Bromelain

TL;DR

Bromelain digestive enzyme supplements (derived from pineapple) can be effective in aiding the digestion of high protein meals or drinks for those who experience discomfort otherwise. Other digestive enzymes that break down protein (proteases) can also be found in supplement form, however, bromelain also has many additional potential health benefits.

Bromelain is derived from the pineapple plant and refers to two proteolytic enzymes (know as proteases), which break down protein;

Stem bromelain is found in the stem of the plant and has varied medical and other uses. It's this which is usually used for commercial purposes and what you'll likely get in any supplement you buy.
Fruit bromelain is found in the pineapple fruit and it's juice but rarely extracted as both are typically of higher value sold as a food or drink rather than used in a supplement. There is also a far lower concentration of bromelain compared to the stem.

Bromelain supplements are frequently used in a health & fitness context to aid the digestion of protein (often in the form of high protein meals, drinks or shakes) for those who experience discomfort otherwise. Note that the fruit and juice of a pineapple do not contain enough bromelain to make consuming it for this purpose worthwhile.

Bromelain (and other proteases) enable protein digestion by breaking down protein molecule chains into pieces called polypeptides (often referred to as peptides) and also breaking polypeptides down into single amino acids. The polypeptides and amino acids can then be absorbed by the cells of the intestinal wall (protein itself cannot be). Any absorbed polypeptides are further broken down into single amino acids intracellularly(1) before entering the bloodstream. This occurs in the stomach and small intestine in a process called proteolysis.

Within the cell(s)

Other proteases include;

Chymotrypsin - produced by the pancreas
Papain (aka papaya proteinase) - from the papaya plant
Pepsin - produced in the stomach (actually pepsinogen is produced and then activated by the hydrochloric acid found in the stomach to become pepsin)
Protease - produced by the pancreas
Trypsin - produced by the pancreas

These can often also be found in supplement form, however, bromelain also has many additional potential health benefits including;

treatment of osteoarthritis ¹
treatment of rheumatoid arthritis ⁶, ⁷, ⁸
easing joint pain
easing swelling
slowing tumour growth
anti-inflammatory properties
anti-histamine properties
reducing sinusitis symptoms ⁹
reduction in pain intensity during dental extraction ¹⁰, ¹¹
improved recovery from tissue damage
slowing of blood clotting (anticoagulation) which may be effective at treating stroke, heart attack, high blood pressure and peripheral artery disease ²,⁵
reducing atherosclerosis ³
increases the bioavailability and reduces the side effects associated with various antibiotics ¹,⁴

In 2022, the U.S. Food and Drug Administration (FDA) approved a drug product containing bromelain for topical use for debridement (removal of dead tissue or contaminants) of severe burns in adults. The product is also approved for this purpose in the European Union (2012).

Quality

As with all supplements - buyer beware. It's quite common for supplements to be contaminated with a variety of impurities, often in the form of heavy metals, and/or contain far more or less of the ingredients stated on the label. There's no simple rule of thumb to avoid this, such as avoiding cheap or imported products; expensive or well-known brands produced in-country may be just as bad. Ideally you should take some time to find products (if you can) that;

have been laboratory tested on behalf of the manufacturer by a reputable body or company that operates in your country or region (here's an example of a Peak Supps creatine supplement available on Amazon in the UK which has been tested by Eurofins: Creatine Monohydrate Powder 1Kg | Pure Micronised | Packaging May Vary - see pictures 3 & 4)
have been laboratory tested by an independent testing company that ranks product purity and ingredient amount accuracy on behalf of consumers (usually funded by affiliate sales of those products). An example of this is Labdoor.

Dosage - How Much?

Look into this...

Doses of up to 240 mg daily have been used safely for up to one year.

500-1000mg a day, split across 1 to 3 doses.

Deficiency - Too Little

Toxicity - Too Much

Side Effects

Bromelain might cause some side effects in some people including;

diarrhoea
nausea
vomiting
heavier menstrual bleeding

Also take a close look at the following section.

When to Avoid Use - Interactions/Contraindications

Bromelain has a number of interactions with a number of medicines so care should be taken if you are taking any medicines or have any surgery planned.

Bromelain might slow blood clotting. Taking bromelain along with medications that also slow blood clotting might increase the risk of bruising and bleeding.
Bromelain might increase the risk of bleeding during and after surgery. Stop using bromelain at least 2 weeks before a scheduled surgery.
Taking bromelain might increase how much antibiotic the body absorbs. Taking bromelain along with some antibiotics called tetracyclines might increase the effects and side effects of these antibiotics.

Random Facts

Digestive enzymes are actually proteins themselves
Pineapple was traditionally used for medicinal purposes in South and Central America - like what???
Pineapple also contains small amounts of the proteases: ananain and comosain
Bromelain has a half-life of 6-9 hours