Role of Pineapple Juice in Promoting Digestion in Adults: A Scoping Review of the Literature

Abstract

Abstract Introduction. Digestive enzymes aid in the digestion of fats, proteins and carbohydrates and facilitate nutrient absorption. Studies report that some fruits also aid in digestion. Pineapple (Ananas comosus), for example, is believed to improve digestion by stimulating gastric juice secretion and intensifying salivary flow. Regular consumption of the fruit is linked to improved nutrition, digestion, immunity and metabolism. These medicinal benefits are due to bromelain, the main protease abundantly present in pineapple. Though widely touted on the internet, the benefits of pineapple are poorly supported, and the use of bromelain in clinical practice remains controversial. One study reported a serious lack of literature in English on the matter of digestion in the human study. Objective. To determine the extent, scope and nature of research related to pineapple juice and/or bromelain use to promote digestion in adults. Methodology. To employ a scoping review of research on the role of pineapple to promote digestion in adults. Using articles published from 1975–2020, the review included: a literature search of electronic databases—Web of Science, PubMed/Medline, the Wiley Online Library, Scopus, Ovid, Embase, ScienceDirect and Cochrane Reviews; reference lists of relevant systematic reviews; and a search of primary studies on related topics, networks, organisations, and conferences to find clinical trials. Results. The database contained a total of 1692 studies, twenty-four of which met the criteria and were included. Nearly half of these originated in developed countries, and all but seven were of poor quality. Overall, the studies found that pineapple juice could help in the digestion of protein and fat. However, some studies found no benefit. Therefore, the findings have yet to be confirmed but must be critically assessed to determine if bromelain can be used as a phytomedical supplement. Conclusion. Current research on pineapple juice may face—as research on other dietary supplements has—a general challenge of methodological limitations, including heterogeneity of interference and dose, small sample sizes, lack of standardized outcome measures and non-uniform food intervention. Therefore, to better define the proper role of enzyme supplements in an impaired digestive system, well-designed experiments with strict methodology are urgently required.