Pineapple May Exacerbate Stomach Ulcer Symptoms

The seemingly innocuous tropical fruit may indeed be a fruit to cross off of your list if you have a stomach ulcer, as its effect on digestion could potentially be a negative influence for those with stomach ulcer symptoms.

Bromelain, an enzyme found primarily in pineapples, has been the topic of recent study for its wide-ranging and powerful effects on the human digestive system. This enzyme breaks down the bonds that hold proteins together and acts as an anti-inflammatory inside the human body.

In a very recent study was examining the effect of pineapple on the effect of bromelain on digestion, researchers mentioned that bromelain (which is found in pineapples) inhibits the secretions of the digestive tract (1).

If the magnitude of this is not yet sinking in, NSAIDs like aspirin, ibuprofen, and naproxen are the primary factor behind non-Helicobacter pylori ulcers. They act in the same way; NSAIDs are a class of anti-inflammatories that happens to have the side effect of reducing stomach secretions. This in turn makes the stomach lining vulnerable to its own acid, which in turn leads to ulceration.

Practical Application – Should I Eat Pineapples?

You will want to take all information such as this with a grain of salt. It is not likely that eating pineapples will give you an ulcer, as we would have likely noticed this long ago. However, you have to consider that pineapple is not a dietary staple in modernized countries.

It is possible that high quantities of bromelain may not be ideal. It is also possible that people with preexisting ulcers find their symptoms worsen after eating pineapple. If you have an ulcer and are not sure, use your own pain as a guide; if you eat pineapple and it makes your stomach hurt, you will want to avoid that in the future, at least for your own personal comfort if nothing less.

More importantly though, some people do get bromelain in supranatural quantities through supplementation. Bromelain supplements have become very popular over the last decade, especially in the holistic and alternative medicine communities.

Given that we know that ulcers can be caused by regular usage of NSAIDs (which reduce stomach secretions), it is possible that people who take large quantities of bromelain or other “anti-inflammatory plant enzymes” could suffer a similar fate through the same mechanism.

I do not mean to throw these supplements under the bus, but you do have to remember that supplements go on the market without any testing for their long-term effects, so really we have no way of knowing if there are still long-term effects for these enzymes.

Just because they come from a plant does not mean they are healthy – we know very large quantities of isoflavones from soy can have all sorts of side effects (due to its estrogen-mimicking effects), so do not think something untested is safe just because it comes from a plant.

Pineapple and Ulcers Conclusion

There is no real evidence to suggest that people eating normal amounts of pineapple in their diet (i.e. occasionally) will be more likely to suffer from ulcers or have heightened symptoms.

However, using supranatural amounts of bromelain through supplementation does decrease intestinal secretions (at least in mice) (1). This may make bromelain supplements unsafe for people who have a current or past history of peptic ulcer(s).


1. Borrelli, F. Inhibitory effects of bromelain, a cysteine protease derived from pineapple stem (Ananas comosus), on intestinal motility in mice. Neurogastroenterol Motil. 2011 Jun 21. [Epub ahead of print]

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