Oral lipolysis and its association with diet and the perception and digestion of lipids: A systematic literature review.

• A small number of papers address salivary lipolysis in animal models or in humans. • A consensus for a normative method to evaluate lipase activity is highly necessary. • Lingual lipase has never been clearly demonstrated in humans. • Human lipases could not be specifically associated with lipid taste, digestion or diet. This systematic literature review aims to summarize the existing scientific evidence on the association of oral lipolysis with diet and with the perception and digestion of lipids in humans and rodents. A validated search strategy of two databases (PubMed and ISI Web of Knowledge) was carried out and the contents were screened by two independent reviewers. The quality of the included studies was critically evaluated on the basis of the Quality Assessment Criteria for Evaluating Primary Research Papers. From the originally identified studies (n = 2295), 17 articles met the eligibility criteria for inclusion in the analysis. Among them, only 6 articles received the maximum assessment score. The main reason for this finding was the absence of a control for the confounding bias between lipases and esterases. In rodents, oral lipolysis was principally due to the activity of lingual lipase, which was associated with the 3 selected parameters. In humans, the association parameters were principally established through indirect evidence without a clear demonstration of cause. Moreover, no specific lipase, such as lingual lipase in the case of rodents, was identified at the oral level. Future research efforts should focus on (i) establishing a standard procedure for oral lipolytic activity evaluation and, in particular, a methodological control to address the lipase vs esterase confounding bias and (ii) identifying the main lipases that contribute to the lipolytic activity in humans at the oral level and their respective contribution to the association parameters defined in this review. [ABSTRACT FROM AUTHOR]