LACTOSE-INTOLERANCE AND BONE MASS IN POSTMENOPAUSAL ITALIAN WOMEN

Previous studies on the role of lactose malabsorption in the pathogene sis of postmenopausal osteoporosis have yielded conflicting results an d further information is needed. To date, all studies have been carrie d out on populations with a low prevalence of lactose malabsorption an d the lactose intestinal absorptive capacity was tested using a non-ph ysiological dose of lactose. In fifty-eight Italian postmenopausal wom en (mean age 57 (SD 7) years), bone mineral density (BMD) at lumbar sp ine, H-2 breath response after ingestion of 20 g lactose, intensity of symptoms of intolerance after a lactose load and daily Ca intake were evaluated. No differences were found between women with or without a positive H-2 breath test with regard to BMD (-1.2 (SD 0.9) v. -0.9 (SD 0.8)) and Ca intake (509 (SD 266) v. 511 (SD 313) mg/d). On the contr ary, both BMD and Ca intake were significantly lower in women with lac tose malabsorption and symptoms of intolerance (-1.5 (SD 0.7) and 378 (SD 220) mg/d) than in those with malabsorption without symptoms (-0.9 (SD 0.9) and 624 (SD 254) mg/d). Moreover, in lactose malabsorbers Ca intake was correlated inversely with symptom score (r(s) -0.31, P < 0 .05) and positively with BMD (r(s) 0.42, P < 0.005). Our results show that in Italian postmenopausal women Ca intake and BMD are not influen ced directly by lactose malabsorption; the appearance of symptoms of i ntolerance seems to influence BMD unfavourably through a reduced Ca in take.