What is Trimethylaminuria or Fish Odour Syndrome and How To Effectively Cure it?


No one likes bad breath (aka halitosis)! In fact, for some people, it can also become a source of considerable social anxiety. In most cases, halitosis can occur due to poor oral hygiene or certain stomach problems, but sometimes the problem goes deeper than that. One reason for bad breath that you probably didn’t know is a genetic disease called Trimethylaminuria. Now before we scare you off, let us simplify this term. Here is what you need to know about this genetic disease –

What is Trimethylaminuria?

Trimethylaminuria or fish odour syndrome is a rare genetic disorder in which the body is unable to break down a chemical called trimethylamine. This chemical is produced by bacteria present in the stomach and has a very strong odour. As a part of the regular digestion process, an enzyme breaks down this chemical. However, in this disease, people have an enzyme deficiency, which prevents the adequate breakdown of this chemical. This leads to the accumulation of trimethylamine in the body. The result? Breath that smells like rotting fish (hence the name).

What are the symptoms of Trimethylaminuria?

The primary symptom of this genetic disorder is breath that is persistently smelling like fish. But excess trimethylaminuria can also be released through other bodily fluids such as:

  • Urine

  • Sweat

  • Reproductive fluids

This disorder is more common in females as compared to males. Research suggests that the female hormones estrogen and progesterone could play a role in it.

Diagnosis and treatment

There is no denying that trimethylaminuria has a significant impact on the quality of your breath. Usually, a urine sample is needed to diagnose this disorder because the physician first needs to rule out any other cause for bad breath and body odour. Genetic testing for the FM03 gene might also be required in some cases. Post diagnosis, you need to consult your doctor to chart out the course of your treatment. It can be managed through some dietary adjustments, such as avoiding foods that are high in trimethylamine-N-oxide like fish. Here are some things you can do in addition to your trimethylaminuria treatment and antibiotics:

  • Maintain good oral hygiene: You don’t want poor oral hygiene to make things worse. Follow a good oral care routine that includes brushing your teeth twice daily, followed by rinsing with a dental-approved mouthwash and flossing. Rinsing with a mouthwash not only kills the bacteria in the mouth that causes bad breath, it also leaves a pleasant taste and smell. And flossing helps remove the tiny leftover food particles effectively and prevents the bacteria in the mouth from forming plaque on the teeth surface. Also, use a tongue scraper to clean your tongue to prevent white tongue.

  • Pop a chewing gum: When you are out and about, chewing gum can be helpful in lessening the fish odour caused by trimethylaminuria. Although this is not a cure, it can act as a quick-fix and help you feel better. But make sure you chew a dental-recommended, sugar-free gum variety. Chewing sugar-loaded gums can damage your teeth in the long run and actually add to the bad breath problem.

  • Visit the dentist: Timely dental visits can save you not only from bad breath but also a number of other gum and tooth diseases. Visiting the dentist regularly can help diagnose conditions like trimethylaminuria at a prior stage and lead to an effective treatment. Periodic teeth cleaning also helps to prevent plaque and tartar accumulation and can aid in keeping the breath fresh.

Trimethylaminuria is a genetic condition that requires medical intervention. Please consult your physician or dentist for effective treatment. Also maintain a good oral hygiene routine to make sure that plaque and mouth bacteria do not worsen the issue. It is also important to use superior dental products such as the Oral-B electric toothbrushes to ensure optimal oral hygiene.

Interested in reading more about the causes of bad breath and remedies? Here’s a complete guide to bad breath causes and remedies.