Here's a good article for you.
http://en.wikipedia.org/wiki/Trimethylaminuria
parts of the article;
The odor is not necessarily fishy, and the type of odor can vary from time to time. In that sense, the nicknames referring solely to a fishy odor are misnomers.
Trimethylamine builds up in the body of patients with trimethylaminuria. The trimethylamine gets released in the person's sweat, urine, reproductive fluids, and breath, giving off a strong fishy or body odor. Some people with trimethylaminuria have a strong odor all the time, but most have a moderate smell that varies in intensity over time. Individuals with this condition do not have any physical symptoms, and typically appear healthy.
Measurement of urine for the ratio of trimethylamine to trimethylamine oxide is the standard screening test. the person would be given a high dose of choline (one of the precursors of trimethylamine) and then have their urine tested for elevated levels of trimethylamine.
Ways of reducing the odor may include:
Avoiding foods such as eggs, legumes, certain meats, fish, and other foods that contain choline, carnitine, nitrogen, and sulfur
Taking low doses of antibiotics such as neomycin and metronidazole in order to reduce the amount of bacteria in the gut
Using slightly acidic detergent with a pH between 5.5 and 6.5
Additionally, at least one study has suggested that daily intake of the supplements activated charcoal and/or copper chlorophyllin may improve the quality of life of individuals afflicted with TMAU by helping their bodies to oxidize and convert TMA to the odorless N-oxide (TMAO) metabolite.
Mutations in the FMO3 gene cause trimethylaminuria. The FMO3 gene makes an enzyme that breaks down nitrogen-containing compounds from the diet, including trimethylamine. These compounds are produced by bacteria in the intestine as they digest proteins from eggs, meat, soy, and other foods. Normally, the FMO3 enzyme converts fishy-smelling trimethylamine into trimethylamine N-oxide which has no odor. If the enzyme is missing or its activity is reduced because of a mutation in the FMO3 gene, trimethylamine is not broken down and instead builds up in the body. As the compound is released in a person's sweat, urine, and breath, it causes the strong odor characteristic of trimethylaminuria. Researchers believe that stress and diet also play a role in triggering symptoms.
Although FMO3 mutations account for most known cases of trimethylaminuria, some cases are caused by other factors. A fish-like body odor could result from an excess of certain proteins in the diet or from an increase in bacteria in the digestive system. A few cases of the disorder have been identified in adults with liver damage caused by hepatitis.
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I'd like to add that I believe bentonite clay may also be taken for the same reason activated charcoal is listed in the article.
I wouldn't trust antibiotics to help the gut, but I'm not a health expert, it's just an opinion.
It would also be helpful to research which foods contain choline, carnitine, nitrogen, and sulfer to have a more complete list of foods which may need to be avoided.
It would also be helpful to research foods and/or supplements that will help break down nitrogen containing compounds. If I have the time sometime I may do some research on that and report back here if I find any more helpful info.
It looks like all the advice you got here was good with cleansing and yogurt for intestinal health as well as having some medical tests run.
Mrs. Chair Warmer