Adequate stomach acid production is crucial for the digestive process. Some people don’t produce enough stomach acid for proper digestion. This may cause uncomfortable symptoms like bloating and gas. In the long term, low stomach acid can have serious consequences for your health.
If you have an autoimmune disease or anemia, there is a 5 to 50 percent chance that you have low stomach acid.
Apple cider vinegar has long been used as a home remedy for bloating and digestive symptoms. Recently, apple cider vinegar has become popular among health enthusiasts who claim that it can help to burn fat, lower blood sugar and reduce inflammation.
Can ACV really help with bloating and digestive symptoms? Are there other options that work better? Is ACV a cure-all for metabolic and inflammatory conditions?
The Problem with Low Stomach Acid
When food arrives in your stomach, your stomach produces acid to help start the digestive process. This is called stomach acid or hydrochloric acid (HCl). Stomach acid is important for a few reasons: digestion of proteins, absorption of minerals, control of parasites/bacteria/fungi, and because it signals to other parts of the digestive tract that food is on its way.
Research into the long-term effects of drugs that lower stomach acid gives us some insights into the risks of low HCI production (1, 2, 3, 4). Over the long term, inadequate stomach acid can:
Increase the risk for SIBO and fungal infections
Impair nutrient absorption (calcium, magnesium, iron, B12) which, in the long term, can lead to osteoporosis and complications such as hip fracture
Cause problems with digestive function in the esophagus and small intestine
There is also the possibility of increased growth of stomach tumors, although it’s unclear whether these tumors are harmful
Typical symptoms of too little stomach acid include:
Feeling excessively full after eating/feeling like food just sits in your stomach
Reflux, heartburn and indigestion
Who is at Risk for Low Stomach Acid?
Only 2% of the US population have documented low stomach acid (5). However, the actual numbers may be higher.
Some conditions increase the likelihood you have low stomach acid, including:
Being over age sixty-five
Chronic use of painkillers or antacids
Autoimmune Conditions and Anemia Increase the Risk of Low Stomach Acid
If you have anemia or an autoimmune condition, the chances you have low stomach acid range anywhere from 5% up through 50%. Autoimmune conditions are common – they affect almost as many people as cancer.
What’s the connection between autoimmune disease and stomach acid? Up to 50% of those with an autoimmune disease also have autoimmunity against their stomach cells. Over time, this stomach autoimmunity can interfere with your stomach’s ability to release the important digestive acid HCl (6).
This suggests that low stomach acid might be more common than previously thought.
These autoimmune conditions are associated with low stomach acid: (7, 8, 9, 10, 11, 12, 13, 14, 15):
Type 1 diabetes
Thyroid disease – Hashimoto’s and Graves’
This corresponds with what I see in the clinic: A subset of patients seem to benefit from supplemental acid.
Low Stomach Acid Increases Your Risk of Bacterial Overgrowth
Small intestinal bacterial overgrowth (SIBO) is a condition that can develop when stomach acid is too low. If you have SIBO, chances are that you may also have low stomach acid (16).
Why Drinking Apple Cider Vinegar Might Help Bloating and Digestive Issues
Apple cider vinegar (AVC) does appear to have uses beyond salad dressing but it also may not be the panacea it is claimed to be. There is no research evidence to support claims that apple cider vinegar relieves bloating and digestive issues. But just because something has never been researched, it doesn’t mean it’s not true. We can, however, make some inferences here.
There are two possible links between ACV and gut health. One is acetic acid, a mild acid which is found in all vinegars. The other is the probiotic bacteria which is found in some brands of apple cider vinegar.
Acetic Acid in Apple Cider Vinegar
It’s common practice for practitioners to prescribe apple cider vinegar or digestive acid supplements to patients with low stomach acid. This is based on the premise that since prolonged low stomach acid is bad, supplementing with extra acid must be good. Neither of these therapies are based on scientific evidence. Despite exhaustive literature searches, I haven’t found any compelling research to back up acid supplementation. That doesn’t mean that acid supplementation doesn’t work, but it is a mostly untested therapy.
Probiotics in Apple Cider Vinegar
Some brands of apple cider vinegar like Bragg’s contain “the mother,” which is a naturally-formed, cloudy layer of acetic acid bacteria. While this bacteria is used to ferment all types of vinegar, most commercial vinegar brands filter it out. The mother is made up of good bacteria.
There is plenty of good science that shows the benefits of probiotics for digestive issues, including SIBO (17, 18, 19, 20, 21).
On its own, small amounts of apple cider vinegar won’t provide a therapeutic dose of probiotics. However, it’s one type of fermented food that you can add to your diet.
What Else is Apple Cider Vinegar Good For?
A lot of claims are made for the health benefits of apple cider vinegar. Some of them are science based and some of them are not.
Apple Cider Vinegar for Weight Loss
Can apple cider vinegar help you lose weight? Here we have some mixed results:
A Japanese study followed 175 obese individuals who consumed either 0, 1 or 2 tablespoons of vinegar per day. Those who consumed vinegar had a modest weight loss of 2-4 lbs after 12 weeks (22).
A later study suggests that vinegar does suppress appetite, however this may be the result of nausea caused by consuming vinegar as a supplement (23).
So, not great for weight loss.
Apple Cider Vinegar for Blood Sugar Control
There is good evidence to suggest that vinegar can help with blood sugar control for some people:
A systematic review and meta-analysis (a detailed summary of available research) showed that vinegar consumption (both white vinegar and apple cider vinegar) can reduce glucose levels and insulin responses after a starchy meal. This effect was not seen after a non-starchy meal (24).
Some studies show a moderate effect on blood sugar while other studies show little effect. It appears that the more insulin-resistant the patient, the stronger the effect of apple cider vinegar on blood sugar (25), (26), (27), (28).
If you are diabetic, insulin resistant or eat very starchy meal, apple cider vinegar can provide moderate help with blood sugar control.
Apple Cider Vinegar as an Anti-Inflammatory
Does apple cider vinegar have anti-inflammatory benefits? One study of ACV showed a slight increase in one inflammatory marker. Two studies of other types of vinegars showed decreases in other inflammatory markers:
A study of ACV supplementation showed a slight increase in C-reactive protein (29).
A study of balsamic vinegar showed that it can reduce some inflammatory markers (30). It’s possible that this is because of the polyphenols in balsamic vinegar rather than a result of consuming acetic acid.
A study of persimmon vinegar showed that it has antioxidant properties, which can help with inflammation (31).
It seems unlikely that apple cider vinegar significantly helps with inflammation.
Apple Cider Vinegar for Reducing Triglycerides
Here we have some conflicting results:
Two clinical studies found that 1 to 2 tablespoons of ACV per day led to a minor reduction in triglycerides (32, 33).
Another study found that ACV consumption resulted in a small increase in triglycerides (34).
There’s not much here that suggests apple cider vinegar is an effective way to reduce triglycerides.
The Dangers of Apple Cider Vinegar
If a little bit is good for you, more should be better, right?
This is a common but dangerous assumption about many health products and it should never be applied to apple cider vinegar. Since ACV is so acidic, there are potential serious side effects if you drink apple cider vinegar to excess.
In one case study, a young woman was admitted to hospital with low blood potassium levels and osteoporosis. She had been consuming about a cup of ACV per day for 6 years. The doctors concluded that the excess acid caused minerals to leach from her bones (35).
In another case study, a teenager caused erosion of her tooth enamel by consuming large quantities of apple cider vinegar (36).
If you experience acid reflux or heartburn after consuming ACV, you should stop using it. While some people have low stomach acid, others have too much. The symptoms for both conditions are very similar. If consuming ACV makes your digestive symptoms worse, it’s possible that you have excess stomach acid.
How to Safely Consume Apple Cider Vinegar
If you want to drink ACV as a supplement, always dilute it in warm water and rinse your mouth after you drink it. It’s normally taken before a meal to help with digestion. Start with a small amount and if you tolerate it well, work up to a maximum of 2 tablespoons per day.
You can also simply incorporate ACV as part of a healthy diet.
A small amount of ACV works well in:
If you have gastroparesis (a disease that prevents the stomach from emptying normally) you should avoid using apple cider vinegar as it can worsen the condition (37).
What About a Stomach Acid Supplement?
If you think that you may have low stomach acid, you may want to take a digestive acid supplement instead of ACV. These supplements contain betaine HCl, a digestive acid, and pepsin which is a digestive enzyme.
Taking digestive acid supplements can help you to achieve a more clinical and consistent dose. Also, they are safer for your tooth enamel than ACV.
Keep in mind that hydrochloric acid supplements for digestion are not a scientifically-proven therapy to increase stomach acid.
I did an extensive review of the literature and was shocked to find almost nothing that supported supplementing with digestive acid. The only references available are a handful of studies from the 1960s, most of which can’t be located to fact-check.
Authors funded by supplement companies have written papers recently, but all the claims made in these papers reference these older and unverifiable studies.
Does this mean supplemental acid is a bad idea? Not necessarily. This may be an area where good studies just haven’t been performed yet. We want to use the research to guide our decisions but not to limit them. If the research shows something doesn’t work, we’re not going to recommend it. But, as in this case, what if there is almost no research? We have to use whatever other information is available.
We can use clinical experience, for example.
I have noticed that supplemental acid certainly seems to help some people, but megadosing is not needed.
Never Do This with HCI Supplements for Digestion
There’s a common recommendation for dosing digestive acid (HCl) that I think is very bad advice. This dangerous practice suggests that you increase your dose until you feel a burning sensation and then decrease your dose slightly. For example, if you felt a burning sensation in your stomach when you took seven pills of HCl per meal, your ideal dose is six pills.
By the time you’re feeling burning, damage may be occurring.
Also, those with a healthy stomach lining may never feel burning. Very high intake of stomach acid supplements may lead to increased risk of stomach and small-intestinal ulcers. Some people are taking as much as fifteen capsules of supplemental acid with each meal. I do not recommend this.
Dosing Guidelines for Betaine HCI Supplements
There’s no readily available test for low stomach acid. However, if you have a risk factor like autoimmune disease, anemia or SIBO, you may want to try a digestive acid supplement to see if it helps your symptoms.
Take 1 to 2 capsules with each meal for a trial period of 1 to 2 weeks.
If you feel burning or have any other bad reaction, discontinue the product.
If you notice an improvement in your symptoms, continue to take the product.
If you don’t notice any improvement in your symptoms after 2 weeks, discontinue the product.
The Bottom Line on Apple Cider Vinegar
Apple cider vinegar does have some therapeutic uses but it’s benefits are modest.
Please don’t think of ACV as a panacea for weight loss, blood sugar control or digestive issues. You can take 1-2 tablespoons of diluted ACV per day as a supplement, however for all of these conditions, there are more effective therapies. A better approach might be to use ACV and other vinegars in moderation as part of your healthy diet.
I care about answering your questions and sharing my knowledge with you. Leave a comment or connect with me on social media asking any health question you may have and I just might incorporate it into our next listener questions podcast episode just for you!
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