Dietary intake of linoleic acid, its concentrations and the risk of type 2 diabetes: a systematic review and dose-response meta-analysis of prospective cohort studies
Purpose: To quantitatively summarize previous studies on the association between dietary LA intake, its biomarkers, and the risk of type 2 diabetes mellitus (T2DM) in the general population.
Data source: PubMed/Medline, Scopus, and ISI Web of Science until 24 October 2020, and reference lists of all related articles, and key journals.
Study selection: Prospective cohort studies that examined the associations of LA with the risk of T2DM in adults.
Data synthesis: The inverse variance method was applied to calculate summary relative risk (RR) of LA intake and its biomarkers, and dose-response associations was modeled using restricted cubic splines. Twenty-three publications, covering a total of 31 prospective cohorts, were included; these studies included 297,685 participants (22,639 incident diabetes cases) with dietary intake assessment and 84,171 participants (18,458 incident diabetes cases) with biomarker measurements. High intake of LA was associated with a 6% lower risk of T2DM (summary relative risk (RR): 0.94, 95% confidence interval (CI): 0.90, 0.99; I2=48.5%). In the dose-response analysis, each 5% increment in energy from LA intake was associated with a 10% lower risk of T2DM. There was also evidence of a linear association between LA intake and diabetes, with the lowest risk at highest intakes. The summary RR for diabetes per SD increment in LA concentrations in adipose tissue/blood compartments was 0.85 (95%CI: 0.80, 0.90; I2=66.2%). The certainty of the evidence was assessed as moderate.
Limitation: Observational design of studies included in the analyses.
Conclusions: We found that a high intake of dietary LA and elevated concentrations of LA in the body were both significantly associated with a lower risk of T2DM. These findings support dietary recommendations to consume dietary LA.