Constipation & High Fibre Diet

Constipation is very common not only in children but in adults too. In this article dietary and physiological aspects of constipation shall be discussed and not diseases leading to constipation. Today's lifestyle and eating habits have a bearing on this problem:

Over a period of time, small amounts of faeces gets accumulated in the rectum, which in turn hardens. This is known as `faecoliths'. If corrective measures are not taken then as time passes, structural changes in the rectum occur, leading to acquired megacolon in children.

The principal function of the large intestine (colon) is to remove excess water from food waste passing into it from the small intestine. When food passes through the large intestine too quickly, not enough water is absorbed by the intestine, and diarrhoea results. In contrast, if waste material is passed too slowly, too much water is absorbed. This results in hard stool and constipation, often leading to straining.

Fibre, also called roughage or bulk, is necessary to promote the wave like contractions that move food through the intestine. High fibre foods expand the inside walls of the colon, easing the passage of waste. As fibre passes through the intestine undigested, it absorbs large amounts of water, resulting in softer and bulkier stool.

Rural Africans digest and eliminate the foods they eat in one-third of the time it takes for the people living in Western cultures. This is because the diet of Africans is rich in fibre, which in turn speeds up the time required to digest food and expel wastes. It is believed this helps to sweep out harmful substances before they can cause problems in the body. In fact, these rural people suffer far less from many of the diseases of the digestive tract that plague Western man, which is thought to be related to the nature of their diet.

A high-fibre diet causes a large, soft, bulky stool that passes through the bowel more easily and quickly. This helps to prevent stop, or even reverse some digestive tract disorders. A softer, larger stool helps prevent constipation and straining which can help avoid or relieve haemorrhoids. More bulk means less pressure in the colon, and this is important in treating irritable bowel syndrome and diverticulosis.

Most of urban folks eat only 5 to 10 grams of fibre a day against the recommended intake of 20 to 35 grams. High fibre foods, such as fruits and vegetables, also tend to be low in calories, which in turn do not cause weight gain. Fibre pills generally should be avoided. They contain relatively little fibre and are expensive. Fibres containing foods and powdered fibre supplements are better sources.

Irritable bowel syndrome, sometimes called spastic colon or IBS, is one of the most common disorders of the lower digestive tract. There is no disease present in irritable bowel syndrome. However, its symptoms can resemble other disorders. The symptoms of IBS are constipation, diarrhoea (or both alternately), abdominal pain, cramps and spasms. Acute episodes can be triggered by emotional tension and anxiety, poor dietary habits, and certain medications. Increased amounts of fibre in the diet can help relieve symptoms of irritable bowel syndrome and if not treated it may lead to diverticulosis of the colo

Colon cancer is a major health problem. It is second only to lung cancer in the number of deaths per year. In countries where grains are unprocessed and retain their fibre, there is lower incidence of colon cancer. Most colon cancer begins as a colon polyp, a benign mushroom shaped growth which in time grows and in some people, becomes a cancer. Colon cancer is preventable if polyps are removed at an early stage. It is now known that the tendency to develop colon cancer may be inherited.

But, there may be other factors involved as well. One theory is that cancer-causing chemicals (carcinogens) in the diet and environment can stay in contract with the colon wall a longer time and in higher concentration when the diet is low in fibre. A large, bulky stool acts to dilute and diffuse these carcinogens and to move them through the bowel more quickly. Less carcinogen exposure to the colon may mean less colon polyps and cancer.

Colon diverticulosis occurs when pockets or sacks bulge out from the bowel wall. It is known that these diverticulae occur gradually over time and are due to excessive pressure or spasms within the bowel. These pockets usually cause no problem, but sometimes they can become infected (diverticulitis) or even break open, causing abscess or peritonitis. A high-fibre diet increases the bulk in the stool, which reduces pressure within the colon. By so doing, diverticula formation may be reduced or even stopped.

As noted above, fibre generally is divided into two categories. Insoluble fibre is found in wheat bran and in celluloses from vegetables and fruits. Soluble fibre is commonly found in oatmeal, oat bran (the best source), guar gum, psyllium seed, fruit pectin and gum arabic. When mixed with water, it produces a gelatinous mucous gel. It, too, has bowel-regulating effects. It also acts to lower blood cholesterol by binding with the cholesterol in the intestine and carrying it away in the stool. So, a high fibre diet should contain both types of fibre.

Dietary fibre is the part of a plant that cannot be digested by the body. Just as there are many types of Plants, there are also many types of fibre. Some fibres, such as oat bran, are soluble in water and from a gelatinous bulk that can lower cholesterol. Other fibres, such as wheat bran, are insoluble and add bulk to the stool. Both are important and provide benefits.

High fibre foods can be found in most food groups. Different types of food should be selected to get the benefits of them all.

Since bran can cause rumbling intestinal gas and even some mild cramping, it should be started in small amounts initially. The amount can be increased as tolerance is acquired. The goal should be 20 to 35 grams of fibre a day, which will usually produce 1 to 2 soft and formed stools a day.

Some People have trouble tolerating too many high fibre foods in the diet. Stool softening and bulking agents are available over the counter. These products are usually plant fibres that absorbs water and produces the bulk necessary for the digestive tract to perform naturally. Psyllium fibre is found in many commercial products. Hemicellulose and polycarboxisal are other bulking agents that can be used. These fibre supplements, in conjunction with foods, offer an easy way to reach the fibre goal of 20 to 35 grams per day.

Dr. R. K. Khandelwal M.D.
Paediatrician