Everything you need to know about the ‘fish smell syndrome’ TMAU

The fish odour syndrome is caused by the body’s inability to turn a strong-smelling chemical called triethylamine - produced in the gut when bacteria break down certain foods - into a different chemical that doesn’t smell. This means trimethylamine builds up in the body and gets into bodily fluids like sweat, urine and vaginal fluids.

Sometimes it's caused by faulty genes that a person inherits from their parents, but this isn't always the case. So how is trimethylaminuria is inherited?

Trimethylaminuria does not have any associated health problems, but the strong odour may affect people socially and psychologically due to stigmatization.

Research shows many people with trimethylaminuria inherit a faulty version of a gene called FMO3 from both their parents. This means they have 2 copies of the faulty gene.

The parents themselves might only have 1 copy of the faulty gene. This is known as being a "carrier". They usually won't have symptoms, although some may have mild or temporary ones.

If you have trimethylaminuria, any children you have will be carriers of the faulty gene so are unlikely to have problems. There's only a risk they could be born with the condition if your partner is a carrier.

There is currently no cure for trimethylamine, so treatment focuses on managing and reducing symptoms. People can reduce the odour of trimethylamine by avoiding substances that increase the production or levels of trimethylamine in the body, such as lecithin and choline.

It can help to avoid certain food that makes the smell worse such as Cow’s milk, saltwater fish, eggs, beans, peanuts, liver, kidneys and supplements containing lecithin.