Lázaro. I., J. Bobi, M. Cofán, G. Kapravelou, A.J. Amor, J. Surra, C. Gómez-Guerrero, E. Ortega, J. Osada, A.P. Dantas, A. Sala-Vila, 2023. Walnut inclusion in a palm oil-based atherogenic diet promotes traits predicting stable atheroma plaque in Apoe-deficient mice. Front. Nutr. 10:1079407. https://doi.org/10.3389/fnut.2023.1079407
INTRODUCTION: The lower rates of cardiovascular disease in Southern Europe could be partially explained by the low prevalence of lipid-rich atheroma plaques. Consumption of certain foods affects the progression and severity of atherosclerosis. We investigated whether the isocaloric inclusion of walnuts within an atherogenic diet prevents phenotypes predicting unstable atheroma plaque in a mouse model of accelerated atherosclerosis. METHODS: Apolipoprotein E-deficient male mice (10-week-old) were randomized to receive a control diet (9.6% of energy as fat, n = 14), a palm oil-based high-fat diet (43% of energy as fat, n = 15), or an isocaloric diet in which part of palm oil was replaced by walnuts in a dose equivalent to 30 g/day in humans (n = 14). All diets contained 0.2% cholesterol. RESULTS: After 15 weeks of intervention, there were no differences in size and extension in aortic atherosclerosis among groups. Compared to control diet, palm oil-diet induced features predicting unstable atheroma plaque (higher lipid content, necrosis, and calcification), and more advanced lesions (Stary score). Walnut inclusion attenuated these features. Palm oil-based diet also boosted inflammatory aortic storm (increased expression of chemokines, cytokines, inflammasome components, and M1 macrophage phenotype markers) and promoted defective efferocytosis. Such response was not observed in the walnut group. The walnut group’s differential activation of nuclear factor kappa B (NF-KB; downregulated) and Nrf2 (upregulated) in the atherosclerotic lesion could explain these findings. CONCLUSION: The isocaloric inclusion of walnuts in an unhealthy high-fat diet promotes traits predicting stable advanced atheroma plaque in mid-life mice. This contributes novel evidence for the benefits of walnuts, even in an unhealthy dietary environment.
Key Area: Heart Health
Cofán, M., A. Checa, M. Serra-Mir, I. Roth, C. Valls-Pedret, A. Lopez-Illamola, M. Doménech, S. Rajaram, I. Lázaro, J. Sabaté, E. Ros, C.E. Wheelock, A. Sala-Vila, 2023. A walnut-enriched diet for 2 years changes the serum oxylipin profile in healthy older persons. J Nutr. S0022-3166(23)72794-6. https://doi.org/10.1016/j.tjnut.2023.12.007.
Background: Oxylipins are products derived from polyunsaturated fatty acids (PUFAs) that play a role in cardiovascular disease and aging. Fish oil-derived n-3 PUFAs promote the formation of anti-inflammatory and vasodilatory oxylipins; however, there are little data on oxylipins derived from α-linolenic acid (C18:3n-3), the primary plant-derived n-3 PUFA. Walnuts are a source of C18:3n-3.Objectives: To investigate the effect on serum oxylipins of a diet enriched with walnuts at 15% energy (30-60 g/d; 2.6-5.2 g C18:3n-3/d) for 2 y compared to a control diet (abstention from walnuts) in healthy older males and females (63-79 y). Methods: The red blood cell proportion of α-linolenic acid was determined by gas chromatography as a measure of compliance. Ultra-performance liquid chromatography-tandem mass spectrometry was used to measure serum concentrations of 53 oxylipins in participants randomly assigned to receive the walnut diet (n = 64) or the control diet (n = 51). Two-year concentration changes (final minus baseline) were log-transformed (base log-10) and standardized (mean-centered and divided by the standard deviation of each variable). Volcano plots were then generated (fold change ≥1.5; false discovery rate ≤0.1). For each oxylipin delta surviving multiple testing, we further assessed between-intervention group differences by analysis of covariance adjusting for age, sex, BMI, and the baseline concentration of the oxylipin. Results: The 2-y change in red blood cell C18:3n-3 in the walnut group was significantly higher than that in the control group (P < 0.001). Compared to the control diet, the walnut diet resulted in statistically significantly greater increases in 3 C18:3n-3-derived oxylipins (9-HOTrE, 13-HOTrE, and 12,13-EpODE) and in the C20:5n-3 derived 14,15-diHETE, and greater reductions of the C20:4n-6-derived 5-HETE, 19-HETE, and 5,6-diHETrE. Conclusions: Long-term walnut consumption changes the serum oxylipin profile in healthy older persons. Our results add novel mechanistic evidence on the cardioprotective effects of walnuts.
Key Area: Heart Health
Carter, S., A.M. Hill, L.C. Mead, H.Y. Wong, C. Yandell, J.D. Buckley, S.Y. Tan, G.B. Rogers, F. Fraysse, A.M. Coates, 2023. Almonds vs. carbohydrate snacks in an energy-restricted diet: Weight and cardiometabolic outcomes from a randomized trial. Obesity (Silver Spring). 31(10):2467-2481. https://doi.org/10.1002/oby.23860
Objective: This study evaluated weight and cardiometabolic outcomes after a 3-month energy-restricted diet (−30%) containing almonds (almond-enriched diet [AED]) or containing carbohydrate-rich snacks (nut-free control diet [NFD]) (Phase 1), followed by 6 months of weight maintenance (Phase 2). Methods: Participants (25–65 years old) with overweight or obesity (BMI 27.5–34.9 kg/m2) were randomly allocated to AED (n = 68) or NFD (n = 72). Results: Both groups lost weight during Phase 1 (p < 0.001) (mean [SE], −7.0 [0.5] kg AED vs. −7.0 [0.5] kg NFD, p = 0.858) and Phase 2 (p = 0.009) (−1.1 [0.5] kg AED vs. −1.3 [0.6] NFD, p = 0.756), with improvements in percentage lean mass after Phase 2 (4.8% [0.3%], p < 0.001). Reductions occurred in fasting glucose (−0.2 [0.07] mmol/L, p = 0.003), insulin (−8.1 [4.0] pmol/L, p = 0.036), blood pressure (−4.9 [0.8] mm Hg systolic, −5.0 [0.5] mm Hg diastolic, p < 0.001), total cholesterol (−0.3 [0.1] mmol/L), low-density lipoprotein (LDL) (−0.2 [0.1] mmol/L), very low density lipoprotein (−0.1 [0.03] mmol/L), and triglycerides (−0.3 [0.06] mmol/L) (all p < 0.001), and high-density lipoprotein increased (0.1 [0.02] mmol/L, p = 0.011) by the end of Phase 2 in both groups. There were group by time interactions for lipoprotein particle concentrations: very small triglyceride-rich (−31.0 [7.7] nmol/L AED vs. −4.8 [7.9] nmol/L NFD, p = 0.007), small LDL (−109.3 [40.5] nmol/L AED vs. −20.7 [41.6] nmol/L NFD, p = 0.017), and medium LDL (−24.4 [43.4] nmol/L AED vs. −130.5 [44.4] nmol/L NFD, p = 0.045). Conclusions: An energy-restricted AED resulted in weight loss and weight loss maintenance comparable to an energy-restricted NFD, and both diets supported cardiometabolic health. The AED resulted in greater improvements in some lipoprotein subfractions, which may enhance reductions in cardiovascular risk.
Yang, J., R. Lee, Z. Schulz, A. Hsu, J. Pai, S. Yang, S.M. Henning, J. Huang, J.P. Jacobs, D. Heber, Z. Li., 2023. Mixed nuts as healthy snacks: effect on tryptophan metabolism and cardiovascular risk factors. Nutrients. 15, 569; https://doi.org/10.3390/nu15030569.
We recently demonstrated that the consumption of mixed tree nuts (MTNs) during caloric restriction decreased cardiovascular risk factors and increased satiety. Tryptophan (Trp) metabolism has been indicated as a factor in cardiovascular disease. Here, we investigated the effect of MTNs on Trp metabolism and the link to cardiovascular risk markers. Plasma and stool were collected from 95 overweight individuals who consumed either MTNs (or pretzels) daily as part of a hypocaloric weight loss diet for 12 weeks followed by an isocaloric weight maintenance program for an additional 12 weeks. Plasma and fecal samples were evaluated for Trp metabolites by LC–MS and for gut microbiota by 16S rRNA sequencing. Trp–kynurenine metabolism was reduced only in the MTNs group during weight loss (baseline vs. week 12). Changes in Trp–serotonin (week 24) and Trp–indole (week 12) metabolism from baseline were increased in the MTNs group compared to the pretzel group. Intergroup analysis between MTN and pretzel groups does not identify significant microbial changes as indicated by alpha diversity and beta diversity. Changes in the relative abundance of genus Paludicola during intervention are statistically different between the MTNs and pretzel group with p < 0.001 (q = 0.07). Our findings suggest that consumption of MTNs affects Trp host and microbial metabolism in overweight and obese subjects.
