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Introduction
Thomas Hatzold
1.1 COFFEEāA POPULAR BEVERAGE
Billions of cups of coffee are enjoyed every year by consumers around the world. Coffee consumption is common among both younger and older adults, and at all times of the day: early morning upon waking, for breakfast, after a meal, and even in the evening. It is taken at home, at work, and in cafĆ©s, bars, and restaurants. The preparation methods range from cafĆ© ristretto, a special type of espresso containing little water, to large cups of āregularā coffee. It is taken as black coffee or with addition of other food ingredients such as sugar or other sweeteners, milk or nondairy creamer, and in the form of special preparations such as cappuccinos, lattes, or flavored coffees.
Coffee is consumed for its unique aromatic taste and stimulating effects. The pleasant taste originates from the roasting process, where the bitter tasting and the characteristic volatile aroma components are formed [1]. More than 1000 different aroma compounds have been identified in coffee, making it a complex and diverse beverage. Moreover, the effects of coffee can be either stimulating or relaxing, depending on the situation one finds oneself in and how one feels [2].
Consumers may take coffee for emotional reasons because they enjoy it; it may help them relax or improve their mood. Other reasons for drinking coffee may be more rational; it may help one to wake up, be stimulated, have improved concentration, or avoid falling asleep when wakefulness is desired. Coffee is also used for social reasons, which is evident from the 400-year history of coffee houses, where people meet while enjoying their coffee.
Coffee is one of the most popular drinks in Western countries. In many countries, most adults consume this beverage. In the United States, for example, only 22% of adults never drink coffee [3].
1.2 COFFEE FROM A NUTRITIONAL PERSPECTIVE
Coffee is a unique drink and could be regarded as a healthy beverage choice. If taken as black coffee, it is virtually free of saturated fatty acids, sodium, and sugar. Further, it contains an insignificant amount of energy: 2 kcal/178-g serving [4]. However, many consumers add sugar, milk, or cream to their coffee. The amount of calories provided daily by sweetened coffee has been calculated as 130 kcal/day (consumers of this beverage only), which is less than half of the estimated 321 kcal/day obtained from all sweetened beverages (including sodas/colas), based on intake data from the United States [5]. Consumers who want to control their calorie intake or consumption of nonessential nutrients such as sugar or saturated fat may choose to add noncaloric sweeteners and low-fat milk to their beverage.
Certain so-called gourmet coffee beverages should be consumed in moderation. These include cappuccino and lattes that contain ingredients such as cream, full-fat milk, and sugar. These beverages can contain up to 240-kcal/237-mL serving [6], but beverages with significantly lower energy levels are also available. An intake study of college women indicated that gourmet coffee drinkers consumed an additional 206 kcal/day and 32 g sugar/day compared with nonconsumers [7].
Roast coffee produced by traditional roasting processes can be regarded as a natural food or food ingredient. It is a single ingredient product without additives and thus fulfills the criteria for the term ānaturalā that was established by the UK government, for example [8]. In certain roast coffee products, the only other substances used are packaging gases such as carbon dioxide, an inert gas that preserves the flavor. In other roast coffee products, other technologies such as vacuum packaging may be used for this purpose.
1.3 POTENTIAL BENEFICIAL EFFECTS OF COFFEE
The health aspects of coffee drinking have been subject to many controversial debates. This history is nicely summarized in Ian Berstenās book Coffee, Sex & Health, a history of anti-coffee crusaders and sexual hysteria [9]. As the author points out:
ā¦ even though coffee, tea and cocoa all contain caffeine, seemingly the root cause of many problems to do with health, coffee seemed to be the only one of the three that had a health image problem.
Even today, a substantial number of articles about coffee are negative. In the United Kingdom, for example, 51% of media publications on coffee, caffeine, and health are negative, 22% are neutral, and 27% positive [10].
Only recently have scientists begun to document the potential health benefits of coffee drinking, whereas research data on the acute/short-term stimulating properties of coffee due to caffeine are well known. Caffeine is naturally found in about 60 different plants including tea leaves, cocoa beans, guaranĆ”, and kola nut. It is also added to many soft drinks including energy drinks and to medicinal products such as analgesics and cough syrups [11,12].
Acute caffeine effects on the central nervous system have been reviewed extensively [13ā15]. Although these effects are not the focus of this book, they are briefly summarized here.
At common consumption levels, the most important acute effect of caffeine and its predominant metabolites (paraxanthine and theophylline) is the blockade of adenosine A1 and A2A receptors. This leads to activation of a variety of neurotransmitter systems and finally to the well-known effects on improved arousal, vigilance, and attention. There is evidence that caffeine has the potential to improve cognitive functions that are timed such as reaction time, decision-making, or cancellation tasks. Its influence on mood depends on the amount of caffeine consumed, individual differences, and arousal states. In real-life simulations, caffeine appears to improve performance of artificial tasks and simulations of driving and industrial work.
The European Food Safety Authority (EFSA) recently reviewed the science of caffeine effects for the purpose of establishing a health claim, concluding that a cause-and-effect relationship existed between caffeine consumption and increased alertness and attention with at least 75 mg caffeine [16], which is approximately the amount contained in a cup of coffee. Thus, a cup of coffee may well help to start the morning, get through the day when tired, overcome the postlunch slump, or maintain attention at night (e.g., during overnight work). Other effects of caffeine on the nervous system are covered in Chapter 13.
Caffeine is also an ergogenic aid, and thus has the potential to enhance physical performance during prolonged, exhausting exercise in particular and during short-term, high-intensity athletic performance to a lesser degree [17]. Its efficacy has been proven in a variety of endurance sports including cycling, running, swimming, tennis [17,18], and recently even in simulated soccer [19] and rugby playing [20]. The EFSA evaluated these effects, and concluded that a cause-and-effect relationship exists between caffeine intake and increased endurance performance and capacity (at 3 mg/kg body weight) and perceived exertion/effort during exercise (at 4 mg/kg body weight) [21].
Other potential benefits such as reduced risk for certain diseases, as assessed by observational studies, have become widely known to the scientific community in recent years. For example, the relationship between coffee drinking and diabetes based on epidemiologic studies was first described less than 10 years ago [22], triggering many more observational, human intervention, and mechanistic studies (see Chapter 8).
In fact, when searching for ācoffee and healthā in the ISI Web of Knowledge, the record count per year increased from 21 to 30 in the years 1996ā2001 to 74ā107 in the years 2007ā2010, demonstrating the significant increase in scientific investigations in this field.
Moreover, some of the diseases that appear to be influenced by coffee drinking are important public health issues. For example, diabetes affects 346 million people worldwide, and the World Health Organization projects that diabetes deaths will double between 2005 and 2030 [23]. Alzheimerās disease is another area in which emerging science indicates that coffee might play a role in risk reduction (see Chapters 4 and 5). Alzheimerās Disease International [24] estimated that 35.6 million people were living with dementia worldwide in 2010; this figure is projected to increase to 65.7 million by 2030 and 115.4 million by 2050. Nearly two-thirds live in low- and middle-income countries, where the sharpest increases in numbers are set to occur. Alzheimerās Disease International calls on governments and other major research funders to act now to increase dementia research funding, including research into prevention, to a level more proportionate to the economic burden of this condition [24].
Other potential beneficial effects of coffee relate to Parkinsonās disease (Chapter 6), liver health (Chapter 7), cancers (Chapter 10), overall mortality (Chapter 11), and risk of suicide (Chapter 13).
Even if coffee drinking only slightly reduces the risk of developing some of these diseases, it may add to the effect of already well-known healthy lifestyle recommendations. In this way, this common behavior could be of significant public health importance.
1.4 LIMITATIONS TO THE BENEFICIAL EFFECTS
The potential negative aspects of coffee drinking have been discussed for a longer time. In particular, the International Agency for Research on Cancer in 1991 published the view that coffee āis possibly carcinogenic ...
