I NUTRITIONNOTES I ~ ~~~

Letter to the Editor

More Effects of Caffeine

Sir: Graham’s review of caffeine (Nutrition Reviews 36: 97-102, 1978) gave short shrift to that drug’s possible teratogenicity, saying only that, “. . . at oral doses of 50 mg per kilogram of body weight and lower, teratogenic effects were generally absent.” While Graham’s state- ment is true, it obscures the real meaning from the reader. Oral doses of about 50 mg per kilo- gram or more have caused birth defects and reduced fertility in mice and other In one unpublished study, 30 mg per kilogram caused missing supraoccipital bones in rats.5 Most of these studies were done on a small number of animals. Larger studies might detect effects at proportionately lower levels of caffeine.

Many people drink surprisingly large amounts of coffee. For a 46 kg woman, one cup of coffee would provide a caffeine dose of 2 to 3 mg per kilogram; ten cups would amount to 20 to 30 mg per kilogram; and 20 cups would provide 40 to 60 mg per kilogram. Thus, levels of human consumption are very near the levels that cause adverse effects in animals. Normally, when the Food and Drug Administration sets tolerance levels for food additives, it limits ex- posure to 1/100 of the highest level that causes no effect. If this rule were applied to coffee, a pregnant woman would be advised to consume no more than about one-tenth of a cup of coffee a day.

The review also missed a recent report on the effect of coffee consumption on human preg- nancies6 This study showed that 15 out of 16 pregnant women who consumed about 600 mg or more of caffeine per day had problem preg-

nancies, including spontaneous abortions, still- births or premature births.

Pregnant women-or women of child- bearing agewou ld be well advised to avoid caffeine.

Michael Jacobson, Ph.D. Executive Director Center for Science in the Public Interest 1755 S Street, N. W. Washington, D.C. 20009

1. 0. Nieschulz, V. Ch. Knoche and J. Kdnig: Zur Pranatalen Toxizitat von Diphenylpyralin-8-Chlor- Theophyllinat unter Beruchsichtigung von Erfahrungen mit Thalidomid und Coffein. Arzneirnittel-Forschung 14: 41 5-424, 1964

2. Group D’Etude des Risques Teratogdnes: Tdra- togdnese Expdrimentale: Etude de la Cafdine chez la Souris. Thgrapie 24: 575-580, 1969

3. M. Bertrand, E. Schwam, A. Frandon, A. Vagne and J. Alary: Sur un Effect Tdratogene Systd- matique et Spdcifique de la Cafdine chez les Rongeurs. C.R. SOC. Biol. 159: 2199-2201, 1965

4. M. Bertrand, J. Girud and M.F. Rigaud: Ectro- dactylie Provoquee par la Cafeine chez les Rongeurs. Role des Facteurs Spdcifiques et Gdndtiques. C. R. SOC. Biol. 164: 1488- 1489, 1970

5. P.S. Thayer and P.E. Palm: A Current Assess- ment of the Mutagenic and Teratogenic Effects of Caffeine. Crit. Revs. Toxicol. 3: 345-369, 1975

6. P.S. Weathersbee, L.K. Olsen and J.R. Lodge: Caffeine and Pregnancy. ARetrospective Survey. Postgrad. Med. 62: 64-69, 1977

NUTRITION REVIEWS I VOL. 36, NO. 7 JULY 1978 231