Using Magnesium for Constipation and IBS-C

If you experience constipation-predominant irritable bowel syndrome (IBS-C), you may have come across the recommendation to take a magnesium supplement. This is a common way of regulating bowel movements and easing constipation.

Before taking magnesium, or any vitamin, it is extremely important to be educated about possible risks as well as the possible benefits. Let's explore the questions you should consider to make an informed decision for yourself regarding taking a magnesium supplement.

Magnesium does have a well-established reputation for its laxative qualities. However, there does not appear to be any direct research support for the use of magnesium as a treatment for IBS-C.

Of interest is a study that looked at the relationship between constipation and water, fiber, and magnesium intake. The study was conducted in Japan with 3,835 subjects who were between the ages of 18 and 20. Constipation was not found to be associated with low fiber intake or low intake of water from fluids. Constipation was, however, associated with low intake of magnesium and low intake of water from foods.

Magnesium is a mineral that is essential for overall physical health. Approximately half of the magnesium in our bodies is found in our bones. The rest serves to help cell functioning throughout the body’s various systems.

Magnesium plays an important role in muscle function, heart rhythm, blood pressure, immune system functioning, and blood sugar level. In general, healthy individuals have enough magnesium in their system and do not need to take a magnesium supplement.

The laxative effect of magnesium appears to come through two different mechanisms. Magnesium relaxes the muscles in the intestines, which helps to establish a smoother rhythm. Magnesium also attracts water. The increased amount of water in the colon serves to soften the stool, helping to make stools easier to pass.

Before taking supplemental magnesium or any over-the-counter remedy, it is extremely important that you discuss the matter with your doctor. Only your doctor knows your complete medical history.

Your physician will be able to tell you if there is anything about your medical picture that would put you at risk should you start taking a magnesium supplement. A particular red flag would be raised if you suffer from any kind of kidney disease because magnesium is excreted through the kidneys. If your kidneys are not functioning well, you could be at risk for having excessive magnesium in your system.

As a general rule, people tend to view vitamins as harmless substances. However, the possibility of negative side effects exists for vitamins in the same way as for any prescription medication.

In the case of magnesium, it may be unwise to take an additional supplement if you are already regularly taking antacids or laxatives that contain magnesium. Read the labels carefully so as to prevent a buildup of unhealthy magnesium levels in your body.

Supplemental magnesium also carries the risk of interfering with the effectiveness of some prescription medications. Again, it is essential to discuss the use of magnesium with your doctor if you are taking any of the following:

• Diuretics
• Chemotherapy agents
• Certain antibiotics

The National Institutes of Health has published a fact sheet that offers a table with an outline of the recommended daily intake of magnesium. The amount recommended varies by age and different guidelines are offered for women who are pregnant or breastfeeding. Note that this is the total amount, which includes magnesium intake from foods, too.

Magnesium supplements come in a variety of forms, with the most popular being citrate, chelate, and sulfate. There does not appear to be any significant health or absorption differences among the various kinds.

Just be careful that the magnesium supplement you choose does not contain calcium, as calcium supplements may increase the risk for constipation. If for other health reasons your doctor recommends that you take supplemental calcium, discuss a possible magnesium/calcium ratio that does not compound your constipation problem.

It is important to know that milk of magnesia is a very different product. Milk of magnesia is not intended to be used as a dietary supplement. It is an osmotic laxative, which works by drawing water into the intestines. This increase in water stimulates bowel motility and increases the size of the stool so as to prompt a bowel movement. Physicians rarely recommend milk of magnesia nowadays, as there are safer and more effective products available to treat constipation.