Updated 04 November 2014

Smart foods to boost your brain power

Stressed about your exams? Keep your mind sharp and beat stress by including these smart foods in your diet, writes DietDoc.


Many students ask what supplements they can take to boost their mental performance. There's a plethora of supplements available, all promising to "improve mental performance" and "beat exam stress". The question, however, is if any of these often expensive supplements will actually make a difference to study results and pass rates?

It is important to keep the following in mind:

  • No supplement on earth will help you pass an exam if you have not studied diligently throughout the year
  • No supplement taken for a short period can replace the use of a balanced diet over the entire year
  • Many of the products that advertise that they will help you to concentrate or control exam stress, contain ingredients that have not been scientifically tested and for which no proof of efficacy exists.

Supplements that contain omega-3 fatty acids, vitamin D and B complex, as well as certain phytochemicals (see below),  may well make a positive contribution to brain functioning. But it may be advantageous to use such supplements for longer periods in the run up to exams, rather than to swallow a few bottles at the eleventh hour.

The basics

To succeed with your studies and do well in the exams, the following basic factors in your life must be in place:

  • A well balanced normal diet (see below)
  • An adequate supply of energy - the human brain is highly sensitive to blood glucose levels and will not function properly if starved of glucose, so avoid weight-loss diets and fad diets that exclude carbohydrates
  • Plenty of oxygen and physical exercise
  • Enough rest when required

 A well balanced diet

When we speak of a well balanced diet we mean that the person in question should, if possible, eat a variety of foods from all the different food groups, which include carbohydrates (starches and sugars), proteins (animal and plant proteins) and fats and oils (particularly essential fatty acids).

This type of diet should contain:


  • Starches with a high energy, vitamin B and dietary fibre content, and a low glycaemic index (GI) - e.g. high-bran fortified breakfast cereals, ProNutro (wholewheat, original or apple bake flavour), muesli, Up ‘n Go; rye and low-GI breads; brown rice, pasta made from Durum wheat; corn on the cob and sweet potatoes (Steenkamp & Delport, 2007).
  • Sugars - honey and chocolate (esp dark chocolate which is rich in phytochemicals), in small amounts to provide energy and keep blood glucose levels high enough for the human brain to function at its best.
  • Fruits and Vegetables - make sure you eat some citrus fruit, guavas, tomatoes, cabbage, broccoli, pawpaw, or berries every day to top up your vitamin C intake so that your immune system is healthy enough to prevent infections like flu and colds; also have at least one serving of dark green (broccoli, cabbages, spinach) or dark orange/yellow fruits (apricot, mango, spanspek) or vegetables (carrots, sweet potatoes, pumpkin or butternut) daily to provide beta-carotene which improves immunity and is responsible for normal eye function.


  • Animal proteins which contain essential amino acids and valuable minerals such as calcium (milk, yoghurt, cheese), iron and zinc (liver, red meat, fish, chicken, egg yolk), iodine (fish and sea food), and vitamin B12 to prevent anaemia. Low blood iron and vitamin B12 levels can cause different types of anaemia which in turn can lead to reduced brain function due to oxygen deficiency. Iodine is essential for the normal function of the thyroid gland which orchestrates the metabolism of the entire body.
  • Plant proteins as found in legumes (cooked or canned dry beans, peas, lentils or soya), which help to make animal proteins go further and also contain valuable minerals such as iron and zinc, and dietary fibre to promote bowel regularity.

Fats and oils

  • Essential fatty acids such as omega-3 fatty acids (EPA and DHA) , which make ‘unique, important and irreplaceable contributions to overall brain and nervous system functioning’ throughout life (Mahan et al, 2011). EPA and DHA help brain cells to communicate and transmit messages and improve memory. These omega-3 fatty acids also help to reduce anxiety and may help to control stress levels, as well as depression. Omega-3 fatty acids are found in fish and sea food, particularly in fatty fish such as sardines, tuna, salmon, anchovies and snoek. Fish oil supplements are regarded as important sources of omega-3 fatty acids for a healthy brain and nervous system especially in stressful periods such as exam time.
  • Monounsaturated fatty acids found in olive, canola and safflower oils, nuts, peanuts and peanut butter, olives and avocado which are a healthy source of energy and protect our arteries and cardiovascular system.

Read: Beat stress with your diet

Other brain nutrients

In addition to the basic balanced macronutrients mentioned above, the human brain requires certain vitamins and other nutrients to function efficiently.

a) Vitamin D

Vitamin D, which was for many years, the ‘forgotten vitamin’ has recently been identified as one of the most important vitamins in the human body. It is responsible for hundreds of genes and plays a vital role in brain health. Although human beings are able to synthesise vitamin D when our skins are exposed to sunlight, research indicates that nowadays many people have a vitamin D deficiency. 

Modern lifestyle habits such as spending more time indoors (watching TV and playing video games) and the need to use sunscreens to protect ourselves against damaging UV radiation in the Southern hemisphere because of the hole in the ozone layer, all contribute to low vitamin D levels. Oily fish and egg yolks are the richest dietary sources of vitamin D in this country where very few basic foods are fortified with vitamin D (Mahan et al, 2011).

ReadSecrets of longest living people

b) Vitamin B complex vitamins

The so-called vitamin B complex comprises vitamins B1 (thiamine), B2 (riboflavin), B6 (pyridoxine), niacin, folic acid, biotin, and pantothenic acid, as well as vitamin B12, which have important positive effects on neural function and brain health. The most important sources of B complex are brewer’s yeast, wholegrains, liver, meat and leafy vegetables. Neurotransmitters like serotonin and dopamine are also influenced by B vitamins.

c) Phytochemicals

These are bioactive chemicals found in berries, citrus fruit, green tea and certain spices like ginger, turmeric, oregano, sage, rosemary and garlic or onion. Future research will hopefully identify which of these phytochemicals are important to brain health because of antioxidant, and anti-inflammatory functions which protect the cell structures and metabolism of the brain (Mahan et al, 2011).

Brain foods include apples, all types of berries, chocolate, citrus fruit (oranges, grapefruit, lemons, naartjies and clementines), grapes, grape juice and raisins, and different types of tea (green, black, oolong, and rooibos) (Mahan et al, 2011).

If you combine steady work throughout the academic year with a well balanced diet, plenty of rest, exercise to increase the blood and oxygen supply to the brain, and 30 minutes of sun exposure per day to boost your vitamin D production, then you should not have a problem when it comes to school, college or varsity exams.

(References: Mahan LK et al, 2011. Krause’s Food and the Nutrition Care Process. 13th Edition. Elsevier Saunders, USA’ Steenkamp G, Delport L (2007). The South African Glycemic Index & Load Guide. GIFSA, SA.)

Any questions? Ask DietDoc

Read more:

Slideshow: what to eat during exams
10 foods that relieve stress
Why your brain needs fish


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