Acid Reflux Causes

The Causes Of Heartburn Are Many & Varied

Just to remind you of the terminology that we’ve been employing on this site, acid reflux is actually the movement of stomach contents up into the esophagus, while heartburn is the sensation that results from this — a very noticeable and often painful burning sensation.

So what causes acid reflux? Well, where the esophagus enters the stomach, there’s a sphincter, a ring of muscle, which is designed to act as a valve to prevent the stomach contents moving back into the esophagus instead of passing forward into the small intestine.

This is needed because the esophagus is not lined with cells which are able to protect themselves from the effect of the gastric juices in the stomach. The valve is called the lower esophageal sphincter or LES; it’s located at the point where the esophagus goes through the diaphragm into the stomach. The diagram makes this clearer.

Obviously if anything goes wrong with this sphincter, the stomach contents can move up into the esophagus, causing acid reflux and the burning sensation we know as heartburn.

There are several reasons why the LES may not work properly.

The first is that the muscles have lost the ability to contract correctly. Or they may simply be unable to keep the valve shut if the opening in the diaphragm through which the esophagus enters the stomach has expanded in some way. For example, the tissue may get weaker as you get older.

Another reason why the LES may fail to keep the stomach contents where they should be is that the pressure in the stomach, for some reason, is much higher than the valve can withstand. This can be one of the causes of acid reflux happening spontaneously.

Before we look at the more scientific aspects of this condition, we can summarize the immediate causes of acid reflux – the kind of things you do in everyday life which may stimulate it.

(And before we do that, here’s a video from the Mayo Clinic! Very nice!)

However, this does not mean that all of the factors listed below are likely to produce reflux – that’s particularly true in the case of asthma, where scientists are still arguing whether asthma causes acid reflux, or acid reflux causes asthma, or if indeed there is any causative relationship between them at all.

1) Eating Large Meals

Eating large meals may not be a primary cause of reflux, but it can certainly make the symptoms worse in those who are experiencing it.

Certainly if you have acid reflux symptoms it’s well worth eating fewer and smaller meals, and also keeping a food diary for an acid reflux diet in which you record everything you eat, so that you can establish which foods might be making your symptoms worse.

If you keep a food diary and you notice that eating a certain food produces more reflux, it’s easy to cut that food out of your diet. You may then find that your symptoms improve.

2) Bending Over and Other “Provocative Postures”

As you may have noticed, gravity is an important factor in keeping the contents of the stomach where they should be. When you bend forward or lie down, it’s much easier for the stomach contents to rise into the esophagus, with the resulting acid reflux causing heartburn. Unfortunately, you may also find the same is true of lifting heavy objects, and it’s not always possible to avoid this.

Even so, taking responsibility for your condition and learning which factors are likely to intensify the reflux and cause heartburn pain can be helpful in changing your lifestyle so that you can minimize things which promote reflux.

3) Hiatus Hernia (Also Known As Hiatal Hernia)

This is a very important acid reflux cause (see more about hiatal hernia here). For now, suffice it to say that hiatus hernia is a condition in which the opening in the diaphragm through which the esophagus passes is so large that part of the stomach is able to move upwards into the chest cavity alongside the esophagus.

The majority of hiatal hernias are the sliding type, which means that the stomach is free to move backwards and forwards through the opening. These tend to be much less serious than theparaesophageal hernia, when part of the stomach is permanently fixed in the chest cavity.

Hiatal hernias are linked to belching, discomfort, burping, acid regurgitation, nausea and even vomiting.

You can reduce the chance of your hiatal hernia causing acid reflux by avoiding those activities which tend to make it problematic: lifting heavy weights, coughing, straining on the toilet, excessive physical exertion, and bending forward. We also know that pregnancy and obesity can promote hiatal hernias and acid reflux, although you may find it less easy to avoid the impact of these two conditions than some of the others.

4) Peptic Ulcers

Stomach problems in themselves can accentuate the likelihood of acid reflux. We know that an imbalance or shortage of digestive enzymes is linked, somehow, to the occurrence of reflux.

Although you may not be able to do anything about that, it’s certainly well worth experimenting with lifestyle factors such as what you eat and the quantity you eat in one sitting. A food diary can be invaluable here in establishing links between how you eat, what you eat, and reflux.

5) Asthma

The causative relationship, if indeed there is one, between asthma and acid reflux is unclear. One possibility is that an asthma attack can promote acid reflux due to changes in the chest; another possibility is that the inhalers used to alleviate symptoms of asthma are actually responsible for relaxing the esophageal sphincter.

Whatever the connection, a lot of asthma sufferers say that acid reflux causes asthma attacks. If true, this is most likely because the acidic contents of the esophagus stimulate the nerves that cause bronchial constriction.

6) Smoking

Smokers are particularly at risk for several reasons. Firstly, their saliva contains low levels of bicarbonates, which neutralize the acidity of stomach contents. In addition, they produce less saliva than non-smokers. In short, smoking is a major acid reflux cause.

We also know that the lower esophageal sphincter is weakened by smoking, that digestion is slowed down, making the stomach contents more likely to reflux, and that smoking makes the stomach acid more acidic by encouraging movement of bile salts from the intestine back into the stomach.

7) Drinking Alcohol

Anecdotally, many patients have observed that when they stop drinking alcohol, acid reflux tends to improve. You can probably check out for yourself whether drinking is a likely acid reflux cause.

8) Foods which tend to be associated with causing acid reflux

Food linked to acid reflux and heartburn symptoms include alcohol, pepper, coffee, spices, caffeine containing products, citrus fruit and juices, acidic foods like vinegar, garlic, chili and other products.

High-fat foods are often blamed, and some people have reported that certain foods associated with the production of gas can cause an increased level of reflux. Your food diary, should you keep one, may therefore reveal a link between vegetables like cabbage, beans and Brussels sprouts and acid reflux. Certainly we know that carbonated drinks promote acid reflux and should therefore be avoided.


Scientific Work

This study was an investigation of the factors that might produce acid reflux. A control group of volunteers was compared with a number of individuals who were experiencing gastroesophageal reflux disease, using 24-hour pH and motility recording on both sides of the diaphragm. The patients classified as having GERD had been experiencing symptoms for more than six months and showed an abnormal pH profile on 24-hour ambulatory study.

In control subjects almost every episode of reflux was caused by belching. This is a normal response to the presence of excess gas in the stomach, and the esophagus quickly clears the acidic material by contracting so that the stomach contents are propelled back into the stomach.

In individuals who have GERD, it seems that belching is still an important cause of reflux, but becomes increasingly less so as the severity of the symptoms of esophagitis increase. In these individuals, it seems that spontaneous reflux is much more important.

Also, in individuals with GERD, reflux episodes are preceded by spontaneous contractions of the LES in up to 10% of episodes. It seems that transient lower esophageal sphincter relaxation is actually one of the most important causes of acid reflux in patients with GERD. Even when the sphincter is exerting very low pressure anyway, it still appears to relax before many episodes of reflux. There is a tendency to decreased sphincter pressure in patients with acid reflux, and this association between the low pressure exerted by the sphincter is directly related to the severity of the esophagitis.

Of course belching is a normal physiological activity designed to expel ingested gas from the stomach. It’s highly likely, therefore, that reductions in sphincter pressure are not physiologically abnormal, but represent a natural mechanism that allows the body to expel excessive gas from the stomach. Transient lower esophageal sphincter relaxation may simply be more important in the case of acid reflux patients because it’s linked to other precipitating factors such as a hiatus hernia, a weaker than normal sphincter, or excessive swallowing.

The significance of the hiatus hernia is that if it is large, it may contain a large quantity of gas in the herniated part of the stomach, which may stimulate more belching episodes.

This document, about acid reflux treatment, emphasizes that 24-hour study of pH in the esophagus is actually the most helpful and direct way to establish how often acid reflux is occurring, although this may not always allow for diagnosis of GERD, for which an endoscopy may be necessary. Indeed, the difference between acid reflux and gastroesophageal reflux disease is simply one of degree: when the symptoms become troublesome to the patient, or damage to the esophagus has been diagnosed. Similarly, the use of esophageal manometry is able to establish if the lower esophageal sphincter  is actually functioning correctly in its role as a valve between the esophagus and stomach.

A study reported here demonstrated that obesity is a risk factor for causation of acid reflux. Other factors which play a part include the presence of a hiatal hernia.

The hiatus is the hole in the diaphragm which allows the esophagus to pass through as it enters the stomach. In general there should be a close connection between the esophagus and the diaphragm, but the hiatus may weaken and then expand so that the stomach protrudes through it into the chest cavity. This occurs in more than half of people over 60 years of age, but it’s not really serious unless the hernia is of the paraesophageal type where part of the stomach is permanently trapped in the chest cavity.

It appears that a hiatal hernia may cause the lower esophageal sphincter muscle to function incorrectly. Whether or not the hernia is in itself a cause of GERD is open to question, but it’s certainly associated with it, and as the above study shows, can precipitate belching episodes, which in themselves are associated with causing acid reflux.

This tendency may be made worse if there are motility problems in the esophagus. When peristalsis fails to propel the refluxed stomach contents out of the esophagus, the opportunity for the stomach acid to damage the wall of the esophagus is increased. However, once again the relationship between cause and effect is unclear, since it is not apparent whether motility problems in the smooth muscle of the esophagus are either cause or the result of chronic gastroesophageal reflux disease.

This document – management of gastroesophageal reflux disease – describes diagnostic criteria and conditions for the management of GERD. Symptoms for diagnosis include noncardiac chest pain, dysphagia (difficulty swallowing), motility problems in the esophagus, heartburn and regurgitation.

Other symptoms are not so reliable as indicators. The authors state that relationship between GERD and atypical or extraesophageal symptoms remain unclear without advanced investigative techniques such as endoscopy. Recommendations about the use of endoscopy – basically that it is rarely required – have been produced because the vast majority of patients who show symptoms of reflux will not have damage to the esophageal tissue.

GERD is frequent during pregnancy and may begin at any stage. It occurs in up to 80% of pregnant women, and is most likely due to the increased pressure in the abdomen which forces the stomach contents through the lower esophageal sphincter. Acid reflux causation is not difficult to establish in cases like this.

Investigation of lifestyle and dietary factors has demonstrated that the consumption of tobacco, chocolate, and carbonated drinks is linked to the occurrence of reflux. However, the evidence seems to suggest that alcohol, caffeine, spicy foods and citrus have no effect. This is in direct contradiction to a widespread view of the role of these substances, supported by anecdotal evidence from sites offering self-help remedies for acid reflux, and from the individuals who have tried them. However, the researchers report that stopping the use of tobacco or alcohol has not been shown to raise the pressure exerted by the lower esophageal sphincter or improve the esophageal pH. Some work remains here on the importance of these substance as acid reflux causes in the majority of men and women.

Finally it’s important to emphasize the fact that both gastric and duodenal contents can produce damage to the esophageal mucosa. Measurements of the acidity or alkalinity of material refluxing into the esophagus has demonstrated that while acid and pepsin are extremely important causes of damage, conjugated bile acids can cause damage in an alkaline environment because of the the role that pepsin plays in tissue damage. There are synergistic damaging effects from bile and acid in the esophageal mucosal injury.

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