CONSTIPATION

Constipation is a symptom (not a disease) that afflicts a large proportion of the population and can have unpleasant health consequences. Studies have shown that constipation afflicts 10-30% of the general population, and the figure rises to 60% in the elderly. Research also suggests that it affects twice as many women as men. However, 25% of those who suffer from constipation do nothing to relieve it.

One reason for this is that the diagnosis of constipation varies from person to person. The frequency of bowel movements can range from 3 a day to only 2 or 3 times a week, normally, without changing quality of life or compromising health. However, if you have difficulty emptying, hard stools, infrequent bowel movements or a feeling of incomplete emptying, then you have some form of constipation – organic or functional. To understand them, we need to remember the physiology and function of the bowel.

Physiology of the gut

To understand constipation, we need to see how the large intestine works. As food passes through the large intestine, its fluids are absorbed by the mucosa and stools are formed. The large intestine, under normal conditions, absorbs more than 95% of the water that reaches it. Then the contraction of the muscles pushes the contents towards the rectum. Once the stool reaches the rectum it is hard, because most of the water has been absorbed. Constipation is caused either when the lining of the large intestine absorbs too much water, or when muscle mobility is slow, so that stools are delayed in coming out and become even harder and drier.

The process of digestion

1. 1. 1. The food enters the stomach, where it is masticated and dissolves in the acidic environment, gradually creating a porridge
      2. The slurry travels to the small intestine where the nutrients are absorbed
      3. The porridge enters the large intestine, now poor in nutrients and slightly dehydrated
      4. As they travel to the large intestine, the products of digestion lose moisture and take shape. At the same time, the indigestible substances that now constitute them feed the intestinal microbiome, which is most numerous in the last part of the large intestine
      5. The faeces, now formed, remain in the rectum until they have accumulated sufficiently to make defecation imperative

Organic constipation

This is due to a physiopathology that prevents the normal flow of stool, for example neoplasms, benign tumours, inflammatory strictures, or adhesions in the colon. In this case you are likely to have other symptoms.

Functional constipation

According to the Rome IV Criteria (2016), you have functional constipation if at least two of the following apply for 12 weeks (not necessarily consecutive) in the last six months:

• • • Have fewer than three stools per week for at least 3 out of 12 weeks
    • At least 25% of stools:

1. 1. 1. 1. have hard or lumpy stools
         2. you have a feeling of incomplete bowel movements
         3. you have a feeling of anal blockage
         4. you need to assist passage by hand

• • • You have not been diagnosed with irritable bowel syndrome (IBS)

Functional constipation can have primary or secondary causes. Primary functional constipation may be due to slow passage of the intestinal contents into the large intestine, or to a rectal dysfunction that prevents the elimination of faeces.

Secondary causes include metabolic disorders (hypothyroidism, hypokalemia, hyperkalemia), neurological disorders (Parkinson’s disease, multiple sclerosis, etc.), connective tissue diseases, intake of certain drugs, reduced food or water intake and insufficient fibre intake.

Factors of functional constipation

If you have certain habits then you are more likely to develop functional constipation at some point.

One of the most important risk factors is poor diet, i.e. insufficient intake of fibre and water. In fact, changes in eating habits over the past 20 years are partly responsible for the doubling of constipation cases over the past 20 years in China, according to a recent survey of 1.2 million people (Zhe Chen et al, 2022).

Another factor is the conscious inhibition of voiding, usually out of necessity (not being near a toilet) or for social reasons. While digestion and food transport function normally, if the contents of the bowel are withheld more than necessary then it becomes more dehydrated and emptying becomes more difficult and painful. Often this creates a vicious cycle, especially in children: difficulty in emptying causes further inhibition, which makes the situation worse.

Stress and depression are also strong factors of constipation. On the one hand, they are associated with a sedentary lifestyle, insufficient physical activity and poor diet. On the other hand, some antidepressants (anticholinergic drugs) can cause constipation.

Finally, constipation often occurs during pregnancy, which may be due to internal stresses or disturbances in progesterone and oestrogen levels that reduce bowel function.

Constipation causes…

In addition to a significant reduction in quality of life, constipation can also cause unpleasant or more serious complications.

If symptoms occur several days every month and for a period of 3 months or more, it can also be associated with the development of haemorrhoids, rectal prolapse, ring striae, colon cancer and diverticulomas, among others.

Pressure from accumulated stool is associated with flatulence, bloating and abdominal pain. It can also cause chronic back pain and hypertension, especially in the elderly.

Finally, due to the strong biochemical connection with millions of neurons between the brain and the gastrointestinal system (Gut-Brain Axis, GBA) that transmits two-way “signals”, constipation can cause psychosomatic disorders, anxiety and depression.