If you have any kind of digestive related ailment (like yours truly), you have probably received all kinds of (probably unwelcome) advice from those who like to play doctor on the internet. I'm sure some of you, like me, have been told (not always nicely) that you need to use "digestive enzymes" to cure whatever ails you. So that's why I was pleased to see this article which gives a brief overview of who can really benefit from taking enzymes and what kind of enzymes you might actually need. In short, you only need to take enzymes if you have pancreatic insufficiency (yes, your pancreas helps you digest fat besides making insulin), lactose intolerance (and you just can't resist that bowl of ice cream), or a high fiber diet (e.g. you are a vegan who uses legumes as a primary protein source). Note that those type of enzymes are usually have a special coating so that the gastric (stomach) juices do not render the enzymes useless and they can actually reach your intestines. There are a few other enzymes that are often recommended to people, however, that are worth talking about.
1) Papain, also known as "papain enzyme" or "papaya extract."
Papain does actually contain enzymes that break down proteins, and this is why it is used in enzymatic cleaners (such as those used for contact lenses) or to tenderize meats. Unfortunately there is little to no evidence to support helping vague "digestive problems" or the more specific "intestinal worms." (Link) Eating papaya doesn't seem to produce any side effects (unless you overeat), but taking the extract in excess might actually cause irritation of the stomach. So unless you have some money to burn or need a low caloric way to tenderize meat I wouldn't spend the money on this one.
2) Bromelain, also known as "pineapple extract."
Bromelain has actually gotten more attention as something that might be effective for arthritis (osteoarthritis) pain when used in combination with another compound. When it comes to digestive issues I have seen it recommended to people who have inflammatory bowel disease, like ulcerative colitis, and also for vague "stomach problems." Once again, there is little to no evidence that bromelain works (Link), and excessive amounts might even cause diarrhea and stomach irritation. I also found it interesting that people who have allergies to wheat and grass pollen might have a similar reaction if they take bromelain. If you are just going to eat pineapple your stomach will probably be fine unless you have a problem with GERD.
Take home message--Enjoy pineapple and papaya as part of your daily fruit allowance (just avoid the dried sugar-added versions), taking the supplements will likely cause irritation to your wallet.