Laxatives

The aim of taking laxatives is easily stated: to produce the perfect little pile. Laxatives can coax even the shyest gut out of its shell. Laxatives come in various types, which work in different ways. For all hopelessly constipated travelers, slow transporters, campsite toilet objectors, or hemorrhoid-hindrance conquerors, here’s a look at that box of tricks.

The Perfect Little Pile by Means of Osmosis

… is well formed and not too hard. Osmosis is water’s sense of equality. When one region of water contains more salt, sugar, or similar substances than another, the less rich water will flow toward the richer water until both contain the same amount of solute and they can live on in peaceful equilibrium. The same principle helps to revive wilting lettuce—simply soak the sad salad in water and half an hour later your greens will be crispy again. Water flows into the lettuce because its cells contain more salts, sugars, and so on than the pure water in the bowl.

Osmotic laxatives use the same principle of equality. They contain certain salts, sugars, or tiny molecular chains that can travel into the large intestine. Along the way, they gather all the water they can to make the act of going to the toilet as comfortable as possible. But overdoing it with such laxatives causes them to extract too much water. Diarrhea is a sure sign that you have taken too many.

With osmotic laxatives, you can choose whether to take sugars, salts, or short molecular chains to help retain water in the gut. The salts, such as sodium sulfate (also known as Glauber’s salt) are rather rough on us. They take effect very suddenly, and if they are taken too often, they disrupt the body’s electrolyte balance.

The most widely known laxative sugar is lactulose. It has a useful double effect, both retaining water in the large intestine and feeding the flora of the gut. Those little creatures can help, for example, by producing some substances that act as stool softeners and others that stimulate movement in the gut wall. But this can also cause unpleasant side effects. Overfed or misplaced bacteria can produce gases, causing cramps and flatulence.

Lactulose is formed from the milk sugar, lactose, when milk is heated to high temperatures. Pasteurization involves heating milk briefly, so pasteurized milk contains more lactulose than raw milk. UHT (ultra-high-temperature-processed) milk contains more lactulose than pasteurized milk, and so on. Non-milk laxative sugars are also available, including sorbitol. Sorbitol occurs naturally in some kinds of fruit—plums, pears, and apples, for example. That is one reason for the reputation plums have as a natural laxative and for warnings that too much fresh apple juice can cause diarrhea. Since human beings can barely absorb sorbitol (or lactulose) into their bloodstream, it is often used as a sweetening agent. It then appears on food labels as E420, and this explains why sugar-free cough candies, for example, always include the warning, “Excessive consumption may have a laxative effect.” Some studies have shown that sorbitol has a similar effect to lactulose, but causes fewer side effects overall (no unpleasant wind).

Of all laxatives, the short molecular chains are most easily tolerated by the body. They have the kind of complicated names that molecular chains love—polyethylene glycol, for example, known as PEG for short. They don’t disrupt the body’s electrolyte balance like salts do, and they do not produce wind like sugars do. The length of the chain is often included in the name: PG-3350, for example, is a chain made up of enough atoms to give it the molecular weight 3350. It is much better than PEG-150, because that compound is made of such short chains that they can be inadvertently absorbed by the gut wall. That might not necessarily be dangerous, but it can certainly confuse the nerves of the gut, since polyethylene glycol is definitely not part of our natural diet.

For this reason, short chains like PEG-150 are not contained in laxatives, but they are used in products such as skin cream, where they perform a very similar service—they make the skin more supple. It is unlikely that they are harmful, but the matter is still not finally settled. Laxatives based on PEGs contain only indigestible chains, and for that reason they can be taken over longer periods without causing problems. The latest studies show there is no risk of addiction or long-term damage. Some studies indicate that these substances can even improve the gut’s protective barrier.

Osmotic laxatives work not only by making the feces moister, but also by sheer mass. The more moisture, well-fed gut bacteria, or molecular chains are contained in the gut, the more motivated it will be to move. This is the basic principle of the peristaltic reflex.

The Perfect Little Pile by Means of Slippery Stool

… sounds like a children’s party game. Slippery stool—lots of fun but maybe quite messy. But in fact this is the technique known medically as fecal lubrication. Robert Chesebrough, the man who invented Vaseline®, swore by a spoonful of the petroleum jelly every day. Swallowing petroleum jelly probably has the same effect as swallowing other fat-based fecal lubricants—an overdose of indigestible fat coats the goods in transit, making for an easier exit. Chesebrough lived to the ripe old age of ninety-six, which is quite surprising since eating a fat-based lubricant every day will cause the body to lose too many fat-soluble vitamins. They get covered in the fatty lubricant and go the same way as the feces. This can cause vitamin deficiencies that lead to illness, especially if fecal lubricants are taken too often or in excessive amounts. Petroleum jelly is not one of the official fecal lubricants (and really shouldn’t be eaten), but the time-honored candidates such as liquid paraffin are hardly less suitable for regular use. They can be useful as short-term treatments—for example, in the presence of hemorrhoids or small but painful injuries to the anus. In such cases, it can be good to make the feces softer to avoid pain or further injury during defecation. However, gel-forming fibers available from the pharmacy do just as good a job and are less dangerous and better for the body.

The Perfect Little Pile by Means of Hydragogues

… is achieved by giving the gut a big kick up the butt. These laxatives are ideal for those with very shy, lethargic gut nerves. There are various tests to find out whether that applies to you. One test involves swallowing little medical pellets that doctors then X-ray as they pass through the gut. If, after a certain time, the pellets are still spread throughout the tract, having failed to gather by the back door as they should, hydragogues are the appropriate treatment.

Hydragogues latch onto a couple of the receptors that the gut waves around inquisitively. They then send signals to the gut to stop extracting fluid from the food passing through and to fetch more water from other parts: muscles—shake a leg! To put it bluntly, cleverly constructed hydragogues simply boss nerve cells and water transporters around. When osmotic laxatives fail to provide enough stimulus or softness, a shy gut needs a few clear commands. If hydragogues are taken before bedtime and left to do their thing overnight, the gut will react the next morning. If time is an issue, the express mail service of a suppository can usually deliver the message within half an hour.

for example, is a chain made up of enough atoms to give it the molecular weight 3350. It is much better than PEG-150, because that compound is made of such short chains that they can be inadvertently absorbed by the gut wall. That might not necessarily be dangerous, but it can certainly confuse the nerves of the gut, since polyethylene glycol is definitely not part of our natural diet.

For this reason, short chains like PEG-150 are not contained in laxatives, but they are used in products such as skin cream, where they perform a very similar service—they make the skin more supple. It is unlikely that they are harmful, but the matter is still not finally settled. Laxatives based on PEGs contain only indigestible chains, and for that reason they can be taken over longer periods without causing problems. The latest studies show there is no risk of addiction or long-term damage. Some studies indicate that these substances can even improve the gut’s protective barrier.

Osmotic laxatives work not only by making the feces moister, but also by sheer mass. The more moisture, well-fed gut bacteria, or molecular chains are contained in the gut, the more motivated it will be to move. This is the basic principle of the peristaltic reflex.

The Perfect Little Pile by Means of Slippery Stool

… sounds like a children’s party game. Slippery stool—lots of fun but maybe quite messy. But in fact this is the technique known medically as fecal lubrication. Robert Chesebrough, the man who invented Vaseline®, swore by a spoonful of the petroleum jelly every day. Swallowing petroleum jelly probably has the same effect as swallowing other fat-based fecal lubricants—an overdose of indigestible fat coats the goods in transit, making for an easier exit. Chesebrough lived to the ripe old age of ninety-six, which is quite surprising since eating a fat-based lubricant every day will cause the body to lose too many fat-soluble vitamins. They get covered in the fatty lubricant and go the same way as the feces. This can cause vitamin deficiencies that lead to illness, especially if fecal lubricants are taken too often or in excessive amounts. Petroleum jelly is not one of the official fecal lubricants (and really shouldn’t be eaten), but the time-honored candidates such as liquid paraffin are hardly less suitable for regular use. They can be useful as short-term treatments—for example, in the presence of hemorrhoids or small but painful injuries to the anus. In such cases, it can be good to make the feces softer to avoid pain or further injury during defecation. However, gel-forming fibers available from the pharmacy do just as good a job and are less dangerous and better for the body.

The Perfect Little Pile by Means of Hydragogues

… is achieved by giving the gut a big kick up the butt. These laxatives are ideal for those with very shy, lethargic gut nerves. There are various tests to find out whether that applies to you. One test involves swallowing little medical pellets that doctors then X-ray as they pass through the gut. If, after a certain time, the pellets are still spread throughout the tract, having failed to gather by the back door as they should, hydragogues are the appropriate treatment.

Hydragogues latch onto a couple of the receptors that the gut waves around inquisitively. They then send signals to the gut to stop extracting fluid from the food passing through and to fetch more water from other parts: muscles—shake a leg! To put it bluntly, cleverly constructed hydragogues simply boss nerve cells and water transporters around. When osmotic laxatives fail to provide enough stimulus or softness, a shy gut needs a few clear commands. If hydragogues are taken before bedtime and left to do their thing overnight, the gut will react the next morning. If time is an issue, the express mail service of a suppository can usually deliver the message within half an hour.

The commando squad need not rely on chemical weapons—some plants work in much the same way. These include aloevera and senna, for example. But they do have one rather interesting side effect. Anyone who has ever wished to dye the inside of their gut black is welcome to have a go. This discoloration is not dangerous, and it fades with time.

However, some scientists have reported effects of an excess of hydragogues or aloe vera that would be rather less fun—if they turn out really to be caused by those substances—as they include damage to the nerves. The reason is that nerves that are bossed around too much eventually become overwrought. When that happens, they withdraw into themselves, like snails when you tap their feelers. For this reason, patients with longterm problems should not take hydragogues more than every two or three days.

The Perfect Little Pile by Means of Prokinetics

. . . is the very latest thing—for two reasons. These drugs can only support the gut in doing what it naturally does anyway, and they cannot issue any unwanted orders. They work along the same lines as a loudspeaker. The exciting thing for many scientists is that they can help in an extremely targeted way. Some prokinetic agents affect only one single receptor, while others are not absorbed into the bloodstream at all. However, scientists are still researching the way many of these substances work, and new ones are just now appearing on the market. So, anyone who does not absolutely need to try something new should stay on the safe side and rely on better-tested drugs for now.

The Three-Day Rule

Many doctors prescribe laxatives without explaining the three day rule, although it is easy to remember and is a useful aid. The large intestine has three sections: the ascending, transverse, and descending colon. When we go to the toilet, we usually empty the last section. By the next day, it has filled up again and the game starts all over again. Taking a strong laxative may cause the entire large intestine—all three sections—to be emptied. It can then easily take three days before the large intestine is full again.

Those unfamiliar with the three-day rule will likely start to get nervous during that time. Still no bowel movement? And before they know it, they’ve taken the next laxative tablet or powder. This is a vicious and unnecessary circle. After taking a laxative, the gut deserves a couple of days’ respite. Monitoring for normal bowel movements should begin on the third day. Slow transporters may need to give a helping hand to their gut after two days.

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