Fiber is one of those things you might associate with your grandmother, who always told you to get your "roughage" so you stay "regular." While you're probably not quite as focused on having a daily bowel movement as grandma was, you might religiously sprinkle granola on your yogurt and eat all of your veggies to up your fiber intake. But fiber can have a downside -- too much fiber and too little fluid can cause constipation rather than cure or prevent it.
How Fiber Works
All fiber is indigestible, but the similarities end there. Fiber actually comes in a number of types that are generally classified as either soluble or insoluble. Most foods high in fiber, such as whole grains, nuts, legumes, fruits and vegetables, contain both types of fiber in varying amounts. Soluble and insoluble fiber have different actions. Soluble fiber partially dissolves in water, forming a gel-like substance. it helps lower cholesterol and regulate blood sugar levels. Insoluble fiber forms a large, bulky stool that can help prevent constipation. Wheat bran and oat bran appear to have the best effect for moving waste along, but fruits and vegetables also help.
Women need less fiber than men, but most women still don't get all they need. If you're a woman under age 50, you need 25 grams per day; if you're over 50, you need 21 grams of fiber per day. Men need 38 grams before age 50 and 30 grams after 50. Most Americans get less than 15 grams per day, according to the Harvard School of Public Health. If you suddenly increase your fiber intake, you might be rewarded with a stomach ache and gas; up your intake slowly over several weeks rather than increasing fiber intake all at once.
Insoluble fiber combines with fluid to make softer, bulkier stools that move easily through the intestine. To get this benefit, you need fluid in the intestine. You need at least 64 ounces of fluid per day to keep things moving. This could include water from soup, juice or herbal tea, for example. Keep in mind that caffeinated drinks tend to encourage excretion of water, however.
Taking in too much fiber could, in rare cases, cause more serious problems than constipation. Excessive fiber intake without drinking enough fluid can stop up your digestive tract completely, possibly causing an intestinal blockage. Oat bran and wheat bran are two fibers most often associated with obstruction or blockage; not chewing your food well or having some type of intestinal narrowing such as strictures can also increase your risk. When stool can't pass, your intestine could rupture, and a severe infection could develop. If you develop an obstruction, you won't pass any stool or will only pass a small amount of watery stool, since that's all that can get by the obstruction. Abdominal pain and distention are other symptoms that you should consult your doctor about.
A registered nurse with more than 25 years of experience in oncology, labor/delivery, neonatal intensive care, infertility and ophthalmology, Sharon Perkins has also coauthored and edited numerous health books for the Wiley "Dummies" series. Perkins also has extensive experience working in home health with medically fragile pediatric patients.