Nuts have a prebiotic effect mainly due to their content of fiber and polyphenols, which provide substrates for the human gut microbiota. It is known that prebiotic substances are metabolized by microbiota generating postbiotics substances (products or metabolic by-products secreted by live bacteria or released after bacterial lysis). These products may improve host health and partly explain the health benefits of nut consumption. However, no study has been performed about the pre- and postbiotic effects of peanut and peanut butter consumption. Therefore, researchers propose a new interventional study to assess the impact of daily peanut and peanut butter intake on the organism, evaluating the pre- and postbiotic effects. The metabolome data generated will be correlated with the beneficial effects and cognitive skills. The final aim of this work is to spread a message of the health benefits of peanut consumption for the general population.
To evaluate the possible changes in microbiota and cognitive skills after consumption of roasted peanuts and peanut butter, a three-arm parallel-group randomized, and controlled study is being carried out. Ninety healthy college students were enrolled, according to the sample size estimated. Blood, urine, feces and saliva are being drawing at baseline, 3 and 6 months. Peripheral blood mononuclear cells are being extracted to evaluate the metabolic changes caused by the proposed nutritional interventions. To assess diet and physical activity a 151-items food frequency questionnaire plus a 7-day dietary record and a validated questionnaire Minnesota are being used. To determinate the effects of the intervention on body composition and vascular risk factors, anthropometric, biochemical and clinical measurements are being collected. Possible changes in cognitive skills will be determined from a validated cognitive questionnaire (WAIS-IV, Wechsler Memory Scale-IV (WMS-IV), COPE and HAD). To evaluate inflammation and metabolic status before and after intervention, levels of hormones and signaling molecules will be analyzed in blood samples. The effect of roasted peanut and peanut butter consumption on microbiota will be assayed through identification and quantification of polyphenols and short-chain fatty acids in biological samples, as well as the gut microbiota characterization from DNA extraction.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
90
After 2 weeks following a peanut-free diet, the participants of this group consume 25 g/ day of whole skin roasted peanuts (RP) within the habitual diet during 6 months.
After 2 weeks following a peanut-free diet, the participants of this group consume 2 tbsp/ day (32 g/ day) of peanut butter (PB) within the habitual diet during 6 months.
After 2 weeks following a peanut-free diet, the participants of this group consume 2 tbsp/ day (32 g/ day) of control supplement (containing the same proportion of macronutrients as peanuts and peanut butter) within the habitual diet during 6 months.
Department of Nutrition, Food Sciences and Gastronomy. School of Farmacy and Food Sciences. University of Barcelona.
Barcelona, Spain
Changes in the polyphenols and their metabolites after a daily intake of peanuts and peanut butter in biological samples of healthy college students
Identification and quantification of polyphenols will be determined using a high performance liquid chromatography-high resolution mass spectrometry (HPLC-HRMS) method (Sasot et al., 2017) and quantified by ultra high-performance liquid chromatography coupled with triple quadrupole mass spectrometry (UHPLC-QqQ-MS/MS) methodology (Martínez-Huélamo et al., 2015).
Time frame: Baseline and after completed the intervention (6 months)
Changes in the short-chain fatty acids after a daily intake of peanuts and peanut butter in biological samples of healthy college students
After acidifying the fecal samples with formic acid, a quantification of short-chain fatty acids will be performed using gas chromatography by direct injection according to previously described methodology (Zhao et al., 2006).
Time frame: Baseline and after completed the intervention (6 months)
Changes in the gut microbiota after a daily intake of peanuts and peanut butter in fecal samples of healthy college students
Fecal samples will be collected by the volunteers using a system for easy self-collection and stabilization of microbial DNA for gut microbiome profiling (OMNIgene - GUT). The genomic DNA will be extracted from fecal samples using the DNeasy PowerSoil Kit. Then, the 16s metagenomic analysis will be performed.
Time frame: Baseline and after completed the intervention (6 months)
Changes in the intelligence and cognitive ability in healthy college students after a daily intake of peanuts and peanut butter
To measure intelligence and cognitive ability, the Wechsler Adult Intelligence Scale IV (WAIS IV) will be used.
Time frame: Baseline and after completed the intervention (6 months)
Changes in the memory function in healthy college students after a daily intake of peanuts and peanut butter
To measure memory function, the Wechsler Memory Scale IV (WSM IV) will be used.
Time frame: Baseline and after completed the intervention (6 months)
Changes in language and executive function in healthy college students after a daily intake of peanuts and peanut butter
To measure language and executive function, lexical fluency tests will be used.
Time frame: Baseline and after completed the intervention (6 months)
Changes in cope to stressful situations in healthy college students after a daily intake of peanuts and peanut butter
The 48-items Coping Orientation to Problems Experienced questionnaire (COPE-48) will be performed to assay how healthy college students cope with highly demanding situations demanding situations of healthy college students.
Time frame: Baseline and after completed the intervention (6 months)
Changes in levels of anxiety and depression in healthy college students after a daily intake of peanuts and peanut butter
To measure the levels of anxiety and depression of healthy college students the Hospital Anxiety and Depression Scale (HAD) will be used.
Time frame: Baseline and after completed the intervention (6 months)
Changes in body mass index after a daily intake of peanuts and peanut butter in healthy college students
Body mass index (kg/m\^2) are calculated after measure weight (kg) and height (meter).
Time frame: Baseline, 3 months and after completed the intervention (6 months)
Changes in waist-to-hip ratio after a daily intake of peanuts and peanut butter in healthy college students
To evaluate waist-to-hip ratio, waist and hip circumferences (cm) are measured in triplicate
Time frame: Baseline, 3 months and after completed the intervention (6 months)
Changes in percentage of body fat after a daily intake of peanuts and peanut butter in healthy college students
Total adiposity are measured by bioelectrical impedance (percentage of fat).
Time frame: Baseline, 3 months and after completed the intervention (6 months)
Changes in blood pressure after a daily intake of peanuts and peanut butter in healthy college students
Systolic and diastolic blood pressure (mmHg) are measured with an automatic blood pressure monitor in triplicate.
Time frame: Baseline, 3 months and after completed the intervention (6 months)
Changes in heart rate after a daily intake of peanuts and peanut butter in healthy college students
Heart rate (bpm) is measured with an automatic monitor in triplicate.
Time frame: Baseline, 3 months and after completed the intervention (6 months)
Changes in lipidic profile after a daily intake of peanuts and peanut butter in healthy college students
Total cholesterol, HDL-cholesterol, LDL-cholesterol and triglycerides (mg/dL) are measured by molecular absorption spectrometry.
Time frame: Baseline, 3 months and after completed the intervention (6 months)
Changes in glucose after a daily intake of peanuts and peanut butter in healthy college students
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Glucose (mg/dL) is measured by molecular absorption spectrometry.
Time frame: Baseline, 3 months and after completed the intervention (6 months)
Changes in cortisol after a daily intake of peanuts and peanut butter in healthy college
Cortisol (nmol/l) is measured by immunochemiluminescence
Time frame: Baseline, 3 months and after completed the intervention (6 months)
Changes in pro- and anti-inflammatory biomarkers after a daily intake of peanuts and peanut butter in healthy college
Cytokines (pg/mL), tumor necrosis factor α (TNF-α) (pg/mL) and C-reactive protein (CRP) (mg/dL) will be assayed by immunoenzymatic methods.
Time frame: Baseline and after completed the intervention (6 months)
Changes in nutrients and energy intake after regular peanut and peanut butter consumption in healthy college
Dietary changes are evaluated with a 151-item semi-quantitative food frequency questionnaire (Fernández-Ballart et al., 2010). In addition, a 7-day food recall on the day of the intervention are used to validated this results. These were analyzed using a software called Programa de Càlcul Nutricional Professional (PCN Pro).
Time frame: Baseline and after completed the intervention (6 months)
Changes in physical activity after regular peanut and peanut butter consumption in healthy college
Physical activity is measured by the validated Spanish version of the Minnesota Leisure-Time Physical Activity Questionnaire (Elosua et al., 1994).
Time frame: Baseline and after completed the intervention (6 months)