The benefits of pineapples have been touted in folk medicine for years. Increasing knowledge of its active ingredient bromelain has lead to a therapeutic pineapple renaissance. Bromelain is a complex natural mixture of proteolytic enzymes derived from pineapple (Ananas cosmosus) and possesses notable medicinal properties, including anti-inflammatory, antithrombotic and fibrinolytic effects, anticancer activity and immunomodulatory effects. It is also used for improving wound healing [debridement] (1).
According to de Lencastre Novaes et al, “Bromelain is a biomolecule of great industrial and medical interest and there are several areas to be explored in terms of its puriﬁcation, mode of action, and potential applications in industry and medicine.” Mechanistically, its biologic effects are protean: As an anti-inflammatory agent, it downregulates COX-2 and PGE-2. Interestingly, when a healthy immune system is under stress, bromelain may activate production of cytokines IL1-b, IL-6, interferon-g, and TNF-a, however, it may decrease their secretion in patients with active inflammatory diseases. Their antineoplastic effect is based on inhibiting the NFkB pathway and activation of caspases, leading to apoptosis. Angiogenesis of tumors is suppressed by inhibition of platelet aggregation and activation, and decreasing VEGF levels. Bromelain has also demonstrated antibacterial, antifungal, and antihelminthic activity (3).
You might think that pineapples might be beneficial for inflammatory disorders such as mucous membrane pemphigoid – that was clearly not the case for a patient presented by Belcher et al, in whom his oral cicatricial pemphigoid flares were preceded by pineapple consumption. Utilizing confluent neonatal epidermal keratinocytes exposed to different concentrations of bromelain, they determined that keratinocytes treated with10mg/mL bromelain for 10 minutes exhibited a decrease in the levels of intact type XVII collagen, but not the myosin IIa loading control compared with untreated keratinocytes. To determine whether bromelain had an effect on intact skin, adult facial skin removed to facilitate was exposed to bromelain (300mg/mL) for 30 minutes, fixed with 10% formalin, and sectioned for histologic analysis. Separation at the dermal-epidermal junction was observed in treated but not control tissue (3).
Given their patient’s experience it’s hard to argue with their conclusion urging caution regarding pineapple ingestion to patients with autoimmune blistering disorders affecting the oral mucosa. What if a bromelain pill was utilized instead? Could its anti-inflammatory effects actually be beneficial in such cases?*
*Bromelain supplements are available – I am not advocating their use until I see specific studies related to inflammatory dermatoses. For example, as of October 4, 2016 there were no PubMed articles discussing bromelain with psoriasis, atopic dermatitis, or pemphigus.
- Rathnavelu V, et al. Potential role of bromelain in clinical and therapeutic applications. Biomed Rep 2016; 5: 283-8.
- de Lencastre Novaes LC, et al. Stability, purification, and applications of bromelain: A review. Biotechnol Prog 2016; 32: 5-13.
- Belcher MD, et al. The proteolytic effect of bromelain on bullous pemphigoid antigen-2. J Am Acad Dermatol 2016; 75: 838-40.