’s full. Seems pretty pointless then so we use when entertaining. I cram stuff in when feeling lazy. Bit like students. You end up using odd plates and the wrong cutlery just to avoid washing up before you have to.
Ah you spotted the additional info in the dishwasher article too! I must admit, I found it annoying that the emphasis in every article I’ve seen about this in the last few days has been on the dishwasher – completely disregarding the other info!
As far as I’m concerned I won’t stop using my dishwasher, as our allergies all erupted before we had one and I now get piece of mind from knowing that it can help prevent cross-contamination – I feel something is really clean if it’s been through the dishwasher and all the pesky dairy and gluten particles are eradicated!
Plus, a dishwasher really saves time – I find myself having to cook a lot more than I did before my little one came along and before I had to go gluten free – especially when (as I had to do yesterday), you have a whole load of cakes to bake on behalf of your little one for their school cake sale!!
However, very good news about the peanut study – roll on the day when treatment can be available for all!
A lovely summary of a fascinating week indeed! It’s so good to see robust research in this area. The current advice and guidelines on weaning (and inclusion of allergens) is so foggy, that I certainly felt like I was muddling through (with a cow’s milk allergic child to boot); so this is to be welcomed – although as you say with many open questions I wonder how long before it translates into guidance in the manuals of the health visitors?
Just a question on the dishwasher bit – are we sure it’s a ‘more efficient’ way of cleaning dishes? Certainly mine picks up all sorts of crumbs and spreads them everywhere! So much so I won’t have gluteny foods in there and prefer to wash by hand where I can make a visual inspection for crumbs! Maybe that’s just our dodgy dishwasher though… I would be interested to know what other environmental factors or correlations they corrected for in this research too.
Dishwashers!! Thanks, ladies, for your input! As far as dishwashers are concerned I am afraid that the consequences would have to be very dire – and proven – for me to stop using mine. Can NOT be doing with dirty dishes around the place!!
And Carly, I think you just need a new dishwasher!!! Not a crumb would dare to show its face in mine…..
Re the research – not totally convinced…. To be honest, I am not totally convinced about quite a lot of research that comes our way – but that does definitely not include the LEAP study!
I am 71 and have had allergies all my life and asthma in the last 30 years.
I certainly didn’t grow up in a clean home! And I slept in a feather bed. And I did a lot of gardening and walking in fields. It hasn’t helped me at all.
My sentiments entirely Anne. I am well known to Foods Matter. I was brought up in a house that was bombed, we never got rid of the dust and I slept with a feather eiderdown , which gave me asthma. I have also gardened for England all my life. I can however eat peanut butter, which my godfather, a doctor, produced for us in the war in enormous tins.
Ecozone do a tablet that creans the dishwasher which may revive your dishwasher Carly. And I have found that if I use the Ecozone magnoball for dishwashers or washing machines (get all this stuff at John Lewis or google Ecozone) my dishwasher washes better! Don’t know why, but it works.
Mine is more efficient, but is only a few years old. I did notice our old dishwasher would get like this from time to time. That was usually when I got my husband to take a look at it. It usually just involved adding salt or cleaning the filter bit out, I think. That said, I do tend to pre-wash gluteny saucepans that have had spaghetti in them – I soak and wipe wipe kitchen roll (so I can chuck it away). Anything that comes out of the dishwasher not looking clean (I check, believe me) goes back in, until it is!