Magnesium for Constipation

Hi, Bestie! We’re back with another chat about—you guessed it—poop! Or rather, a lack thereof. Today, I thought we could talk about magnesium and how it can be helpful for improving symptoms of constipation (1, 2). If you have a history of constipation, you may have been recommended magnesium at some point or even tried it out yourself! Let’s chat a bit about what magnesium is and how the current literature available supports the use of magnesium for treating constipation.

First off, what even is magnesium? When I picture magnesium, I’m basically picturing a piece of metal. If your brain does the same thing, you’re not wrong! Magnesium is an element commonly found on Earth and it is also a mineral that is crucial to the function of the body. Magnesium is usually found in high-fiber foods and if you don’t get enough magnesium in your normal diet, supplements are widely available (3). Magnesium comes in many different forms including magnesium citrate, magnesium sulfate, magnesium oxide, magnesium hydroxide (found in milk of magnesia), and more.

 How does it work?

Magnesium helps reduce symptoms of constipation by softening hard stools (4). Think back to our chat on constipation. We talked about something called the Bristol Stool Chart (5). This chart is a way for us to categorize stool texture and firmness. Lower numbers indicate harder stool while higher numbers indicate softer stool. Ideal stool consistency is somewhere in the middle because both really hard and really soft stool types are difficult to pass. Magnesium comes into play when it comes to really hard stools, or those that can be categorized by lower numbers on the Bristol Stool Chart. It has an osmotic effect, which means it draws water into the colon and this makes the stool a bit softer and therefore easier to pass (4).

Bristol Stool Chart (5)

 Which types of magnesium are best for constipation?

The three forms of magnesium most commonly used for constipation include magnesium hydroxide (milk of magnesia), magnesium citrate, and magnesium oxide. In general, these three forms have been shown to be safe and to help improve constipation (1, 2, 4). However, there is no strong consensus regarding which is best. Personally, I think the research most strongly endorses magnesium oxide. Even so, some recommend magnesium citrate over magnesium oxide because it has been shown to have better bioavailability in the body, which basically means your body has an easier time using it because it is more readily available (6). Most regulating bodies (aka the people in each country or state who determine what’s safe and what isn’t) recommend the use of magnesium hydroxide in the treatment of chronic constipation, as needed. However, some have recommended against it due to potential side effects (see: The German Society for Digestive and Metabolic Diseases) (4).  

Which types of constipation respond to magnesium supplements?

Not all types of constipation have been shown to improve with an increase in magnesium. For example, opioid-induced constipation, which occurs when taking opioids like OxyContin or Vicodin has not been shown to improve with the use of magnesium (4). Magnesium has been shown to be effective in improving functional constipation in both adults and children (7, 8). Remember, it is important to talk with your medical provider before starting a new supplement as it is not appropriate for everyone (for example, those with kidney disease).

 How to increase your magnesium intake:

As mentioned above, magnesium can be found in many high-fiber foods. These include greens, seeds and nuts, whole grains, and legumes. You may want to try improving your constipation symptoms by increasing your dietary magnesium intake (aka no supplements). In doing this, you will likely also increase your fiber intake, which is also beneficial for constipation. It’s a win-win!

If choosing to take supplemental magnesium, you can purchase your choice of supplement from your local drug store or pharmacy. It’s over-the-counter and pretty inexpensive. The normal recommended dose of magnesium for males is around 410mg and for females is around 315mg (9). However, if you are dealing with functional constipation, a higher dosage of between 500 and 1000mg of magnesium per day might benefit you (4). The maximum daily dose of magnesium is 2000mg, so be sure to check the labels of your magnesium supplements to make sure you are not going over this limit. Take note that supplemental magnesium is a good tool for treating constipation in the short-term (a week or less), but usually shouldn’t be used for long-term chronic constipation.

Magnesium can be a game-changer for folks experiencing constipation. It may not be for everyone, but there are few, if any, adverse effects associated with taking it and it is cost-effective and accessible.

Happy Pooping!

XOXO,

Your Pelvic Bestie

References:

1.    Mori S, Tomita T, Fujimura K, Asano H, Ogawa T, Yamasaki T, Kondo T, Kono T, Tozawa K, Oshima T, Fukui H, Kimura T, Watari J, Miwa H. A Randomized Double-blind Placebo-controlled Trial on the Effect of Magnesium Oxide in Patients With Chronic Constipation. J Neurogastroenterol Motil. 2019 Oct 30;25(4):563-575. doi: 10.5056/jnm18194. PMID: 31587548; PMCID: PMC6786451.

2.    Zhang L, Du Z, Li Z, Yu F, Li L. Association of dietary magnesium intake with chronic constipation among US adults: Evidence from the National Health and Nutrition Examination Survey. Food Sci Nutr. 2021 Sep 29;9(12):6634-6641. doi: 10.1002/fsn3.2611. PMID: 34925793; PMCID: PMC8645769.

3.    https://www.webmd.com/vitamins/ai/ingredientmono-998/magnesium

4.    Mori H, Tack J, Suzuki H. Magnesium Oxide in Constipation. Nutrients. 2021 Jan. DOI:10.3390/nu13020421

5.     Lewis, S. J., & Heaton, K. W. (1997). Stool form scale as a useful guide to intestinal transit time. Scandinavian Journal of Gastroenterology, 32(9), 920-924

6.    Lindberg JS, Zobitz MM, Poindexter JR, Pak CY. Magnesium bioavailability from magnesium citrate and magnesium oxide. J Am Coll Nutr. 1990 Feb;9(1):48-55. doi: 10.1080/07315724.1990.10720349. PMID: 2407766.

7.    Kubota M, Ito K, Tomimoto K, Kanazaki M, Tsukiyama K, Kubota A, Kuroki H, Fujita M, Vandenplas Y. Lactobacillus reuteri DSM 17938 and Magnesium Oxide in Children with Functional Chronic Constipation: A Double-Blind and Randomized Clinical Trial. Nutrients. 2020 Jan 15;12(1):225. doi: 10.3390/nu12010225. PMID: 31952280; PMCID: PMC7019518.

8.    Morishita D, Tomita T, Mori S, Kimura T, Oshima T, Fukui H, Miwa H. Senna Versus Magnesium Oxide for the Treatment of Chronic Constipation: A Randomized, Placebo-Controlled Trial. Am J Gastroenterol. 2021 Jan 1;116(1):152-161. doi: 10.14309/ajg.0000000000000942. PMID: 32969946.

9.    https://my.clevelandclinic.org/health/articles/15650-magnesium-rich-food

*The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a qualified health provider regarding any questions you may have about a medical condition or health objectives