Tuna fish causes halitosis, and then some

It doesn't take a rocket scientist to figure out that eating tuna causes halitosis. This big, edible fish has one of the most distinct "fishy" smells around, which means that if you eat a tuna melt or tuna salad for lunch, you can expect to smell like a pier shortly thereafter.

What is it about tuna that naturally leads to oral odor? Evidently, it's the fact that this oily fish is loaded with an array of volatile aromatic compounds, each with its own strange scent. Taken together, these molecules give you fishy halitosis.

Scientists brave the briny scent of tuna

To determine what gives tuna its especially fishy funk, more than a few research teams have used gas chromatography or other advanced methods to break down its odor into its component aromas.

What they've found is that a whole host of different molecules in tuna causes halitosis. Here are some of the stinkiest, according to a study published in the Journal of Agricultural and Food Chemistry:

- (E,E)-2,4-heptadienal smells like stale peanuts.

- (E,Z)-2,6-nonadienal has a cucumber-like odor.

- (E,E)-2,4-decadienal is fatty or rancid-smelling.

- 3-(methylthio)propanal has an odor like baked potatoes or soy sauce.

- Dimethyl trisulfide smells distinctly like cooked cabbage.

The team also noticed an unidentified compound that smelled grassy. In a different study, this one appearing in the journal Biotechnology and Bioprocess Engineering, another research team analyzed the odors of tuna that had begun to go bad. They found dimethyl disulfide, which smells like rotten meat, and diallyl disulfide, which creates the odor of garlic.

Yikes. If you love tuna and wouldn't give it up for anything, then at the very least pop a specialty breath freshening mint or lozenge in your mouth after lunch.