Low serotonin levels are associated with various types of depression. Indeed drugs such as SSRI’s and tricyclic anti-depressants work by inhibiting the breakdown of serotonin in the gaps between brain cells (synapses). As a precursor of serotonin several studies have shown 5-HTP to be an effective way to increase serotonin levels and therefore to be helpful in patients with depression.
Researchers have found that 10-15 percent of depressed patients have low plasma levels of phenylalanine. Two double-blind comparative studies reported that phenylalanine was as effective as the antidepressant medication Tmipramine.
Phenylalanine is a precursor to the mood elevating compound dopamine (which is found to be low in some depressed patients). It also enhances other mood enhancing chemicals such as PEA and endorphins. DLPA is converted into tyrosine before eventually becoming dopamine and tyrosine may be preferred in some cases – see below.
Tyrosine is a precursor to the mood elevating compound dopamine. A number of studies conducted in the 1970,’s demonstrated tyrosine’s ability to lessen symptoms of depression. The most impressive results were seen when tyrosine and 5- hydroxytryptophan were combined. DLPA is a precursor of tyrosine and may be preferable to tyrosine in some cases – see above.
Rhodiola (Rhodiola rosea)
Rhodiola’s active compounds enhance the transport of serotonin precursors (tryptophan and 5-HTP) into the brain, leading to a significant increase in brain serotonin activity. Rhodiola has also been shown to reduce the degradation of moodelevating neurotransmitters. As stress accelerates the depletion of mood-boosting neurotransmitters, the adaptogenic (anti-stress) effects of rhodiola may be additionally valuable.
St John’s Wort (Hypericum perforatum)
Research has shown that St John’s Wort can relieve mild to moderate depression, anxiety and related sleep disturbances. Although early in vitro research suggested that the primary mechanism of action was due to an MAO inhibiting effect of the compound hypericin, recent evidence suggests that the mechanism appears to be a reuptake inhibiting effect on serotonin, dopamine and noradrenaline (primarily associated with the compound hyperforin).
Various B vitamins play a major role in maintaining proper brain chemistry, particularly relating to the activity and metabolism of neurotransmitters. Deficienciesvin certain B vitamins are common in depression with B6 and folic acid being of particular note. For example, in studies up to 35% of depressed patients have been found to be folic acid deficient. B vitamins work synergistically so it is important to ensure adequate intake of all the B complex vitamins.
Omega 3 Fatty Acids
Cholesterol lowering diets appear to increase the incidence of depression, which is possibly a result of decreased omega 3 intake impacting on DHA levels in the brain. If this highly unsaturated omega-3 fatty acid, which is an essential part of the neuronal cell membranes, is replaced by an omega-6 fatty acid, changes in the membrane properties may occur, which increase the vulnerability to depression. In studies higher consumption of omega 3 fatty acids correlates with a decreased incidence of depression.
Nutrient/Herb Typical intake range
Rhodiola rosea (4)
Sf John’s Wort (0.3% hypericin) (5)
Omega 3 fatty acids6
1 00 – 300mg per day (away from food)
500 – 1 OOOmg per day (away from food)
500 – 1 OOOmg per day (away from food)
250 – 750mg per day
300 – 600mg per day
As per manufacturer’s directions
1 000 – 3000mg fish oil or equivalent per day
Allergens (e.g. wheat, dairy)
Refined and processed foods
Nuts and seeds
Green leafy vegetables
Vegetarian protein sources
• Take regular gentle exercise
• Consider light therapy if depression is associated with low light levels (SAD)
• Consider counselling
• Reduce impact of stress – support adrenal function if necessary identify potential food allergies – these are common in depression
1. May increase risk of scleroderma-like symptoms in susceptible individuals. May cause serotonin syndrome if combined with antideprcssant drugs that increase serotonin levels – avoid concurrent use. Best avoided by pregnant women and nursing mothers.
2. Combined use with antipsychotic drugs may Increase the risk of developing tardivc dyskinesla. Phenylalanine may cause hypertension if taken with MAOPs. PKU sufferers should avoid. Should be avoided by pregnant women and nursing mothers.
3. Not to be used with MAO inhibitor drugs without the consent of a qualified medical health practitioner. Should be avoided by pregnant women and nursing mothers and those with melanoma.
4. Do not use during pregnancy or lactation. Concurrent use with anti-depressant medication under medical supervision only.
5. May cause photosensitivity (increased sensitivity to ultraviolet light), especially with regular use of high doses. Avoid using St. John’s Wort anti-depressant drugs.
6. Do not take in conjunction with anticoagulant medication.