My 4 year old son’ behaviour has always been challenging, but has been particularly bad in recent weeks. After complaining of bloating, diarrhoea etc a breath test revealed that he was fructose intolerant (Note: about 50% of people have a positive breath test, so it is not very useful - Fructose malabsorption factsheet). So we started on the strict fructose elimination diet. My GP asked me a couple of weeks later how the diet was going. I responded that it was going well and that my son had not complained of bloating, stomach pains, etc since. However the thing I had noticed the most was his improved behaviour. I'm sure my GP thought I was a little odd, and commented that it wasn't something he'd heard of before but perhaps my son's behaviour is better because he doesn't have tummy pains. I wasn't convinced.

After a few weeks, we started a challenge by reintroducing the high fructose foods. He seemed to tolerate them well as long as he doesn't eat too much fruit each day. However, his behaviour has been foul! He seems more angry than ever, and last week I was wondering if he may be ODD. The Magic 123 which worked well for so long, now has no impact as he is just so defiant.

So, I started FAILSAFE eating 6 days ago. We haven't done it perfectly as his diet is very restricted due to food allergies and the fructose intolerance. But I've removed the high salicylate items, particularly tomatoes, strawberries and cantelope; and we're really just having the good ol meat and 3 veg for tea every night. I've cut his fruit intake to 1 serve every 2-3 days.

Day 1 perfect behaviour although it was still like walking on egg shells.

Day 2 bad morning, good afternoon.

Day 3 good behaviour a little less eggshells!

Day 4, 5, 6 great behaviour.

When things are good he is the perfect gentleman, well-mannered a real angel. But when things aren't going his way he still gets grumpy but most of the time he can now control the anger. A week or more ago, he just couldn't.

Update 3 months later after doing the elimination diet with a dietitian: Things went really well for some time. However, my son was desperate for some of the non-failsafe foods, particularly tomato sauce and jam. So I gradually caved in, and allowed him to have some. Initially it was a little bit every few days, then a little each daily. Although I'm still careful with his diet, he mustn't be able to tolerate even these quantities as we've started to notice some of the same old behaviour. The salicylates seem to have a cumulative effect on him. Whilst his behaviour hasn't been as aggressive or defiant, I'm certainly noticing that he is loud and unsettled. He can't concentrate on playing with his toys, but instead races around the house and jumps on the furniture! So this week were back on failsafe - strictly! – Carly, by email.

What the researchers say: (See page 14 of the RPAH Elimination Diet Handbook 2009 available from ‘Having excessive amounts of fruit especially fruit juice and dried fruit can cause symptoms such as bloating, reflux, abdominal discomfort, wind and diarrhoea. Although incomplete fructose absorption can cause stomach and bowel symptoms, it does not cause other symptoms such as headaches, fatigue or skin rashes … improvement of symptoms after going onto a low fructose diet is most likely to be due to the simultaneous reduction of intake of natural chemicals in fruits and vegetables’.