What is bromelain?
Bromelain, derived from the stems and juice of the pineapple plant (Ananas comosus), is a mixture of proteolytic enzymes-in other words, enzymes that digest protein.
Although the general view is that most orally ingested enzymes are destroyed by digestive juices before being absorbed into the body, the evidence suggests that significant amounts of bromelain are absorbed intact, which means that the agent can have effects outside of the digestive tract.
Indeed, as well as being a popular aid to digestion, bromelain appears to be a powerful anti-inflammatory, analgesic, antimicrobial and immune-system-modulating agent, which makes it a useful supplement for a variety of health conditions.
What does bromelain do?
Research suggests that bromelain supplements-either alone or in combination with other nutrients-may be beneficial for an impressive array of diseases and conditions, particularly those that involve inflammation.
- Arthritis. In a double-blind randomized study of 90 osteoarthritis patients, a supple-ment containing bromelain (90 mg), along with the enzyme trypsin (48 mg) and the flavonoid rutin (100 mg), was compared with the non-steroidal anti-inflammatory drug (NSAID) diclofenac (50 mg). After six weeks, the results showed that the enzyme supplement (two tablets three times a day) was just as effective as diclofenac (one tablet twice a day) for improving pain, joint stiffness and physical function-and the supplement was also better tolerated (Clin Exp Rheumatol, 2006; 24: 25-30).
- Respiratory conditions. Several studies carried out in the 1960s reported that bromelain had a beneficial effect on sinusitis-inflammation of the sinuses caused by viral or bacterial infections. In one study, 85 per cent of the patients receiving bromelain had complete clearance of inflamma-tion in the nasal mucosa and complete resolution of their breathing difficulties, whereas only 40-50 per cent of those in the placebo group saw their inflammation and breathing difficulties resolve (Altern Med Rev, 2010; 15: 361-8).
Bromelain is also showing promise for asthma. Animal studies conducted at the University of Connecticut discovered that bromelain can reduce airway reactivity and sensitivity to irritants as well as markers of lung inflammation (Evid Based Complement Alternat Med, 2008; 5: 61-9; Cell Immunol, 2005; 237: 68-75). These results, however, now need to be confirmed in human studies.
- Musculoskeletal injuries. In an uncontrolled study of 59 patients with blunt-force injuries to the musculoskeletal system, treatment with bromelain resulted in a reduction of swelling, pain and tenderness (Fortschr Med, 1995; 113: 303-6). In another study, an enzyme preparation including bromelain, in combination with dietary counselling and acupuncture, promoted better healing of rotatorcuff tendonitis than did the standard physical exercises (Arthritis Rheum, 2009; 61: 1037-45). Bromelain also appears to speed-up the healing of bruises and haematomas (Altern Med Rev, 2010; 15: 361-8).
- Inflammatory bowel disease (IBD). A laboratory study by Duke University researchers assessed the effectiveness of bromelain on tissues from the colon biopsies of 51 patients-20 with ulcerative colitis and 23 with Crohn's disease (both are types of IBD)-and eight control subjects. The biopsies were treated with bromelain, then the production of the enzymes that fuel IBD were measured. The researchers found that bromelain significantly reduced the production of these enzymes and "may be a novel therapy for IBD" (Clin Immunol, 2008; 126: 345-52).
- Postoperative swelling. In a controlled study of 60 patients who had undergone surgery for bone fractures, bromelain in combination with trypsin and rutin was more effective for reducing post-operative swelling than the usual drugs given for the problem. The bromelain preparation also appeared to have an analgesic (pain-killing) effect (Acta Chir Orthop Traumatol Cech, 2001; 68: 45-9).
- Cancer. Some evidence indicates that bromelain may be useful as an anticancer agent. In a recent test-tube study of breast cancer cells, bromelain triggered a process called 'autophagy', which led to apoptosis (programmed cell death) of the cancerous cells (Biofactors, 2010; 36: 474-82). In studies of mice, bromelain has displayed both chemopreventative and antitumour effects (Cancer Lett, 2009; 282: 167-76; Toxicol Appl Pharmacol, 2008; 226: 30-7). Although clinical trials are lacking, proteolytic-enzyme preparations including bromelain have been used as a complementary therapy for human cancer treatment. Studies have shown that these preparations significantly decreased tumour-induced and therapy-related side-effects and complaints such as nausea, gastrointestinal problems, fatigue, weight loss and restlessness, while also improving the quality of life (Integr Cancer Ther, 2008; 7: 311-6).
What are the risks?
In clinical trials of bromelain, side-effects have rarely been reported, although the supplement may cause gastrointestinal upsets such as nausea, flatulence and diarrhoea, as well as headache, tiredness and dry mouth (Evid Based Complement Alternat Med, 2004; 1: 251-7). It might also cause an allergic reaction in people who are allergic to pineapples, wheat, celery, papain (from papayas), carrots, fennel, cypress pollen or grass pollen. One report suggests that individuals with high blood pressure might experience tachycardia (rapid heartbeat) following high doses of bromelain (Hawaii Med J, 1978; 37: 143-6).
Because of possible drug interactions (bromelain could increase the amount of antibiotics absorbed by the body and increase the effect of blood thinners such as warfarin) (Altern Med Rev, 2010; 15: 361-8), make sure you seek the advice of a qualified medical professional if you are considering taking bromelain along with other medications.
The bottom line
Bromelain's anti-inflammatory action and other physiological effects make it a useful supplement for a wide range of disorders-from arthritis to cancer. However, many more high-quality clinical trials are needed, especially those investigating the use of bromelain alone rather than in combination with other nutrients and therapies. Indeed, in some studies, it hasn't been possible to tell whether the beneficial effects were down to bromelain or the other proteolytic enzymes that were used, or whether they worked because of synergistic effects.
Nevertheless, both animal and laboratory studies show that bromelain has several mechanisms of action that can be beneficial to the body during injury and disease.
Considering its good safety profile, it may be worthwhile paying this often overlooked supplement more attention.
Factfile: How much to take?
Bromelain has shown beneficial effects in doses as small as 160 mg/day. However, it's thought that, for most conditions, the best results are seen with larger doses of 750-1000 mg/day-usually in four divided doses (Altern Med Rev, 2010; 15: 361-8). The German Commission E recommends 80-320 mg two or three times a day (for adults). For specific conditions, higher doses may be prescribed (but consult a qualified practitioner for a personal recommendation). So, to help with:
- digestion, take 500 mg/day in divided doses with meals
- injuries, take 500 mg four times a day on an empty stomach
- arthritis, take 500-2000 mg/day in two divided doses.
WDDTY VOL 22 NO 10 January 2012