Serotonin acts as a chemical messenger in the brain where it regulates mood, sleep rhythm, appetite and some cognitive functions. A decrease in brain serotonin levels is linked to depression. Taking serotonin supplements or eating foods rich in serotonin does not increase brain levels of serotonin because it does not penetrate the blood brain barrier. The amino acid tryptophan is the precursor to serotonin and it does cross the blood-brain barrier. Supplements containing tryptophan and other molecules involved in serotonin synthesis have been shown in some studies to be effective in treating depression and other mood disorders.
Consult a medical doctor before taking supplements to increase serotonin.
Tryptophan
Tryptophan is an essential amino acid required in the human diet. It is a building block used to synthesize serotonin, melatonin, niacin and many proteins in the body. A review in the journal "Psychosomatic Medicine" notes that animal studies have demonstrated that oral supplementation with tryptophan raises serotonin levels in the brain. A review of several clinical trial studies in the journal "Cochrane Database of Systematic Reviews" reports that tryptophan supplements are more effective than placebo in reducing the symptoms of depression. A study in the "Journal of Psychiatry and Neuroscience" reports that the doses of tryptophan that are effective in alleviating symptoms of depression and sleep disorders range between 2 g and 4 g per day and that in combination with other antidepressants is more effective.
SAMe
S-Adenosyl-L-methionine, also called SAMe, is a molecule involved in the biosynthesis of serotonin, among many other compounds. A review study in the "American Journal of Clinical Nutrition" reports that in a few clinical trials oral SAMe supplements, at doses between 200 mg and 1,600 mg per day are as effective as some other antidepressants in alleviating depression. These studies did not provide evidence that SAMe supplements significantly increased brain levels of serotonin and that this is the mechanism of its antidepressant activity; however, a study in rats published in "General Pharmacology" did show that intravenous administration of SAMe increased brain levels of serotonin.
B Vitamins
B vitamins, including B9 and B12 are essential for the synthesis of serotonin and other chemical messengers in the brain. If people are deficient in these vitamins supplements that may raise serotonin levels will not work as these vitamins are required for serotonin synthesis. The review in the "American Journal of Clinical Nutrition" notes that deficiencies in either B9 or B12 have been linked to depression. This source also suggests that correction of these vitamin deficiencies may improve depression symptoms and enhance the effectiveness of other antidepressant therapies.
Omega-3 Fatty Acids
A review in the journal "Neurosignals" reports that several studies suggest omega-3 fatty acid supplements are effective in treating several types of mood disorders. Additionally, omega-3 fatty acid supplements improve the effectiveness of other drugs that treat depression. This review also notes that supplements containing omega-3 fatty acids raise serotonin levels in the brain, although other biological actions omega-3 fatty acids may also contribute to alleviating the symptoms of depression and other mood disorders.
References
- "Cochrane Database of Systematic Reviews"; Tryptophan and 5-Hydroxytryptophan for Depression; K. Shaw et al.; 2001
- "Journal of Psychiatry and Neuroscience"; Preliminary Randomized Double-Blind Placebo-Controlled Trial of Tryptophan Combined with Fluoxetine to Treat Major Depressive Disorder: Antidepressant and Hypnotic Effects; R. D. Levitan et al.; May 2000
- "Neurosignals"; Biological Mechanism of Antidepressant Effect of Omega--3 Fatty Acids: How Does Fish Oil Act as a 'Mind-Body Interface'?; Kuan-Pin Su; February 2009
- "American Journal of Clinical Nutrition"; Role of S-Adenosyl-L-Methionine in the Treatment of Depression: A Review of the Evidence; D. Mischoulon and M. Fava; November 2002
- "General Pharmacology"; Acute Changes in 5-HT Metabolism After S-Adenosyl-L-Methionine Administration; M. E. Otero-Losada and M.C. Rubio; 1989
