TIME-DEPENDENT SENSITIZATION OF PLASMA BETA-ENDORPHIN IN COMMUNITY ELDERLY WITH SELF-REPORTED ENVIRONMENTAL CHEMICAL ODOR INTOLERANCE

This study examined plasma beta-endorphin as a marker of the physiolog ical stress response in community elderly who were either high (n = 15 ) or low (n = 15) in self-rated frequency of illness from environmenta l chemical odors. Individuals who report nonatopic multiple sensitivit ies to or intolerances for low levels of environmental chemicals also claim high rates of comorbid food sensitivities or intolerances. Subje cts gave 9 AM blood samples for plasma beta-endorphin 90 min after ing esting either 1% fat cow's milk or a soy-based nondairy drink, on six different mornings in the laboratory after all-night sleep recordings. The six sessions were divided into three sets of two successive days each, with each set [involving baseline (ad lib milk) nondairy (soy-ba sed), and dairy diets] separated from the next by 3 weeks. In the chem ically tolerant subjects, stably lower beta-endorphin levels suggested that milk may have been a physiologically less stressful beverage tha n was the soy drink In contrast, the chemical odor intolerant group ex hibited a) increased levels of plasma beta-endorphin averaged over the 6 days (p = .02); and b) marked fluctuations in endorphin from one la boratory day to the next (Group X Diet X Day interaction, p = .005). T he findings were consistent with time-dependent, context-dependent sen sitization of beta-endorphin in the chemical odor intolerant individua ls.