Why does my urine smell like fish

Urine smells like fish: causes and treatment

If the urine smells like fish, a rare metabolic disease called trimethylaminuria, or TMAU for short, is responsible. With this disease, not only does the urine smell fishy, ​​but also the sweat and the air you breathe.

Urine smells like fish: The reason is a metabolic disease

Trimethylaminuria is a hereditary disease in which one region on chromosome 1 is mutated.

  • When certain nutrients are broken down, your body forms the metabolite trimethylamine. Normally, this is broken down into the odorless trimethylamine-N-oxide by further metabolic processes.
  • In the case of trimethylaminuria, the metabolic product cannot be converted into the odorless variant. The enzymes required for this are missing here.
  • The fish-smelling trimethylamine is then excreted in the urine, breath and sweat.
  • In addition to the inherited TMAU, there is also what is known as secondary trimethylaminuria. This can be the result of cirrhosis of the liver or viral hepatitis.

Treatment of trimethylaminuria

Your doctor can make the diagnosis by doing a urine test. The trimethylamine concentration is determined.

  • There is no therapy or cure for the disease.
  • However, it can be influenced through diet. Food whose ingredients are converted to trimethylamine in the body should be avoided if possible.
  • Choline is one of these substances. Choline is found in offal and egg yolks as well as in avocado, corn and cabbage, for example.
  • Trimethylamine-N-oxide can also be converted back into trimethylamine by intestinal bacteria. Therefore, foods with this substance must also be removed from the menu. Trimethylamine-N-oxide is found in shellfish and fish.
  • By administering antibiotics at regular intervals, certain bacterial strains in the intestine can be reduced. These cures can at least reduce the odor somewhat.
  • As those affected are often socially isolated and in some cases suffer from depression, psychological support should be part of the treatment.

In our next post, we'll look at another rare metabolic disease. We explain what is behind Pompe disease.