Bromelain

Bromelain's anti-inflammatory effects extend beyond protein digestion. It reduces levels of bradykinin and prostaglandin E2, decreases fibrinogen and promotes fibrinolysis, and lowers levels of the pro-inflammatory cytokines TNF-α, IL-1β, and IL-6 while modulating immune cell surface molecules (removing CD44 and other adhesion molecules from leukocytes, which reduces their migration into inflamed tissue). It reduces swelling by lowering vascular permeability and helping clear fibrin and fluid from tissues. In the gut it digests proteins, aiding digestion and reducing protein-derived allergenic peptides. Bromelain also inhibits platelet aggregation, thins mucus, and may enhance antibiotic absorption. In osteoarthritis it appears to act as a modest COX-2-independent anti-inflammatory and analgesic.

Bromelain has a moderate evidence base. A 2004 review of clinical studies in osteoarthritis found bromelain (typically 540–1,890 mg daily, often in combination with trypsin and rutin as Phlogenzym) comparable to NSAIDs such as diclofenac for pain and function in several trials, though a later 2006 RCT of 400 mg daily alone in 47 people with knee osteoarthritis found no benefit over placebo at 12 weeks. For post-surgical swelling, a meta-analysis of dental surgery trials and multiple RCTs in rhinoplasty and other procedures found reduced swelling, bruising, and pain, with effects comparable to some anti-inflammatory drugs. Small trials have shown faster recovery from sports injuries and bruising. A 2005 German trial in 62 children with acute sinusitis found bromelain shortened symptom duration compared with standard therapy. Preliminary studies suggest benefit for allergic airway inflammation and inflammatory bowel disease, and laboratory studies show anticancer activity, but these are not supported by human trials. The NCCIH notes some evidence for sinusitis and post-surgical swelling but considers other uses unproven.

Cysteine proteases (stem bromelain, fruit bromelain, ananain, comosain), plus phosphatases, glucosidases, peroxidases, cellulases, and protease inhibitors; activity measured in GDU or MCU

Bromelain is absorbed intact across the intestine to a surprising degree: studies detect active enzyme in plasma after oral dosing, with peak levels at about an hour and a half-life of 6–9 hours, and roughly 40% of the proteolytic activity surviving transit. For anti-inflammatory effects it must be taken on an empty stomach (between meals) so it is not used up digesting food; for digestive support it is taken with meals. Potency depends on enzyme activity (GDU/g), not milligrams; 2,000–2,400 GDU/g is a common standard. Enteric coating helps protect activity.

• Fresh pineapple (fruit bromelain, mainly in the core; destroyed by canning and cooking)
• Fresh pineapple juice
• Pineapple stem (not typically eaten; source of supplement enzyme)