Olive oil in the prevention and management of type 2 diabetes mellitus: a systematic review and meta-analysis of cohort studies and intervention trials

Abstract

Background/Objectives:Olive oil (OO) as food is composed mainly of fatty acids and bioactive compounds depending from the extraction method. Both had been discussed as health promoting with still open questions. Thus, we conducted a meta-analysis to illustrate the impact of this food on type 2 diabetes (T2D) by investigating the association between OO intake and risk of T2D, and the effect of OO intake in the management of T2D.Subjects/Methods:Searches were performed in PubMed, Cochrane Library and google scholar. First, we conducted a random effect meta-analysis of prospective cohort studies and trials investigating the association between OO and risk of T2D. Second, a meta-analysis was performed to detect the effects of olive oil on glycemic control in patients with T2D.Results:Four cohort studies including 15 784 T2D cases and 29 trials were included in the meta-analysis. The highest OO intake category showed a 16% reduced risk of T2D (RR: 0.84; 95% CI: 0.77, 0.92) compared with the lowest. However, we observed evidence for a nonlinear relationship. In T2D patients OO supplementation resulted in a significantly more pronounced reduction in HbA1c (MD: −0.27% 95% CI: −0.37, −0.17) and fasting plasma glucose (MD: −0.44 mmol l−1; 95% CI −0.66, −0.22) as compared with the control groups.Conclusions:This meta-analysis provides evidence that the intake of OO could be beneficial for the prevention and management of T2D. This conclusion regards OO as food, and might not been valid for single components comprising this food.

Toxicity of fatty acid profiles of popular edible oils in human EndoC-βH1 beta-cells

“…Many popular oils belong to this group, including olive oil. The T2DM risk reduction through oils with a high content of unsaturated FFAs as observed in several studies 3,14 could not be translated to human EndoC-βH1 beta-cells in our study. This does not exclude that other plant ingredients such as polyphenols might have a protective effect 15,16 .…”

“…Dietary habits can have a major impact on health and may cause obesity and type 2 diabetes mellitus (T2DM). Numerous studies have examined the effects of dietary oil consumptions on human health; however, with conflicting results [1][2][3] . A prominent example is olive oil, containing mostly the monounsaturated free fatty acid (FFA) oleic acid, which is thought to have beneficial effects on cardiovascular health and the metabolic state in T2DM 3 .…”

“…Numerous studies have examined the effects of dietary oil consumptions on human health; however, with conflicting results [1][2][3] . A prominent example is olive oil, containing mostly the monounsaturated free fatty acid (FFA) oleic acid, which is thought to have beneficial effects on cardiovascular health and the metabolic state in T2DM 3 . On the other hand, coconut oil, rich in medium-chain FFAs, has been promoted for positive effects on health 1 although clinical trials could not provide solid evidence for this assumption 2 .…”

Prevention of type 2 diabetes in prediabetic patients by using functional olive oil enriched in oleanolic acid: The PREDIABOLE study, a randomized controlled trial

“…Testing the effects of the OA‐enriched olive oil against not a placebo or a low‐fat diet, but against the same olive oil unreinforced in the triterpene, should also be considered a strength of the trial. Meta‐analysis of the effects of olive oil‐supplemented diets indicates that the consumption of olive oil is associated both with a decreased risk of developing the disease in healthy individuals and with an improvement of glucose homeostasis in patients with diabetes . Most of those studies used virgin olive oil and focused their attention on the fatty acid composition or the presence of phenolics, overlooking the biological activity of the other natural functional components of olive oils, such as OA.…”

Application of Infrared Spectroscopy for Functional Compounds Evaluation in Olive Oil: A Current Snapshot

“…EEC Regulation 29/2012 determines the compulsory and optional information to include on olive oil labels, supplementing the general rules relating to foodstuffs and their marketing in EEC Regulation 2000/2013. e chemical composition of olive oil is characterized mainly by triacylglycerols, monoacylglycerols, diacylglycerols, and free fatty acids [17,18], as well as fatty acid derivatives (i.e., phospholipids and waxes) [19,20]. Moreover, there is a diverse group of compounds such as sterols, aliphatic alcohols, chlorophylls, carotenoids, and hydrocarbons [21][22][23].…”