Which Is Better to Help You Poop?

Having regular bowel movements not only keeps your tummy happy, it’s also good for your health. Yet, about 16% percent of American adults suffer from constipation, an uncomfortable and sometimes painful condition.

When you’re tackling constipation, there are two nutrients that you might hear a lot about: magnesium and fiber. These are both known for moving things along in the gastrointestinal tract–but which should you try first?

To give you a game plan, we spoke with gastroenterologists about whether magnesium or fiber is more important for healthy bowel movements. They also discussed how magnesium and fiber relieve constipation, sources of each and other important strategies to keep you regular. 

What is Magnesium?

Magnesium is a mineral present in many foods. In the body, magnesium plays a role in protein synthesis, muscle and nerve function, blood glucose control, blood pressure regulation, energy production, bone development, DNA synthesis, nerve function, muscle contraction and normal heart rhythm. (If that seems like a lot, it’s because magnesium is involved in hundreds of reactions in the body.) In other words, magnesium is important for many bodily processes, including helping you poop.

“Magnesium, particularly in forms like magnesium citrate and magnesium oxide, works by drawing water into the intestines, which softens the stool and stimulates bowel movements,” says,” David Clarke, M.D., gastroenterologist and President of the Psychophysiologic Disorders Association.

In addition, magnesium relaxes the digestive muscles, which can also help promote bowel movements, says Harold G. Tepler, M.D., a gastroenterologist at Gastroenterology Medical Associates in North Bergen, New Jersey. 

Magnesium Sources

Magnesium is found in many foods, such as pumpkin seeds, chia seeds, almonds, spinach, cashews, peanuts and soy milk. Eating enough magnesium is important for bowel regularity, but most studies on constipation look at supplemental magnesium, says Brisas Truncali, M.D., a gastroenterologist with Connecticut GI in Framingham, Connecticut. Although there are many different types of magnesium sold as supplements, “magnesium oxide is the only formulation that has been studied sufficiently for chronic constipation, ” she says. 

Magnesium Side Effects

Magnesium is a recommended daily mineral, which is safe for healthy individuals. However, “if someone has a heart condition or kidney disease, they should speak with their providers before starting a magnesium supplement of any kind,” adds Truncali.

Although magnesium supplements can act as a natural laxative for chronic constipation, says Tepler, using magnesium for extended periods of time for this purpose can cause side effects, such as dehydration, nutritional deficits and weight loss.

What is Fiber?

Fiber is a type of carbohydrate that promotes regular bowel movements, heart health, healthy weight, balanced blood sugar and longevity. “Dietary fiber, both soluble and insoluble, works by adding bulk to the stool and promoting the growth of beneficial gut bacteria,” says Clarke. He also notes that fiber works better with good hydration and can support long-term regulation of bowel movements since it is safe for the daily diet.

Types of Fiber

There are two types of fiber: soluble and insoluble. Soluble fiber absorbs water and forms a gel as it passes through the digestive tract, making it easier to poop. Insoluble fiber does not absorb water, but rather, adds bulk to the stool and makes it easier to pass.   

Fiber Recommendations

The Dietary Guidelines for Americans recommends eating 28 to 34 grams of fiber per day. However, there are no set recommendations for the amount of insoluble and soluble fiber you should have each day. Eating plenty of plant foods will provide a mix of fibers, such as fruits, vegetables, legumes, beans, peas and whole grains, that help keep you healthy–and regular.

Fiber Side Effects 

Fiber is supposed to ease digestive woes, but it can also cause some GI issues. “The most common side effect of fiber supplementation is gas and bloating, but not everyone will experience this,” says Truncali. One thing that will help as you increase fiber intake is to drink plenty of water, she says. To boost your fiber intake, focus on increasing your food sources of fiber before starting a fiber supplement.

Magnesium vs. Fiber: Which is Better for Relieving Constipation?

All three doctors agree that both magnesium and fiber can relieve constipation, but it is difficult to know what will be effective for whom and to what degree. “Fiber should never be ignored, especially if you experience a constant fluctuation in your bowel movements,” says Tepler.

“Magnesium and fiber are safe to use together and may cause a more robust response than each on its own, but one does not make the other more effective,” says Truncali. Start with boosting your fiber intake via food then move on to a possible magnesium and/or fiber supplementation if you do not experience relief.

But your efforts are not paying off, contact your healthcare provider. They’ll want to consider the reasons why you’re constipated (such as medications you’re taking or an underlying medical condition) and then determine a treatment plan.

Other Strategies to Help You Poop

Many lifestyle factors contribute to regular bowel movements, such as hydration, exercise and stress management, so it may be worth reevaluating how your overall lifestyle might be contributing to your regularity. Find ways to destress, change up your hydration with this lemon, cucumber and mint infused water and consider how you might enjoy some movement throughout the day. To increase your intake of important nutrients – including magnesium and fiber – focus on simple recipes with many plant-based ingredients, such as smoothies, soups, salads and casseroles. 

The Bottom Line

Both fiber and magnesium are important nutrients for digestive and overall health. Focusing on consuming fiber or magnesium may help alleviate constipation, and you may want to try boosting your intake of fiber-containing foods first, then add a magnesium and/or fiber supplement if needed. Still, gastroenterologists agree supplementation recommendations depend on the person and their unique case. Speak with your healthcare provider to figure out if you should use any kind of magnesium or fiber supplementation for constipation.