This 8-week parallel-arm randomized controlled trial (N=70; ages 6-13) will determine the impact of daily almond butter consumption on gut microbiome composition and function, intestinal barrier integrity, and cardiometabolic health in school-aged children. Participants will be randomized to either a once-daily snack of personalized-portion almond butter (ALB; 16g, Creamy Natural Almond Butter) or an isocaloric nut-free chocolate spread control (CTL; 16g, Cadbury Milk Chocolate), each served on two plain unsalted saltine crackers, added to their habitual diet. The primary outcomes include oro-gut microbial composition and diversity, gut microbial functional capacity and metabolomics (SCFAs, bile acids, amino acid metabolites), and intestinal barrier integrity. Secondary outcomes include fasting cardiometabolic markers, systemic inflammation, appetite-regulatory and metabolic hormones, and sleep-related biomarkers. Feasibility, adherence (weekly logs; serum α-tocopherol), and precision nutrition potential will also be assessed, with stratified analyses by age, sex, BMI, ethnicity, and pubertal stage. This pilot trial will generate the first multi-omics characterization of almond butter's effects on the gut-immune-metabolic axis in children.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
70
Almond Butter (ALB) Group: Participants in this group will receive a daily snack consisting of a personalized portion of smooth natural almond butter (Creamy Richards 100% Almonds! Creamy Natural Almond Butter) spread between two plain unsalted saltine crackers (Unsalted Tops Premium Saltine Crackers). The amount of almond butter will be limited to 16g per two crackers; additional crackers will be provided if the personalized portion exceeds this limit.
Control (CTL) Group: Participants in this group will receive a daily snack consisting of an isocaloric amount of a nut-free, vegetable oil-based chocolate spread ("Cadbury Milk Chocolate") spread between two plain unsalted saltine crackers ("Unsalted Tops Premium Saltine Crackers"). Similar to the peanut butter group, the chocolate spread will be limited to 16g per two crackers, with additional crackers provided if needed.
The Gut Biome Lab
Tallahassee, Florida, United States
RECRUITINGChange in Gut Microbiome Alpha and Beta Diversity Measured by 16S rRNA Gene Sequencing of Fecal Samples
Freshly voided fecal samples will be collected and DNA extracted using the PowerFecal Pro DNA kit. The V3-V4 hypervariable region of the bacterial 16S ribosomal RNA gene will be PCR-amplified and sequenced. Sequences will be processed using the QIIME2 software package to assess microbial diversity (alpha and beta diversity) and taxonomic composition.
Time frame: Baseline (day 0), midpoint (week 4) and endpoint (week 8)
Change in Oral Microbiome Alpha and Beta Diversity Measured by 16S rRNA Gene Sequencing of Oral Swabs
Oral biofilm swabs (omniswab - tongue, palate, cheek/lip lining, gums) and unstimulated saliva will be collected in 5ml tubes. DNA will be extracted and the V3-V4 region of the bacterial 16S ribosomal RNA gene PCR-amplified and sequenced. Sequences will be processed using the QIIME2 software package to assess oral microbial diversity (alpha and beta diversity) and taxonomic composition.
Time frame: Baseline (day 0) and Endpoint (week 8)
Change in Fecal Metabolome
The endpoint of fecal metabolomics will be assessed by collecting fecal samples from participants at the beginning and end of the study. These samples will be analyzed using advanced techniques, such as mass spectrometry, to identify and quantify various metabolites present in the feces. The changes in the levels of specific metabolites, which can reflect shifts in gut microbiome composition and metabolic health, will be compared between pre- and post-intervention periods. This analysis will help determine how regular almond butter intake affects metabolic processes and gut health.
Time frame: Baseline (day 0) and endpoint (week 8)
Change in Serum Metabolome
The endpoint of serum metabolomics will be assessed by collecting blood serum from participants at the beginning and end of the study. These samples will be analyzed using advanced techniques, such as mass spectrometry, to identify and quantify various metabolites present in the serum. The changes in the levels of specific metabolites, which can reflect shifts in gut microbiome composition and metabolic health, will be compared between pre- and post-intervention periods. This analysis will help determine how regular almond butter intake affects metabolic processes and gut health.
Time frame: Baseline (day 0) and endpoint (week 8)
Change in Gut Transit Time
Evaluate changes in gut transit time after almond butter or control snack consumption from baseline to final analysis, using a blue-dye capsule.
Time frame: Baseline (day 0) and endpoint (week 8)
Change in Waist/Hip Circumference
Evaluate changes in waist and hip circumference (centimeters), as well as waist-hip ratio at each study visit before, after and during almond butter consumption, compared to a control snack.
Time frame: Baseline (week 0), midpoint (week 4), and endpoint (week 8)
Change in Habitual Dietary Intake
Assess changes in habitual dietary intake via 3-day food logs, analyzed using nutrient analysis software (NDSR).
Time frame: Baseline (day 0), midpoint (week 4), and endpoint (week 8)
Change in Body Weight
The endpoint of body weight (kg) will be measured at each visit to assess changes in weight before and after 8 week consumption of almond butter or a control snack spread.
Time frame: Baseline (day 0), midpoint (week 4), endpoint (week 8)
Change in Urinary Melatonin
Changes in melatonin (urine metabolite 6-sulphatoxymelatonin) will be assessed before, during and after 8-week consumption of almond butter or control snack spread.
Time frame: Baseline (day 0), midpoint (week 4), and endpoint (week 8)
Change in Body Fat Percentage
Evaluate changes in body composition, including fat mass, expressed as a percentage of total weight (%). This is assessed using a bioimpedance spectroscopy device (ImpediMed SBF7) at each study visit before, after and during almond butter or control snack consumption.
Time frame: Baseline (day 0), midpoint (week 4), and endpoint (week 8)
Change in Lipid Profiles
Relevant biomarkers are to be collected via venous blood samples to determine changes in cardiometabolic health including HDL, LDL, total cholesterol, and triglycerides. All will be expressed in units of mg/dL.
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Time frame: Baseline (day 0) and endpoint (week 8)
Change in Biomarkers of Inflammation
Relevant biomarkers are to be collected via venous blood samples to determine changes in inflammation, including but not limited to C-reactive protein (CRP), IL-1 (Interleukin-1), IL-1 beta, IL-6, IL-10, IL-17, IL-23, Tumor Necrosis Factor Alpha (TNF-a), Interferon-gamma (IFN-Y). All will be expressed in units of pg/mL.
Time frame: Baseline (day 0) and endpoint (week 8)
Change in Biomarkers of Intestinal Barrier Function
Relevant biomarkers are to be collected via venous blood samples to determine changes in intestinal barrier function including LPS (lipopolysaccharides), LBP (lipopolysaccharide binding protein), CD14, Secretory IgA. All will be expressed in units of pg/mL.
Time frame: Baseline (day 0) and endpoint (week 8)
Change in Lean Mass
Evaluate changes in body composition, including lean mass (kg). This is assessed using a bioimpedance spectroscopy device (ImpediMed SBF7) at each study visit before, after and during almond butter or control snack consumption.
Time frame: Baseline (day 0), midpoint (week 4), and endpoint (week 8)
Change in Biomarkers of Appetite
Relevant biomarkers are to be collected via venous blood samples to determine changes in appetite including Insulin, Glucagon, glucagon-like peptide 1 (GLP-1), Adiponectin, Leptin, Ghrelin, and Peptide YY. All will be expressed in units of pg/mL.
Time frame: Baseline (day 0) and endpoint (week 8)
Change in Rested, Seated Blood Pressure
This outcome measure will measure changes in blood pressure taken at rest in the seated position at each visit, before during and after almond butter or control snack consumption, expressed as systolic over diastolic blood pressure in units of millimeters of mercury (mmHg).
Time frame: Baseline (day 0), midpoint (week 4), and endpoint (week 8)
Change in Fasting Blood glucose
Venous blood samples will be collected to determine changes in fasting blood glucose (expressed as mg/DL).
Time frame: Baseline (day 0) and endpoint (week 8)
Dietary Adherence
Assess adherence to the intervention and control snack throughout the study, as determined by dietary adherence logs kept by the participants each week. Adherence is expressed as a daily percent (%) consumption of their assigned snack
Time frame: Daily, baseline (day 0) through endpoint (week 8)
Change in Total Body Water
Evaluate changes in body composition, including, total body water (L). This is assessed using a bioimpedance spectroscopy device (ImpediMed SBF7) at each study visit before, after and during almond butter or control snack consumption.
Time frame: Baseline (day 0), midpoint (week 4), and endpoint (week 8)
Change in Intracellular Fluid
Evaluate changes in body composition, including intracellular fluid (L). This is assessed using a bioimpedance spectroscopy device (ImpediMed SBF7) at each study visit before, after and during almond butter or control snack consumption.
Time frame: Baseline (day 0), midpoint (week 4), and endpoint (week 8)
Change in Extracellular Fluid
Evaluate changes in body composition, including extracellular fluid (L). This is assessed using a bioimpedance spectroscopy device (ImpediMed SBF7) at each study visit before, after and during almond butter or control snack consumption.
Time frame: Baseline (day 0), midpoint (week 4), and endpoint (week 8)