Almond Snacking for 8 wk Increases Alpha-Diversity of the Gastrointestinal Microbiome and Decreases Bacteroides fragilis Abundance Compared with an Isocaloric Snack in College Freshmen

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Citation
PMID PubMed identifier for scientific articles.
DOI Digital object identifier for electronic documents.
URI Uniform resource identifier for web resources.
Authors
Dhillon J, Li Z, Ortiz RM
Journal
Current developments in nutrition
Year
2019
Background: Changes in gut microbiota are associated with cardiometabolic disorders and are influenced by diet. Almonds are a rich source of fiber, unsaturated fats, and polyphenols, all nutrients that can favorably alter the gut microbiome. Objectives: The aim of this study was to examine the effects of 8 wk of almond snacking on the gut (fecal) microbiome diversity and abundance compared with an isocaloric snack of graham crackers in college freshmen. Methods: A randomized, controlled, parallel-arm, 8-wk intervention in 73 college freshmen (age: 18-19 y; 41 women and 32 men; BMI: 18-41 kg/m2) with no cardiometabolic disorders was conducted. Participants were randomly allocated to either an almond snack group (56.7 g/d; 364 kcal; n = 38) or graham cracker control group (77.5 g/d; 338 kcal/d; n = 35). Stool samples were collected at baseline and 8 wk after the intervention to assess primary microbiome outcomes, that is, gut microbiome diversity and abundance. Results: Almond snacking resulted in 3% greater quantitative alpha-diversity (Shannon index) and 8% greater qualitative alpha-diversity (Chao1 index) than the cracker group after the intervention (P < 0.05). Moreover, almond snacking for 8 wk decreased the abundance of the pathogenic bacterium Bacteroides fragilis by 48% (overall relative abundance, P < 0.05). Permutational multivariate ANOVA showed significant time effects for the unweighted UniFrac distance and Bray-Curtis beta-diversity methods (P < 0.05; R2 ≤ 3.1%). The dietary and clinical variables that best correlated with the underlying bacterial community structure at week 8 of the intervention included dietary carbohydrate (percentage energy), dietary fiber (g), and fasting total and HDL cholesterol (model Spearman rho = 0.16; P = 0.01). Conclusions: Almond snacking for 8 wk improved alpha-diversity compared with cracker snacking. Incorporating a morning snack in the dietary regimen of predominantly breakfast-skipping college freshmen improved the diversity and composition of the gut microbiome. This trial was registered at clinicaltrials.gov as NCT03084003.

Experiment 1


Needs review

Curated date: 2021/01/10

Curator: WikiWorks743

Revision editor(s): WikiWorks753, WikiWorks743

Subjects

Location of subjects
United States of America
Host species Species from which microbiome was sampled (if applicable)
Homo sapiens
Body site Anatomical site where microbial samples were extracted from according to the Uber Anatomy Ontology
Feces Cow dung,Cow pat,Droppings,Dung,Excrement,Excreta,Faeces,Fecal material,Fecal matter,Fewmet,Frass,Guano,Matières fécales@fr,Merde@fr,Ordure,Partie de la merde@fr,Piece of shit,Porción de mierda@es,Portion of dung,Portion of excrement,Portion of faeces,Portion of fecal material,Portion of fecal matter,Portion of feces,Portion of guano,Portion of scat,Portionem cacas,Scat,Spoor,Spraint,Stool,Teil der fäkalien@de,Feces
Condition The experimental condition / phenotype studied according to the Experimental Factor Ontology
diet Dietary,Diets,diet
Group 0 name Corresponds to the control (unexposed) group for case-control studies
higher fiber (almonds) - interaction by time
Group 1 name Corresponds to the case (exposed) group for case-control studies
lower fiber (cracker)
Group 1 definition Diagnostic criteria applied to define the specific condition / phenotype represented in the case (exposed) group
students eating crackers
Group 0 sample size Number of subjects in the control (unexposed) group
35
Group 1 sample size Number of subjects in the case (exposed) group
38

Lab analysis

Sequencing type
16S
16S variable region One or more hypervariable region(s) of the bacterial 16S gene
V4-V5
Sequencing platform Manufacturer and experimental platform used for quantifying microbial abundance
Illumina

Statistical Analysis

Statistical test
ANCOM
Significance threshold p-value or FDR threshold used for differential abundance testing (if any)
0.05
MHT correction Have statistical tests be corrected for multiple hypothesis testing (MHT)?
Yes


Alpha Diversity

Shannon Estimator of species richness and species evenness: more weight on species richness
decreased
Chao1 Abundance-based estimator of species richness
decreased
Simpson Estimator of species richness and species evenness: more weight on species evenness
unchanged
Richness Number of species
decreased

Signature 1

Needs review

Curated date: 2020-02-28

Curator: Lora Kasselman

Revision editor(s): WikiWorks743

Source: Table 1

Description: ANCOM results of selected taxa prevalent in at least 25% of the samples obtained from college freshmen in the almond and cracker groups at baseline and 8 wk after the intervention

Abundance in Group 1: increased abundance in lower fiber (cracker)

NCBI Links
Bacteroides fragilis

Revision editor(s): WikiWorks743

Experiment 2


Needs review

Curated date: 2021/01/10

Curator: WikiWorks743

Revision editor(s): WikiWorks753, WikiWorks743

Subjects

Location of subjects
United States of America
Host species Species from which microbiome was sampled (if applicable)
Homo sapiens
Body site Anatomical site where microbial samples were extracted from according to the Uber Anatomy Ontology
Feces Cow dung,Cow pat,Droppings,Dung,Excrement,Excreta,Faeces,Fecal material,Fecal matter,Fewmet,Frass,Guano,Matières fécales@fr,Merde@fr,Ordure,Partie de la merde@fr,Piece of shit,Porción de mierda@es,Portion of dung,Portion of excrement,Portion of faeces,Portion of fecal material,Portion of fecal matter,Portion of feces,Portion of guano,Portion of scat,Portionem cacas,Scat,Spoor,Spraint,Stool,Teil der fäkalien@de,Feces
Condition The experimental condition / phenotype studied according to the Experimental Factor Ontology
diet Dietary,Diets,diet
Group 0 name Corresponds to the control (unexposed) group for case-control studies
baseline
Group 1 name Corresponds to the case (exposed) group for case-control studies
week 8
Group 1 definition Diagnostic criteria applied to define the specific condition / phenotype represented in the case (exposed) group
students eating crackers
Group 0 sample size Number of subjects in the control (unexposed) group
35
Group 1 sample size Number of subjects in the case (exposed) group
38

Lab analysis

Sequencing type
16S
Sequencing platform Manufacturer and experimental platform used for quantifying microbial abundance
Illumina

Statistical Analysis

Statistical test
ANCOM
Significance threshold p-value or FDR threshold used for differential abundance testing (if any)
0.05
MHT correction Have statistical tests be corrected for multiple hypothesis testing (MHT)?
Yes



Signature 1

Needs review

Curated date: 2020-02-28

Curator: Lora Kasselman

Revision editor(s): Lwaldron, WikiWorks743

Source: Table 1

Description: ANCOM results of selected taxa prevalent in at least 25% of the samples obtained from college freshmen in the almond and cracker groups at baseline and 8 wk after the intervention

Abundance in Group 1: increased abundance in week 8

NCBI Links
Lachnospira
unclassified Mollicutes

Revision editor(s): Lwaldron, WikiWorks743

Signature 2

Needs review

Curated date: 2020-02-28

Curator: Lora Kasselman

Revision editor(s): Lwaldron, WikiWorks743

Source: Table 1

Description: ANCOM results of selected taxa prevalent in at least 25% of the samples obtained from college freshmen in the almond and cracker groups at baseline and 8 wk after the intervention

Abundance in Group 1: decreased abundance in week 8

NCBI Links
Alistipes
Butyricimonas
Odoribacter
Muribaculaceae

Revision editor(s): Lwaldron, WikiWorks743

Experiment 3


Needs review

Curated date: 2021/01/10

Curator: WikiWorks743

Revision editor(s): WikiWorks753, WikiWorks743

Subjects

Location of subjects
United States of America
Host species Species from which microbiome was sampled (if applicable)
Homo sapiens
Body site Anatomical site where microbial samples were extracted from according to the Uber Anatomy Ontology
Feces Cow dung,Cow pat,Droppings,Dung,Excrement,Excreta,Faeces,Fecal material,Fecal matter,Fewmet,Frass,Guano,Matières fécales@fr,Merde@fr,Ordure,Partie de la merde@fr,Piece of shit,Porción de mierda@es,Portion of dung,Portion of excrement,Portion of faeces,Portion of fecal material,Portion of fecal matter,Portion of feces,Portion of guano,Portion of scat,Portionem cacas,Scat,Spoor,Spraint,Stool,Teil der fäkalien@de,Feces
Condition The experimental condition / phenotype studied according to the Experimental Factor Ontology
diet Dietary,Diets,diet
Group 0 name Corresponds to the control (unexposed) group for case-control studies
higher fiber (almonds)
Group 1 name Corresponds to the case (exposed) group for case-control studies
lower fiber (cracker)
Group 1 definition Diagnostic criteria applied to define the specific condition / phenotype represented in the case (exposed) group
students eating crackers
Group 0 sample size Number of subjects in the control (unexposed) group
35
Group 1 sample size Number of subjects in the case (exposed) group
38

Lab analysis

Sequencing type
16S
Sequencing platform Manufacturer and experimental platform used for quantifying microbial abundance
Illumina

Statistical Analysis

Statistical test
ANCOM
Significance threshold p-value or FDR threshold used for differential abundance testing (if any)
0.05
MHT correction Have statistical tests be corrected for multiple hypothesis testing (MHT)?
Yes



Signature 1

Needs review

Curated date: 2020-02-28

Curator: Lora Kasselman

Revision editor(s): WikiWorks743

Source: Table 1

Description: ANCOM results of selected taxa prevalent in at least 25% of the samples obtained from college freshmen in the almond and cracker groups at baseline and 8 wk after the intervention

Abundance in Group 1: decreased abundance in lower fiber (cracker)

NCBI Links
Sutterella

Revision editor(s): WikiWorks743