Buzz: The Science and Lore of Alcohol and Caffeine [Hardcover]

Science journalist Stephen Braun explores the science and lore of alcohol and caffeine in this slim but informative little volume. Recent progress in understanding brain chemistry has given scientists a different perspective on the workings of these two of mankind's oldest chemical friends.
Alcohol is a small molecule which is soluble in both fat and water and consequently its physiological effects are manifold. Rather than the simple depressant it was once presumed to be, it is in fact a "pharmacy in a bottle" which can mimic cocaine, amphetamines, opium and valium. Given that the brain contains 40 or so neurotransmitters, it is fair to say that the full effects of alcohol are still far from being understood; broadly, however, it can reduce anxiety and stimulate the reward centres of the brain. Its effects on sexual desire and sleep are contradictory. It raises desire, yet in large quantities impedes performance. The stimulating effect is in part psychological: research volunteers who believed they had consumed alcohol but hadn't, became more aroused than those who had but thought they hadn't. It promotes sleepiness, yet worsens the quality of sleep and interferes with the sleep cycle. The effects vary with gender. In one survey 68% of women, but only 45% of men, replied that alcohol enhances sex. The oft-observed fact of women becoming intoxicated faster then men on a given dose is apparently due not to differences in blood volume (otherwise why would small men not also become drunk faster?) but rather to a difference in the effectiveness of alcohol dehydrogenase (an enzyme which can exist in 17 different varieties in the same person), a difference which fades with age. The other major effect of alcohol is that in moderate quantities it appears to reduce the risk of heart disease, a benefit which is lost, but accompanied by many detriments to health, with increasing consumption.
The genetics of sensitivity to alcohol are also fascinating. Alcoholism in humans appears to be environmental in origin, although it does have a weak genetic component. In mice, the story really gets interesting. Certain physiological responses to alcohol can be bred into or out of mice. Members of one strain sleep for a long time after consuming alcohol, but others sleep only briefly. Or the metabolism of one strain speeds up following a drink, but that of another slows down. Such differences also exist in people: some actually become drowsy on small doses, but more alert on larger ones, the opposite of the majority response. The key point is that the effects of alcohol are complicated and occasion a great diversity of responses. For an individual the only way to fully gauge the effects is by (hopefully judicious) experimentation.
Caffeine, metabolically speaking, is another kettle of fish. Although it also has a wide range of effects it specifically targets receptors of the neurotransmitter adenosine (also, incidentally, affected by alcohol). Thus the average dose is much smaller: a regular cup of coffee contains about 100 milligrams, versus 14,200 of alcohol in a standard drink. Like most psychoactive substances, caffeine is a plant product (found in over 100 plant species), and may well have evolved as a natural pesticide designed to disrupt the neurological function of its predators. Of special interest to smokers is that smoking causes caffeine to be metabolized faster than normal, an effect which stops when smoking does. Thus, without having changed his caffeine consumption, the newly resolved non-smoker will find himself with about twice as much caffeine in the bloodstream as usual. Adding being wired to nicotine withdrawal is probably unpleasant for most, so the implication is that smokers should cut coffee consumption before kicking the weed. The effects of coffee as a stimulant are indirect and due to interference with a natural feedback system whereby the more neurons fire the more adenosine they produce, which inhibits firing. Caffeine binds to adenosine receptors, thereby blocking adenosine, but without producing this inhibition. The effect is like putting a block of wood under the brake pedal of a car. The effects on mental acuity are unclear. Caffeine users may feel sharper and smarter, but their measurable performance is not greatly improved. On the other hand caffeine may affect more complex mental processes than those tested, or perhaps it is simply the sensation of intellectual enthusiasm which makes the difference to the work of creative masters, such as Bach and Balzac, who were mighty coffee drinkers and swore by its powers.
By regulating the amount of neurochemical receptors available the body can acquire tolerance to drugs. In the case of heroin, habituated users may consume 10,000 times as much as novices, far beyond the range of tolerance shown by consumers of coffee or booze. Yet caffeine users also develop a tolerance; to the point that caffeine may actually produce little noticeable effect in those used to it. This suggests that people keep drinking primarily to avoid withdrawal. It also offers a possible explanation of why many postoperative surgical patients suffer from headaches: it's not the anaesthetic, but simply that they've been without a cup of coffee for a full day before recovery.
Americans are drinking perhaps a little less coffee than they used to. But caffeine intake is propped up by soft drinks, about 80% of which are caffeinated, with caffeine which, naturally enough, is extracted and sold by the purveyors of decaf coffee. There is also a lot of caffeine in both prescription and over-the-counter medications, which are also consumed in large quantities.
"Buzz" is well-written in an easy and pleasing style. Given the imposing scope of its subject matter, however, it is necessarily somewhat limited. It would certainly be interesting to read more in greater depth, especially with regard to the neurobiochemistry. A discussion of the negative social consequences of alcohol, which is deeply implicated in suicide, homicide and other violence might also have merited a few pages. Overall, however, this is an enjoyable and informative read.

"Buzz" blasts a lot of long-held myths about two of our favorite drugs. The history - and the resulting culture around them - of booze and the most common pick-me-upper is engrossing and madly entertaining. I wish, really, there had been a little more of that. But the book tilts ultimately (somewhat gently, thankfully) into the relatively deep biochemistry behind our reactions to and devotions to caffeine and alcohol, too. A lot, but not quite all, of that is cast in beautiful lay context that really connects the science to the personal.

Caffeine and alcohol are two of the most popular drugs on earth, and yet until recently not a whole lot has been found out about how they affect us. Stephen Braun's "Buzz" compiles the latest research on them, and examines the truth of various myths that have grown up around them. Braun looks at each drug separately and records his findings with a clarity of prose that will delight the general reader. His book goes down like a smooth cup of Joe, or a sip of Kentucky bourbon. -- Bill Pesche