Loose Stools and Fiber


Can too much fiber in the diet of a 17-month-old cause loose bowels?

Dr. Greene's Answer

What a great problem to have! The loose stools may just be a temporary sign that someone who was not getting enough fiber earlier, is now suddenly getting an appropriate amount.

In its 2006 report Food Marketing to Children and Youth, the Institute of Medicine warned that, overall, American children are not meeting basic nutritional goals. In particular, fiber intake in most kids is well below recommendations — sufficiently low to warrant concern. It’s one of the reasons for the childhood obesity and diabetes epidemics, and a host of other health problems.

Is it possible to get too much fiber? How much do kids need? And what are the best ways to get it? Let’s start by looking at the upper limits…

For many nutrients (such as vitamin A), safe upper limits have been set, because too high a level can cause more harm than good. For fiber, however, no upper limit has been set because, as part of an overall healthy diet, high levels of fiber found naturally in foods don’t cause health problems in healthy kids.

Nevertheless, if fiber levels increase quickly, or jump up and down from day to day, this can cause loose bowels in any of us. How much fiber it takes to do this varies from person to person and over time. When people suddenly switch to a veggie diet, for instance, they often have loose stools until their bodies have a chance to adjust.

The good news is that usually, over about two weeks, the system will adjust to accommodate the higher fiber levels (from fiber found naturally in foods – synthetic, added, or enhanced fiber can be another story). If the loose stools are not bothering him, making a mess, or causing a rash, there is no need to cut back – getting enough fiber is well worth the wait. On the other hand, you might want to cut back the fiber a bit and then try gradually reintroducing it a little more every few days.

How much do kids need? The Adequate Intake (AI) of fiber is 19 grams a day for kids 1 to 3 years old. The AI increases to 25 grams a day from 4 to 8 years old. After age 8, boys usually need more fiber each day than girls do. Boys 9 to 13 do best with at least 31 grams a day, increasing to 38 grams a day at age 14. Girls’ needs increase to 26 grams a day at age 9, and don’t increase again until they are pregnant or nursing. Sadly, most kids get a fraction of this amount.

Dietary fiber occurs naturally in whole grains (including oats, rice, and wheat, among many other wonderful grains). Unfortunately, in the process of refining these grains into over-processed flours, we have too often stripped them of their fiber and other key nutrients. Part of what makes a food a junk food is removing the fiber.

Kids should get at least 3 servings of whole grains daily for optimal health. We enjoy Rudi’s Organic Apple ‘n Spice bread in our house; it tastes yummy and each slice of this whole grain bread contains 5 gm of fiber. Cereals are another good place to get whole grains and fiber. Many scrumptious, whole grain, fiber-rich cereals have been introduced in recent years. And Bob’s Red Mill makes delicious whole grain products for every meal of the day. The whole-wheat pastry flour biscuits are especially popular in our house right now. Each tasty biscuit has 3 gm of fiber.

Fiber also occurs naturally in vegetables and fruits. A serving of strawberries or blueberries would each have about 3 gm of fiber. An average-sized apple, banana, or orange would each have about 3 gm (a large apple might have 5 gm). A single serving of broccoli might have 6 gm, and carrots, 5 gm.

French fries, hot dogs or hamburgers on white buns, chicken nuggets, mac n’ cheese made from white flour, grilled cheese sandwiches on white bread, white flour pasta, and most chips, pretzels, and crackers – including the fish shaped ones – are fiber wastelands. The same goes for white flour pancakes, waffles, or toast. Ditto for cookies and cakes. And ice cream. Fiber wastelands, one and all. Tragically, this list sounds a lot like a typical American kids’ meal menu. And although lean meat, poultry, egg, and dairy products contain many valuable nutrients, they are not good sources of natural fiber.

By getting plenty of fruits, vegetables, and whole grains every day, kids can get the fiber they truly need. It will help their bowel health, as well as helping them to be healthier overall, now and for the rest of their lives.

Last medical review on: August 17, 2011
About the Author
Photo of Alan Greene MD
Dr. Greene is a practicing physician, author, national and international TEDx speaker, and global health advocate. He is a graduate of Princeton University and University of California San Francisco.
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