What Causes Acid Reflux?

Heartburn Causes /

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What do you get if you combine the best sleeping position (the left side) and add an incline? The MedCline Acid Reflux Pillow System (wedge pillow).

Before we get into what causes acid reflux, we need to understand what acid reflux is and the function of the lower esophageal sphincter (LES).

When food is swallowed it travels from the mouth down the esophagus to the stomach. Where a strong acid called hydrochloric acid helps break down food. The stomach has a special protective lining that protects against this acid, but the esophagus does not.

Acid reflux is the backflow of stomach acid from the stomach into the esophagus. Without a protective lining, acid can irritate the esophagus. This irritation is the pain we call heartburn. This is just one of the many acid reflux symptoms.

The body was designed with a mechanism to deter acid from refluxing. A ring of muscle at the base of the esophagus called the lower esophageal sphincter (LES) closes off to keep acid in the stomach. Unfortunately, the LES doesn’t always close tightly enough or is compromised allowing acid to escape into the esophagus.

We all experience acid reflux on occasion. That’s normal. Chronic acid reflux, however, should not be ignored. Chronic acid reflux, known as gastroesophageal reflux disease (GERD), can develop into Barrett’s esophagus and esophageal cancer. Visit your doctor if you have chronic acid reflux.

What do you get if you combine the best sleeping position (the left side) and add an incline? The MedCline Acid Reflux Pillow System (wedge pillow).

20 Causes Of Acid Reflux

The following are the most common causes of acid reflux. They may weaken the LES or increase sensitivity to acid reflux symptoms by irritating the esophagus and raising stomach acid levels.

You may find one or more causation to be the blame for your acid reflux.

1. Heartburn Trigger Foods

Certain foods and liquids can trigger heartburn in most people. These should be avoided or eaten sparingly. These foods that trigger heartburn include but are not limited to:

  • Alcohol
  • Allium family
  • Caffeinated drinks
  • Carbonated drinks
  • Chocolate
  • Citrus fruits
  • Dairy products
  • Fatty meats
  • Fried food
  • Mint
  • Processed food
  • Spicy food
  • Tomatoes

The healthier your diet the less risk of heartburn.

2. Low Dietary Fiber

Low dietary fiber can lead to constipation which increases abdominal pressure. This pressure can weaken the LES closure.

3. High Salt Intake

A high salt intake decreases LES muscle pressure allowing acid to reflux.1 and irritates the esophagus leading to increased pain from heartburn.2

4. Eating Large Meals

Eating large meals Increases abdominal pressure leading to added pressure on the LES.

5. Eating Before Bedtime

Eating before bedtime can lead to acid reflux. When laying down, stomach contents will place pressure on the LES and leak through into the esophagus.

6. Hiatal Hernia

A hiatal hernia is an impairment of body structure where part of the stomach pushes through the opening known as the hiatus where the esophagus passes through the diaphragm. A hiatal hernia effects LES function prohibiting it from closing properly and allowing acid reflux.

Typically the larger the hiatal hernia greater the likelihood of acid reflux. Some people may have a hiatal hernia and not experience heartburn. These people may not be experiencing acid reflux due to a hiatal hernia or they may be experiencing laryngopharyngeal reflux (LPR).

7. Being Overweight

Acid reflux and obesity have a strong connection in both men and women, though there is a stronger association in women.3,4

Three ways being overweight leads to acid reflux:

  1. Stomach fat causes increased abdominal pressure. This increased pressure can, in-turn, cause added pressure on the LES.
  2. Those who are overweight have a greater risk of developing a hiatal hernia.
  3. Estrogen levels in both women and men increase as weight increases. Increased estrogen levels lead to acid reflux by relaxing the muscles that make up the LES.5,6

8. Being Pregnant

A high majority of women experience heartburn during pregnancy. Increased levels of estrogen and progesterone cause the LES to relax and physical changes increase abdominal pressure which prohibits the LES from closing strongly enough to keep acid out of the esophagus.

9. Stress Levels

Stress increases acid reflux symptoms:

  • The fight-or-flight response associated with stress causes hypersensitivity to pain including the pain of heartburn.
  • Stress increases the production of cortisol which inhibits digestion which can lead to constipation and pressure on the LES causing reflux.
  • Stress can cause an increase in acid production.

10. Anxiety

A strong connection exists between acid reflux and anxiety. The two have the potential to create a problematic cycle where mental and physical discomfort play off of each other.

11. Posture and Position

Posture and position can both add to abdominal pressure and pressure on the LES. Sit up straight and stand up straight. Do not recline after meals and when laying down, lay on your left side to lower your risk of acid reflux.

12. Bending Over at the Waist

Bending over at the waist is similar to posture. It increases abdominal pressure and can compromise the LES.

13. Physical Exercise

Many positions used in exercises and exercise movements cause acid reflux by adding to abdominal pressure and thus pressure on the LES.

14. Tight Clothing

Tight-fitting clothes can increase pressure on the abdomen causing stomach contents to place pressure on the LES and compromise its closure.

15. Nicotine Use

Nicotine causes acid reflux. All forms of nicotine can relax the LES muscles. This includes nicotine patches.

Related Content: E-Cigarettes and Heartburn Connection

16. Hypochlorhydria

Hypochlorhydria is a digestive condition where stomach acid is too low. Stomach acid is necessary for digesting food. Without proper stomach acid levels digestion slows leading to constipation and a build-up of bad bacteria.

Both constipation and gas increase abdominal pressure allowing acid to push through the LES into the esophagus. Belching also weakens the LES closure and can force acid into the esophagus.

17. Age

Three issues contribute to increased acid reflux as we age.

  • Just like other muscles, the muscles that make up the LES can weaken with age allowing acid to reflux.
  • Low stomach acid is another issue with age. See hypochlorhydria above to see how low stomach acid leads to acid reflux.
  • As we get older, we experience increased physical ailments. Many of these ailments require medication that can cause acid reflux.

18. Medications

Many medications contribute to acid reflux or directly irritate the lining of the esophagus to cause heartburn. These include:

  • Alpha Blockers
  • Antibiotics
  • Anticholinergics
  • Anxiety medications
  • Asthma medication
  • Erectile dysfunction medications
  • Estrogen replacements
  • High blood pressure medications
  • Iron supplements
  • Muscle relaxers
  • Narcotics
  • Nitrates
  • NSAIDs
  • Osteoporosis medications
  • Potassium supplements
  • Quinidine
  • Sleeping pills and sedatives
  • Tricyclic antidepressants

19. Body pH

Maintaining an alkaline diet can help avoid acid reflux. Being too acidic will negatively affect the performance of the digestive tract by reducing electrical signals along its neural network and lowering oxygenation.

When the digestive tract functions poorly, the digestive process slows causing constipation and added abdominal pressure. The increased abdominal pressure can compromise the LES leading to acid reflux.

20. Food Allergies and Intolerances

Food allergies and intolerances to certain foods like wheat and dairy can cause gas. This build-up of gas can lead to bloating and belching. Bloating causes abdominal pressure which in-turn places pressure on the LES allowing acid to reflux.

Acids also reflux during belching. The escape of gas compromises the LES and pushes acid up into the esophagus.

20 of the most common causes of acid reflux that you need to know about. These acid reflux causes may weaken the LES or increase sensitivity to acid reflux symptoms by irritating the esophagus and raising stomach acid levels. Know what’s causing acid reflux and heartburn in order to find the correct acid reflux remedies.


1) Marissa C. Aanen, MD, Albert J. Bredenoord, & André J. P. M. Smout. “Effect of dietary sodium chloride on gastro-oesophageal reflux: A randomized controlled trial.” Taylor & Francis Group Online, Scandinavian Journal of Gastroenterology, Volume 41, 2006 – Issue 10, July 8, 2009.

2) Nilsson M, Johnsen R, Ye W, Hveem K, & Lagergren J. “Lifestyle related risk factors in the aetiology of gastro-oesophageal reflux.” National Center for Biotechnology Information, U.S. National Library of Medicine, BMJ Journals: Gut, December, 2004.

3) Magnus Nilsson, MD, Roar Johnsen, MD, PhD, & Weimin Ye, MD. “Obesity and Estrogen as Risk Factors for Gastroesophageal Reflux Symptoms.” JAMA Network, July 2, 2003.

4) El-Serag, H.”The association between obesity and GERD: a review of the epidemiological evidence.” Europe PMC, Digestive Diseases and Sciences, July 24, 2008.

5) Best PJ, Berger PB, Miller VM, & Lerman A. “The effect of estrogen replacement therapy on plasma nitric oxide and endothelin-1 levels in postmenopausal women.” National Center for Biotechnology Information, U.S. National Library of Medicine, Annals of Internal Medicine, February 1, 1988.

6) Ravinder K. Mittal, M.D., & David H. Balaban, M.D. “The Esophagogastric Junction.” The New England Journal of Medicine, March 27, 1997.