Since the early 90^ties gender related differences have been proposed for caffeine, although the published results were somewhat variable. Zwyghulzen-Doorenbos et al. (1990) firstly demonstrated sleep latency and better auditory vigilance induced by caffeine in one group of 24 men, but subsequently James (1998) concluded that caffeine did not improve mental or physical performance among male and female habitual caffeine users.

Recently, Adan et al. (2008) investigated the early effects of a single low dose of caffeine (100 mg), as well as of the administration of decaffeinated coffee, on sleepiness and subjective activation. The experiment was performed using a gender-oriented, randomized, double blind, placebo-controlled procedure applied to 688 healthy undergraduates volunteers (238 men and 450 women – mean age 22.03 +/- 2.21 years). The results of the study demonstrated that caffeine shows a greater effect (lesser somnolence and higher activation) in men rather than in women. In addition, contrary to what was previously thought, decaffeinated coffee also produced an increased state of alertness. Although the effect of decaffeinated drink was small, in contrast to the caffeine containing beverage and was slightly more noticeable in women.

Further works are needed to study more accurately a gender-oriented risk/benefit profile of caffeinated beverages, according to different ages, dosages, CYP-related metabolism, dietary interactions, and individual sensitivity.

Luigia Favalli (Nutrition)
Department of Experimental and Applied Pharmacology
University of Pavia
Pavia - Italy
E-mail: farola@unipv.it

Articles’ abstract available at:
Psychopharmacology 1990; 100 (1): 36-9

Neuropsychobiology 1998; 38 (1): 32-41

Prog Neuropsychopharmacol Biol Psychiatry 2008; 32 (7): 1698-703