What is in it
Bromelain is a mixture of protein-digesting enzymes found in the pineapple plant. Bromelain from the stem has more protein-digesting activity than bromelain from the fruit (Mendes et al., 2019). It is sensitive to heat: it is irreversibly inactivated at high temperatures and loses its activity when heated to 100°C for 10 minutes (Colletti et al., 2021).
How much bromelain is absorbed when we eat pineapple is not known. A 2021 review describes its pharmacokinetics in people as still unclear (Colletti et al., 2021).
Polyphenols at a glance
These figures come from the Phenol-Explorer database and are given in mg per 100 g of the fresh food (Neveu et al., 2010; Phenol-Explorer, n.d.). The database records how each value was measured, and the methods are not interchangeable: chromatography identifies and measures individual compounds, some values are measured after the compounds have been broken down chemically (hydrolysis), and the Folin assay gives a single figure for total phenolic content.
Reading these figures. Pineapple was tested for 17 flavanols, including catechin and epicatechin, and none was detected. Small amounts of lignans, about 1.1 mg per 100 g in total, were found after hydrolysis. The Folin assay gives a total of about 147.9 mg (4 samples from 4 studies). The two methods measure different things, so the totals should not be compared directly.
Bromelain is an enzyme, not a polyphenol, so it does not appear in these figures.
What the evidence tells us
Well supported
None of the pineapple findings we have read so far reaches this label.
Promising
Bromelain after wisdom tooth removal. A meta-analysis of six randomised trials with 312 patients found that bromelain supplements reduced pain in the first 24 hours and at day 7 after surgery, improved eating, sleep and other measures of quality of life, and cut rescue painkiller use by about one tablet. It did not reduce swelling or jaw stiffness. The authors rated the evidence as moderate quality, received no funding and declared no conflicts of interest (Mendes et al., 2019).
Plausible pathway
From fresh fruit to the same effect. All six trials used bromelain tablets or capsules, and no human study we have read tested eating pineapple. Whether a portion of fresh pineapple delivers enough active bromelain to matter is unknown (Colletti et al., 2021; Mendes et al., 2019).
What we do not know
We do not know how much bromelain survives digestion from fresh pineapple. Bromelain supplements can cause side effects including diarrhoea and allergic reactions, and may increase the risk of bleeding, especially in people taking anticoagulants such as warfarin or clopidogrel (Colletti et al., 2021), so anyone on these medicines should check with a doctor or pharmacist before taking bromelain supplements.
References
Chong, C. W., Liew, M. S., Ooi, W., Jamil, H., Lim, A., Hooi, S. L., Tay, C. S. C., & Tan, G. (2024). Effect of green banana and pineapple fibre powder consumption on host gut microbiome. Frontiers in Nutrition, 11, Article 1437645. https://doi.org/10.3389/fnut.2024.1437645
Colletti, A., Li, S., Marengo, M., Adinolfi, S., & Cravotto, G. (2021). Recent advances and insights into bromelain processing, pharmacokinetics and therapeutic uses. Applied Sciences, 11(18), Article 8428. https://doi.org/10.3390/app11188428
Mendes, M.-L.-T., Nascimento-Júnior, E.-M. do, Reinheimer, D.-M., & Martins-Filho, P.-R.-S. (2019). Efficacy of proteolytic enzyme bromelain on health outcomes after third molar surgery: Systematic review and meta-analysis of randomized clinical trials. Medicina Oral, Patología Oral y Cirugía Bucal, 24(1), e61–e69. https://doi.org/10.4317/medoral.22731
Neveu, V., Perez-Jiménez, J., Vos, F., Crespy, V., du Chaffaut, L., Mennen, L., Knox, C., Eisner, R., Cruz, J., Wishart, D., & Scalbert, A. (2010). Phenol-Explorer: An online comprehensive database on polyphenol contents in foods. Database, 2010, Article bap024. https://doi.org/10.1093/database/bap024
Phenol-Explorer. (n.d.). Showing all polyphenols found in pineapple (Version 3.6) [Data set]. Retrieved October 18, 2026, from http://phenol-explorer.eu/contents/food/161
