Abnormal Tryptophan Metabolism in Depression

Introduction

"The future depends on what we do in the present." Mahatma Gandhi

A British group found abnormal tryptophan metabolism in depression.

"The accumulation of tryptophan by the platelet is significantly greater in the acutely depressed patients than the control group." Wood et al (1979)

This same British group had reported reduced urine tryptophan in depression. It might be that the reduced excretion of tryptophan was due to increased metabolism of tryptophan.

"Patients with endogenous features of depression excrete significantly less tryptophan in 24 h than do the patients with reactive features and the control subjects. The relationship between plasma tryptophan concentration and 24-h urine tryptophan excretion in control subjects has been investigated and the results discussed in the light of abnormalities of tryptophan metabolism in depressive illness."

Tryptophan

Amazingly this work led to the use of tryptophan as a therapy, which led to disastrous results with many patients getting very sick.

"Plasma free tryptophan is significantly decreased in monopolar, depressed patients. No evidence was found to suggest that poor nutritional history prior to hospital admission was responsible for these low levels. Factors known to influence tryptophan-albumin binding in plasma, e.g. concentration of plasma proteins, albumin and non-esterified fatty acids, did not account for the low levels of free tryptophan in depressed patients." Coppen & Wood (1978)

Perhaps a Low Tryptophan Diet?

Despite a lot of evidence for abnormal tryptophan metabolism in depression, it appears that nobody ever tried a low tryptophan diet in the disease. If tryptophan is flooding the cells, the this would explain why it is low in the blood. The free tryptophan would enter the cells, possibly due to a transport error.

Conclusions

There is also the matter of schizophrenia. Schizophrenia may also have abnormal tryptophan flooding of the brain cells. A low tryptophan diet is a vegan diet in which plant proteins are restricted. Meat, eggs, fish, dairy products, etc. are banned.