Foods of love? Not so fast, Casanova

1) Oysters
THE MYTH: Love them or hate them, but no other food is more frequently linked with desire than this humble bivalve. The birth of the legend, literally, can be found in Greek mythology: The goddess Aphrodite emerged from the sea on an oyster shell to give birth to Eros, along with a few thousand years of winking innuendo, some lovely Renaissance paintings and the word “aphrodisiac.”

To know a mollusk by reputation wasn’t quite enough for Casanova, who reputedly consumed several oysters dozen each morning — just how many depends on your source — in his bathtub. (Hopefully not while chugging chocolate.)

What’s good for Casanova is good for your average schlub, no?

THE REALITY: Oysters have great nutritional value. They’re low in fat and calories (around 10 calories per raw oyster) and packed with healthy minerals. Each oyster contains nearly a day’s worth of zinc, which helps boost immune response.

But the romance part?  Mostly myth, bolstered by centuries of reinforcement.

“The idea that it works like a drug ... is medically unlikely,” says psychologist Joy Davidson, author of “Fearless Sex.” “You can’t mainline oysters.”

Oyster fans were heartened about a March 2005 research paper that revealed in mollusks the presence of two amino acids, D-aspartic acid and NMDA, which have been linked to the release of testosterone and estrogen.

An ocean's worth of media coverage ensued, but some concerns were overlooked. First, the research merely confirmed the presence of the two chemicals, not what they might do; it remains unclear how much of either would be needed to raise hormonal levels in humans. In part, that's because most research tying the two compounds to arousal was based on lab rats.

“We did not make any proof or correlation with the libido,” says George Fisher, a chemistry professor at Florida’s Barry University who published the paper.

Oh, did we mention that the study was conducted on three types of Mediterranean mussels? “We did not evaluate any oysters,” Fisher adds.

Another big problem with oyster research: They’re difficult to place into a scientifically rigorous study.  As Robert Shmerling of Harvard Medical School notes, it’s nearly impossible to create an oyster placebo.

What about those psychological triggers, or the oyster’s frequent comparison to certain body parts, or their wet, slippery appearance? They are better explanations, though psychologist Linda DeVillers found oysters far down on her respondents’ list of reputed aphrodisiacs, with just 25 percent naming them as a libido-booster.

If nothing else, perhaps oysters’ silky, slightly unsettling texture taps into the attraction-repulsion dynamic that is a component of most so-called aphrodisiacs.

“I think there may be something to mouthfeel,” says Fergus Clydesdale of the University of Massachusetts Amherst, before quickly catching himself.

“Look, I’m just guessing,” he says. “There’s no data.”

Though he adores asparagus, MSNBC.com lifestyle editor Jon Bonné wants to know how anyone ever thought it was an aphrodisiac.