cooling effect doesn't vary much with temperature, which means that menthol has a reasonably strong impact even at room temperature.
And of course, even if you eat a relatively hot food that has menthol in it, once it coats your oral cavity, just breathing through your mouth produces evaporative cooling. Menthol enhances the effect of evaporative cooling; it is as though you are breathing cooler air.
PARTICIPANT: Is that what menthol does in cigarettes?
DR. GREEN: Yes. However, I am told by experts at the tobacco companies that people don't like menthol in cigarettes to counteract the heat as much as they merely enjoy it as another sensory dimension.
PARTICIPANT: It has been published that when people have to drink volumes of water for sweat fluid replacement—that is to say, between 12 and 18 quarts a day—that the preferred temperature is somewhere between 14° and 17°C (55° to 60°F).
My own experience from the southwestern deserts of the United States, is that this temperature estimate is a bit high. Do you have any feeling or could you make any comments?
DR. GREEN: The only feeling I have about it is that you are speaking about field tests in an extreme climate. One of the things that needs to be done—perhaps it has been done for thirst—is to look at possible effects of acclimatization on preferred temperatures. Perhaps once you become acclimatized to a hot environment, you prefer to avoid a sharp, cold contrast in favor of a more mild coolness.
PARTICIPANT: Are there any systematic racial or gender differences?
DR. GREEN: With regard to the basic tastes, I know of no significant racial or gender differences.
There is a gender effect with irritants in the nose but not in the mouth; females tend to be more sensitive than males. There are also some data which suggest that odor sensitivity varies across the menstrual cycle.
A bigger factor in each of these modalities, though, is individual differences. There are large individual differences in the chemical senses.
PARTICIPANT: Do sour stimuli give any sensations of coolness?
DR. GREEN: Not that I am aware of.
People have, in the past, tried to associate tastes with temperatures the same way that colors have been associated with temperature. For example, sweetness is thought of as being warm, salt as being less warm. I don't know where sourness might fit in.
DR. NESHEIM: Thank you, Barry.