7.1 Is coffee acidic?

As noted in section 2.3, "acidity" refers to a flavor note, not to the actual acid content; coffee is relatively low in acid. Its pH averages around 5.0 - 5.1, which is more neutral than beer or any fruit juice and similar to carbonated water (which contains carbonic acid as a result of the dissolved carbon dioxide). As Ukers notes in All About Coffee, if a vinegar/water solution were made within an equivalent pH, its acidity could not be detected by taste

Darker roasted coffees are less acidic—both in their flavor profile and in any actual acid content.

7.2 How much caffeine is in decaf?

According to Commercial Item Description (CID) A-A-20213B , the United States Department of Agriculture mandates that decaffeinated coffee cannot contain more than 0.10 percent on a dry basis in the packaged item, as determined by Association of Analytical Communities (AAOC) International Official Method 979.1 1. However, a reduction in caffeine by 97.5% is the legally accepted method of calculation.



Arabica coffee contains 0.8-1.4% caffeine. In other words, it is naturally 98.6 to 99.2 percent caffeine free. That 1.1% average must be further reduced by 97.5 percent to be considered decaffeinated.

7.3 Is coffee harmful?

Coffee's effect on health has been attacked throughout the ages. Its stimulatory effect was quickly noted, and that, possibly, formed the basis for some very unscientific accusations early on, with "nervous disorders" forming the core of these accusations. Perhaps the peak of the anti-coffee hysteria occurred during the nineteenth century, with coffee being blamed for every imaginable illness and disorder. Conveniently, many of those who blasted coffee also offered alternate products, the most successful being C. W. Post's Postum.

More careful research has been conducted in the last few decades, though fallacious conclusions still occur; some relatively recent studies, for example, failed to take concomitant tobacco use into account. The current research is mixed.

Most of the focus has been on coffee's most (in)famous component, caffeine. Caffeine is a central nervous system stimulant, a bitter alkaloid that probably forms part of the coffee plant's defense system—caffeine also works as an antifungal, a selective phytotoxin, and a limited insectival chemosterilant. It is highly soluble in water, and is one of the first components to dissolve into the brewing coffee.

Many of the effects of caffeine are obvious, depending upon the quantity consumed: increased alertness, anxiety, irritability, interference with sleep, and jitteriness. It works as a mild diuretic. Caffeine can cause headaches, but also, as a vasoconstrictor, has in certain instances been used to help relieve migraine headaches. Yet again, regular consumers of caffeine-containing products can suffer withdrawal symptoms if they suddenly stop taking them (see Smith, Barry D. and Tola, Kenneth, "Caffeine: Effects on Psychological Functioning and Performance" in Spiller, Gene A., editor, Caffeine). In this regard, coffee can be said to be habit-forming. Caffeine consumption has been linked to short-term increases in blood pressure, heart rate, and to occasional irregular heartbeat. Studies linking coffee and caffeine to osteoporosis have been largely inconclusive.

Doctors generally advise patients with gastroesophageal reflux disease (GERD, also known as heartburn) to eliminate coffee consumption. According to "Coffee and gastrointestinal function: facts and fiction" (Boekema PJ, Samsom M, van Berge Henegouwen GP, Smout AJ., Scand J Gastroenterol Suppl. 1999;230:35-9), coffee promotes reflux, but is not associated with dyspepsia (indigestion).

But caffeine is not coffee's only component. A study conducted in the Netherlands found that the coffee diterpenes cafestol and kahweol increase serum lipid levels (causing a rise in total cholesterol, low-density-lipoprotein (LDL) cholesterol, and triglycerides) and affect liver function (Rob Urgert, Natasja Essed, Guido van der Weg, Truus G Kosmeijer-Schuil, and Martijn B Katan, Separate Effects of the Coffee Diterpenes Cafestol and Kahweol on Serum Lipids and Liver Aminotransferases, American J Clinical Nutrition 65(2):519-524 (Feb 1997)). Subsequent studies appear to affirm these findings. Note, however, that unfiltered coffee was found to contain these substances; paper removes them.

Coffee consumption may also have benefits: according to the National Institute of Neurological Disorders and Stroke, "[s]everal large studies have shown that caffeine intake is associated with a reduced risk of developing Parkinson's disease ... in men, but studies in women have been inconclusive," the latter perhaps due to the effects of hormone therapy for women. The September 2004 issue of Harvard Women's Health Watch found that, for most people, moderate coffee consumption is safe. It also found that coffee drinkers may have a lower risk for developing type 2 diabetes, gallstones, colon cancer, and have a lower risk of liver damage for those at high risk for liver disease. The Annals of Internal Medicine detailed a Dutch study linking a large daily coffee consumption (7 or more cups a day) with a halving of the risk for type 2 diabetes.; the study could not, however, conclusively state that it was the coffee that lowered the risk, rather than other factors (Eduardo Salazar-Martinez, Walter C. Willett, Alberto Ascherio, JoAnn E. Manson, Michael F. Leitzmann, Meir J. Stampfer, and Frank B. Hu, Coffee Consumption and Risk for Type 2 Diabetes Mellitus, Ann Intern Med, Jan 2004; 140: 1-8).

The February 16, 2005 issue of the Journal of the National Cancer Institute detailed two studies on coffee and cancer.The first found a decreased risk of liver cancer (specifically, hepatocellular carcinoma, or HCC) resulting from daily consumption of coffee. According to the study, conducted by Manami Inoue, M.D., Ph.D., at the National Cancer Center in Tokyo, the HCC rate among people who never drank coffee was 547.2 cases per 100,000 people over 10 years, and 214.6 cases per 100,000 people for daily coffee drinkers. Further, the risk decreased with the amount of coffee consumed. Decaffeinated coffee was not separately evaluated, so the study could not conclude whether caffeine was a factor.

The second study, conducted by Karin B. Michels, Sc.D at Brigham and Women's Hospital in Boston, examined data from the Nurses' Health Study on women and the Health Professionals' Follow-up Study on men. The data indicated there was no association between consumption of caffeinated coffee and the incidence of colon or rectal cancer. Interestingly, the study found that those who regularly drank two or more cups per day of decaffeinated coffee had almost half the incidence of rectal cancer, 12 per 100,000 person-years (person-years refers to the number of people studied multiplied by the total observation time), of those who never drank decaffeinated coffee (19 per 100,000). This latter finding may be misleading, however, as the decaf drinkers might simply be leading otherwise healthier lifestyles.

The above text is for informational purposes only, and should not for the basis of medical treatment. As always, a physician should be consulted for medical decisions. The topic of coffee and its effects upon health is vast, and this is by no means an exhaustive discussion.

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