How your antacid drug is making you sick (Part A)

April 10, 2010 in GERD, Myths & Truths | 16 comments

nexiumNote: this is the fourth article in a series about heartburn and GERD. If you haven’t done so already, you’ll want to read Part I, Part II and Part III before reading this article.

Believe it or not, stomach acid isn’t there just to punish you for eating Indian food. Acid is in the stomach because it’s supposed to be there. It is found in all vertebrates. And while it isn’t necessary for life, it is certainly required for health.

Most people have no idea how many vital roles stomach acid plays in our bodies. Such misunderstanding is perpetuated by drug companies who continue to insist that stomach acid is not essential. Meanwhile, millions of people around the world are taking acid suppressing drugs that not only fail to address the underlying causes of heartburn and GERD, but put them at risk of serious (and even life-threatening) conditions.

There are four primary consequences of acid stopping drugs:

  1. Increased bacterial overgrowth
  2. Impaired nutrient absorption
  3. Decreased resistance to infection
  4. Increased risk of cancer and other diseases

I had originally intended to cover all four of these issues in this article, but as I started to write I realized it would be far too long. So I will cover increased bacterial overgrowth and impaired nutrient absorption in this article, and decreased resistance to infection and increased risk of cancer and other diseases in the next article.

A stomach full of germs

We’re not going to spend much time on this here since the connection between low stomach acid and bacterial overgrowth was the focus of Part II and Part III.

To review, low stomach acid causes bacterial overgrowth in the stomach and other parts of the intestine. Bacterial overgrowth causes maldigestion of carbohydrates, which in turn produces gas. This gas increases the pressure in the stomach, causing the lower esophageal sphincter (LES) to malfunction. The malfunction of the LES allows acid from the stomach to enter the esophagus, thus producing the symptoms of heartburn and GERD.

Bacterial overgrowth has a number of other undesirable effects, including reducing nutrient absorption, increasing inflammation, and raising the risk of stomach cancer. Studies have confirmed that proton-pump inhibitors (PPIs) can profoundly alter the gastrointestinal bacterial population by suppressing stomach acid. Researchers in Italy detected small bowel bacterial overgrowth (SIBO) in 50% of patients using PPIs, compared to only 6% of healthy control subjects. The prevalence of SIBO increased after one year of treatment with PPIs.

Well-fed but undernourished

Stomach acid is a prerequisite to healthy digestion. The breakdown and absorption of nutrients occurs at an optimum rate only within a narrow range of acidity in the stomach. If there isn’t enough acid, the normal chemical reactions required to absorb nutrients is impaired. Over time this can lead to diseases such as anemia, osteoporosis, cardiovascular disease, depression, and more.


Stomach acid plays a key role in the digestion of protein, carbohydrates and fat. When food is eaten, the secretion of stomach acid (HCL) triggers the production of pepsin. Pepsin is the enzyme required to digest protein. If HCL levels are depressed, so are pepsin levels. As a result, proteins don’t get broken down into their component amino acids and peptides. This can lead to a deficiency of essential amino acids, which in turn may lead to chronic depression, anxiety and insomnia.

At the same time, proteins that escape digestion by pepsin may end up in the bloodstream. Since this is not supposed to happen, the body reacts to these proteins as if they were foreign invaders, causing allergic and autoimmune responses. I’ll discuss this more below.


We can eat the most nutritious diet imaginable, packed with vitamins, minerals and other essential nutrients, but if we aren’t absorbing those nutrients we won’t benefit from them.

As acid declines and the pH of the stomach increases, absorption of nutrients becomes impaired. Decades of research have confirmed that low stomach acid – whether it occurs on its own or as a result of using antacid drugs – reduces absorption of several key nutrients such as iron, B12, folate, calcium and zinc.


Iron deficiency causes chronic anemia, which means that the body’s tissues are literally starving for oxygen.

In one study, 35 of 40 people (80 percent) with chronic iron-deficiency anemia were found to have below normal acid secretion. Iron-deficiency anemia is a well-known consequence of surgical procedures that remove the regions of the stomach where acid is produced.

Researchers have found that inhibition of acid secretion by Tagamet, a popular acid stopping drug, resulted in a significant reduction of iron. At the same time, studies have shown that adding acid has improved iron absorption in patients with achlorydia (no stomach acid production).


Vitamin B12 (cobalamin) is needed for normal nerve activity and brain function. B12 enters the body bound to animal-derived proteins. In order for use to absorb it, the vitamin molecules must first be separated from these proteins with the help of – you guessed it – stomach acid.

If stomach acid is low, B12 can’t be separated from its carrier proteins and thus won’t be absorbed. In one study of 359 people aged 69-79 years with serious atrophic gastritis, a disease characterized by low stomach acid, more than 50 percent had low vitamin B12 levels.

A number of studies have examined the negative effect of PPI therapy on B12 absorption. In a study on healthy subjects treated with 20 mg and 40 mg of Prilosec per day for two weeks, B12 absorption was reduced by 72% and 88% respectively.


Among other things, folate (folic acid) is vital for keeping the cardiovascular system healthy and for preventing certain birth defects. Low stomach acid levels can interfere with folate absorption by raising the pH in the small intestine. At the same time, when folate is given to achlorydric patients (with no stomach acid) along with an HCL supplement, absorption of the vitamin increases by 54 percent.

Both Tagamet and Zantac reduced folate absorption in another study, though the reduction in the Zantac group was not statistically significant. The overall reduction of folate absorption was sixteen percent. This modest reduction is probably not enough to harm a healthy person consuming adequate levels of folate, but it may cause problems in those with folate deficiency (relatively common) or other health problems.


Calcium makes our bones and teeth strong and is responsible for hundreds, if not thousands, of other functions in our body. The importance of stomach acid in the absorption of calcium has been known since the 1960s, when one group of researchers noted that some ulcer patients were barely absorbing any calcium at all (just 2 percent). When they investigated they found that these subjects had a high gastric pH (6.5) and very little stomach acid. However, when the researchers gave them HCL supplements, lowering the pH to 1, calcium absorption rose five-fold.


Zinc takes part in several metabolic processes related to keeping cell membranes stable, forming new bone, immune defense, night vision, and tissue growth. In one controlled trial, Tagamet treatment reduced zinc absorption by about 50 percent. Another study found that Pepcid, which raises intragastric pH to over 5, had the same effect.

Although there is little systemic research on the absorption of other nutrients, there is good reason to believe that low acid levels may also effect levels of vitamin A, vitamin E, thiamine (vitamin B1), riboflavin (vitamin B2), and niacin (vitamin B3). Theoretically, the absorption of any nutrient that is bound to protein will be inhibited (PDF).

In Part B of this article I will explain how acid stopping drugs decrease our resistance to infection and increase our risk of stomach cancer and other diseases.

{ 16 comments… read them below or add one }

Forty2 April 10, 2010 at 6:32 pm

I have been off Aciphex for almost two weeks now. Other than a mild twinge of burn, I’m fine.


Chris Kresser April 10, 2010 at 6:39 pm



Eve M. April 10, 2010 at 7:07 pm

I’ve been following this series with keen interest; thanks! As a result of reading the first couple of installments, I rashly (boldly?) went off my Prilosec OTC regimen of 18 months’ duration, and after a couple of slightly difficult days, have had no significant heartburn.
Both on the PPI and still occasionally off it, however, I do have stomach pains (which sometimes translate into scary “chest pains” in the middle of the night) that are helped by antigas meds (like dimethicone). Do you suppose the story is as simple as “Ingest anything that creates IAP, and you will need to tamp down abdominal gas to keep the LES closed”?
(By the way, in my comment on Part 1, I mentioned planning to get an upper endoscopy. I’m now thinking of scrapping that part of the plan. :-)


Chris Kresser April 10, 2010 at 7:36 pm


Congratulations! It certainly sounds like your pain and heartburn are being caused by gas. As I mentioned in the previous articles, that is probably caused by maldigestion of carbohydrate. What is your carb intake like at present? I’ll be writing more about how to treat GERD naturally soon, but in the meantime I’d recommend a period of strict carbohydrate restriction, HCL w/pepsin and a high quality probiotic (foods are best, sauerkraut, kombucha, kefir, etc.). Smaller meals can also be helpful as you make the adjustment.


Eve M. April 11, 2010 at 12:34 am

On an average day my carb intake is probably below 50 grams, often well below. I haven’t seen a consistent pattern, to be honest. Some of the worst pain was during a week when I was trying out some intermittent fasting and sticking to eating small amounts of high-quality fats. But then, as admitted in the earlier thread, I do like the occasional drink!  It sounds like I’m going to have to eliminate the gin martinis and scotches, or at least track them carefully to see how they contribute, and experiment with probiotics and HCL/pepsin supplementation if the improvement doesn’t continue.  Thanks again.


kilton April 11, 2010 at 5:44 am

Any idea how water consumption affects stomach acidity?  Maybe we shouldn’t be drinking with meals?


Chris Kresser April 11, 2010 at 9:18 am

Consuming liquid during meals dilutes the concentration of stomach acid, impairing digestion. It’s best not to drink liquid during meals for that reason – especially water. A few sips of wine probably won’t hurt.


Todd S. April 12, 2010 at 7:55 am

This is a fantastic series of articles.  I’d like to print them out and give them to my father, if you don’t mind.  He’s type 1 diabetic and has been on PPI’s for years now.
My own experiences with GERD (or, as I called it “chronic heartburn” since I never went to get diagnosed) fall in-line exactly with what you have described in this series.  Most notably, the food causes of my heartburn as I found through my own experiments of eliminating certain foods: sugars, starches, and grains.  Wheat and sugar being the two biggest culprits for me.
A few months ago I embarked on a paleo-esque plan à la Mark Sisson’s “Primal Blueprint”.  Within 72 hours of eliminating grains and sugars from my diet, my heartburn that kept me up 3-4 hours per night was gone.  Completely.
Now, I’ve heard of not drinking during meals to improve digestion.  How long is it recommended to wait after the meal before drinking?  Also, I have a habit of mixing a bit of apple cider vinegar in a glass of water and drinking it.  Not necessarily at meal time, but just throughout the day.  I actually like the taste and find it quite refreshing.  What impact would this have on my stomach acid production?


Chris Kresser April 12, 2010 at 8:18 am

Hi Todd,

Please feel free to print the articles and give them to your father. That’s what this blog is all about! Thank you for asking, though.

I wouldn’t drink much liquid for 1-2 hours after eating, to give the stomach a chance to empty. The exception would be hot herbal teas that promote digestion, like fennel and peppermint.

Apple cider vinegar is an old home remedy for indigestion. I’m planning on mentioning it in the upcoming treatment article. I think a small amount before meals, mixed with some warm or room temperature water, can be helpful.


Chris Kresser April 12, 2010 at 12:16 pm

Hi folks,

The continuation of this article (Part B) is now up.



Chris Kresser April 16, 2010 at 10:41 am

Final article in the series is up.

Also, the entire series as well as recommendations for books and offsite articles can be found here.


Tom May 9, 2010 at 12:09 pm

I may have missed it, but I did not see something else worth mentioning about GERD.
In some (many) people, the valve between the esophagus and stomach does not close properly or quickly enough. This causes stomach acids to enter the esophagus and cause the burning discomfort.
This problem can be dealt with by some yogic practices, by paying attention to that area, and also by not going to be or lying down with food in the stomach.
If you get a bad case of GERD in the middle of the night, often it is due to food in the stomach not being able to drain out. Just sit up for a while and it will leave the stomach and the GERD incident will be over.


Chris Kresser May 9, 2010 at 12:16 pm


The entire series is about why the LES malfunctions: because of excess carbohydrates and low stomach acid.


Tom May 11, 2010 at 5:33 am


I did not make my point clearly, sorry.

What I am saying is that yoga and the other techniques mentioned can help with this problem in the way that resting, elevating, and using ice on a sprained toe can help with that problem.

Yoga may not be the bottom line on GERD, but it can help alleviate an instance of the problem and the awareness can make people better understand what is triggering the problem.

Also, thanks for this series and your blog in general. They are very good.


Donna September 14, 2010 at 6:25 am

Chris, I am beside myself and don’t know what to do.  My 89 year old uncle is ailing and I believe it is due to Prilosec.  He was complaining of occasional heartburn several months ago so his doctor put him on Prilosec 40mg. in a.m. and Pepcid in p.m.  Over the last few weeks he has been having severe stomach pains, ie. burning to the point that he has gone to the ER.  What do they do…endoscopy…which showed nothing.  Hence, more prilosec, carafate, and dilaudid. He has lost weight over the this time because he can barely eat without being in pain.  He drinks a lot of milk (whole milk) thinking that it miight help, but, of course, it doesn’t and his arthritis, whether rheumatoid or osteo seems to be much worse. He lies down most of the time because he is so weak and his joints hurt so bad when he’s up.  Prior to all of this, he could outwalk me at the grocery store. I have always been skeptical of long term antacids. I’m also aware that as we age, we tend to produce less stomach acid anyway. So now that acid production in my uncle is virtually stopped, it’s no wonder he’s getting very sick.  But how do I convince him (you know, old people believe everything their doctor’s say without question and I question everything)and his doctor that he’s killing him albeit unintentionally? I’m having a real hard time just standing by watching this happen to an otherwise relatively healthy man.  HELP, PLEASE! 


Chris Kresser September 14, 2010 at 7:46 am

Donna: I empathize with your plight, but unfortunately I don’t have an easy answer. The best we can do is educate and inform, but from there people have to make their own choices. You could try getting him a copy of Dr. Wright’s book called Why Stomach Acid is Good For You. He’s an M.D., so perhaps your uncle would take it more seriously.


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