Constipation: Nutritional Considerations

Constipation is common in developed countries. According to most estimates, 20% of North Americans are affected, which is similar to the percentage of people affected in other Westernized cultures.^12,13 The most common cause is a diet low in fiber, which is found only in plant-derived foods such as beans, vegetables, fruits, and whole grains. Americans eat an average of 5 to 14 grams of fiber daily,¹⁴ far less than individuals residing in developing countries. In persons eating more traditional, higher-fiber diets, constipation is rare.^15-17 The following considerations are important in preventing or alleviating constipation:

Increasing intake of high-fiber foods. A lower intake of dietary fiber differentiates children with chronic constipation from those with regular bowel habits.^18,19 Increasing dietary fiber improves constipation and significantly reduces the need for laxatives in children,²⁰ the elderly,²¹ and postsurgery patients.²²

Although high-fiber foods should generally be the first choice, there may be a role for fiber supplements in some individuals (eg, edentulous patients or those with dysphagia). Evidence indicates that fiber supplements permit discontinuation of laxatives in about 70% of constipated patients.²³ Several types of fiber supplements have been shown to be effective for constipation relief, including psyllium (Metamucil)²⁴; methylcellulose (Citrucel)²⁵; and Japanese konjac root (glucomannan).²⁶

Increasing fluid intake. A hypohydrated or dehydrated state contributes to constipation.²⁷ Poor fluid intake is often found in constipated children.¹⁸ A combination of 25 grams of fiber and 1.5 to 2.0 liters of fluid daily was more effective for constipation relief than fiber intake alone in patients with functional chronic constipation.²⁸

Avoiding cow's milk. Many children with chronic constipation are allergic to cow's milk, manifesting IgE antibodies to cow's milk antigens. Cow's milk consumption is also significantly higher in infants and children with constipation and anal fissure than in those without these disorders.²⁹ In roughly half of constipated, cow's-milk-allergic children and adolescents who have had a colonoscopy, lymphoid nodular hyperplasia was found, compared with 20% of controls. In one third of all cow's-milk-allergic individuals, a significantly higher number of intraepithelial T cells were also found, indicating an enhancement of local immune responses against food antigens.³⁰ Immune activation is known to affect gastric motility,³¹ possibly indicating a role for an immune response to food antigens in constipation. Roughly one third to two thirds of constipated children with cow's milk sensitivity improve on milk-free diets.^30,32 A controlled clinical trial found that constipation returned within 5 to 10 days of reintroduction of cow's milk.³³ When calcium adequacy is in question, calcium-fortified soymilk, rice milk, or juices may be substituted for cow's milk.

Orders

See Basic Diet Orders chapter.

What to Tell the Family

Constipation is a common disorder that is usually preventable with a diet high in minimally processed, high-fiber foods, consumption of ≥1.5 to 2.0 liters of fluid per day, and regular exercise. Health practitioners can provide helpful information about dietary approaches to prevention and treatment. Most patients and their families are not fully aware of the best sources of dietary fiber (beans and other legumes, vegetables, fruits, and whole grains), or of the absence of fiber in animal-derived or heavily processed food products. They may also have been inappropriately influenced by advertisements for over-the-counter treatments or specific foods, such as breakfast cereals and snack bars. Children with milk sensitivity may respond to the removal of dairy products from their diet. Laxatives should be the treatment of last resort, because they prevent normal bowel function. Biofeedback training is an option for patients, especially children who do not respond well to other treatments.