At this time of year, your children are locked away with their books (hopefully not on their Facebook), studiously revising for their exams. The pressure is also on parents to make sure that they are fed and fuelled, eating the right foods to help them produce 'A' star results.

So what exactly is brain food? And how can you provide the right ingredients to enable your child to reach their full capability, with meals and snacks that will naturally enhance their mood, memory, motivation and mental performance, all of which have been scientifically proven to be powerfully influenced by diet?

Here is a helpful study guide.

● Keep hydrated

Remember, eating and drinking is about making smart choices. Therefore, the first thing to remember is a hydrated brain is a happy one (water makes up approximately 70 per cent of the brain.) If a child is slightly dehydrated, this can lead to a loss of concentration and performance can suffer. However, drinking water works immediately and has a revitalising effect. So make sure there is plenty of water on tap, in a jug, sports bottle or by any other means, for example sucking on ice cubes in hot weather is great, as is flavouring water with fresh lemon, lime or mint.

● Easy on the coffee

Many students rely on coffee or energy drinks to keep them awake and alert. These may provide a quick fix and can increase stamina and boost performance; bearing in mind that it takes 20-30 minutes for the caffeine to peak, and therefore can be useful if used in moderation. However, constantly sipping on Red Bull or having a bottomless mug of coffee to hand, can make even the calmest student jittery, irritable, and anxious and can even lead to heart palpitations.

Caffeine fools the body into thinking it is in a stressful situation, which added to pre-exam nerves can be a recipe for disaster. However, there has been research; a study published in the Journal of Nutrition which revealed that rats given a green tea extract showed an improvement in working memory and the ability to learn, plus green tea is low in caffeine. If green tea is not your child's tea bag, hot chocolate (which may contain traces of caffeine depending on which variety you choose) is a firm favourite. Hot chocolate has also been shown to have positive effects on brain function, due to its polyphenols, which increase blood flow to the brain. So chocolate may be beneficial, but only dark chocolate with a high cocoa content.

● Junk the junk food

When children are in study mode, it seems to encourage their need to nosh and can even cause compulsive eating. A combination of being stuck inside, with only text books for company, pre-exam stress, boredom, plus the brain's need for fuel, can make students reach for high-sugar, high-fat foods, such as cakes, biscuits, chocolate bars and white bread. Keeping blood sugar levels balanced and eating healthy fats (ie omega fatty acids) are vitally important for optimising brain power - the brain uses 60 per cent of all the glucose in the body and is made up of 60 percent fat (this figure is based on the water element of the brain being eliminated). Therefore, many of the high-sugar, fast-releasing carbohydrate snacks our children are reaching for do not do them any favours and can actually bring on headaches, causing loss of concentration.

So why not restock your nosh cupboard with snacks that will enhance studying, rather then giving your child that sugar rollercoaster ride? Some snack suggestions are nuts, seeds, fruit kebabs, a variety of crudités with dips (if you are buying ready-made, keep away from trans-fat products). Try hummus or home-made mackerel or salmon dips, or for those with a sweet tooth, fruit smoothies.

● Make regular pit stops

Eating, like studying, needs to be strictly structured and timetabled, and meals should not be missed. "Your body is like a car, it needs regular fuel," says gastroenterologist Sir Anthony Dawson. A lack of fuel to the brain can cause fatigue, dizziness, irritability, poor concentration, forgetfulness and even depression. Therefore, a student needs to run on grade A fuel to gain grade A results. To do this, meals should be made up from lean proteins found in chicken, fish and egg whites.

Good fats made up from omega 3 and omega 6 essential fatty acids are found in nuts, seeds, avocados and oily fish such as salmon, mackerel and tuna. Complex carbohydrates have been shown by research undertaken at the Massachusetts Institute of Technology to raise a child's IQ. They can be found in brown rice, brown pasta and whole grain crackers. Complex carbohydrates are low on the Glycaemic Index; they keep one's mind alert and energy levels high. The Glycaemic Index is a diet based on slow energy release foods which will help manage the highs and lows of studying.

● Take your vitamins

Should students take supplements? "If you want to improve your child's IQ, put them on a good quality multivitamin and mineral combined with 1,000mg fish oils to provide good omega 3 EFA and 500mg of primrose oil for omega 6 EFA as soon as possible," says Dr Wendy Denning – co-presenter of The Diet Doctors on Five. Of course in an ideal world, if your child is eating a well balanced, nutritious diet there should be less need for supplements, but the truth is, most people's diets are not satisfactory due to our hectic lifestyles and the quality of food produced. Therefore, if you want to boost brain power, supplement their diet, However, remember, the supplements take time to work so if you have not started yet, it might be too late.

Diet really can be the difference between a fail and an F1 performance, so parents need to do their homework as much as their children.