Starch Malabsorption and Stool Excretion Are Influenced by the Menstrual Cycle in Women Consuming Low-Fibre Western Diets

Abstract

The objectives of the study were to determine whether the follicular (F; days 6–11) and luteal (L; days 16–21) phases of the menstrual cycle were associated with changes in starch malabsorption, stool bulking, stool mucinase, and β-glucuronidase activities in 10 women (24.1 ± 0.7 years old) eating a standardized low-fibre diet. Starch malabsorption, measured by breath hydrogen excretion after a breakfast of pureed chickpea (days 10 and 20) versus 10 g lactulose (days 11 and 21), decreased from 9.7 ± 1.8 g/50 g starch ingested (F) to 6.6 ± 1.8 g/50 g starch ingested (L) (p < 0.05). Stool wet weight decreased from 84.5 ± 10.1 g/day (F) to 52.2 ± 5.8 g/day (L) (P < 0.002). Stool dry weight decreased from 20.2 ± 1.9 g/day (F) to 14.2 ± 1.1 g/ day (L) (p < 0.006). Stool nitrogen excretion decreased from 1.81 ± 0.19 g/day (F) to 0.82 ± 0.06 g/day (L) (P < 0.006). Stool mucinase and β-glucuronidase activities were unaffected by the menstrual cycle. These results indicate that women eating low-fibre Western diets may be more prone to constipation during the luteal phase of the menstrual cycle.

Key Words:

• Breath hydrogen
• menstrual cycle
• starch malabsorption
• stool excretion