Hypolactasia and metabolic changes in post-menopausal women

The aims of the study were to evaluate the prevalence of hypolactasia in a group of post-menopausal women in Southern Italy, and to relate hypolactasia to possible changes occurring in biochemical indicators of carbohydrate and fat metabolism as well as in biochemical markers of bone metabolism.

Fifty post-menopausal women entered the study. Lactose malabsorbers were identified by breath hydrogen test. The kinetics of D-xylose was evaluated by a graphic-mathematical analysis after oral administration of a solution of 10 g of D-xylose in water. Serum glucose, insulin, C-peptide, cholesterol and triglycerides were assayed by commercial kits. The evaluation of dietary habits and physical activities was performed by a questionnaire. The assessment of bone turnover was obtained by measuring osteocalcin, serum alkaline phosphatase, calcium, phosphorus, and urinary hydroxyproline and urinary calcium expressed as a ratio or urinary creatinine.

Twenty-six of 50 women showed hypolactasia. Significant differences were found in serum levels of insulin, glucose, and triglycerides, which were lower in malabsorbers than lactose absorbers, and in HDL-cholesterol levels which were higher in the first group than in the second. As regards bone turnover, dietary habits or lactose intake, there were no significant differences between the two groups.

The significant differences found in serum levels of glucose, triglycerides, and HDL-cholesterol between lactose absorbers and malabsorbers may be imputable to the low or absent lactase activity which does not allow the whole amount of lactose in the small bowel of malabsorbers to be metabolized. Moreover, changes in lactose absorbing capacity of intestinal mucosa did not modify the intake of milk or its by-products in malabsorbers as demonstrated by the analysis of food.