Next time you tell your kids they can’t have junk food and they whine, “Why not?” tell them they won’t be so brainy if they eat rubbish all the time. Fast food is bad for you for plenty of reasons, but studies now show that children who eat more fast-food meals grow up to have lower IQs than those who regularly eat freshly cooked meals.
Researchers at the University of London found that childhood nutrition has lasting effects on IQ, even after factors such as previous intelligence, wealth and social status are taken into consideration. The study looked at 4000 Scottish children aged between three and ve and the type of main meal they ate every day. Their cognitive ability and growth were also tested.
The results showed that those who ate more meals prepared with fresh ingredients tended to score higher in intelligence tests. Children who consumed more takeaways scored lower on intelligence tests and were likelier to struggle in school. It’s thought this is due to the fact that diets which are high in fresh foods, such as fruit and vegetables, and healthy proteins provide children with more of the nutrients their brains need to develop.
The head of the study, Dr Sophie von Stumm, says it’s common sense that the type of food we eat affects brain development and the study shows “the freshness and quality of food matters more than just being full, in particular when children are young and developing”. Similar results have been found in other research.
- An Australian study published in August reported that toddlers who had a diet high in sugary drinks and sweets were less bright as they got older. By the age of eight the “junk food” kids had IQs up to two points lower than their peers on healthier diets, according to the researchers from the University of Adelaide.
- A US study carried out two years ago found that children who have a diet consisting of lots of pizza, chips and biscuits before they were three may end up having lower IQs than those who tucked into mainly home-cooked meals with plenty of fruit and vegetables. When they were tested ve years later their IQs were as much as ve points lower than those of their counterparts who had been fed on healthier food.
One of the scariest findings from all the studies is that even if these junk-food kids were switched to a healthy diet later on in childhood, it could be too late to do anything about their brain development. The research suggests that if they eat badly in those crucial early years, the damage that occurs at that time may not be reversible.
So although it is important that children of all ages eat a healthy diet, it appears to be especially critical in the first three or so years of life, when their brains are still developing. The part of the brain linked to intelligence may not be all that can be affected – there’s also evidence that junk food may take a toll on the area that controls behaviour. And it’s not just intelligence that’s affected.
An Oxford University study found kids who ate diets high in processed foods were likelier to behave badly. The researchers found that not eating enough foods containing vitamins, minerals and essential fatty acids made it harder to concentrate, and children lacking those essential nutrients in their diets were more likely to be underachievers at school and get into trouble for disruptive behaviour.
The good news from this study is that when the scientists gave a group of children supplements of omega-3 fatty acids – known to help with brain development – they found around 40% of them noticed big improvements in reading and spelling after just three months.
Top tips for what to feed your kids' growing brains
- Limit junk food. Try to have takeaways once a week at the very most and eat home cooked meals made from scratch the rest of the time.
- Ban junk food completely for under-threes. If they’re eating lots of rubbish they are not getting the vital nutrients they need for their brains to develop properly.
- If you are going to have takeaways, try to choose those that do at least come with vegetables, such as Chinese and Thai food, or serve something healthy along with the fast food, such as a side order of salad with pizza, or cook up some favourite veges, like carrots and peas, with sh and chips. This may sound odd, but do it every time and it will come to seem normal to your kids.