Читать книгу Why Men Don’t Iron: The New Reality of Gender Differences - Anne Moir - Страница 12

Neurotransmitters are chemicals released from nerve endings. They transmit impulses – pass messages – from one nerve cell (neuron) to another. Mostly they work within the brain, but some are manufactured elsewhere in the body. In later chapters we shall see that there are differences in the levels of neurotransmitters used by men and women, but for now it is enough to note a few salient facts that are related to men’s and women’s dietary needs.

Serotonin is a brain chemical that is much involved with mood control. It promotes sleep and helps govern impulsive behaviour. Low levels, much more common in males, are related to aggressive behaviour. Serotonin, like the female hormone oestrogen, also acts as an appetite suppressant, which is why weight-reducing drugs are designed to raise serotonin levels in the brain. Women, on average, have slightly more serotonin than men, and many more men than women have the lower levels. (See Chapter six for more details about serotonin.)

Neurotransmitters affect far more than appetite. A high carbohydrate meal (starch or sugars, say) will raise the level of tryptophan.²⁵ Tryptophan is a chemical forerunner of serotonin, and an increase in its level acts as a sedative.²⁶ A high protein meal like red meat, on the other hand, lowers tryptophan and serotonin levels, thus increasing mental alertness. Men facing a challenging task can sharpen their edge by eating steak for breakfast and by drinking coffee. Caffeine increases our ability to concentrate.²⁷ What you eat changes how you think.²⁸