Culinary seduction is as old as humankind. Food is the prime ingredient; the "artillery of love". Yet its magical constituents are just one part of the highly complex process of eros. Love food has baffled scientists, it seems - identification of biochemical triggers of sexual engagement in our diet is only beginning. One couple may become enflamed with passion on consuming lobster with black truffles and chardonnay cream sauce, followed by chocolate creme brulee, plus lubrication in the form of champagne (as recommended for Valentine's Day 1999 by Sugarplums "the lovers' website"). Another may be ignited by skirts and kidneys on a bed of carrageen moss followed by Peggy's Leg; all washed down with Guinness. The scientific basis for such responses is not entirely clear.
A lot of foods considered to be aphrodisiacs over many centuries were selected because of their shape, such as bananas, figs and carrots (a favourite among royality in the Middle East), or because of their association with fertility, such as pumpkin seeds. Then again, there's nothing like rarity and expense to invoke Cupid. So Beluga caviar from Iran may stir gourmets like nothing else.
Activation of other senses heightens the experience. The peach has a long sexual history; its "red blush colour, silken fuzzy skin and juicy flavour", (to quote Sugarplums' directory of aphrodisiacs,) means it scores on several fronts. For believers, therefore, consumption heightens sexual desire. Some participate for the fun of it - the remainder don't know what the fuss is about.
Chocolate is the one item common to most lists, and here there is scientific evidence to justify its inclusion. It contains pleasure endorphins, including phenylethylamine; a neurotransmitter believed to evoke feelings of bliss such as those felt on falling in love. It is also suspected of overriding brain activity and compromising logical thinking. Chocolate also releases serotonin, another neurotransmitter with a calming effect.
The bad news, says Prof Keith Tipton of TCD's Department of Biochemistry, is not all chocolate contains phenylethylamine. Moreover, chocolate contains tyramine, which is also in cheese and red wine, and linked with migraine. But cheese, for example, does cause blood-flow and pressure effects leading to short-term feelings of warmth and well-being which, he says, could be interpreted as an aphrodisiac effect. It all depends on what people want to get out of this sensation.
Much attention in food-mood research is being paid to hormones and their relation to behaviour and brain activity. Some foods release hormones, though evaluating such effects is difficult. And there is no definitive list of endorphin-rich foods to be devoured in great quantity, though milk protein contains significant amounts of endorphin. "Why not drink a gallon of milk. It would be probably better for you," Prof Tipton suggests. Then again, nitrites and nitrates used to preserve tinned and frozen food have been described as "the poor man's Viagra".
There may well be a magical ingredient in a banana, says Tipton's TCD colleague, Prof Mike Gibney, a nutritionist. But there is no research he is aware of to indicate if it or a pear is more enlivening. There is a risk that the vital ingredient in a banana, for example, might be in such small quantity that one is likely to be sick from eating too much before one can become aroused. In spite of some inconclusive evidence, New Scientist magazine has reviewed the biochemical basis of love and advised: "Nothing says `I love you' like a box of caffeinated serotinin-agogic phenylethylamine-laden confections" - i.e. the old reliable, chocolate. A perfectly cooked steak features on many Valentine's Day menus, so where does meat fit into the romantic equation? The leading cognitive scientist, Prof Steven Pinker, explains men want sexual liaisons more than women, while women's acquiescence has facilitated the evolvement of men's desire for liaisons. But what, he asks in How the Mind Works, could ancestral women have stood to gain? The short answer is meat.
In foraging societies, women openly demand gifts from their lovers - usually meat. Pinker adds: "You may be offended at the thought that our foremothers gave themselves away for a steak dinner, but to foraging peoples in lean times when high quality meat is scarce, meat is an obsession."
A Valentine's day filet mignon, therefore, is probably manifestation of an acute sense of our sexual evolution. Pinker notes female college students' belief that an extravagant lifestyle and willingness to give gifts are important qualities in picking a short-term lover. If, however, food-mood science is confusing and undermining romantic spontaneity, perhaps the advice of Miss Manners' Guide to Excruciatingly Correct Behaviour (a self-help book popular for years in the US) should be relied on: "There are three possible parts to a date, of which at least two must be offered: entertainment, food and affection. It is customary to begin a series of dates with a great deal of entertainment, a moderate amount of food and the merest suggestion of affection. As the amount of affection increases, the entertainment can be reduced proportionately. When the affection is the entertainment, we no longer call it dating. Under no circumstances can the food be omitted."