Coffee consumption

Caffeine. About 3% by weight of the roasted coffee bean is caffeine (16). The second U.S. Department of Agriculture world coffee crop estimate for 1988—1989 was 4.24 x 10 kg (93.3 million 100-lb bags) (102). World coffee consumption was predicted to rise in the foreseeable future at the rate of 1—2% per year and thus the total amount of caffeine and related alkaloids ingested from this source can also be expected to increase. Caffeine and related bases (eg, theophylline) are also found in various teas but, because most of the major producers (India, China, etc) export relatively Htfle of thek crops and keep most for domestic consumption, accurate figures on year-to-year production are more difficult to obtain. Nevertheless, these crops are of significant economic import (103). 

Health concerns about the effects of coffee are also an important consideration in coffee drinking trends. While many health issues have not been systematically and thoroughly evaluated, these concerns have undoubtedly contributed to consumption patterns. However, the most significant changes in coffee consumption occurred prior to scientific research and knowledge of health effects due to caffeine exposure. 

Table 15 shows the trends in consumption of various beverages in the U.S. during the period of 1980 to 1992.38 The patterns that are most apparent include the reduction in per capita coffee consumption, a slight in-... 

This blood pressure and the plasma epinephrine and norepinephrine (2 and 3 above) effect of caffeine disappear after a few days, even if heavy coffee consumption continues. 

Heavy coffee drinking raises the levels of plasma homocysteine, a risk for heart disease. The dose response of plasma homocysteine to coffee appears stronger than the association to serum cholesterol levels. Heavy coffee consumption was found to cause an increase of about 2 mmol/... 

La Vecchia, C., Gentile, A., Negri, E., Parezzini, F. and Franceschi, S., Coffee consumption and myocardial infarction in women. American Journal of Epidemology 130, 481 485, 1989. 

Battig, K., Cardiovascular effects of everyday coffee consumption. Schweizerische Medizimische 122, 1536-1543, 1992. 

Dekker, D., Paley, M. Popken, S. and Tepas, D., Locomotive engineers and their spouses Coffee consumption, mood and sleep disorders. Ergonomics 36(1-3), 233 238, 1993. 

Forde et al.20 used a more complex study design to examine the effect of boiled coffee vs. paper-filtered coffee vs. coffee abstinence. The investigation involved 33 men with elevated baseline serum cholesterol levels (average 8.7 mmol/L [335 mg/dL]) who apparently were habitual boiled coffee drinkers (implied but not stated). The 10-week study was divided into two 5-week periods. Subjects were assigned to one of four groups (1) continuation of habitual consumption (control), (2) abstinence from coffee for the full 10 weeks, (3) abstinence from coffee for the first 5-weeks, followed by 5 weeks of paper-filtered coffee consumption, and (4) abstinence from coffee for the first 5 weeks, followed by 5 weeks of boiled coffee consumption. 

The full effect of changes in coffee consumption on serum cholesterol does not occur as quickly as it does to changes in dietary fat intake. Typically, when a stable high-saturated fat diet is replaced with a stable low-saturated fat diet, the maximum changes in serum lipid levels are achieved in two to four weeks.29 30 The serum lipid response to changes in coffee consumption does not appear to reach its full effect until after four weeks or more. 

These studies suggest that at least four weeks are needed before maximum changes in serum cholesterol levels, resulting from coffee consumption or cessation, are likely to be achieved. 

Summary of Clinical Trials on Coffee Consumption and Serum Cholesterol Levels... 

Tuomilehto, J., Tanskanen, A., Pietinen, P., Aro, A., Salonen, J. T., Happonen, P., Nissinen, A., Puska, P., Coffee consumption is correlated with serum cholesterol in middle-aged Finnish men and women, J Epidemiol Community Health, 41, 237, 1987... 

Jansen, D. F., Nedeljkovic, S., Feskens, E. J. M., Ostojic, M. C., Grujic, M. Z., Bloemberg, B. P. M., Kromhout D., Coffee consumption, alcohol use, and cigarette smoking as determinants of serum total and HDL cholesterol in two Serbian cohorts of the Seven Countries Study. Arterioscler Thromb Vase Biol., 15, 1793, 1995... 

Forde, O. H., Knutsen, S.F., Arnesen, E., Thelle, D. S., The Tromso heart study Coffee consumption and serum lipid concentrations in men with hypercholesterolemia A randomized intervention study, BrMedJ, 290, 893, 1985... 

Pietinen, P., Geboers, J., Kesteloot, H., Coffee consumption and serum cholesterol An epidemiological study in Belgium, Inti J Epidemiol, 17, 98, 1988... 

Although earlier work had showed a positive association between coffee consumption and pancreatic cancer rates across countries,2 it was the much-publicized case-control study of MacMahon et al.3 in 1981 that attracted widespread attention to the question of a possible link. In that study, which was designed primarily to investigate the role of smoking and alcohol in pancreatic cancer, 369 pancreatic cancer patients prior to diagnosis and 644 hospital controls reported their typical daily coffee and tea consumption. Unexpectedly, the authors found a significantly increased risk of pancreatic cancer associated with coffee consumption (overall rela-... 

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