How Your Antacid Drug Is Making You Sick (Part A) | Chris Kresser

How Your Antacid Drug Is Making You Sick (Part A)


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Note: 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.

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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.


Join the conversation

  1. Hi Chris I have had a gastric bypass and I have been told I have to take vitamins iron and calcim twice aday is there anything I can take without taking 3 different pills

  2. am wondering if taking a product called carbgest would help, as this product is designed to help digest carbohydrates

  3. I’ve found sprinkling citric acid on my meals seems to prevent some excessive gas and nausea after eating breakfast. Chris – is adding HCl much better than adding citric acid? Thanks Candice

  4. Is it correct that if I take methylcobalimin in place of cyanocobalimin that my body will not need to separate the cyanide from the good stuff. If this is correct then why bother to take the poisonous cyanide type B12 and why aren’t you promoting that change??

  5. Not sure if you’re still monitoring this post from 2010, but I was hoping you could give me your opinion on a related issue. I have been diagnosed with cholinergic urticaria (heat induced hives), and have been taking Zantac and Zyrtec daily to control that condition for between 6-7 years. This article has caused me some concern, because for the last 6 months I have been dealing with serious dry mouth issues, dermatitis, and an overgrowth of facial and scalp yeast. My dermatologist gave me both oral and cream-based ketoconazole, which helps, but the problem comes right back once I stop taking the keto. Based on your article, it seems like the problem may be related to the fact that I’ve taken Zantac for so many years. The problem, obviously, is that if I stop taking Zantac, the heat-induced hives come right back. Any thoughts/comments would be appreciated.

  6. Hi, I was referred to you by my boss, a Dept Chair. who is a total vegan etc. Have had GI problems for years, including a GI bleed in the 80″s. I understand your reasoning for limiting the PPI’s but especially among the elderly on blood thinners,etc, there is a problem with bleeds.. My main question concerns abnormal “giant” cells in the small intestine, with a hx of IBS, GI bleed,diabetes, et al. The area referenced has caused discomfort for two months now. That is with and without PPI, tagamet, pain med, etc. Thyroid is low normal, on metformin. Have asked for B12, internist sees no need. I understand there is now a correlation of brain to bowel, and would a hx of inc. fluids, cord compression, and s/p surg for same contribute to this ongoing bowel irritation?? I realize there is alot in here but it is the correlation of brain, bowel I am most interested in. Thanks for any insight. PElden

  7. I am a 60 year old female that has suffered with restless legs syndrome and upper airways resistance syndrome for decades. Even though I have never told them that I have heartburn, doctors insist that I have GERD. Recently, I gave in and stated taking Protonix. I have unintentional weight loss (due to early satiety) at a rate of one pound a week and have lost over 10% of my body weight. Since starting taking proton inhibitor I feel as if my body isn’t receiving any nutrition. (I have been checked for cancer). Thanks for the article on proton inhibitors because I now have a reason to review the effects of this prescription with my doctors.

  8. 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! 

    • 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.

  9. Chris:

    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.

  10. 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.

    • Tom,

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

      • Hi Chris,
        My wife has this problem for over 20 years.
        Can you give a reference to how to cure LES malfunctions?
        Thanks very much

    • Can you comment on the rebound of acid after stopping ppi’s. If we assume that long term ppi use may result in bacterial overgrowth, does the excess of rebound kill the bacteria or should we take antibiotic to do so? Also, how to protect the lower esophagus while recovering from ppi influences?

    • Another question or two. When you stop ppi’s after several years of treatment, does the les actually recover and start to function properly again? If so, how long might it take to transition back to normal? How risky is the acid reflux experience during this transition for Barretts cells?

  11. 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?

    • 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.

      • Bacterial overgrowth in throat; tongue/throat/burning pain for 4 months. Taking Prilosec, probiotic, sinus rinse, Allegra, scrapping tongue with vinegar. No thrush. No heartburn. Small burping often. Lipoma on right Side of abdomen. Bacteria seen in throat. Ent says allergies- right side limited opening (old sinus surgery scaring). Ct scan said no sinusites.constipation often. Passed from doctor to doctor. Dentist sees mouth is fine, drainage and bacteria in throat area. Visable Bacteria will move to tongue in some days. Tip of tongue always bothersome. Nothing visable. Often bloated. Often use gasx. Add menaoouse. Tried eating nothing, changing foods, stopping meds, taking others. Thoughts? Not stomach pain, it’s felt in mouth. And bacteria overgrowth seen in throat. I’ve had blood work done. Only bilirubin flagged. Have not seen a gastro doctor. Plan to next week. But feel like I’m brushed off by many doctors. I believe because they just don’t know what to do. Had oral swab done. (After being treated for thrush for a 6 weeks- found didn’t have it) – bacterial overgrowth. Hurts & depressing. Always feel mouth/tongue hurt- burning sensation. On one has suggested antibiotics.

        • I’m sorry to hear your having all these problems you should have your whole digestive system checked for a possible blockage. If that doesn’t come to anything I would get mchecked for lupus.

        • Have you tried a technique called oil-pulling? Sounds kooky, but when I have had serious inflammation issues in my mouth, I have been able to get well by doing this. It is simple but profound: you swish coconut oil in your mouth for 20-30 minutes and then spit it in the trash. Even our medical plan is now recommending it. I believe if you could try this for a few weeks you would see improvement.

          • Oil pulling is briliant, when I do this as part of my morning routine, it definitely makes a difference. I always start my mornings with a pint of warm water with a squeeze of fresh lemon juice, turmeric powder and root ginger. My doctor has just prescribed Gavison, an antacid for what we think is heartburn, but after doing some research, I’m going to take raw apple cider vinegar (2 tablespoons) 10 minutes before each meal and not drink any liquid until an hour after my meals. Will avoid wheat, dairy and sugar, not sure about grains, maybe I should switch to Paleo type eating. Thank you so much for all the brilliant sharing and information. “Let food be thy medicine and medicine be thy food” Hippocrates was so wise…

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

    • 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.

      • Ok, so don’t drink water with meals. But how about overall water consumption taken correctly – as in 1 hour before a meal and 2 to 3 hours after a meal? I used to get most of my daily water intake (I’m not even kidding) from Pepsi (caffeine + sugar) and coffee/juice/milk. Yet Pepsi never caused heartburn, only milk and coffee (or just plain water when and if I ever drank it) did.

        I heard it argued that taking in insufficient amounts of water can reduce the overall amount of stomach acid since the acid contains water. Is that correct? That’s what the author of “The Body’s Many Cries for Water” says.

        Also, someone said that the content of chlorine in the water may also be responsible for heartburn. I’m wondering if that’s true, since Pepsi never caused heartburn, but water – not even a full 8 ounces – still to this day causes heartburn. I avoid it even though I know I should drink it.

        Will you point me to a link where I can gain some better understanding here?


  13. 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.

  14. 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. 🙂

    • Eve,

      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.

    • I take offense to your saying Indian food causes acid problems. There are millions of Americans who do not eat Indian food and still have the problems. There are millions of Indians who eat there food and do not have the problem. I don’t know if you wrote it in jest or meant it seriously.

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

      • So for someone like me who has been on ppi’s long term and was just diagnosed with h. Pylori with esophagitis and erosive gastritis and just got done the triple therapy antibiotic treatment for it… would it be smart to just stop ppi’s? I do still have some acid reflux going in. And they continue to treat me with the ppi’s. I also have been low on b12 and recently needed 2 b12 injections. Should I stop ppi treatment and let stomach acid return to normal?

        • Hi Amanda,

          I was prescribed (off handily) Omeprazole PPI by a locum doctor for acid reflux and a suspected Stomach ulcer. I was to take them for 6 weeks, but was handed a prescription for 12 weeks and was told to come back if I needed more. Strange I thought, but reading this article and going by my experience I now understand why. Two weeks into the course my stomach pain had gone, great, I thought, but I still had 4 weeks left to go, after another two weeks I started to feel unwell in general. I was bloated most of the day and had diarrhoea. I didn’t know what to think. I thought I was getting better. Over the next few days I noticed my urine was cloudy, my kidneys ached and I had a sore throat. I don’t know why, but something made me feel like the Omeprazole was the problem and found this site. After viewing this article I went to my doctor. He agreed that I should stop taking the Omeprazole. That was about two weeks ago. My symptoms didn’t go away at first and my stomach upset got a bit worse in the first few days, but I can happily say that for the first time in ages I feel normal. I changed my diet slightly, made sure I ate as early as I can and cut down on alcohol. I have more energy and my digestive system seems to have returned to normal. Based on this I think a lot of people could do with trying methods like diet changes etc. Stomach Acid is immensely important, otherwise why would we be made to have it? I found that not eating breakfast or eating my breakfast too late made me reflux. I ate breakfast within 20 minutes of waking up, even though I didn’t want to, but its cured my reflex (hopefully). I realise that everyone is different, but I hope you can over come this problem. And as always…discuss with your GP before doing anything.

          • Hi, I too was told I have hp pylori. I’ve done a lot of research. Apparently most of us have it, when its over production is when it becames a problem. I would not take antibiotics or antiacids. I’m taking mastic gum, Manuka honey, colloidal silver 500pp 3x a day,LOTS and LOTs of cabbage juice with lemon, cucumber, aloe juice, celery. Eating very lite, lots of fruits and veggies. Have been on all this stuff for a week, and surp
            Surprise, no more heartburn!! Gona try pine nut oil too. Gonna stay on this diet for a couple months and see how it gose so far feeling GREAT!!!

            • I strongly agree from own experience. Stay away from Antibiotics, too, as they kill other “good bacteria” disturbing the pH balance thus creating new problemsI just went to the Dr. today because I finally recognize the issue after ignoring it for about 6 months. I know exactly what caused the problem:
              Over 20 years ago I was diagnosed with acid reflux receiving acid blockers, threat of surgery, etc. and fixed it by simply adjusting my diet.
              Ever since then I had been eating a fairly healthy, balanced diet in order to maintain energy levels I needed for teaching dancing and working out.
              Then two years ago I moved in with friends for 9 months waiting for a short sale house. I adjusted to their household and started eating almost vegan. Even though their diet was organic it was unbalanced. All carbs, not enough protein. The first thing I noticed about 6 months into it, that my muscle definition and tone decreased significantly. The following year I got sick thus exercising even less and my diet worsened.: I ate more processed, high carb foods, still low protein as I had gotten accustomed to that change. The initial illness and it’s radical treatment with a series of potent antibiotics (infection from a spider bite) in combination with the stress from it, no exercise and poor diet caused me to age visibly at an alarming rate within just a year. (Loss of elasticity of skin and facial muscles, decreased eye sight, acid reflux, spider and varicose veins, you name it.)
              Bottom line: As the article indicates: diet is a key factor in eliminating the problem. If you are experiencing serious symptoms, your pH balance, your nutrient absorb-ability, etc. are already out off whack.
              I have an issue with self discipline, so today I am eating pie, but will start over tomorrow: First I will alter my diet, drink chamomile tea (soothes inflamed lining) and take pro-biotics . Also I am planning on changing my sleep patterns and adding more thorough stretching to my dancing, which will decrease stress levels. All of the above will help absorb-ability of nutrients, minerals and vitamins which will boost my endorphin production and hormone balance. As a result I will feel more energetic and healthier, which will help me with a more positive overall view of things. My body, which is designed to do so, might recover on it’s own once again…

        • Most of time the problem is an under production of acid, and not tye other way as one may think. I’m also taking HCL. Changed my diet as I mentioned above, and so far feeling great. No anicids.

        • Most of time the problem is an under production of acid, and not tye other way as one may think. I’m also taking HCL. Changed my diet as I mentioned above.

    • I can say with certainty that my ability to digest food and my bone strength have gone down significantly after using ppi’s and gelusil etc. thanks for the article.

    • What is your diet Like? I am curious because I have been on aciphex for 3 years now and so far its been the best medicine I have used. I am really interested in not taken meds forever!!

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