Sumislawski, K., A. Widmer, R.R. Suro, M.E. Robles, K. Lillegard, D. Olson, J.R. Koethe, H.J. Silver, 2023. Consumption of tree nuts as snacks reduces metabolic syndrome risk in young adults: a randomized trial. Nutrients. 15(24):5051. doi: 10.3390/nu15245051.
Metabolic syndrome (MetSx) and its chronic disease consequences are major public health concerns worldwide. Between-meal snacking may be a modifiable risk factor. We hypothesized that consuming tree nuts as snacks, versus typical carbohydrate snacks, would reduce risk for MetSx in young adults. A prospective, randomized, 16-week parallel-group diet intervention trial was conducted in 84 adults aged 22-36 with BMI 24.5 to 34.9 kg/m2 and ≥1 MetSx clinical risk factor. Tree nuts snacks (TNsnack) were matched to carbohydrate snacks (CHOsnack) for energy (kcal), protein, fiber, and sodium content as part of a 7-day eucaloric menu. Difference in change between groups was tested by analysis of covariance using general linear models. Multivariable linear regression modeling assessed main effects of TNsnack treatment and interactions between TNsnack and sex on MetSx score. Age, BMI, and year of study enrollment were included variables. There was a main effect of TNsnack on reducing waist circumference in females (mean difference: -2.20 ± 0.73 cm, p = 0.004) and a trend toward reduced visceral fat (-5.27 ± 13.05 cm2, p = 0.06). TNsnack decreased blood insulin levels in males (-1.14 ± 1.41 mIU/L, p = 0.05) and multivariable modeling showed a main effect of TNsnack on insulin. Main effects of TNsnack on triglycerides and TG/HDL ratio were observed (p = 0.04 for both) with TG/HDL ratio reduced ~11%. A main effect of TNsnack (p = 0.04) and an interaction effect between TNsnack and sex (p < 0.001) on total MetSx score yielded 67% reduced MetSx score in TNsnack females and 42% reduced MetSx score in TNsnack males. To our knowledge, this is the first randomized parallel-arm study to investigate cardiometabolic responses to TNsnacks versus typical CHOsnacks among young adults at risk of MetSx. Our study suggests daily tree nut consumption reduces MetSx risk by improving waist circumference, lipid biomarkers, and/or insulin sensitivity-without requiring caloric restriction.
Brown, R. C., L. Ware, A.R. Gray, S.L. Tey, A. Chisholm, 2023. Comparing the effects of consuming almonds or biscuits on body weight in habitual snackers: a 1-year randomized controlled trial. Amer. J. Clin. Nutr. 118(1):228–240. https://doi.org/10.1016/j.ajcnut.2023.05.015
Background: Almonds are nutrient rich, providing a healthier alternative to many snacks. Studies report health benefits with regular almond consumption without adverse weight gain. However, most interventions have been relatively short or have included additional dietary advice. Objectives: Taking a pragmatic approach, we compared consumption of almonds compared with biscuits on body weight and other health outcomes in a population of regular snackers of discretionary foods, hypothesizing the almonds will displace some of the less-healthful snacks in their current diets. Methods: We randomly assigned 136 nonobese habitual discretionary snackers to receive almonds or biscuits daily for 1 y. These isocaloric snacks provided either 10% of participants’ total energy (TE) requirements or 1030 kJ (equivalent to 42.5 g almonds), whichever was greater. Anthropometry, blood biomarkers, diet, appetite, sleep, and physical activity were assessed at baseline, 3, 6, and 12 mo, and body composition and RMR at baseline and 12 mo. Results: The difference in changes for body weight from baseline to 12 mo was not statistically significant (geometric means: 67.1 and 69.5 kg for almonds and 66.3 and 66.3 kg for biscuits, P = 0.275). There were no statistically significant differences in changes for body composition or other nondietary outcomes (all P ≥ 0.112). Absolute intakes of protein; total, polyunsaturated, and monosaturated fat; fiber; vitamin E; calcium; copper; magnesium; phosphorous; and zinc, and % TE from total monounsaturated, and polyunsaturated fat statistically significantly increased from baseline (all P ≤ 0.033), whereas % TE from carbohydrate and sugar statistically significantly (both P ≤ 0.014) decreased from baseline, in the almond compared with the biscuit group. Conclusions: Almonds can be incorporated into the diets of habitual snackers to improve diet quality, without evidence for changes in body weight, compared with a popular discretionary snack food.
Carter, S., A.M. Hill, J.D. Buckley, S.Y. Tan, G.B. Rogers, A.M. Coates, 2023. Acute feeding with almonds compared to a carbohydrate-based snack improves appetite-regulating hormones with no effect on self-reported appetite sensations: a randomised controlled trial. Eur. J. Nutr. 62(2):857–866. https://doi.org/10.1007/s00394-022-03027-2
Purpose: Early satiety has been identified as one of the mechanisms that may explain the beneficial effects of nuts for reducing obesity. This study compared postprandial changes in appetite-regulating hormones and self-reported appetite ratings after consuming almonds (AL, 15% of energy requirement) or an isocaloric carbohydrate-rich snack bar (SB). Methods: This is a sub-analysis of baseline assessments of a larger parallel-arm randomised controlled trial in overweight and obese (Body Mass Index 27.5-34.9 kg/m2) adults (25-65 years). After an overnight fast, 140 participants consumed a randomly allocated snack (AL [n = 68] or SB [n = 72]). Appetite-regulating hormones and self-reported appetite sensations, measured using visual analogue scales, were assessed immediately before snack food consumption, and at 30, 60, 90 and 120 min following snack consumption. A sub-set of participants (AL, n = 49; SB, n = 48) then consumed a meal challenge buffet ad libitum to assess subsequent energy intake. An additional appetite rating assessment was administered post buffet at 150 min. Results: Postprandial C-peptide area under the curve (AUC) response was 47% smaller with AL compared to SB (p < 0.001). Glucose-dependent insulinotropic polypeptide, glucagon and pancreatic polypeptide AUC responses were larger with AL compared to SB (18%, p = 0.005; 39% p < 0.001; 45% p < 0.001 respectively). Cholecystokinin, ghrelin, glucagon-like peptide-1, leptin and polypeptide YY AUCs were not different between groups. Self-reported appetite ratings and energy intake following the buffet did not differ between groups. Conclusion: More favourable appetite-regulating hormone responses to AL did not translate into better self-reported appetite or reduced short-term energy consumption. Future studies should investigate implications for longer term appetite regulation.
Lopez-Neyman, S. M., N. Zohoori, K.S. Broughton, D.C. Miketinas, 2023. Association of tree nut consumption with cardiovascular disease and cardiometabolic risk factors and health outcomes in US adults: NHANES 2011-2018. Curr. Dev. Nutr. 7(10):102007. https://doi.org/10.1016/j.cdnut.2023.102007
Background: Tree nuts are nutrient dense, and their consumption has been associated with improvements in health outcomes. Objective: To estimate the usual tree nut intake and examine the association between tree nut consumption and cardiometabolic (CM) health outcomes in a nationally representative sample of US adults. Methods: Cross-sectional data were analyzed from a sample of 18,150 adults aged ≥ 20y who provided at least one reliable 24-h dietary recall and had complete data for the variables of interest in the NHANES 2011-2018. Tree nut consumers were defined as those consuming ≥ ¼ ounce/d (7.09 g). The National Cancer Institute Method was used to estimate the usual tree nut intake among consumers. Measurement error calibrated regression models were used to assess the association between tree nut consumption and each health outcome of interest. Results: Approximately 8% of all participants (n = 1238) consumed tree nuts and had a mean ± SE usual intake of 39.5 ± 1.8 g/d. Tree nut consumers were less likely to have obesity (31% vs. 40%, P < 0.001) and low high-density lipoprotein cholesterol (22% vs. 30%, P < 0.001) compared with nonconsumers. Moreover, tree nut consumers had a lower mean waist circumference (WC) (97.1 ± 0.7 vs. 100.5 ± 0.3 cm, P < 0.001) and apolipoprotein B (87.5 ± 1.2 vs. 91.8 ± 0.5 mg/dL, P = 0.004) than nonconsumers. After adjusting models for demographics and lifestyle covariates, the difference in WC between average intake (33.7 g/d) and low threshold intake (7.09/g) of tree nuts was -1.42 ± 0.58 cm (P = 0.005). Conclusions: Most US adults do not consume tree nuts, yet modest consumption was associated with decreased prevalence of cardiovascular disease and CM risk factors and improvement for some health outcome measures.
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 31(10):2467–2481.
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.
Gulati, S., A. Misra, R. Tiwari, M. Sharma, R.M. Pandey, A.D. Upadhyay, H. Chandra Sati, 2023. Premeal almond load decreases postprandial glycaemia, adiposity and reversed prediabetes to normoglycemia: a randomized controlled trial. Clinical nutrition ESPEN, 54, 12–22. https://doi.org/10.1016/j.clnesp.2022.12.028
Background: Asian Indians show rapid conversion from prediabetes to type 2 diabetes (T2D). Novel dietary strategies are needed to arrest this progression, by targeting postprandial hyperglycaemia (PPHG). Design: We conducted a free-living randomized controlled open-label parallel arm study to evaluate the effect of a premeal load of almonds (20 g) 30 min before major meals on anthropometric, glycaemic, and metabolic parameters over 3 months. Sixty-six participants with prediabetes in the age range of 18-60 yrs were recruited. The study was registered at clinicaltrials.gov (registration no. NCT04769726). Results: Thirty participants in each arm completed the study. As per ‘intention-to-treat’ analysis, overall additional mean reductions were statistically significant for body weight, BMI, waist circumference (WC), subscapular and suprailiac skinfolds, and improved handgrip strength (Kg) (p < 0·001 for all) in the treatment arm vs. the control arm (after multiple adjustments). In the blood parameters, the additional mean reduction in the treatment arm vs. control arm was statistically significant for fasting and post-75 g oral glucose-load blood glucose, postprandial insulin, HOMA-IR, HbA1c, proinsulin, total cholesterol, and very low-density lipoprotein cholesterol (p < 0·001 for all). Most importantly, we observed a reversal to normoglycemic state (fasting blood glucose and 2 h post-OGTT glucose levels) in 23.3% (7 out of 30) of participants in the treatment arm which is comparable to that seen with Acarbose treatment (25%). Conclusion: Incorporation of 20 g of almonds, 30 min before each major meal leads to significant improvement in body weight, WC, glycemia (particularly PPHG), and insulin resistance and shows potential for reversal of prediabetes to normal glucose regulation over 3 months.
Keywords: Almonds; Asian Indians; Postprandial glucose regulators; Postprandial hyperglycaemia; Prediabetes.
Creedon, A.C., E.S. Hung, E. Dimidi, T. Grassby, S.E. Berry, K. Whelan, 2023. Particle size distribution and predicted lipid bioaccessibility of almonds and the effect of almond processing: a randomised mastication study in healthy adults. Nutrients. 15(3):489. https://doi.org/10.3390/nu15030489
Almonds are rich in unsaturated lipids, which play a role in some of the reported benefits of almond consumption for human health. Almond lipids are poorly bioaccessible due to almonds’ unique physicochemical properties that influence particle size distribution (PSD) following mastication, allowing much intracellular lipid to escape digestion in the upper gastrointestinal tract. To investigate the impact of commercial processing (grinding almonds into flour), on PSD and predicted lipid bioaccessibility following mastication, a randomised cross-over design mastication study was conducted in healthy adults. The PSDs of masticated whole and ground almonds was assessed using two laboratory methods (mechanical sieving and laser diffraction). PSD from mechanical sieving was used to calculate lipid bioaccessibility using a theoretical mathematical model. Thirty-one healthy adults (18-45 years) completed both mastication sessions. Following mastication, ground almonds had a PSD with significantly fewer larger particles and more smaller particles, compared with whole almonds. Predicted lipid bioaccessibility of masticated ground almonds (10.4%, SD 1.8) was marginally but significantly greater than the predicted lipid bioaccessibility of masticated whole almonds (9.3%, SD 2.0; p = 0.017). Commercial grinding of almonds significantly influences the PSD of almonds following mastication, which results in a modest but significant increase in predicted lipid bioaccessibility.
Gayathri, R., K. Abirami, N. Kalpana, V.S. Manasa, V. Sudha, S. Shobana, R.G. Jeevan, V. Kavitha, K. Parkavi, R.M. Anjana, R. Unnikrishnan, K. Gokulakrishnan, D.A. Beatrice, K. Krishnaswamy, R. Pradeepa, R.D. Mattes, J. Salas-Salvadó, W. Willett, V. Mohan, 2023. Effect of almond consumption on insulin sensitivity and serum lipids among Asian Indian adults with overweight and obesity- A randomized controlled trial. Front. Nutr. 9: 1055923. https://doi.org/10.3389/fnut.2022.1055923
Background: Asian Indians have an increased susceptibility to type 2 diabetes and premature coronary artery disease. Nuts, like almonds, are rich in unsaturated fat and micronutrients with known health benefits. Objectives: This study aimed to assess the efficacy of almonds for reduction of insulin resistance and improving lipid profile in overweight Asian Indian adults. Methods: This parallel-arm, randomized, controlled trial was conducted in Chennai, India on 400 participants aged 25-65 years with a body mass index ≥ 23 kg/m2. The intervention group received 43 g of almonds/day for 12 weeks, while the control group was advised to consume a customary diet but to avoid nuts. Anthropometric, clinical, and dietary data were assessed at periodic intervals. Glucose tolerance, serum insulin, glycated hemoglobin, C-peptide and lipid profile were assessed at baseline and end of the study. Insulin resistance (homeostasis assessment model-HOMA IR) and oral insulin disposition index (DIo) were calculated. Results: A total of 352 participants completed the study. Significant improvement was seen in DIo [mean (95% CI) = + 0.7 mmol/L (0.1, 1.3); p = 0.03], HOMA IR (-0.4 (-0.7, -0.04; p = 0.03) and total cholesterol (-5.4 mg/dl (-10.2, -0.6); p = 0.03) in the intervention group compared to the control group. Incremental area under the curve (IAUC) and mean amplitude of glycemic excursion (MAGE) assessed using continuous glucose monitoring systems were also significantly lower in the intervention group. Dietary 24-h recalls showed a higher significant reduction in carbohydrate and increase in mono unsaturated fatty acid (MUFA) and polyunsaturated fatty acids (PUFA) intake in the intervention group compared to the control group. Conclusion: Daily consumption of almonds increased the intake of MUFA with decrease in carbohydrate calories and decreases insulin resistance, improves insulin sensitivity and lowers serum cholesterol in Asian Indians with overweight/obesity. These effects in the long run could aid in reducing the risk of diabetes and other cardiometabolic disease.
Nieman, D.C., A.M. Omar, C.D. Kay, D.M. Kasote, C.A. Sakaguchi, A. Lkhagva, M.M. Weldemariam, Q. Zhang, 2023. Almond intake alters the acute plasma dihydroxy-octadecenoic acid (DiHOME) response to eccentric exercise. Front. Nutr. 9:1042719. https://doi.org/10.3389/fnut.2022.1042719
Introduction: This investigation determined if 4-weeks ingestion of nutrient-dense almonds mitigated post-exercise inflammation and muscle soreness and damage. Methods: An acute 90-min of eccentric exercise (90-EE) was used to induce muscle damage in 64 non-obese adults not engaging in regular resistance training (ages 30-65 years, BMI < 30 kg/m2). Using a parallel group design, participants were randomized to almond (AL) (57 g/d) or cereal bar (CB) (calorie matched) treatment groups for a 4-week period prior to the 90-EE (17 exercises). Blood and 24-h urine samples were collected before and after supplementation, with additional blood samples collected immediately post-90-EE, and then daily during 4 additional days of recovery. Changes in plasma oxylipins, urinary gut-derived phenolics, plasma cytokines, muscle damage biomarkers, mood states, and exercise performance were assessed. Results: The 90-EE protocol induced significant muscle damage, delayed onset of muscle soreness (DOMS), inflammation, reduced strength and power performance, and mood disturbance. Interaction effects (2 group × 7 time points) supported that AL vs. CB was associated with reduced post-exercise fatigue and tension (p = 0.051, 0.033, respectively) and higher levels of leg-back strength (p = 0.029). No group differences were found for post-90-EE increases in DOMS and six cytokines. AL was associated with lower levels of serum creatine kinase immediately- and 1-day post-exercise (p = 0.034 and 0.013, respectively). The 90-EE bout increased plasma levels immediately post-exercise for 13 oxylipins. Interaction effects revealed significantly higher levels for AL vs. CB for 12,13-DiHOME (p < 0.001) and lower levels for 9,10-DiHOME (p < 0.001). Urine levels increased in AL vs. CB for seven gut-derived phenolics including 5-(3′,4′-dihydroxyphenyl)-γ-valerolactone that was inversely related to changes in plasma 9,10-DiHOME (r = -0.029, p = 0.021). Discussion: These data support some positive effects of almond intake in improving mood state, retaining strength, decreasing muscle damage, increasing the generation of gut-derived phenolic metabolites, and altering the plasma oxylipin DiHOME response to unaccustomed eccentric exercise in untrained adults. The elevated post-exercise plasma levels of 12,13-DiHOME with almond intake support positive metabolic outcomes for adults engaging in unaccustomed eccentric exercise bouts.
Keywords: (poly)phenols; almonds; cytokines; exercise; inflammation; metabolites; oxylipins.
Mandalari, G., T. Gervasi, D.W. Rosenberg, K.G. Lapsley, D.J. Baer, 2023. Effect of nuts on gastrointestinal health. Nutrients. 15(7):1733. https://doi.org/10.3390/nu15071733
Nuts are high nutrient-dense foods containing healthy lipids, dietary fiber, and bioactive phytochemicals, including vitamins and minerals. Although the beneficial effect of nut consumption on different chronic diseases has been well documented, especially in relation to their cardiometabolic benefits, less scientific evidence is available on their possible beneficial effects on gastrointestinal health. In this narrative review, we summarize the most important findings and new research perspectives in relation to the importance of nut consumption on gastrointestinal health. The integrity of the cell wall structure, cell size and particle size after mastication are known to play a crucial role in energy, nutrient and bioactive release from nuts during digestion, therefore affecting bioaccessibility. Other mechanisms, such as cell wall composition, thickness and porosity, as well as stability of the membranes surrounding the oil bodies within the cell, are also important for energy extraction. As the undigested nutrients and phytochemicals are delivered to the colon, effects on gut microbiota composition are predicted. Although the overall effect of nut consumption on microbial alpha- and beta-diversity has been inconsistent, some scientific evidence suggests an increase in fecal butyrate after almond consumption, and a beneficial role of walnuts on the prevention of ulcerative colitis and protection against the development of gastric mucosal lesions.
