1979
What do the harmful substances in tea and coffee do?
December 1979

“What do the harmful substances in tea and coffee do?” Ensign, Dec. 1979, 20

I know that tea and coffee contain substances that are harmful to us, but what exactly do they do?

Dr. Clifford J. Stratton, associate professor of anatomy, University of Nevada School of Medical Sciences; high councilor, Reno Nevada North Stake The effects of tea and coffee come from the caffeine and theophylline they contain—two alkaloids, or natural compounds, that occur in plants throughout the world. Collectively, they are called the “xanthines” because they are so closely related chemically and because they have fairly identical effects on the body. Aspirin (and many other common medicines) also contain xanthine compounds.1 While xanthines do have value when used as medicine, they have harmful effects when used indiscriminately.

The xanthines stimulate the brain and spinal cord, increase heart action, constrict blood vessels feeding the brain (that’s why extra-strength aspirin compounds help a headache so dramatically), relieve respiratory distress by relaxing certain muscles, strengthen the contractions of arm and leg muscles, increase the production of urine, increase the amount of acid secreted into the stomach, and generally increase body metabolism.2 Obviously, their carefully regulated medicinal uses are many and varied; just as obviously, abuse of them can cause serious side effects.

Some people may think that the tannins found in tea and coffee are the reason to avoid them. Again, tannic acid is medically useful for causing tissues to contract and thus controlling bleeding and also for treating diarrhea. But tannins are not xanthines.

A xanthine overdose can cause many harmful symptoms, including diarrhea, dizziness, anxiety, trembling, frequent urination, and insomnia. Xanthine withdrawal can cause painful headaches. What constitutes an overdose differs with different individuals. Some researchers report that between 50 and 200 mg. of caffeine will produce perceptible effects.1 Two major pharmacology texts label doses exceeding 250 mg. as being large.2 One six-ounce cup of coffee contains between 100–150 mg.; a cup of tea the same size contains 65–75 mg.1

Notes

  1. J. F. Greden, “Anxiety or Caffeinism: A Diagnostic Dilemma,” American Journal of Psychology 131 (1974): 1089–92.

  2. J. C. Ritchie, “Central Nervous System Stimulants, the Xanthines,” in The Pharmacological Basis of Therapeutics, ed. L. S. Goodman and A. Gilman (New York: MacMillan Publishing Co., 1975), pp. 367–68; E. B. Truitt, “The Xanthines,” in Drill’s Pharmacology in Medicine, 46th ed., ed. J. R. Dipalma (New York: McGraw-Hill Book Co., 1971), pp. 533–56.

  3. J. F. Greden, “Anxiety or Caffeinism: A Diagnostic Dilemma,” American Journal of Psychology 131 (1974): 1089–92.

  4. J. C. Ritchie, “Central Nervous System Stimulants, the Xanthines,” in The Pharmacological Basis of Therapeutics, ed. L. S. Goodman and A. Gilman (New York: MacMillan Publishing Co., 1975), pp. 367–68; E. B. Truitt, “The Xanthines,” in Drill’s Pharmacology in Medicine, 46th ed., ed. J. R. Dipalma (New York: McGraw-Hill Book Co., 1971), pp. 533–56.

  5. J. F. Greden, “Anxiety or Caffeinism: A Diagnostic Dilemma,” American Journal of Psychology 131 (1974): 1089–92.