Posted by SalArmy4me on August 4, 2001, at 12:12:54
In reply to Depression - amino acid profiles for, posted by nutsy on August 4, 2001, at 11:29:48
From: Psychosomatic Medicine
Volume 61(5) September/October 1999 p 712
Dietary Supplements and Natural Products as Psychotherapeutic Agents
[Special Issue: Psychopharmacology And Psychosomatic Research]Phenylalanine and Tyrosine:
"...The amino acid catecholamine precursors phenylalanine and tyrosine have been reported to enhance mood in some individuals. There is a reasonable theoretical basis for enhancing endogenous tyrosine. Orally administered [alpha]-methyl-para-tyrosine induces relapse in remitted depressed patients (145), apparently by competing with endogenous tyrosine and resulting in depletion of the catecholamines dopamine and norepinephrine (145). Open trials of tyrosine (160) and phenylalanine (161) reported positive effects. However, as is often the case, improvement of trial design disadvantaged the drug. In a controlled trial of 65 patients receiving either 100 mg/kg tyrosine, imipramine, or placebo, investigators found no antidepressant effect of tyrosine (162). As with serotonin precursors, however, it is possible that combination of phenylalanine with an MAO inhibitor may enhance the therapeutic effects (163).
Adverse Effects and Interactions.
There are no reports of adverse effects of phenylalanine or tyrosine. Theoretically, however, these amines could induce a sympathomimetic reaction when combined with an MAO inhibitor..."Tryptophan:
Tryptophan, an amino acid, is a precursor of serotonin and has been used since the 1970s to increase brain levels of serotonin. Small, mostly uncontrolled studies have shown positive effects in some depressed patients (137), whereas others have not (138). The reason proposed for the equivocal effects is that tryptophan by itself may be insufficient to boost serotonin levels (139, 140). On the other hand, using tryptophan to supplement standard antidepressants has been more successful (141). Walinder et al. (142) found that 24 depressed patients started on clomipramine improved more rapidly with tryptophan supplementation. There is also considerable data suggesting that tryptophan depletion can increase depressive symptoms in patients with major depression (143) and seasonal affective disorder (144, 145). Subsequent reversal of depression with intravenous tryptophan (145) supports the notion of an antidepressant effect. Other psychiatric and neurological uses have also been described for tryptophan (146)..."
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