Neale, E., V. Guan, L. Tapsell, Y. Probst, 2020. Effect of walnut consumption on markers of blood glucose control: A systematic review and meta-analysis. Br J Nutr. 124(7):641-653.
Type 2 diabetes mellitus is a chronic disease increasing in global prevalence. Although habitual consumption of walnuts is associated with reduced risk of CVD, there is inconsistent evidence for the impact of walnut consumption on markers of glycaemic control. This systematic review and meta-analysis aimed to examine the effect of walnut consumption on markers of blood glucose control. A systematic search of Medline, PubMed, CINAHL and Cochrane databases (to 2 March 2019) was conducted. Inclusion criteria were randomised controlled trials conducted with adults which assessed the effect of walnut consumption on fasting blood glucose and insulin, glycated Hb and homeostatic model assessment of insulin resistance. Random effects meta-analyses were conducted to assess the weighted mean differences (WMD) for each outcome. Risk of bias in studies was assessed using the Cochrane Risk of Bias tool 2.0. Sixteen studies providing eighteen effect sizes were included in the review. Consumption of walnuts did not result in significant changes in fasting blood glucose levels (WMD: 0·331 mg/dl; 95 % CI −0·817, 1·479) or other outcome measures. Studies were determined to have either ‘some concerns’ or be at ‘high risk’ of bias. There was no evidence of an effect of walnut consumption on markers of blood glucose control. These findings suggest that the known favourable effects of walnut intake on CVD are not mediated via improvements in glycaemic control. Given the high risk of bias observed in the current evidence base, there is a need for further high-quality randomised controlled trials.
Park, J.M., J.M. An, Y.M. Han, Y.J. Surh, S.J. Hwang, S.J. Kim, K.B. Hahm, 2020. Walnut polyphenol extracts inhibit Helicobacter pylori-induced STAT3Tyr705 phosphorylation through activation of PPAR-γ and SOCS1 induction. J Clin Biochem Nutr. 67(3):248-256.
The health beneficial effects of walnut plentiful of n-3 polyunsaturated fatty acid had been attributed to its anti-inflammatory and anti-oxidative properties against various clinical diseases. Since we have published Fat-1 transgenic mice overexpressing 3-desaturase significantly mitigated Helicobacter pylori (H. pylori)-associated gastric pathologies including rejuvenation of chronic atrophic gastritis and prevention of gastric cancer, in this study, we have explored the underlying molecular mechanisms of walnut against H. pylori infection. Fresh walnut polyphenol extracts (WPE) were found to suppress the phosphorylation and nuclear translocation of signal transducer and activator of transcription 3 (STAT3) induced by H. pylori infection in RGM-1 gastric mucosal cells. Notably, H. pylori infection significantly decreased suppressor of cytokine signaling 1 (SOCS1), but WPE induced expression of SOCS1, by which the suppressive effect of walnut extracts on STAT3Tyr705 phosphorylation was not seen in SOCS1 KO cells. WPE induced significantly increased nuclear translocation nuclear translocation of PPAR-γ in RGM1 cells, by which PPAR-γ KO inhibited transcription of SOCS1 and suppressive effect of WPE on p-STAT3Tyr705 was not seen. WPE inhibited the expression of c-Myc and IL-6/IL-6R signaling, which was attenuated in the RGM1 cells harboring SOCS1 specific siRNA. Conclusively, WPE inhibits H. pylori-induced STAT3 phosphorylation in a PPAR-γ and SOCS1-dependent manner.
McArthur, B., R. Mattes, 2020. Energy extraction from nuts: walnuts, almonds, pistachios. Br J Nutr. 123(4):361-371.
The bioaccessibility of fat has implications for satiety and postprandial lipidemia. The prevailing view holds that the integrity of plant cell wall structure is the primary determinant of energy and nutrient extraction from plant cells as they pass through the gastrointestinal tract. However, comparisons across nuts (walnuts, almonds, pistachios) with varying physical properties do not support this view. In this study, masticated samples of three nuts from healthy adults were exposed to a static model of gastric digestion followed by simulated intestinal digestion. Primary outcomes were particle size and lipid release at each phase of digestion. Walnuts produced a significantly larger particle size post-mastication compared to almonds. Under gastric and intestinal conditions, the particle size was larger for walnuts compared to pistachios and almonds (P<0.05). However, the masticated and digesta particle sizes were not related to the integrity of cell walls nor lipid release. The total lipid release was comparable between nuts after the in vitro intestinal phase (P>0.05). Microstructural examination showed ruptured and fissured cell walls that would allow digestion of cellular contents and this may be governed by internal cellular properties such as oil body state. Furthermore, the cell walls of walnuts tend to rupture rather than separate and as walnut tissue passes through the gastrointestinal track, lipids tend to coalesce reducing digestion efficiency.
Lázaro, I., F. Rueda, G. Cediel, E. Ortega, C. García-García, A. Sala-Vila, A. Bayés-Genís, 2020. Circulating omega-3 fatty acids and incident adverse events in patients with acute myocardial infarction. J Am Coll Cardiol. 76(18):2089-2097.
Background: Dietary omega-3 eicosapentaenoic acid (EPA) has multiple cardioprotective properties. The proportion of EPA in serum phosphatidylcholine (PC) mirrors dietary EPA intake during previous weeks. Circulating EPA in ST-segment elevation myocardial infarction (STEMI) relates to smaller infarct size and preserved long-term ventricular function. Objectives The authors investigated whether serum-PC EPA (proxy for marine omega-3 consumption) levels at the time of STEMI were associated with a lower incidence of major adverse cardiovascular events (MACE), all-cause mortality, and readmission for cardiovascular (CV) causes at 3 years’ follow-up. We also explored the association of alpha-linolenic acid (ALA, proxy for vegetable omega-3 intake) with all-cause mortality and MACE. Methods: The authors prospectively included 944 consecutive patients with STEMI (mean age 61 years, 209 women) undergoing primary percutaneous coronary intervention. We determined serum-PC fatty acids with gas chromatography. Results: During follow-up, 211 patients had MACE, 108 died, and 130 were readmitted for CV causes. A Cox proportional hazards model adjusted for known clinical predictors showed that serum-PC EPA at the time of STEMI was inversely associated with both incident MACE and CV readmission (hazard ratio [HR]: 0.76; 95% confidence interval [CI]: 0.62 to 0.94, and HR: 0.74; 95% CI: 0.58 to 0.95, respectively, for a 1-standard deviation [SD] increase). Serum-PC ALA was inversely related to all-cause mortality (HR: 0.65; 95% CI: 0.44 to 0.96, for a 1-SD increase). Conclusions: Elevated serum-PC EPA and ALA levels at the time of STEMI were associated with a lower risk of clinical adverse events. Consumption of foods rich in these fatty acids might improve the prognosis of STEMI.
