It seems that, when given the choice, more Americans choose coffee instead of tea. While green tea is gaining popularity among health-conscious individuals, it still is not consumed as often as coffee.

Tea, Coffee, and Caffeine

Regular tea and coffee both contain caffeine, but coffee typically has 2-3 times more caffeine than tea. Caffeine consumption has some negative physiological effects but probably has little or no impact on the overall risk of cancer and cardiovascular disease. The negative effects of caffeine include increased anxiety and panic attacks, more trouble falling asleep, increased indigestion and reflux, and headaches (1). For those concerned about the negative effects of caffeine, herbal tea and decaffeinated tea/coffee are available.

Coffee and Cholesterol

Some -- but not all -- studies have found that coffee drinkers have increased cholesterol levels and/or an increased risk of coronary heart disease than non-coffee drinkers. These studies also indicate that it is not the caffeine in coffee that is responsible for increasing serum cholesterol levels (2). Coffee has been shown to contain two plant chemicals called diterpene compounds. These compounds are cafestol and kahweol, and have been shown to increase LDL cholesterol (aka “bad cholesterol") levels (3).Five cups of coffee daily could raise serum cholesterol as much as 5 to 10%. If the coffee is consumed with cream and sugar, this would further raise blood lipids. In theory, the regular consumption of 5 or more cups of unfiltered coffee daily with cream and sugar could easily increase cardiovascular disease risk factors enough to increase the risk of a heart attack by at least 30 to 50%.So, what about paper-filtered coffee? Passing coffee through a paper filter appears to remove most of these diterpene compounds, and thus filtered coffee appears to have less of a tendency to raise LDL levels than unfiltered coffee (4). However, a recent study concluded, “Consumption of filtered coffee, in doses that are commonly consumed, was associated with increased levels of homocysteine and total cholesterol” (5).Coffee also appears to contain another yet-to-be-identified substance that raises homocysteine levels. Like increased LDL, higher levels of serum homocysteine have been linked to an increased risk of cardiovascular disease. Lowering homocysteine levels is likely to help reduce heart attacks and strokes (6). In more recent studies, elevated homocysteine levels have been associated with perhaps a two-fold increased risk of developing Alzheimer’s disease (7).

Skip the Coffee

The bulk of the scientific research indicates that the consumption of unfiltered black coffee raises total and LDL cholesterol. It is probably a significant risk factor for the development of atherosclerosis, heart disease, and stroke. While filtered coffee does have less of an impact on blood lipids than unfiltered coffee, it may still modestly elevate serum cholesterol levels and also increase homocysteine levels. This revelation means that even filtered coffee may increase the risk of cardiovascular disease and possibly Alzheimer’s disease.

Why Choose Tea Instead?

In contrast to coffee, there is growing scientific evidence that regular consumption of tea may reduce the risk of cardiovascular disease and even help reduce the overall risk of developing cancer (8, 9). Tea -- both black and green -- contains a variety of beneficial plant chemicals called flavonoids. Flavonoids may reduce the oxidation of LDL particles and/or reduce the tendency of blood platelets to stick to artery walls (10). This evidence suggests that black tea may reduce the risk of clogged arteries and/or heart attacks (11). A Welsh study of 3,454 older subjects found that those who consumed more tea were less likely to have more advanced atherosclerotic lesions in their aortas (12). More recently, a 5.6 year longitudinal analysis of data from the Rotterdam Study found a 70% lower risk of a fatal heart attack in those who consumed at least 2-3 cups of black tea daily, compared to those who were not tea drinkers. The authors concluded, “An increased intake of tea and flavonoids may contribute to the primary prevention of ischemic heart disease” (13).

The Bottom Line

Regular consumption of coffee is likely to increase the risk of cardiovascular disease and may also increase the risk of Alzheimer’s disease. By contrast, choosing black or green tea instead of coffee is likely to reduce the risk of cardiovascular disease and may also reduce the risk of at least some types of cancer. Therefore, tea is the more healthful choice.By James J. Kenney, PhD, RD, LD, FACN

References:

1.  West J Med 1992; 157: 544-53
2. Am J Clin Nutr 1991; 54: 599-605
3. Am J Clin Nutr 1995; 61: 1277-83
4. Am J Epidmiol 2001; 153: 353-62
5. Am J Clin Nutr 2001; 74: 302-7
6. Nutr Rev 1999; 57: 299-305
7. NEnglJMed 2002; 346: 502-7
8. Nutr Rev 2000; 58: 1-10
9. Am J Clin Nutr 2000; 71(suppl): 1698S-702S
10. FASEB J 1996; 10: A793
11. Arch Intern Med 1999; 159: 2170-4
12. Am J Clin Nutr 1997; 65: 1489-94
13. Am J Clin Nutr 2002; 75: 880-6

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