You do not need to spend a small fortune on processed brain boosters. Nutritionists have proven that there are certain types of natural food that can dramatically improve mental ability.

Oily fish, such as salmon, tuna, sardines and mackerel, top the charts of brain boosters. They contain high levels of omega 3 fatty acid, which is crucial in enhancing memory and boosting brain development.

A recent study, for example, revealed that children with poor concentration and learning difficulties showed significant improvement after they were given omega 3 supplements.

If you have never liked brown rice, give it another try. Brown rice - along with oats, cereals, lentils and beans - is rich in wholegrain, a key source of vitamin B. Vitamin B is essential for a healthy nervous system. It is particularly good for the memory.

A top-notch immune system is the best running mate when it comes to the exam marathon - you cannot keep your brain in tip-top form if your body is weak and you feel unwell.

Vitamin C, present in fruit - particularly lychee, oranges and papaya - and vegetables, plays a vital role in fighting off infection.

Since our bodies do not store vitamin C, we need to eat fruit and vegetables daily - a once-a-week binge won't cut it.

As for breakfast, don't skip it - it's your study buddy. 'Scientific studies dating as far back as the 1950s consistently show that children who eat breakfast have better memory, better problem-solving skills and improved test scores than those who don't,' says Young Post nutritionist Wynnie Chan.

'Breakfast gives you energy, and it makes sense to fuel up in the morning. After ... fasting all night, the brain and body need a fresh supply of glucose.'

But it's not just eating breakfast that counts - what you eat is important too.

'It's not good to eat a lot of sugary biscuits, cakes and chocolate or fill up with caffeinated drinks,' says Ms Chan.

'Although these kinds of foods give you an instant boost of energy, a sugar rush is not what you need because an hour or two later sugar levels drop dramatically and you'll be tired and irritable and unable to concentrate.'

It's better to eat food with complex carbohydrates that are slowly digested and absorbed into the body. It will give us a steady supply of energy to last through the morning.

'Examples of healthy breakfast items include wholegrain cereals, such as oatmeal or unsweetened muesli, wholegrain bread with peanut butter and banana, baked beans on toast with mushrooms, fruit smoothies, or a fruit salad with yoghurt,' says Ms Chan.

Last but not least, drink lots of water, eat regularly and get enough sleep and exercise. These are all effective ways to stay focused and improve mental performance.