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Research Area: Body Weight/Satiety

Consumption of tree nuts as snacks stimulates changes in plasma fatty acid profiles and adipose tissue gene expression in young adults at risk for metabolic syndrome

Widmer, A., K. Lillegard, K. Wood, M. Robles, R. Fan, F. Ye, J.R. Koethe, H.J. Silver, 2025. Consumption of tree nuts as snacks stimulates changes in plasma fatty acid profiles and adipose tissue gene expression in young adults at risk for metabolic syndrome. Clinical Nutrition. (48)25 – 34. https://doi.org/10.1016/j.clnu.2025.03.002.

Background and aims: The prevalence of metabolic syndrome has been increasing in young adults, concomitant with the occurrence of increased abdominal adiposity. We previously reported that consuming tree nuts, as replacement for typical high-carbohydrate snacks, reduces visceral fat and waist circumference in young adults who have one or more metabolic syndrome risk factors. We aimed to investigate the effects of tree nuts snack consumption on plasma and adipose tissue fatty acid profiles along with changes in the expression of adipose tissue genes involved in thermogenesis, glycemia, adipocyte signaling, lipolysis, and immunity. Methods: A randomized parallel-arm 16-week intervention trial was conducted in 84 adults aged 22-36 years. Participants in both groups were provided with caloric goals for weight maintenance, daily menus, and pre-portioned snacks at every other week visits with study registered dietitians. Changes in dietary fatty acid intakes, plasma and abdominal subcutaneous adipose tissue (SAT) triglycerides fatty acid profiles using gas-liquid chromatography, and the expression of 241 genes in abdominal SAT were evaluated. Results: Consuming tree nuts snacks increased mono- and polyunsaturated fatty acid intakes yielding a 9-fold greater dietary unsaturated to saturated fat ratio. The tree nuts snack group also had significantly greater improvements in plasma 16:1/16:0 ratio; plasma phospholipids oleic and gamma linolenic acid content; plasma diglycerides, triglycerides, and cholesterol esters oleic acid content; and total plasma monounsaturated fatty acids. While abdominal SAT only showed trends for increased oleic acid content and unsaturated to saturated fat ratio, the tree nuts snacks participants had altered expression of 13 genes in abdominal SAT that have roles in nutrient sensing, energy homeostasis, and vulnerability to obesity. Conclusions: Replacing typical high-carbohydrate snacks with tree nuts results in more favorable dietary, plasma, and adipose tissue fatty acid profiles that could aid in preventing the development of excess adiposity and cardiometabolic disease states including metabolic syndrome.

Visceral adipose tissue area and proportion provide distinct reflections of cardiometabolic outcomes in weight loss; pooled analysis of MRI-assessed CENTRAL and DIRECT PLUS dietary randomized controlled trials.

Klein, H., H. Zelicha, A. Yaskolka Meir, E. Rinott, G. Tsaban, A. Kaplan, Y. Chassidim, Y. Gepner, M. Blüher, U. Ceglarek, B. Isermann, M. Stumvoll, I. Shelef, L. Qi, J. Li, F.B. Hu, M.J. Stampfer, I. Shai, 2025. Visceral adipose tissue area and proportion provide distinct reflections of cardiometabolic outcomes in weight loss; pooled analysis of MRI-assessed CENTRAL and DIRECT PLUS dietary randomized controlled trials. BMC Med. 23(1):57. doi: 10.1186/s12916-025-03891-9.

Background: Visceral adipose tissue (VAT) is well established as a pathogenic fat depot, whereas superficial subcutaneous adipose tissue (SAT) is associated with either an improved or neutral cardiovascular state. However, it is unclear to what extent VAT area (VATcm2) and its proportion of total abdominal adipose tissue (VAT%) are distinguished in predicting cardiometabolic status and clinical outcomes during weight loss. Methods: We integrated magnetic resonance imaging (MRI) measurements of VAT, deep-SAT, and superficial-SAT from two 18-month lifestyle weight loss clinical trials, CENTRAL and DIRECT PLUS (n = 572). Results: At baseline, the mean VATcm2 was 144.8cm2 and VAT% = 28.2%; over 18 months, participants lost 28cm2 VATcm2 (- 22.5%), and 1.3 VAT% units. Baseline VATcm2 and VAT% were similarly associated with metabolic syndrome, hypertension, and diabetes status, while VAT% better classified hypertriglyceridemia. Conversely, higher VATcm2 was associated with elevated high-sensitivity C-reactive protein (hsCRP), while VAT% was not. After 18 months of lifestyle intervention, both VATcm2 and VAT% loss were significantly associated with decreased triglycerides, HbA1c, ferritin, and liver enzymes, and increased HDL-c levels beyond weight loss (FDR < 0.05). Only VATcm2 loss was correlated with decreased HOMA-IR, chemerin, and leptin levels. Conclusions: MRI follow-up of 572 participants over 18 months of weight loss intervention suggests that although increased VATcm2 and VAT% exhibit similar clinical manifestations, it might be preferable to examine VAT% when exploring lipid status, while VATcm2 may better reflect inflammatory and glycemic states.

A cross-sectional study on the association of walnut consumption with obesity and relative fat mass among United States adolescents and young adults in NHANES (2003–2020).

Gletsu-Miller, N., Henschel, B., Tekwe, C.D. and Thiagarajah, K., 2024. A cross-sectional study on the association of walnut consumption with obesity and relative fat mass among United States adolescents and young adults in NHANES (2003–2020). Curr Dev in Nutr. 8(8), p.104407. https://doi.org/10.1016/j.cdnut.2024.104407

Background: Walnuts contain nutrients and phytochemicals that can promote metabolic health. However, the high energy content of walnuts along with other nuts raises the concern that consuming nuts promotes obesity. Objectives: We sought to investigate the associations between consumption of walnuts as well as other nuts and measures of obesity in adolescents and young adults. Methods: This study included 8874 adolescents (12–19 y) and 10,323 young adults (20–39 y) from 8 waves of National Health and Nutrition Examination Survey data (2003–2020). The associations of consumption of 1) walnuts only (WO); 2) walnuts with other nuts (WON); 3) other nuts (ON); and 4) no nuts (NN) with obesity status and relative fat mass (RFM) were assessed using logistic and linear regressions stratified by age group and sex. Sample weights were used in all statistical analyses. Results: The mean daily intake of walnuts was not different between the 2 walnut consumption groups within each age group (adolescents: 2.18 [standard error (SE) 0.14] g; P = 0.917; young adults: 4.23 [0.37] g; P = 0.682). The WON group had the lowest prevalence of obesity (adolescents: 8.3%; young adults: 21.1%) while the NN group had the highest prevalence (adolescents: 24.1%; young adults: 35.4%). The models indicated lower odds of obesity in adolescent girls (odds ratio [OR]: 0.27; P < 0.05) and young adult women (OR: 0.58; P < 0.05) who consumed WON than in those who consumed NN. In both young women and girls, RFM was significantly lower in the WON and ON groups than the NN group (P < 0.001). In young men, WON consumption was also associated with a lower RFM (OR: −1.24; 95% confidence interval: −2.21, −0.28) compared with NN consumption. Conclusions: For adolescent girls and young women, dietary intake of walnuts combined with other nuts has the strongest inverse association with measures of obesity.

Nuts and seeds consumption impact on adolescent obesity: sex-specific associations from 2003 to 2018 National Health and Nutrition Examination Survey.

Yang Y, Zhang D, Chen B, Huang X, 2024. Nuts and seeds consumption impact on adolescent obesity: sex-specific associations from 2003 to 2018 National Health and Nutrition Examination Survey. Int J Food Sci Nutr. 75(5):453-462. https://doi.org/10.1080/09637486.2024.2314682

The nutritional benefits and immunological advantages of consuming nuts and seeds are well-established. However, the link between nuts and seeds consumption and the susceptibility of being overweight or obese among adolescents is not clear. This study aims to explore this relationship in adolescents aged 12-19. Using a weighted multiple logistic regression model, we analysed data of the Food Patterns Equivalents Database and the U.S. National Health and Nutrition Examination Survey (NHANES) from 2003 to 2018. We found a significant association between nuts and seeds consumption and a reduced odds of being overweight or obese in females. Specifically, females who habitually consumed nuts and seeds had lower odds of being overweight or obese (OR = 0.55, 95% CI: 0.32-0.94). Additionally, we found an L-shaped relationship between nuts and seeds consumption and appropriate waist-to-height ratio in males. The findings suggest that nuts and seeds consumption may contribute to healthier physical development in adolescents.