If television commercials for prescription and over-the-counter antacids are any indication, acid reflux has reached epidemic proportions. Stomach acid has launched an all-out attack on people's digestion and quality of life, inching its way up into the esophagus and causing the pain and irritation commonly referred to as "heartburn." But stomach acid is a natural, normal, essential thing. Why does it cause so much trouble for so many people?
For the people who suffer from acid reflux, finding a natural remedy would be most welcome, because reflux can make eating—one of life's simple pleasures and joys—into a painful experience people dread. With this in mind, might there be a role for a ketogenic diet in addressing reflux?
Stomach Acid 101
Owing to the high incidence of acid reflux and gastroesophageal reflux disease (GERD), stomach acid has gotten a bad reputation. It's been portrayed as something to reduce as much as possible, or, better yet, completely neutralize. If only we could eliminate stomach acid altogether, we would have a permanent cure for reflux and indigestion, right?
Your stomach is supposed to be acidic. Very acidic. Between meals, an "empty" stomach has a pH of about 1-3, usually around 2. During a meal, when food is in the stomach, the pH rises to 4-5.
The pH scale measures acidity: 7 is neutral, lower than 7 is acidic, and higher than 7 is alkaline. It's a logarithmic scale, so a pH of 6 is ten times more acidic than a pH of 7, and a pH of 5 is a hundred times more acidic than a pH of 7, so you can see that even when the pH of your stomach rises in the presence of food, it's still highly acidic! To give you a better sense for this, lemon juice has a pH of about 2 and vinegar's pH is around 2-3. The pH of your empty stomach is only slightly less acidic than battery acid!
Not only is your stomach supposed to be acidic, but it must be acidic. The chemical breakdown of carbohydrates begins in your mouth, thanks to enzymes in your saliva. But the breakdown of proteins and fats begins in your stomach, and the primary conductor of the digestion orchestra is your stomach acid.
Think of proteins as strands of Christmas lights: multiple cords that are all tangled up. Job #1 of your stomach acid is to untangle these strands—a process called denaturing. When proteins are denatured, the enzymes in your small intestine that break them down into individual amino acids or small groups of amino acids (called peptides) have better access to them and are able to break them down properly.
Your stomach needs to be highly acidic not just in order to properly denature proteins, but also because the acidity signals other enzymes (such as gastric lipase, which is an early step in digestion of fats) to perform their functions, and these enzymes function optimally in an acidic environment.
Additionally, the stomach is supposed to be highly acidic so that the denaturing of proteins can occur relatively quickly, and your food can be passed along for the rest of your digestive tract to go to work on it. Food isn't supposed to sit in your stomach forever. Stomach acid is supposed to take care of the proteins, enzymes do some initial work on the fats and carbohydrates, and then the food is supposed to move along. Not only that, but when the food does move along, it, too, should be acidic.
The acidity of the partially digested food (called chyme) entering the small intestine signals the intestine to secrete bicarbonate ions, which neutralize the acid, creating an alkaline environment in the small intestine. This is crucial, because unlike the stomach, the digestive enzymes of the small intestine function optimally in an alkaline environment. You can see now that your stomach acid needs to be highly acidic, because it sets the stage for proper digestion not only in the stomach, but also in the small intestine, which is where the majority of digestion occurs.
What Causes GERD?
Contrary to popular belief, many individuals with acid reflux don't have too much stomach acid; they have too little. (1)
If you have too little stomach acid, or the acid you produce is not sufficiently acidic, food will remain in the stomach longer than it should. Some of the carbohydrates you consume—especially grains, but also other starches—may begin to ferment as they remain in your stomach for an extended period of time, and this creates gas.
This gas may put pressure on the lower esophageal sphincter (LES), which is a small bundle of muscles between your esophagus and your stomach. This sphincter is supposed to remain closed except after you swallow and food presses against it, causing it to open and allow the food to pass into your stomach. Most of the time, this is a unidirectional process—one way: food and beverages go from the esophagus into the stomach.
But it's not always unidirectional. Food and liquids can move from the stomach back up into the esophagus. If you've ever vomited, then you've had personal, unpleasant experience with the two-way action.
The thing is, the LES is an involuntary muscle—meaning, you can't deliberately move it, the way you can with your quads or your biceps. It opens and closes on its own. The opening of the LES during vomiting is a natural response to an emergency need to eliminate something toxic. But some people have a weakened LES that's more prone to opening in benign circumstances.
The problem with foods coming back up, or refluxing, into the esophagus is that, unlike the internal lining of your stomach, which contains a layer of mucus that protects it from being eroded by stomach acid, your esophagus contains no such protection. So when foods that have been exposed to stomach acid bubble back into the esophagus, the acidity causes burning and irritation.
But remember, this doesn't happen because the stomach is too acidic; it happens because it isn't acidic enough.
What Causes Reduced Stomach Acid?
Stress is a major culprit—one people rarely think of when they think about indigestion and reflux. The cliché of a stressed-out executive grabbing a fast food lunch, eating it standing up, and then popping antacids for the rest of the day while running from one meeting to the next has a lot of truth to it.
If your sympathetic nervous system—responsible for the "fight or flight" state—is going full speed, it overpowers your parasympathetic nervous system, which is responsible for the "rest and digest" state.
The physical breakdown of food begins in your mouth, with chewing, but the biochemical aspects of digestion begin in your brain. If you're constantly stressed out, then your body interprets this as your being in a perpetual crisis, in which case digesting your food is not a top priority, so stomach acid secretion is reduced.
Another cause of reduced stomach acid is prescription antacids. Two of the common types are proton pump inhibitors (PPIs) and H2 receptor antagonists. These drugs are prescribed to treat acid reflux, and also for stomach ulcers. Like so many pharmaceutical drugs, by suppressing the secretion of stomach acid, these drugs do help alleviate heartburn in the acute sense, but over the long term, they actually make things worse.
Many people with acid reflux don't need less stomach acid; they need more, so these drugs only address the immediate symptoms. They do nothing to correct the underlying problem. Perhaps this is why as much as 30-40% of patients don't respond to pharmacological treatment and 60% report residual symptoms despite drugs for acid reflux being a $12.5 billion dollar industry in the U.S. alone (2).
Other contributors to reflux in some people include smoking (3), high alcohol intake (4), and anatomical issues, such as hiatal hernia (5). (Hiatal hernia is a condition in which a small portion of the stomach protrudes through the diaphragm, putting increased pressure on the LES from below.) Obesity might be another factor in GERD—specifically abdominal obesity, where fat is mainly carried at the midsection.
Conventional Advice for GERD & Acid Reflux
Common recommendations provided for those with acid reflux include:
Remain upright after eating: For individuals with a weakened lower esophageal sphincter, letting gravity do its job may help reduce the likelihood that food will travel back into the esophagus. This means standing or sitting upright, and not lying down or reclining after a meal. (It also means not eating a large meal right before bed.)
Eat smaller meals: Smaller meals mean less food in the stomach, and therefore, potentially less likelihood for upward pressure on the LES to cause reflux.
Avoid acidic, spicy, and fatty foods: While these foods may not be the primary cause of reflux, acidic foods may be more irritating to the esophagus when the LES is weakened. These foods include coffee, carbonated beverages, tomatoes and tomato sauces, lemon and other citrus fruits and juice, hot peppers, garlic, onions, vinegar, and other acidic foods. Chocolate and peppermint may also exacerbate GERD in some people.
Lose weight if you are overweight or obese: A larger concentration of body mass in the abdominal area may mean increased pressure on the LES, potentially resulting in acid reflux. Certainly, not all overweight individuals experience reflux, and plenty of lean individuals do. So excess body weight is not an ironclad cause of reflux; it's simply one among many contributors that could be addressed if an overweight individual experiences frequent heartburn.
Alternative Approaches for GERD & Acid Reflux
Operating under the premise that GERD and acid reflux often result from insufficient stomach acid rather than an excess, some physicians and nutritionists may approach things differently from the advice above:
- Take supplemental HCl: Stomach acid is available in supplement form, as betaine HCl.
Take apple cider vinegar before meals: Providing acid directly may help increase the stomach's acidity. Many people find a squeeze of lemon in their water helps aid digestion; perhaps this is why. Keep in mind that many cultures around the world consume pickled or fermented foods with their meals, especially when the meals are rich or fatty, such as the European tradition of sauerkraut or cornichons with sausages or pâté. Think of these acidic condiments as digestive aids.
Don't consume large amounts of liquid with meals: For people who already produce insufficient stomach acid, it may be wise not to dilute what is produced with excessive amounts of fluid. Hydrate enough throughout the day so you're not overly thirsty at mealtimes. (You shouldn't require large amounts of liquid to "wash down your food.")
Don't eat while acutely stressed: Relax! Allow that rest and digest part of your physiology to shine. Try not to eat in your car, standing up, or otherwise on the go. When possible, avoid conducting business during meals. Try to eat in a calm frame of mind and in pleasant surroundings. Easier said than done, especially if you're a parent of young children, but try to be as calm and unhurried as your circumstances allow.
Dangers of Antacid Drugs
As mentioned earlier, prescription antacids inhibit the natural, normal secretion of stomach acid. But stomach acid is essential for proper digestion, including liberation of vitamins and minerals from food.
The old saying, "You are what you eat" isn't quite accurate. You're not what you eat but rather, what you digest and absorb. So imagine the consequences for someone who has been dutifully taking a powerful antacid for years, maybe decades. Their absorption of key nutrients has been compromised for this length of time, which can affect any number of body systems and functions.
Owing to reduced absorption of calcium, zinc, iron, magnesium, and vitamin B12, long-term antacid use is associated with increased risk for several alarming outcomes: chronic kidney disease (6,7), iron deficiency (8), hypomagnesemia (low blood magnesium) (9,10), bone fractures (11,12,13), B12 deficiency (14), pneumonia (15), and dementia (16,17). People who consume these drugs for extended periods of time think all they're doing is reducing their stomach acid. They often have no idea that the consequences can be so dire.
Over-the-counter antacids may not carry risks quite as severe as prescription versions. Rather than preventing the normal secretion of stomach acid the way the prescription PPIs and H2 receptor antagonists do, OTC antacids buffer or neutralize acid that has been produced. Taken often, though, and over the long term, the way many individuals use them, it's possible for them to ultimately lead to some of the same conditions the prescription medications do.
Considering these very serious issues, it would be helpful to find a natural strategy for eliminating acid indigestion.
Enter carbohydrate restriction!
Ketogenic Diets for Acid Reflux
It may sound counterintuitive at first that a ketogenic diet could be beneficial for acid reflux. After all, conventional medical advice recommends avoiding fatty foods, so you might think a ketogenic diet would be contraindicated for individuals with acid reflux or GERD. Plus, some of the foods people frequently enjoy on ketogenic diets are cautioned against in traditional advice for reflux, such as the aforementioned coffee, dark chocolate, tomato sauces, garlic and onions. (According to that conventional thinking, butter in your coffee would be the worst thing you could do!)
Anecdotes abound on various blogs and forums, but there's also a solid body of scientific research corroborating what many people have discovered for themselves: However illogical it may seem at first glance, low-carb and ketogenic diets have proven very effective for relieving GERD and reflux.
If grains and other starchy carbohydrates are among the foods that increase pressure on the LES, it makes sense that eliminating them from the diet or dramatically reducing consumption of them would have a beneficial effect on acid reflux. (Some people on low-carb or ketogenic diets choose to consume grain in the form of low-carb, high-fiber wraps and tortillas, but even if these are part of someone's diet, the total amount of grain they're eating is still significantly reduced from a standard Western diet.)
Evidence Shows that Carbohydrates Aggravate GERD
Many people who adopt ketogenic diets for fat loss or some other goal find that resolution of acid reflux/GERD is an unexpected and pleasant "side-effect." One study reported on five patients who self-initiated low-carb diets and had resolution of GERD.
To be fair, three of them eliminated coffee, and all of them eliminated acidic foods, but the researchers noted that "carbohydrates may be a precipitating factor for GERD symptoms and that other classic exacerbating foods such as coffee and fat may be less pertinent when a low-carbohydrate diet is followed" (18).
Another study added weight to the possibility that carbohydrates are, indeed, a trigger for GERD symptoms. In a small cohort of adults with GERD, compared to a liquid meal containing 85 grams of carbohydrate, a liquid meal of the same volume but containing about 180 grams of carbohydrate resulted in greater total time experiencing reflux and a greater number of long reflux periods (lasting more than 5 minutes) (19).
A liquid meal of 85 grams of carbs is not something any good nutritionist would recommend for a low-carb or ketogenic diet, but this study wasn't specifically about a low-carb diet. It was designed to evaluate "the effect of different carbohydrate density on low esophageal acid and reflux symptoms," and it certainly did: the high-carbohydrate meal aggravated GERD more than the lower-carbohydrate meal.
A more formal study that did evaluate the effects of a ketogenic diet confirmed the efficacy of carbohydrate restriction: in a small prospective cohort, obese subjects began a ketogenic diet after undergoing a 24-hour esophageal pH probe test (which measures the pH of the esophagus). Within just six days, subjects had dramatic improvements in GERD (20).
The Johnson-DeMeester score is used to measure esophageal acid exposure. A score > 14.72 indicates reflux. At baseline, the subjects' mean score was 34.7, and after just six days it had dropped to 14.0. The percent of time during which their esophageal pH was very low (highly acidic) was cut in half, and they reported significant improvements in their symptoms via a standard GERD questionnaire that assesses subjective feelings of heartburn, pressure or discomfort inside the chest, a sour taste in the mouth, frequent gurgling in the stomach, nausea, a feeling of pressure or a burning sensation in the throat, belching, flatulence, and more (21).
This study is telling, because not only did the subjects report improvements in their own symptoms, but the reduced esophageal acidity was confirmed by direct measurement.
In the most impressive study performed so far, in a cohort of obese women, after just 10 weeks on a low-carb diet, in all subjects with a confirmed GERD diagnosis, "all GERD symptoms and medication usage had resolved in all women" (22). That's right - within only 10 weeks, all subjects with GERD had complete resolution of symptoms, including women who'd experienced symptoms twice daily or as often as 5 times per week. All medication, both prescription and over-the-counter, was discontinued.
The authors noted, "Contrary to long-held belief that higher fat intake promotes GERD symptoms; nationally representative data do not show a strong association between dietary fat and GERD. Thus, the present study provides important insights that contribute to the accumulating evidence of a role for dietary simple carbohydrates in GERD pathophysiology. We found that simple carbohydrates, particularly sucrose, contribute to GERD in obese women and the likelihood of having GERD was predicted by simple carbohydrate (total sugars) intake."
Take Home Message
It appears that ameliorating GERD and acid reflux has less to do with what you put in your mouth—antacids—and more to do with what you don't put in your mouth: large amounts of carbohydrate.
If you're living with discomfort and reduced quality of life from acid reflux, and food has gone from a pleasure to a pain, consider trying a low-carb or ketogenic diet.
You've got nothing to lose except maybe a few excess pounds, your reflux, and perhaps even your antacid prescription. If you've been on prescription antacids for a significant length of time, it is not advised to quit them cold-turkey. Find a physician who can help you get started with a low-carb approach and wean off your medication safely.
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