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Almond Consumption for 8 Weeks Altered Host and Microbial Metabolism in Comparison to a Control Snack in Young Adults.
Dhillon, J, Newman, JW, Fiehn, O, Ortiz, RM
Journal of the American Nutrition Association. 2023;42(3):242-254
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The consumption of almonds can improve cardiometabolic (CM) health. This study explored the effects of consuming a snack of almonds vs. crackers for 8 weeks on changes in cardiometabolic, microbiome and metabolomics markers in young adults. 73 (41 women and 32 men) young adults took part in this 8-week randomized controlled, parallel-arm intervention study. Blood samples were taken at the beginning, at 4 weeks and then at 8 weeks. The results looked at alternations in many serum metabolites involved in metabolic pathways. They therefore provide a deeper understanding of host carbohydrate, lipid and tocopherol metabolism. The findings also show the interconnections between circulating metabolites and microbial metabolism. This provides further evidence for the impacts of dietary changes on host metabolism and associated changes in gut microbe metabolism.
Abstract
Almond consumption can improve cardiometabolic (CM) health. However, the mechanisms underlying those benefits are not well characterized. This study explored the effects of consuming a snack of almonds vs. crackers for 8 weeks on changes in metabolomic profiles in young adults (clinicaltrials.gov ID: NCT03084003). Participants (n = 73, age: 18-19 years, BMI: 18-41 kg/m2) were randomly assigned to consume either almonds (2 oz/d, n = 38) or an isocaloric control snack of graham crackers (325 kcal/d, n = 35) daily for 8 weeks. Blood samples were collected at baseline prior to and at 4 and 8 weeks after the intervention. Metabolite abundances in the serum were quantified by hydrophilic interaction chromatography quadrupole (Q) time-of-flight (TOF) mass spectrometry (MS/MS), gas chromatography (GC) TOF MS, CSH-ESI (electrospray) QTOF MS/MS, and targeted analyses for free PUFAs, total fatty acids, oxylipins and endocannabinoids. Linear mixed model analyses with baseline-adjustment were conducted, and those results were used for enrichment and network analyses. Microbial community pathway predictions from 16S rRNA sequencing of fecal samples was done using PICRUST2. Almond consumption enriched unsaturated triglycerides, unsaturated phosphatidylcholines, saturated and unsaturated lysophosphatidylcholines, tricarboxylic acids, and tocopherol clusters (p < 0.05). Targeted analyses reveal lower levels of omega-3 total fatty acids (TFAs) overall in the almond group compared to the cracker group (p < 0.05). Microbial amino acid biosynthesis, and amino sugar and nucleotide sugar metabolism pathways were also differentially enriched at the end of the intervention (p < 0.05). The study demonstrates the differential effects of almonds on host tocopherol, lipid, and TCA cycle metabolism with potential changes in microbial metabolism, which may interact with host metabolism to facilitate the CM benefits.
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Almond Consumption and Processing Affects the Composition of the Gastrointestinal Microbiota of Healthy Adult Men and Women: A Randomized Controlled Trial.
Holscher, HD, Taylor, AM, Swanson, KS, Novotny, JA, Baer, DJ
Nutrients. 2018;10(2)
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Poor diet is recognised as a contributing factor to the development of common diseases, such as type 2 diabetes, cardiovascular disease and obesity. Increasingly, links are being made between the health and diversity of the human intestinal microbiome (the bacteria resident in our gut) and these chronic metabolic disorders. The microbiome is constantly changing, depending on a number of factors, including dietary intake. This small cross-over study of 18 participants, included five three-week diet periods of almonds in varying forms, with a one week break (wash out) between diets. The diets were 1. No almonds; 2. 42g whole almonds daily; 3. 42g whole roasted almonds daily; 4. 42g roasted, chopped almonds daily and 5. 42g of almond nut butter. Using stool samples at the end of each diet period, the results showed that chopped almond consumption increased the relative abundance of 3 bacteria strains (Lachnospira, Roseburia and Oscillospira) compared to the no almonds control group, while whole almonds increased the Dialister bacteria strain compared to control. There were no differences between the almond nut butter and control. The authors conclude that consumption of almonds affects the intestinal bacteria profile, which differs with the form of almonds eaten. Whilst this is a small study, Nutrition Practitioners should be aware of the ability to manipulate the gut microbiome with targeted dietary changes.
Abstract
BACKGROUND Almond processing has been shown to differentially impact metabolizable energy; however, the effect of food form on the gastrointestinal microbiota is under-investigated. OBJECTIVE We aimed to assess the interrelationship of almond consumption and processing on the gastrointestinal microbiota. DESIGN A controlled-feeding, randomized, five-period, crossover study with washouts between diet periods was conducted in healthy adults (n = 18). Treatments included: (1) zero servings/day of almonds (control); (2) 1.5 servings (42 g)/day of whole almonds; (3) 1.5 servings/day of whole, roasted almonds; (4) 1.5 servings/day of roasted, chopped almonds; and (5) 1.5 servings/day of almond butter. Fecal samples were collected at the end of each three-week diet period. RESULTS Almond consumption increased the relative abundances of Lachnospira, Roseburia, and Dialister (p ≤ 0.05). Comparisons between control and the four almond treatments revealed that chopped almonds increased Lachnospira, Roseburia, and Oscillospira compared to control (p < 0.05), while whole almonds increased Dialister compared to control (p = 0.007). There were no differences between almond butter and control. CONCLUSIONS These results reveal that almond consumption induced changes in the microbial community composition of the human gastrointestinal microbiota. Furthermore, the degree of almond processing (e.g., roasting, chopping, and grinding into butter) differentially impacted the relative abundances of bacterial genera.
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Time and Intervention Effects of Daily Almond Intake on the Changes of Lipid Profile and Body Composition Among Free-Living Healthy Adults.
Liu, Y, Hwang, HJ, Kim, HS, Park, H
Journal of medicinal food. 2018;21(4):340-347
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Existing evidence shows that tree nut intake may reduce risk factors associated cardiovascular diseases. While studies have demonstrated this with almond consumption, the mechanism remains uncertain. The aim of this randomised controlled trial was to evaluate the effects of daily almond consumption on changes in body composition and lipid profiles at four different measurement points to provide further mechanistic insight. Eighty-five participants were randomised to either almond or control group and those in the almond group consumed 56g of almonds per day for 20 weeks. Anthropometric and bioimpedance measures were taken, as well as blood lipid profiles, at weeks 0, 8, 16 and 20. This study revealed patterns in blood lipid profiles fluctuations throughout the 20 weeks by utilising four time points. Continuous almond consumption led to significantly greater reductions in blood lipid levels compared to the control group, demonstrating the cardioprotective effects of almonds.
Abstract
Favorable health benefits of almond have been shown in several previous studies. However, repeated measures, randomized, controlled trials to investigate the changes due to almond intake based on the time effects have not yet been reported. The current study was conducted to evaluate the effects of daily almond intake on changes in body composition and lipid profiles for 20 weeks with four measurements among healthy adults. Participants in the almond group showed favorable changes on blood lipid profiles, including levels of triglycerides (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and non-high-density lipoprotein (non-HDL-C) after consuming 56 g of almond per day for 20 weeks compared with those at baseline. At week 20, subjects in the almond group showed significantly decreased TC, LDL-C, non-HDL-C, TG, body fat mass, and waist-hip ratio compared with those of the control group who consumed isocaloric control food. The mixed model also confirmed that there were significant time effects in several bioimpedance indicators (i.e., total body protein, fat-free mass, etc.) and all of the lipid profile parameters in the almond group. These results confirm the effects of lipid-lowering and modifying body composition of almond consumption. In addition, our results suggest that the measuring time points would be critical to capture the effects of dietary intervention.
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Effects of daily almond consumption on cardiometabolic risk and abdominal adiposity in healthy adults with elevated LDL-cholesterol: a randomized controlled trial.
Berryman, CE, West, SG, Fleming, JA, Bordi, PL, Kris-Etherton, PM
Journal of the American Heart Association. 2015;4(1):e000993
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Research has shown that almond consumption has a positive impact on cardiovascular risk factors and markers for inflammation. The aim of this randomised controlled trial was to compare a cholesterol lowering diet with almonds (1.5oz./day) with the same diet but substituting almonds with a calorie-matched food (i.e. a muffin) in a controlled-feeding setting. The study concluded that almonds reduce non high density lipoproteins, low-density lipoproteins and central adiposity in healthy individuals. The researchers suggest that it is likely to be almonds unique fatty acid profile and in particular, oleic acid that offers these cardiovascular protective effects. It recommended a daily intake of 1.5oz of almonds to replace high carbohydrate snacks.
Abstract
BACKGROUND Evidence consistently shows that almond consumption beneficially affects lipids and lipoproteins. Almonds, however, have not been evaluated in a controlled-feeding setting using a diet design with only a single, calorie-matched food substitution to assess their specific effects on cardiometabolic risk factors. METHODS AND RESULTS In a randomized, 2-period (6 week/period), crossover, controlled-feeding study of 48 individuals with elevated LDL-C (149±3 mg/dL), a cholesterol-lowering diet with almonds (1.5 oz. of almonds/day) was compared to an identical diet with an isocaloric muffin substitution (no almonds/day). Differences in the nutrient profiles of the control (58% CHO, 15% PRO, 26% total fat) and almond (51% CHO, 16% PRO, 32% total fat) diets were due to nutrients inherent to each snack; diets did not differ in saturated fat or cholesterol. The almond diet, compared with the control diet, decreased non-HDL-C (-6.9±2.4 mg/dL; P=0.01) and LDL-C (-5.3±1.9 mg/dL; P=0.01); furthermore, the control diet decreased HDL-C (-1.7±0.6 mg/dL; P<0.01). Almond consumption also reduced abdominal fat (-0.07±0.03 kg; P=0.02) and leg fat (-0.12±0.05 kg; P=0.02), despite no differences in total body weight. CONCLUSIONS Almonds reduced non-HDL-C, LDL-C, and central adiposity, important risk factors for cardiometabolic dysfunction, while maintaining HDL-C concentrations. Therefore, daily consumption of almonds (1.5 oz.), substituted for a high-carbohydrate snack, may be a simple dietary strategy to prevent the onset of cardiometabolic diseases in healthy individuals. CLINICAL TRIAL REGISTRATION URL www.clinicaltrials.gov; Unique Identifier: NCT01101230.