Coffee, Americano

While our forager forebears had no way of boiling water or making infusions, in this regard we agree with the USDA's advice: Suitable fluids can include tea, herbal tea, and coffee in moderation. In the great scheme of things, caffeine is not a huge issue, but it is wise to go easy on it, since it does interfere with blood sugar metabolism and can irritate many other metabolic functions.

Caffeine in coffee and tea is sometimes demonized in health circles. Nevertheless, almost all vegetation contains some caffeine and the body is quite capable of processing it without distress. It is only in certain plants that the concentrations reach mind-altering proportions. In modest quantities, caffeine can give increased mental performance and improve mood. Increasing the dosage can cause some unpleasant symptoms, such as irritability, anxiety, jitteriness, headaches, and insomnia. In addition, at higher doses, caffeine drives up insulin levels, increases insulin resistance, and makes it harder to lose weight. However, the harmful effects of caffeine are reduced when it is present in tea or coffee. Scientists speculate that the other beneficial nutrients in these beverages compensate. Researchers have also found that a high consumption of micronutrient-rich plant food mitigates the harmful effects of caffeine on its own.

The average cup of American coffee contains 100 mg caffeine, whereas coffeehouse strength can be 180 mg per cup. The caffeine content of tea varies, but it averages about 40-50 mg per cup. There are also about 40 mg of caffeine in a 12-ounce can of cola. In a cocoa drink (2 teaspoons of pure cocoa powder), there are only 10 mg caffeine. Our view is that caffeine in modest amounts is well within the normal range for human consumption. (See "What Is 'Modest' Caffeine Consumption?" below.) For a 165- pound adult, that works out to four cups of American coffee per day or eight cups of tea. Be sensible about it, watch how your caffeine intake affects your mood, and avoid overdosing. If you are diabetic, caffeine in the form of moderate tea or coffee drinking might even be helpful.

We know that there are many active compounds in the foods we eat, particularly fruits and vegetables. We are familiar with the "classic" micronutrients that have been identified over the past 100 years: vitamins A, B, C, and so on, and minerals like iron, selenium, zinc, and iodine. However, we now know that there are thousands of other micronutrient compounds that play a part in the smooth functioning of the body. In this book, we call them "background" micronutrients. For example, there is the family of carotenoids, of which there are over 600. They give the color to carrots, oranges, tomatoes, and melons. There is the phenol family with over 5,000 members. They too are present in all fruits and vegetables, and strongly present in tea, coffee, and wine. And there are the 7,000 terpene compounds, which are omnipresent in all plant foods, particularly in spices and aromatic herbs. We must not forget the thousands of bioflavonoids, yet another vast range of compounds that are essential to health.

Our species, like most on the planet, are designed to get most of their liquid intake from water. Until recent times, that was still the case for us, even in the West. But we have seen the rise of alternative drinks, which have come along just in the average grandparent's lifetime. Setting aside wine, distilled spirits, and liqueurs, which are not thirst quenchers, what are we now consuming instead of water? When we add up the figures for beer, tea, coffee, cocoa, soft drinks, juices, and milk, we find that the average American is consuming, in a year, 150 gallons of liquid that is not plain water— that comes to 3.25 pints per day!