Low Tryptophan Diet May Work for Psoriasis

The idea of low tryptophan diet as psoriasis cure exists for about 48 years. All that begun in 1967 when two doctors – Harry Spiera, MD and Albert M. Lefkovits, MD from New York published their paper “REMISSION OF PSORIASIS WITH LOW DIETARY TRYPTOPHAN” in one of the most popular medical journals The Lancet.

They reported that 3 out of 4 long-standing psoriasis patients completely cleared up their skin on low tryptophan diet and even the fourth patient improved.

The question is how does the tryptophan affect the pathogenesis of psoriasis?

The usual answer given on forums and websites is that tryptophan is an essential amino acid needed for cell division and if the intake is low then psoriasis disappear.

What is my opinion about that?

First, I don’t think that low tryptophan diet is generally good for people with psoriasis.

For some it might be an answer if there was some genetic mutation (similar to phenylketonuria – inability to metabolize essential amino acid phenylalanine) which would cause some problems in presence of higher intake of tryptophan but recommending low tryptophan diet for everybody with psoriasis is not good.


Turkey is blamed for drowsiness after eating allegedly due to its high tryptophan content. The truth is that turkey meat contains the levels of tryptophan similar to other meats – chicken, pork and beef.

Deficiency of tryptophan will usually cause low serotonin levels besides many other things so restriction of dietary tryptophan is not a good choice.


Parmesan cheese is one of the foods with high tryptophan content.

Second, I think that low tryptophan diet surely won’t clear up the skin for everyone. Low tryptophan diet is supposed to start working in just 10 days or 2 weeks but many people with psoriasis already tried water fasts, fruit diets, etc.. which surely have one thing common – low tryptophan intake.

  • High tryptophan foods are – egg white, cheese – parmesan, turkey, chicken, pork, beef.
  • Low tryptophan foods are – banana, potatoes, rice.

Bananas have just a very little tryptophan.

We should keep in mind that the success of low tryptophan diet may be very possibly be caused by improved diet overall which results in less inflammation in the body.

So how does tryptophan deficiency improve psoriasis?

I think it may be directly connected to its acetylcholine increasing effects.

In one animal study the rats fed 8 hours with tryptophan had significantly higher levels of acetylcholinesterase activity in their brain (cerebral hemispheres) when compared to water-fed control rats. The exact difference was 28% higher acetylcholinesterase in normal rats fed tryptophan and 53% higher acetylcholinesterase activity in adrenalectomized (surgically removed adrenal glands) rats fed tryptophan.

The fact that the rats without adrenal glands had almost twice as high acetylcholinesterase activity compared to healthy rats may gives us a clue why is psoriasis so affected by stress and adrenal glands function.[1]

The same authors in another paper state that the acetylcholinesterase activity in rats increases 30 minutes after tryptophan force-feeding in heart, lungs, liver, spleen but not in the kidneys.[2]


1) Adhip P. Nandi Majumdar, Atif M. Nakhla. Influence of tryptophan on the activity of acetylcholinesterase in the brain of well-fed normal and adrenalectomized rats. Biochemical and Biophysical Research Communications, Volume 76, Issue 1, 9 May 1977, Pages 71-77

2) Atif M. Nakhla, Adhip P. Nandi Majumdar. Tryptophan force-feeding: Changes in the activities of acetylcholinesterase in various tissues of well-fed normal and adrenalectomized rats. Biochemical and Biophysical Research Communications, Volume 79, Issue 1, 7 November 1977, Pages 96–104

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