Bowel Function and Dietary Fiber

Introduction

Patients with colorectal or anorectal problems are generally unaware of how their own bowel habits may vary from normal. Since their problems usually stem from childhood, representing lifelong habits, and since they have no standards for comparison, most patients assume that their function is normal.

Most patients who develop colon cancer, diverticulosis, diverticulitis, hemorrhoids, fistula and fissure have had a lifelong history of difficulty with their bowels. In most instances, they suffer from chronic habit constipation

The usual cause of chronic constipation is a lack of adequate dietary fiber. Dietary fiber is generally obtained from plant foods, and consists of that portion of the plant which is not digested by man. While the sugars, starches and vitamins are broken down into nutrients and are absorbed by our intestines, the cell walls are not digested and go on to form an important component of the stool, the bulk or roughage. An example of dietary fiber is cellulose, and a food which is high in fiber is wheat bran.

Correcting the fiber inadequacy in one's diet will help one to achieve normal bowel movements and normal bowel habits. If damage has taken place, as in the development of diverticulitis, the adjustment of one's dietary fiber intake may prevent further deterioration of the damage over time. The decision as to how much fiber to use in the face of pre-existing conditions should be made in consultation with your doctor.

For the bowels to work properly, a lifelong daily intake of 25-30 grams, or about one ounce of dietary fiber daily, is required. After the digestion of all proteins, fats and carbohydrates, and the absorption of water and other nutrients in the small intestine, the colon (the last five feet of the intestine) receives approximately one pint of liquid stool together with the undigested fiber.

Under normal circumstances, the colon gradually removes the remaining water, and forms a shaped stool, which moves toward the rectum as a result of gentle pressure waves. In people who eat too little of fiber-containing foods, the stool becomes hard, dry and small. Whereas the soft, bulky stool can move easily along the passage of the colon, the hard, dry stool sticks to the dry wall of the colon and requires that the colon develop high-pressure waves to be moved. Years pass, and the colon is no longer capable of generating such high pressure waves. The colon now requires assistance to push along the hard, dry stool, and the abdominal muscles begin to contribute the necessary force. This we call "straining." The straining produces pressure on all of the abdominal wall, forcing the development of hernias, varicose veins (due to pressure on the long veins of the legs), hiatus hernia (upward pressure forcing the stomach into the chest), diverticulitis and diverticulosis (weakening and infection of the colon wall), hemorrhoids, anal fissures and fistulae. Colorectal cancers may also be more common in patients with lifelong habit constipation. This may be due to the concentrated exposure of carcinogens to the colonic surface, as a result of the hard dry stool and its slow movement or evacuation.

Normal Bowel Habits

It is normal for one to have one or two soft, formed easily passed bowel movements a day, without any effort or straining. The British term is a "bowel action," and literally one should be able to evacuate promptly and easily. This is not the case for most Americans, some of whom have the best "bathroom libraries" in the world, and some of whom actually reserve this time for reading the daily newspaper-cover to cover. The habit of reading in the bathroom is simply a reflection of inadequate function.

It is not normal to miss moving one's bowels on any given day. It is not normal to solve the problem by taking a laxative. If your bowels move daily, but with difficulty or straining, if your stool is dry or hard, or if you don't move your bowels daily, you need to adjust your diet for the right amount of fiber intake.

Normal Physiology

When there is adequate fiber in the diet, the fiber (viewed as millions of tiny water attracting particles) mixes with the stool. Each particle soaks up available liquid, and enlarges into a minute gel bead. These particles give the stool size shape and moisture, making it easy for the colon to move along easily.

To work properly two other circumstances must also be right; adequate water for absorption, and adequate lubrication of the colon lining. We require 8-10 (8 or 10 ounce) large glasses of water daily. Water can be any liquid, whether it is tea, coffee, milk, fruit juices, soft drinks, or other beverages that agree with you. Milk products may be particularly gassy, due to the fermentation of milk sugar, i.e., lactose, in the colon.

In order to lubricate the passage, the colon manufactures mucous. If the colon is dry, i.e., one has too little mucous, or drinks too little water, the stool will be hard and dry and will stick to the colon requiring that one strain to eliminate.

A Proper Diet

A proper diet is conscious of calories, balanced nutrition, vitamins, avoidance of dangerous foods such as saturated fats, and attention to all sources of fiber.

A typical diet of meats, dairy products, breads made from enriched or refined flours, and other starches such as potatoes, pasta and rice are all very low in fiber.

The typical American diet:

Breakfast

Cereal (Corn flakes)
Coffee
Juice
Eggs
Toast (White)
Bagel
Meat

Lunch

Sandwich (Meat,
Chicken, Tuna)
White bread
Pizza
Hamburger
French fries

Dinner

Fish or chicken
Starch
Vegetable (Corn)

Virtually all such meals contain a minimum of fiber, leading to a daily total of 5-8 grams. An optimal diet would typically include:

Breakfast

Bran cereal
(All-Bran 13 gm;
Fiber One 18 gm)

Lunch

A large salad
(Dinner Plate)

Dinner

Two one cup servings
of vegetables (broccoli, etc) Starch 4-5 oz chicken or fish Salad

Learning how to change one's eating habits takes deliberate work over many months. When shopping, one must be familiar with the calorie and fiber content of all foods, and plan and purchase with menus in mind. One must read the content information on the package. This process can take six or more months to master.

Supplements and Substitutes

While one is learning to eat properly, or if one is "too old" or "too set in their ways" to make a major change, one can substitute commercial sources of fiber in one's diet. Psyllium seeds are ground up water absorbing particles which substitute for dietary fiber. Products such as Metamucil, Hydrocil, Konsyl, etc. or other products such as Citrucel (methylcellulose) are perfectly good substitute sources of fiber. One tablespoon a day provides 15 grams of the recommended 25-30 grams daily. Most people take such products at night, generally after completing one's meal. No matter what the label says, these products are not laxatives, but fiber substitutes. Taking them daily provides the fiber which allows the bowels to function normally. Taking them only when one is constipated means that one doesn't understand their proper role and use.

Mineral oil is the best and the most consistent lubricant. Colace, a pill, is easier to take or swallow, however, its result is more erratic. Mineral oil, one tablespoon by mouth daily, from the refrigerator will serve as an excellent lubricant. Lubrication should be considered if one is taking the prescribed amounts of fiber and water, and one is still straining, or the stool remains hard.

Some people, when they hear of the importance of fiber in their diet, overdo the fiber intake. This can be harmful too. Fiber, especially in the absence of adequate water intake, can be so binding, as to cause severe constipation. If that happens, enemas and mineral oil may be needed to eliminate the hard, dry impassable stool before resuming a normal schedule. An occasional fiber abuser will have diarrhea.

Remember, there is a necessary balance between fiber content of the diet, water intake and lubrication. Give each one some thought before figuring that reasonable bowel function is a hopeless pursuit. Do not expect immediate or day-by-day results. If you have had sluggish bowels and constipation all of your life, expect to see the effects of your new fiber intake over the weeks that follow. All changes will be gradual, and any adjustments that you make will require days to weeks before the results may be noticeable.

Laxative Abuse

Some people have had chronic habit constipation for as long as they can remember. It is possible that they were born with a sluggish bowel that does not function easily. Furthermore, if they were not taught to eat properly at a young age, their underlying problem may be aggravated by a diet that lacks the correct amount of fiber.

To people who are not aware of fiber's importance, years may have been spent experimenting with laxatives or natural substances that act as laxatives obtained through health food stores, such as powders, teas and other supplements.

Taking laxatives (or other unknown remedies) as a lifelong solution to constipation is extremely dangerous. The fatigued colon becomes so reliant on the laxatives for emptying, that after decades of "bowel abuse" older people become completely dependent upon these products. It is as much an addiction as are other types of dependencies, and people become afraid to try the proper solution. Do not get "hooked" on products containing senna leaves, or other "natural" laxatives. Most laxatives come from natural sources, and all can be dangerous except when prescribed for specific uses.

Sources of Fiber in One's Diet

Without guidance, most people don't know where to find fiber in their diet. Reading materials are available on the diet and nutrition shelves of your local libraries. Any such book can be a good guide to getting started. On the attached pages, you will find two lists with fiber content information. Both are taken from a book called the "F" Plan Diet by Audrey Eyton. It was first published in the early 1980s, and is now out of print.

The first table can serve as a general guide. It lists the foods that are the richest sources of dietary fiber. The second table provides more specific calorie and fiber content information for a large variety of foods. This table can help you estimate your daily and weekly fiber intake.

General Guidelines

For people who have developed hemorrhoids, fissures, or fistulae, benign anal conditions associated with straining, hard stool and chronic constipation, the above information is intended to help you get the dietary requirements that you will need for your lifetime. Fiber is not a temporary remedy, to be stopped whenever you've temporarily overcome the problem. For patients who have experienced complications of chronic fiber shortage, such as diverticulitis, getting started with a normal fiber intake can be more difficult, and may have to be very gradual. The same may be true for patients who have undergone colorectal surgery. Nevertheless, the goal remains the same. Only the steps to achieve it, or the final amounts of fiber for each person, may differ.

Good luck with your lifelong adventure to normal bowel function. If after reading this information and working on your own you still have questions, please bring your concerns to the attention of your clinician.

Understanding Your Own Fiber Intake

As an exercise, we recommend that you list each item that you eat for breakfast, lunch, dinner and snacks. Include all representative foods. Look up the calories and fiber content in the tables and see how close your daily diet comes to providing you with the daily requirement of 25-30 grams of fiber. Always ask yourself, out of a seven-day week, how many days do I really eat each item.

The Top Twenty Fiber Foods

This list can serve as a general guide. For more specific calorie and fiber content of particular foods, to estimate your daily and weekly quotas, refer to the alphabetical chart here.

  1. Dried beans, peas, and other legumes. This includes baked beans, kidney beans, split peas, dried limas, garbanzos, pinto beans and black beans.
  2. Bran cereals. Topping this list are Bran Buds and All-Bran, but 100% Bran, Raisin Bran, Most and Cracklin' Bran are also excellent sources.
  3. Fresh or frozen lima beans, both Fordhook and baby limas
  4. Fresh or frozen green peas
  5. Dried fruit, topped by figs, apricots and dates
  6. Raspberries, blackberries and strawberries
  7. Sweet corn, whether on the cob or cut off in kernels
  8. Whole-wheat and other whole-grain cereal products: Rye, oats, buckwheat and stone-ground cornmeal are all high in fiber. Bread, pastas, pizzas, pancakes and muffins made with whole-grain flours.
  9. Broccoli-very high in fiber!
  10. Baked potato with the skin (the skin when crisp is the best part for fiber). Mashed and boiled potatoes are good too, but not french fries, which contain a high percentage of fat.
  11. Green snap beans, pole beans, and broad beans (These are packaged frozen as Italian beans, in Europe they are known as haricot or french beans.)
  12. Plums, pears, and apples. The skin is edible, and are all high in pectin.
  13. Raisins and prunes. Not as high on the list as other dried fruits (see #5) but very valuable.
  14. Greens: Including spinach, beet greens, kale, collards, swiss chard and turnip greens.
  15. Nuts: Especially almonds, Brazil nuts, peanuts, and walnuts (Consume these sparingly, because of their high fat content).
  16. Cherries
  17. Bananas
  18. Carrots
  19. Coconut: (dried or fresh-but both are high in fat content).
  20. Brussels sprouts