Heartburn and Reflux Review

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What Causes Heartburn/GERD?

The causes of GERD are complex. A small number of patients with GERD produce abnormally large amounts of acid, but this is uncommon and not a contributing factor in the vast majority of patients. The factors that can contribute to causing GERD are problems in the lower esophageal sphincter, hiatal hernias, esophageal contractions, and emptying of the stomach.

Lower esophageal sphincter

The action of the lower esophageal sphincter (LES) is perhaps the most important mechanism for preventing reflux. The esophagus is a muscular tube that extends from the lower throat to the stomach. The LES is a specialized ring of muscle that surrounds the lower-most end of the esophagus where it joins the stomach. The muscle that makes up the LES is active most of the time. This means that it is contracting and closing off the passage from the esophagus into the stomach. This closing of the passage prevents reflux. When food or saliva is swallowed, the LES relaxes for a few seconds to allow the food or saliva to pass from the esophagus into the stomach, and then it closes again.

Several different abnormalities of the LES have been found in patients with GERD. Two of them involve the function of the LES. The first is abnormally weak contraction of the LES, which reduces its ability to prevent reflux. The second is abnormal relaxations of the LES, called transient LES relaxations.  Transient LES relaxations also occur in individuals without GERD, but they are infrequent.

The most recently-described abnormality in patients with GERD is laxity of the LES. Specifically, similar distending pressures open the LES more in patients with GERD than in individuals without GERD.

Hiatal hernia

Hiatal hernias contribute to reflux, although the way in which they contribute is not clear. A majority of patients with GERD have hiatal hernias, but many do not. Therefore, it is not necessary to have a hiatal hernia in order to have GERD. Moreover, many people have hiatal hernias but do not have GERD. It is not known for certain how or why hiatal hernias develop.

Normally, the LES is located at the same level where the esophagus passes from the chest through the diaphragm and into the abdomen. (The diaphragm is a muscular, horizontal partition that separates the chest from the abdomen.) When there is a hiatal hernia, a small part of the upper stomach that attaches to the esophagus pushes up through the diaphragm. As a result, a small part of the stomach and the LES come to lie in the chest, and the LES is no longer at the level of the diaphragm.

When the LES moves into the chest with a hiatal hernia, the diaphragm and the LES continue to exert their pressures and barrier effect. However, they now do so at different locations. Consequently, the pressures are no longer additive. Instead, a single, high-pressure barrier to reflux is replaced by two barriers of lower pressure, and thus reflux occurs more easily. So, decreasing the pressure barrier is one way that a hiatal hernia can contribute to reflux.

There is a second way in which hiatal hernias might contribute to reflux. When a hiatal hernia is present, there is a hernial sac, which is a small pouch of stomach above the diaphragm. The sac is pinched off from the esophagus above by the LES and from the stomach below by the diaphragm. What's important about this situation is that the sac can trap acid that comes from the stomach. This trap keeps the acid close to the esophagus. As a result, it is easier for the acid to reflux when the LES relaxes with a swallow or a transient relaxation.

Finally, there is a third way in which hiatal hernias might contribute to reflux. The esophagus normally joins the stomach obliquely, which means not straight on or at a 90-degree angle. Due to this oblique angle of entry, a flap of tissue is formed between the stomach and esophagus. This flap of tissue is believed to act like a valve, shutting off the esophagus from the stomach and preventing reflux. When there is a hiatal hernia, the entry of the esophagus into the stomach is pulled up into the chest. Therefore, the valve-like flap is distorted or disappears and it no longer can help prevent reflux.

This is an extract from an eBook on Acid Reflux by Brett Harrison. The book looks in detail at the causes of Acid Reflux and then offers advice on how to use diet, lifestyle and natural remedies to treat it effectively. To read more about Acid Reflux and how to cure it naturally.....

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