Calcium is a vital mineral known for its role bone development and support and for the treatment of osteoporosis, or bone loss. However, recent studies show that calcium can reduce the risk for high blood pressure and colorectal cancer and is also beneficial in weight loss. However, consuming supplemental calcium in large amounts can sometime result in constipation. Magnesium consumed with calcium helps offset this side effect.
Calcium binds to bile and fat in the intestine and is excreted during a bowel movement, which helps cleanse the colon. However, when calcium is consumed in excess, this same binding effect can harden the stool, leading to constipation. Most people obtain a low-to-moderate amount of calcium in their diets through dairy, fruit and vegetables. Adding calcium supplementation to the mix may cause problems.
Magnesium is a mineral that is important for cardiovascular and muscular health. It also works as a mild laxative by relaxing the smooth muscles in the intestine and by helping the gut retain water. This, in turn, helps to promote smoother bowel movements.
Dietary calcium can be obtained from dairy and also a variety of fruits and vegetables, especially leafy greens. Dietary sources of calcium rarely cause constipation because these foods are often rich in magnesium, fiber and other micronutrients that assist digestive health. Supplementary calcium is available in pill, liquid and chewable form, as is magnesium.
The average dose of calcium is 1,000 mg per day for adults. Adolescents and aging individuals may need up to 1,300 mg per day. It is recommended that the calcium be taken in smaller doses because the body can only absorb about 300 mg to 500 mg at any time. The maximum dose of calcium is about 2,500 mg to 3,000 mg per day. The NIH recommended daily allowance of supplemental magnesium for adults ranges from about 300 mg to 400 mg per day.
- What You Need to Know About Calcium; Havard Health Letter; April 2003
- NIH Dietary Supplement Fact Sheet: Magnesium
- NIH Dietary Supplement Fact Sheet: Calcium
- Review of the Treatment Options for Chronic Constipation; John F. Johanson; MedGenMed. 9(2): 25; 2007