DEAR DR. BLONZ: Could you point me toward a food or herbal substance that is a natural stool softener, not a laxative? I need to increase my iron intake, so I am considering blackstrap molasses, but I am concerned it might cause constipation. -- M.W., Sun City, Arizona
DEAR M.W.: Stool softeners soften bowel contents for an easier, more natural passage, but not all laxatives work that way. Osmotic laxatives form water-holding compounds that increase the semi-solid bulk on the move. Stimulant laxatives affect the bowel's muscular action, and lubricant laxatives ease movement by lubricating the colon wall and preventing water from being absorbed as it approaches the exit. High-fiber foods and herbal substances act as laxatives using one or more of these mechanisms. (For more on laxatives and constipation in general, see b.link/7qhcbkfl. For more on over-the-counter laxatives, see b.link/222bf5vw.)
How things are consumed can impact their laxative effects. Magnesium oxide, a common dietary supplement, attracts water as it dissolves. If it is consumed with a meal, stomach acid, food mixing and the resulting slower passage rate through the digestive system will allow the magnesium compound to break down and absorb. But take that same magnesium oxide with a glass of water on an empty stomach, and less can dissolve before it passes the absorptive surface of the small intestine. The magnesium oxide that makes it to the large intestine can act as an osmotic laxative.
A good strategy is a diet based on fresh fruits, whole grains and vegetables. High-fiber fruits known for their laxative effects include prunes and prune juice, dates and figs. Whole grains and high-fiber granola cereals can also help. Water intake is essential. Whenever adding soluble and insoluble fibers to your daily regimen, aim for a slow increase to allow your digestive system to adapt.
You asked about molasses, which is a byproduct of sugar manufacture. There are different types of molasses. Blackstrap is the most intense in color, texture and taste, and has several nutrients: One tablespoon contains 3.5 mg iron (20% DV), 200 mg calcium (15% DV) and 600 mg potassium (13% DV). (Nutrient amounts can vary between brands, so check the Nutrition Facts labels.) Up until the 1940s, it was popular as a dietary supplement. Blackstrap molasses won't cause constipation, nor is it a superstar laxative, but it has been used to help treat constipation in children. (More on benefits from blackstrap molasses at b.link/93cvb8gg.)
Send questions to: "On Nutrition," Ed Blonz, c/o Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to firstname.lastname@example.org. Due to the volume of mail, personal replies cannot be provided.