Amino acids are derived from protein and they are the main building blocks in the body. For example, they are used to make hormones, neurotransmitters and enzymes. Some of them are essential, meaning they need to be taken in from the diet, whilst the others can be manufactured in the body.

As you hopefully can see from the above, amino acids are pretty important. But some of them can become problematic for people with bladder pain. These are tyrosine, tryptophan, tyramine and phenylalanine (called the ‘arylalkylamines’).

The Roles of Arylalkylamines

Tyrosine is a conditionally essential amino acid (meaning it can also be made in the body). Tyrosine can also be synthesized in the body from the essential amino acid phenylalanine. Tyrosine is eventually converted into the neurotransmitters dopamine, epinephrine (also called adrenaline) and norepinephrine (noradrenaline). These neurotransmitters (the ‘catecholamines’) are responsible for the excitatory emotional response.

Tyramine is a derivative of tyrosine and it increases the release of norepinephrine.

Tryptophan is an essential amino acid that is converted into the neurotransmitter serotonin, which is mainly known as the neurotransmitter responsible for making us feel calm, content and happy.

How Arylalkylamines Can Create Bladder Pain

Arylalkylamines are precursors to certain neurotransmitters, as you can see from the above. Neurotransmitters carry messages in the brain and throughout the body.

In a normal bladder, these neurotransmitters should have no effect. However, in someone with a damaged GAG layer, which is often seen in interstitial cystitis, these neurotransmitters could potentially become active across the membrane and create discomfort.

High levels of norepinephrine, for example, could stimulate norepinephrine-related nerves in the lamina propria of the bladder, potentially causing increased cramping.

Serotonin can cause narrowing of blood vessels and increased levels of serotonin could send the vessels into spasm, potentially causing a throbbing sensation – like a migraine of the bladder.

A study from 1993 showed that many interstitial cystitis sufferers had abnormal metabolites of these amino acids [1]. Excess metabolites may be excreted through urine, where they could cause problems.

For example, abnormal metabolites of tryptophan called kynurenic and xanthurenic acid are highly charged and could cause problems with the GAG layer. These metabolites were found to be higher in IC sufferers [1].

Another by-product of tryptophan metabolism, called indicans, can cause a terrible smell when excreted through urine (described as ‘dead mouse odour’ or ‘rancid pineapple’).

The Root Cause: Faulty Digestive Chemistry

Dietary protein is broken down into amino acids. Inefficient breakdown of protein could therefore play a role in poor metabolism of amino acids.

Protein digestion begins in the stomach through the action of stomach acid and the enzyme pepsin. If there are insufficient levels of stomach acid present, this first step may be inefficient.

Protein and amino acids are then further broken down and absorbed in the small intestine. Again, a lot could go wrong here if there aren’t enough enzymes present for further breakdown or if absorption is hampered (e.g. through increased gut permeability, damaged vili etc).

Excess or abnormal metabolites may now be excreted via the bladder, potentially causing issues for IC sufferers.

The gut microbiome also plays an important role, for example in metabolism of serotonin precursors [2]. Therefore, an imbalances in the gut microbiome could also predispose to problems with arylalkylamines.

Interestingly, genes also seem to play a role – people with red hair or a redheaded relative are thought to have six times the amount of an enzyme needed to convert tyrosine into neurotransmitters and are therefore more prone to bladder problems caused by norepinephrine.

Foods High in Arylalkylamines

Please also see the ‘Interstitial Cystitis Diet’ for lists of foods.

• The highest dietary sources of tyrosine are seaweed, soy, fish, meat, egg, pumpkin and sesame seeds, bananas, avocados and cottage cheese.
• Tryptophan can be found in foods such as bananas, turkey, soya, sesame and pumpkin seeds and cheese.
• Foods high in tyramine are wine, cheese, yoghurt, beer, pickles (aged foods) and chocolate.
• The artificial sweetener aspartame is a source of phenylalanine.

Apart from diet, there are also some drugs that can increase levels of norepinephrine or serotonin – for example drugs containing ephedrine. So if you feel you get symptoms after certain drugs this may be worth looking into.

Action Steps To Take if These Amino Acids give you Symptoms

If you have noticed that foods containing the problematic amino acids give you symptoms, the first step would be to temporarily remove these foods. This is only symptom management, however.

In the meantime, it may be a good idea to work on digestive chemistry. Find out more about stomach acid here. Digestive enzymes may be something worth looking into.

Taking care of the microbiome is also important – pre- and probiotics may be worth looking into.

Have you noticed that foods containing the above mentioned amino acids give you problems? Has removing them helped? Let me know in the comments!




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Sources

1. GILLESPIE, L. (1993), Metabolic Appraisal of the Effects of Dietary Modification on Hypersensitive Bladder Symptoms. British Journal of Urology, 72: 293-297
2. Jano, J. et al Indigenous Bacteria from the Gut Microbiota Regulate Host Serotonin Biosynthesis Cell Volume 161, Issue 2, 9 April 2015, Pages 264-276 https://www.sciencedirect.com/science/article/pii/S0092867415002482

• Gillespie, Larrian You Don’t Have to Live With Cystitis (New York: Avon Health, 1996)
• SELFNutritionData Foods high in Tyrosine http://nutritiondata.self.com/foods-000087000000000000000-2.html?
• Wikipedia Tyrosine https://en.wikipedia.org/wiki/Tyrosine
• University of Maryland Medical Centre Tyrosine http://umm.edu/health/medical/altmed/supplement/tyrosine
• University of Bristol Serotonin http://www.chm.bris.ac.uk/motm/serotonin/home1.htm
• Wikipedia Serotonin https://en.wikipedia.org/wiki/Serotonin
• Wikipedia Tyramine https://en.wikipedia.org/wiki/Tyramine