Polyunsaturated fatty acid intake and incidence of type 2 diabetes in adults: a dose response meta-analysis of cohort studies

Abstract

Background To evaluate the association and dose–response relationship between polyunsaturated fatty acid (PUFA) intake and incidence of type 2 diabetes (T2D) in adults. Methods PubMed, Embase, Cochrane Library, and Web of Science databases were searched for cohort studies that examined the association between PUFA and T2D incidence published up to September 6, 2021. Relative risk (RR) or hazard ratio (HR) was used as the effect indicator, each effect size was expressed by 95% confidence interval (CI). The presence of heterogeneity of effect size between studies was assessed by the Q-test and I2 statistics. If I2 ≥ 50%, the random-effects model was applied, otherwise the fixed effects model was used. Sensitivity analysis was performed for all models. Potential publication bias was assessed. We conducted linear and nonlinear dose–response meta-analyses, calculated summary relative risk (SRR). Results Twenty-five articles were selected including 54,000 patients in this study. Our estimates observed no linear associations between total PUFA and the incidence of T2D. However, the summary dose–response curve of T2D risk increased in a nonlinear pattern with the consumption of omega-3 PUFA (Pnonlinearity < 0.001) and docosahexaenoic acid (DHA) (Pnonlinearity = 0.040). Our subgroup analysis showed that total PUFA intake was associated with increased incidence of T2D in Europe (RR: 1.040, 95% CI 1.009 to 1.072), and Australia (RR: 1.188, 95% CI 1.113 to 1.269). However, total PUFA intake was associated with decreased T2D incidence in Asia (RR: 0.897, 95% CI 0.860 to 0.936). Subgroup analysis based on PUFA types showed that DHA intake was associated with decreased T2D incidence (RR: 1.164, 95% CI 1.048 to 1.294) while linoleic acid (LA) decreased T2D incidence (RR: 0.956, 95% CI 0.930 to 0.983). Regarding the sex subgroup, women’s intake of total PUFA would increase the risk of T2D (RR: 1.049, 95% CI 1.019 to 1.079) while total PUFA intake decreased the risk of T2D in men (RR: 0.955, 95% CI 0.913 to 0.999). Conclusion For specific PUFA, dose–response curves show nonlinear significant associations between PUFA intakes and T2D. It may be necessary to pay attention to the effects of PUFA and type of intake on T2D. Trial registration Not applicable

Linoleic acid, an omega-6 fatty acid that reduces risk for cardiometabolic diseases: premise, promise and practical implications

“…For T2DM, a recent meta-analysis revealed the hazard ratios of diabetes incidence to be between 0.79 and 0.92 for long chain omeha-3 fatty acids; unfortunately, there was no relationship between alpha-linolenic acid, the main omega-3 fatty acid consumed in the human diet. Furthermore, other studies show that long chain omega-3 fatty acid intake may increase type 2 diabetes risk [3]. In contrast, higher LA in diet or blood is associated with lower incidence of heart disease and T2DM and better glycemic control and/or insulin sensitivity [1 ▪ ,2,3,4 ▪▪ ,5,16 ▪ ].…”

“…In the United States, monounsaturated fatty acids (MUFAs) are the dominant type of fat eaten (∼40% of fat Calories), followed by saturated fatty acids (SFAs; ∼35% of fat calories) then polyunsaturated fatty acids (PUFAs; ∼25% of fat calories) [13]. Dietary intake of MUFAs (e.g., palmitoleate, oleate) or omega-3 PUFAs (e.g., alpha-linolenic, eicosapentaenoic, and docosahexaenoic acids) have mild or inconsistent effects on heart disease and T2DM risk [3,14,15]. For T2DM, a recent meta-analysis revealed the hazard ratios of diabetes incidence to be between 0.79 and 0.92 for long chain omeha-3 fatty acids; unfortunately, there was no relationship between alpha-linolenic acid, the main omega-3 fatty acid consumed in the human diet.…”

“…Furthermore, other studies show that long chain omega-3 fatty acid intake may increase type 2 diabetes risk [3]. In contrast, higher LA in diet or blood is associated with lower incidence of heart disease and T2DM and better glycemic control and/or insulin sensitivity [1 ▪ ,2,3,4 ▪▪ ,5,16 ▪ ]. In order to determine how dietary LA affects insulin resistance, Summers et al [17] conducted a crossover trial using LA-rich vs. SFA-rich fats.…”

“…Cardiovascular disease and type 2 diabetes mellitus (T2DM), aka cardiometabolic disease (CMD), share many mechanistically linked risk factors. Diets enriched with linoleic acid (LA; 18:2n6) as well as biomarkers of LA intake are associated with reduced CMD risk [1 ▪ ,2,3,4 ▪▪ ]. Relative risk of LA biomarker for CVD incidence and mortality was 0.87 [1 ▪ ] and 0.93 [2] in two separate analyses.…”

Evaluation of Plant Protein Hydrolysates as Natural Antioxidants in Fish Oil-In-Water Emulsions

“…Polyunsaturated fatty acids (PUFA), and more specifically, those belonging to the omega-3 family such as eicosapentaenoic (C20:5n-3, EPA) and docosahexaenoic (C22:6n-3, DHA) acids, have attracted growing interest over the past decades as functional ingredients for food formulations. Several studies support the health benefits associated with a regular intake of omega-3 fatty acids, such as the prevention of cardiovascular disease [ 1 ], diabetes [ 2 ] and inflammatory diseases (e.g., asthma, rheumatoid arthritis, inflammatory bowel diseases and Alzheimer) [ 3 , 4 ], among others. EPA and DHA are semi-essential fatty acids since their natural conversion from α- linolenic acid is insufficient to meet human dietary requirements [ 5 ].…”