We are all aware of the devastating consequences that a junk diet of endless fizzy drinks, sugary snacks and foods containing little more than unhealthy fats and salt can have on our children's health and with Christmas almost upon us, this is the time of year most parents cave in and allow our little ones to indulge in a feast of chocolate and candy, with scant regard to healthy eating messages.
Every year, Government surveys1 tell us that our children are eating food of a low nutritional quality and are getting poor intake of vitamins, minerals and other nutrients essential for good health. And we don't need to be reminded that a poor diet in childhood can lead to obesity, early type 2 diabetes, high blood pressure and poor bone health. But the double whammy is that poor eating habits can also have catastrophic effects on your child's learning, behaviour and ability to do well at school.
There is a widespread belief among experts that nutrition and diet influences cognitive function in a number of ways; nutrients such as certain types of fats and vitamins have a positive effect as do eating habits such as starting the day with a healthy breakfast, whilst excessive amounts of sugar can cause problems.
A number of studies2 have considered the effect of sugar intake on learning and behavioural outcomes, most of which were conducted in children with symptoms of ADHD. While most of these studies have found that short-term exposure to sugar has no dramatic detrimental effects on learning and behaviour there is evidence that choosing carbohydrate foods that release their energy slowly and offering balanced meals can help performance in the classroom3. These carbohydrate foods are said to have a low GI (glycaemic index) which means they can help to keep blood sugar levels stable and reduce hunger pangs between meals. Examples are oats, Basmati rice and wholegrain cereals. A mixed meal consisting of carbohydrate and protein can have a similar effect, so adding a poached egg or peanut butter to toast is a good idea.
The mantra breakfast is the most important meal of the day rings especially true when it comes to a child's performance at school. Studies4 have found that setting up a breakfast club at school can have a positive impact on not only education and behavior but also attendance. Other studies5 have looked at the effect of eating breakfast compared with skipping it, one saw some improvements in problem solving, attention and memory after eating cereal while another saw better results in complex visual display tests after consuming breakfast.
All of the studies that looked at breakfast versus no breakfast and found a positive effect on cognitive function, observed that these improvements were more obvious later in the morning.
Omega 3 fats
Researchers from Oxford University have focused their attention on one particular fatty acid known as DHA (short for docosahexanoic acid). Their DHA Oxford Learning and Behaviour or DOLAB trial6 showed that taking a daily supplement of DHA improved the reading skills of underperforming but otherwise healthy children. Researchers recruited 362 healthy children aged 7-9 years from mainstream state schools in Oxfordshire who were underperforming in literacy (below the 33rd percentile on a standardized reading test). After 16 weeks of taking a 600 mg dose of DHA derived from algal oil there was improved reading performance for the worst readers, which helped these children catch up with their peer group. An added bonus was that many of the parents reported improved behavior and attention in their children during the trial.
DHA is a long chain omega 3 fatty acid found in oily fish such as fresh tuna, salmon, mackerel, which is why we are recommended to have at least one portion per week. But this advice is falling on deaf ears as intakes of fish for both children and adults are woefully low making it difficult for most people to get enough DHA in their diet. The fish get the DHA by eating algae, which is a rich source, so algae supplements are a way of cutting out the middle man for fussy and non fish eaters.
Fish oil supplements and other omega 3 supplements contain DHA as well as other fatty acids known as EPA and ALA, and while these have their own health benefits, it is only DHA that is associated with improvements in brain health and cognitive function.
Vitamins and minerals
Getting enough vitamins and minerals is also crucial to learning and school performance. Poor intakes of iron can lead to iron deficiency anaemia which in turn impairs cognitive function. Other vitamins and minerals important for children's brain health and learning ability are iodine, iron, zinc and vitamin B12, and low magnesium levels have been reported in children with ADHD (attention deficit hyperactivity disorder). The Government survey mentioned earlier shows that many children are not having the recommended daily amount and worse, some children have such tiny amounts they are risking deficiency. In a trial7 where children received a multivitamin and mineral supplement over several months an increase was seen in nonverbal IQ.
Clearly we have to stop the rot in our children's diets. An over reliance on nutritionally inferior processed foods fills them up with sugar, fats and salt and means they miss out on vitamins and other nutrients vital for their health. However, the challenges of an immature palate and an innate liking for sweet, calorie rich food will always pose challenges in trying to achieve the perfectly balanced diet. Your child is not unique if he or she does not like oily fish for instance, in which case we can rely on supplements with proven benefits.
- Bates B, Lennox A & Swan G (2010) National Diet and Nutrition Survey. Headline Results from Year 1 of the Rolling Programme 2008/2009. Food Standards Agency, Department of Health: London.
- Ells LJ, Hillier FC, Shucksmith J et al. (2008) A systematic review of the effect of dietary exposure that could be achieved through normal dietary intake on learning and performance of schoolaged children of relevance to UK schools. British Journal of Nutrition 100: 927-36.
- Gilsenan MB, de Bruin EA & Dye L (2009) The influence of carbohydrate on cognitive performance: a critical evaluation from the perspective of glycaemic load. British Journal of Nutrition 101: 941-9.
- Defeyter MA, Graham PL, Walton J et al. (2010) Breakfast clubs: availability for British schoolchildren and the nutritional, social and academic benefits. Nutrition Bulletin 35: 245-53.
- Hoyland A, Dye L & Lawton CL (2009) A systematic review of the effect of breakfast on the cognitive performance of children and adolescents. Nutrition Research Reviews 22: 220-43.
- Black MM (2003) Micronutrient deficiencies and cognitive functioning. The Journal of Nutrition 133: 3927S-3931S.
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