What is Fish Odour Syndrome and How Can it be Managed?

Trimethylamine (TMA) is a chemical that is produced by bacteria present inside the human gut. This chemical has a fish-like odour. In some people, the liver enzymes are unable to break down this chemical, resulting in a metabolic condition called Trimethylaminuria, also commonly known as Fish Odor Syndrome (FOS). It must be noted that FOS is completely different from poor hygiene, gingivitis, urinary infections, infected vaginal discharge, and advanced liver and renal disease.

Symptoms of trimethylaminuria

FOS is a rare condition that is genetically inherited. It can be present from birth but usually manifests later in life, mostly around puberty.

The main symptom is an unpleasant smell, which is often described as a “rotten fish smell”. The strong odour affects the breath, sweat, urine, menstrual blood and vaginal fluid. The smell could be constant or intermittent and get worse with:

• Excessive sweating
• Intake of certain food items (eggs, fish, milk products, etc.)
• Menstruation
• Use of oral contraceptives
• Physical or emotional stress

Cause and prevention

During digestion, an enzyme pathway (CntA/B) in the gut produces TMA. The liver then breaks down the TMA into a TMA precursor called L-Carnitine with the help of a functional liver enzyme called FMO3. If a person’s liver lacks the FMO3 enzyme, they cannot disintegrate TMA into an odourless chemical, trimethylamine oxide. Therefore, the TMA gets accumulated in the body, resulting in a strong odour from the body fluids.

Researchers from the University of Warwick recently published a paper in the Journal of Biological Chemistry where they concluded that the production of the CntA protein of the CntA/B enzyme pathway is the culprit enzyme for the production of TMA. The paper also identifies novel drug-like inhibitors that could prevent the production of TMA in the gut. This is not only a breakthrough in the treatment of FOS but also a step forward to prevent heart diseases as TMA can accelerate heart-related diseases.

Food items to be avoided

Food items that are choline-rich can worsen the body odour. It is advised to avoid such foods as much as possible, following are a few examples:

• Beans
• Peanuts
• Liver (meat)
• Cows? milk
• Seafood and/or shellfish (except freshwater fish)
• Eggs
• Supplements containing lecithin

Minimizing the smell 

Following are a few things people suffering from trimethylaminuria could do to reduce the unpleasant smell that co:

• Use antiperspirants
• Change and wash your clothes frequently
• Avoid strenuous exercise or workout to prevent excessive sweating
• Try to find ways to relax as stress worsens the symptoms
• Wash your skin with slightly acidic soap or body wash (pH between 5.5 and 6.5)

For more information, read our article on Bad Breath.

Health articles on News18 are written by myUpchar.com, India’s first and biggest resource for verified medical information. At myUpchar, researchers and journalists work with doctors to bring you information on all things health.