When you consider that the body and brain are entirely made from molecules derived from food, air and water, it's to be expected that changes in diet can have an effect on our mood and mental health. There is much evidence that proves that you can change how you think and feel by what you eat.

Common imbalances connected to nutrition that can affect your mood and motivation levels are:

• Blood sugar imbalances- these are often associated with excessive sugar and stimulant intake. Blood sugar levels can be kept more even by eating small, regular meals of natural, unprocessed foods.

• Deficiencies of nutrients - the most important nutrients associated with mood are vitamin B6, B12, C, folic acid, zinc, magnesium, chromium and essential fatty acids.

• Deficiencies of the brain chemicals tryptophan and tyrosine- tryptophan is a constituent of protein from which the body makes serotonin- an important neurotransmitter that is associated with mood.

Supplementing the diet with typtophan is well proven to improve mood. One study from Oxford University found that when people were deprived of tryptophan but otherwise had a nutritionally balanced diet, they showed signs of worsening of their mood and depression, and their mood improved when tryptophan was added. This is because tryptophan leads to an increase in the synthesis of serotonin in the brain, and research demonstrates that this chemical improves mood as well as many antidepressant drugs.

Tyrosine is an amino acid that is made from another amino acid- phenylalanine. These amino acids make the neurotransmitter dopamine, responsible for the production of two neurotransmitters associated with depression and lack of motivation- adrenalin and noradrenalin. Studies have found that the amino acids tyrosine and phenylalanine are as effective for depression as some antidepressant drugs, and that depressed patients had low levels of phenylalanine in their body.

If you want to eat your way to happiness the key is to follow a diet that keeps your blood sugar levels stable and provides plenty of tryptophan and omega-3 fats, which help to make and use serotonin in the brain. This means:

• Avoid or limit your intake any form of sugar

• Reduce your intake of stimulants - including caffeine containing tea, coffee, chocolate and colas.

• Increase nutrient-rich foods - fruit, vegetables, herbs, wholefoods, nuts and seeds.

• Eat more sources of tryptophan - it's especially rich in fish, turkey, chicken, cheese, beans, tofu, oats and eggs.

• Eat omega-3 rich foods - this includes fish such as salmon, mackerel, herring, sardines or trout.

• Eat raw, unsalted seeds and nuts- the best seeds are flax (or linseed), hemp, pumpkin, sunflower and sesame. You get more goodness out of them by grinding them first.

• Use cold-pressed seed oils. -choose an oil blend containing flaxseed oil or hemp oil for salad dressings and cold uses, such as drizzling on vegetables instead of butter. Don't cook with these oils as their fats are easily damaged by heat.

• Minimize your intake of fried food and processed food.

References

• Smith KA, et al. Relapse of depression after rapid depletion of tryptophan, Lancet, Vol 349, 1997, pp.71-8.

• Beckmann H et al. DL-phenylalanine versus imipramine: a double-blind controlled study. Arch Psychiartr Nervenkr, Vol 227(1), 1979 pp.49-58.

• Sabelli HC et al. Clinical studies on the phenylethylamine hypothesis of affective disorder: urine and blood phenylacetic acid and phenylalanine dietary supplements. J. Clin Psychiartry, Vol (2), 1986, pp.66-70.