DEAR MAYO CLINIC: I experience constipation almost weekly, and eating bran flakes every day isn’t helping. Are fibre supplements safe to use regularly and long term? Is there anything else I can do? I’m a 53-year-old woman and otherwise in excellent health.
ANSWER: When consumed at recommended levels, dietary fibre is widely recognized to have health benefits, including relief of constipation. Adult women 50 and younger should consume at least 25 grams of fibre a day. Women 51 and older should have at least 21 grams a day. Adult men need at least 38 grams of fibre a day if they are younger than 50 and at least 30 grams of fibre a day if they are 51 and older. Ninety percent of the U.S. population consumes far below those recommendations, averaging only 15 grams of daily fibre.
Fibre-rich foods include fruits, vegetables, whole grains and legumes. Many cereals, such as bran flakes, are good sources of fibre. Although fibre supplements can fill the daily fibre gap, they usually have only one type of fibre, rather than a variety of fibres and micronutrients, and they may not provide all the health benefits associated with fibre in food. Therefore, boost your fibre intake in your diet first by eating a wide variety of high-fibre foods.
If you still can’t get enough fibre to meet the daily recommendation, consider using a supplement. But keep in mind, not all fibres provide laxative effects. Some, unfortunately, can even cause constipation.
Fibres can be classified as soluble versus insoluble, fermentable versus unfermentable and coarse versus fine. In general, fermentable fibres may increase flatulence, with no effect in providing relief of constipation. Finely ground wheat bran and solid/fermented wheat dextran have been shown to worsen constipation. Coarse wheat and psylium can increase stool water content and fecal mass, and can be used to alleviate constipation.
Before taking a fibre supplement, ask your health care provider or pharmacist to review your medications. fibre supplements can decrease the absorption of certain medications, including drugs that treat thyroid disorders, depression, diabetes, high cholesterol, seizures and various heart ailments. Even common medications, such as aspirin, ibuprofen and penicillin, can be affected by an increase in fibre. You may take your medications one hour before or two hours after eating fibre to minimize the interaction.
Some fibre supplements may not be appropriate for people with certain medical conditions. For example, if you have celiac disease, you may need to stay away from fibre products derived from wheat. If you have diabetes, you may need to use a flavourless formula to avoid extra sugar. Consult your health care provider for guidance about the appropriate fibre supplement.
Go slow as you begin fibre therapy. fibre supplements may cause abdominal bloating, cramping and flatulence, especially if you start at a high dose. Begin with a low dose, gradually increasing the amount of fibre. Don’t add more than 50 grams of fibre in a supplement per day, as that may affect how your body absorbs nutrients. Your health care provider can help you determine what’s right for you.
Drinking plenty of water and exercising regularly can ease constipation too. You also may want to consider nonfibre products, such as stool softeners, stimulant medications that cause your intestines to contract, enemas or suppositories.
If increasing fibre doesn’t improve your symptoms, see your health care provider. Constipation can be a symptom of various underlying medical disorders, such as pelvic floor muscle dysfunction, slow gastrointestinal motility, anatomical abnormalities or endocrine dysfunction, that may require different treatment.