Background: The relationship between lactose maldigestion, lactose intolerance, and calcium intake in premenopausal African American women is unknown.

Objective: To determine how intolerance of lactose and dairy products affects intake of calcium in lactose maldigesting premenopausal African American women.

Methods: Dietary intake of calcium was assessed in 50 premenopausal lactose maldigesting African American women as determined by the breath hydrogen test. Twenty-six women were lactose intolerant and 24 were lactose tolerant by self-reports.

Results: The average intake of calcium in lactose maldigesting and intolerant women was significantly lower than in lactose tolerant women (388 +/- 150 mg/day vs. 763 +/- 333 mg/day, p < 0.0001, t test). Neither group reached the newly established Dietary Reference Intake (DRI) for calcium (1,000 mg/day). Major source of dietary calcium in lactose tolerant women were milk and dairy products (45%), and mixed foods containing calcium from non-dairy sources (30%). In lactose intolerant women, 46% of calcium was from mixed foods and only 12% was from milk and dairy products. Lactose intolerant women had higher body mass index (BMI) than lactose tolerant women (p = 0.008, t test), and calcium intake was negatively associated with BMI (R2 = 0.470).

Conclusions: In African American premenopausal women, lactose tolerance facilitates the dietary intake of calcium when compared with their lactose intolerant counterparts. Low calcium intake is associated with higher BMI.