Listen to some experts, and apple cider vinegar gets recommended as a heartburn treatment — almost like a cure-all. At first glance, it doesn’t quite add up. Heartburn is caused by acid reflux, so adding something acidic into the mix seems like it would make things worse, not better.

The idea comes from the “low stomach acid” theory. It suggests the valve between the stomach and oesophagus only closes properly when acidity is high. By that logic, increasing stomach acid, for example with apple cider vinegar, should improve symptoms rather than reduce them.

But is this actually true? Does apple cider vinegar help with heartburn? Or is it another bit of useless “podcast wisdom”? Let’s find out.

What Causes Heartburn in the First Place?

Heartburn is caused by acid entering the oesophagus from the stomach. Usually, the lower oesophageal sphincter (LES) stops acid from backflowing. However, if it’s weakened or the pressure is too great, it can open, allowing acid in.

That’s the mainstream theory.

Why People Use Apple Cider Vinegar for Heartburn

The “Low Stomach Acid” Theory

Not everyone is convinced by the idea that the LES opens due to weakness or increased pressure in the stomach. While mainstream medicine acknowledges the role of factors like smoking, alcohol, and certain foods in opening the LES, other people argue it’s caused by too little acid in the stomach.

According to this theory, “low stomach acid” can mimic the symptoms of acid reflux. But the mechanism is different. A lack of stomach acid causes poor digestion. This creates gas bubbles that rise into the oesophagus, carrying stomach acid with them.

Where This Idea Falls Short

The “Low Stomach Acid” theory goes a step further. It argues that LES dysfunction occurs specifically because there’s not enough acid, and that only by increasing stomach acidity will the LES clamp shut properly.

However, there’s limited clinical evidence supporting ACV for reflux. Most cases of heartburn are caused by too much acid production (e.g., due to fatty foods) or because certain factors weaken the LES. It’s not usually a lack of acid.

What Does the Evidence Actually Say?

There really isn’t a lot of evidence.

Apple cider vinegar itself has numerous health benefits. But its effect on acid reflux hasn’t been fully investigated. A 2015 graduate thesis found that ACV may prevent heartburn. However, the sample size here was small.

In the case of low stomach acid, it may provide some benefits. However, it’s hard to diagnose low stomach acid from symptoms alone, so it may make things worse.

That being said, a lack of evidence is not proof that it works or doesn’t work.

Can ACV Make Heartburn Worse?

Yes. Introducing an acidic substance to an already acidic environment could exacerbate symptoms, especially if you’ve already got an overproduction of acid.

You may notice:

·Irritation in the oesophagus

·Worsening reflux symptoms

·Dental enamel damage/erosion

If you want to try using ACV, it’s best to start small. A teaspoon is enough to see if there’s a negative effect. You can always gradually increase the dose.

Are There Situations Where ACV Might Help?

In rare cases where genuine low stomach acid is involved, ACV might be a suitable treatment. But it’s only suitable for mild symptoms and should never be used as a primary treatment.

You’ll want to undergo testing first to rule out other potential causes of heartburn or chest pain. The Functional Gut Clinic offers acid reflux testing that measures the presence of acid in the oesophagus. They also offer testing for low stomach acid. Both could help narrow down the underlying cause of your symptoms.

Better-Established Ways to Manage Heartburn

Dietary Adjustments

Heartburn is often linked to diet. Eating trigger foods such as fatty foods, caffeine, alcohol, or late meals, can cause an episode of acid reflux. By reducing these triggers, you could see if your heartburn is due to high acid levels.

Lifestyle Changes

Just tweaking your lifestyle can reduce heartburn. Try these tips:

·Maintain a healthy weight — excess abdominal pressure can worsen reflux

·Elevate your head during sleep — helps prevent acid from travelling upward

·Avoid lying down straight after meals — wait at least 2–3 hours before resting

Medical Options

If heartburn persists, your doctor may prescribe medications. Antacids are the best option to relieve an immediate acid attack, while PPIs and H2 blockers can provide long-term acid suppression.

Get Your Heartburn Checked

Heartburn is common, but the cause isn’t always obvious. Treating the wrong cause can make things worse. If your symptoms keep coming back, it’s worth moving beyond trial and error.

The Functional Gut Clinic offers targeted testing for acid reflux and GERD to help identify what could be driving your symptoms. With a clearer diagnosis, you can follow a plan that’s tailored to you rather than relying on guesswork or trends.

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