Can Calcium Supplements Cause Constipation? Science Weighs In

Calcium supplements are widely used, with around 22% of men and 32% of women taking them. However, some people experience constipation as a side effect. Research suggests calcium may slow intestinal movement and reduce gut fluid secretion. A 2018 study linked calcium carbonate to constipation. An older research review also found constipation among the most common side effects of calcium supplements. The National Institutes of Health acknowledges that calcium can cause constipation in some individuals.

Yet, a 2016 study reported that calcium carbonate and calcium phosphate did not affect stool frequency in healthy women. This suggests the issue may vary between individuals. Other supplements like iron, folic acid, and berberine can also lead to constipation.

Chronic constipation is defined as having three or fewer bowel movements per week for over six months. To ease calcium-related constipation, experts recommend consuming fibre-rich foods and staying hydrated. A calcium-magnesium combination might also help prevent the problem. Calcium supplements can cause constipation in some cases, though not everyone is affected. Simple changes like increasing fibre, drinking more water, or adding magnesium may reduce the risk. Further research may clarify why responses to calcium supplements differ.