Effects of Plant Foods on Gastrointestinal and Cardiometabolic Health

King's College London248 enrolled

Overview

The aim of this randomised controlled trial is to investigate the effects of plant foods on gastrointestinal and cardiometabolic health in healthy adults aged 30-70 years old. The main question it will answer is "what is the effect of plant foods on alpha-diversity of the gut microbiota?". Researchers will compare two diets containing plant foods to see if they have different effects on gastrointestinal and cardiometabolic health. Participants will be asked to replace all their meals, snacks and drinks with those provided by the study team for four weeks (6 days/week). Participants will also be asked to attend the research facility on three occasions to: * Provide a blood sample * Provide a urine sample * Provide a stool sample * Have their body composition assessed * Have an ultrasound of their artery (arm) * Have their blood pressure measured * Answer questionnaires related to dietary intake, mental health, physical activity, quality of life, diet acceptability and adherence

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

TRIPLE

Enrollment

248

Conditions

Healthy Adult Volunteers Nutrition

Interventions

Eligibility

Sex: ALLMin age: 30 YearsMax age: 70 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * Adults aged 30-70 years of age * Capacity to give informed consent in English * Consume equal or less than the average UK plant food intake (number and quantity) * Consume less than 30 g/d of fibre * BMI 18.50-29.99 kg/m2 * Willing to complete the trial by adhering to the diet intervention, complete questionnaires, provide stool, urine and blood samples, record weight and other anthropometric values and record food intake throughout the study * Willing and able to adhere to the protocol for the diet intervention for the whole duration of the trial (e.g., appropriate space in freezer to store meals, access to oven/microwave, no planned travelling) * Willing to discontinue use of prebiotics and probiotics 4 weeks prior and during the intervention period * Willing to consume animal products daily * Medication use is stable in women receiving hormone replacement therapy (stable use for the past 3 months) Exclusion Criteria: * Medical history of any of the following: diabetes, major active or historic psychiatric conditions (e.g., schizophrenia), current eating disorder, alcohol abuse, active treatment for cancer in the last year, severe neurological, endocrine, renal, cardiac or pulmonary disease (or any other chronic medical condition), severe oesophagitis, gastritis or duodenitis, active diverticulitis or intestinal/colonic strictures, Coeliac disease, Crohn's disease or Ulcerative colitis, stem cell or organ transplant, gut resection surgery (excluding appendicectomy and cholecystectomy), bleeding disorder, anaphylaxis or any other major or chronic condition known to impact study outcome measures. * A current diagnosis of IBS, as defined by the Rome IV criteria. * Taking medications known to affect outcomes of interest, including: * Prebiotics and probiotics 4 weeks prior to enrolment. * Antibiotics within 4 weeks of enrolment. * Medications known to affect blood pressure, appetite, gut motility, glucose control, or lipid levels within 4 weeks of enrolment. * Taking any dietary supplements, apart from vitamin D or calcium supplements, 4 weeks prior to enrolment. * Allergy or intolerance to any study food ingredients. * Unable/dislike/unwilling to consume study foods or adhere to study protocol (e.g., not willing to drink a maximum 9 units of alcohol a week or consume animal products). * Currently reported pregnant or lactating. * Unwilling or unable to consume non-halal or non-kosher products. * Estimated energy requirements of \<1,500 kcal/day or \>3,000 kcal/day. * Unexplained or unintentional weight loss in the past six months.

Outcomes

Primary Outcomes

Alpha-diversity of the gut microbiota

The diversity of microbial taxa in faecal samples at 4 weeks assessed by calculating alpha-diversity score from 16S ribosomal RNA sequencing.

Time frame: Week 4

Secondary Outcomes

Absolute and change in alpha-diversity of the gut microbiota

Absolute and change in alpha-diversity as measured by the diversity of micriobial taxa in faecal samples via 16S RNA sequencing.

Time frame: Baseline, Week 4

Beta-diversity of the gut microbiota

The diversity of microbial taxa in faecal samples by calculating beta-diversity via 16S ribosomal RNA sequencing.

Time frame: Baseline, Week 4

Microbiota composition

Absolute and change in microbiota composition of faecal samples between baseline and Week 4 as assessed by 16S ribosomal RNA sequencing.

Time frame: Baseline, Week 4

Targeted faecal and plasma metabolomics

Absolute and change in short-chain fatty acids through Liquid Chromatography - Mass Spectrometry using validated assays.

Time frame: Baseline, Week 4

Targeted faecal and plasma metabolomics

Absolute and change in bile acids through Liquid Chromatography - Mass Spectrometry using validated assays.

Time frame: Baseline, Week 4

Untargeted faecal metabolomics

Metabolomics analysis via 1H NMR spectroscopy.

Time frame: Baseline, Week 4

Faecal water content via oven drying

Absolute and change in water content of faecal samples assessed via oven drying.

Time frame: Baseline, Week 4

Stool frequency

Absolute and change in stool frequency measured via prospective 7-day stool diary

Time frame: Baseline, Week 4

Stool consistency

Absolute and change in stool consistency measured by Bristol stool form scale. Scale from 1 to 7.

Time frame: Baseline, Week 4

Gastrointestinal symptoms

Absolute and change in gastrointestincal symptons measured by Gastrointestinal symptoms rating scale score. Scored from 15 to 105 with lower scores indicating less severe symptoms.

Time frame: Baseline, Week 4

Endothelial function

Flow mediated dilation measured via ultrasound of arm.

Time frame: Baseline, Week 4

Untargeted urine and plasma metabolomics

Metabolomics measured via 1H NMR spectroscopy.

Time frame: Baseline, Week 4

Targeted plasma and urine metabolomics

Metabolomics via Liquid Chromatography-Mass Spectroscopy using validated assays.

Time frame: Baseline, Week 4

Blood pressure

Absolute and change in diastolic and systolic blood pressure.

Time frame: Baseline, Week 4

Body composition

Absolute and change in body composition measured via biolelectrical impedance analysis (BIA).

Time frame: Baseline, Week 4

Waist circumference

Absolute and change in waist circumference assessed by tape measure.

Time frame: Baseline, Week 4

Dietary intake

Dietary intake measured by aggregating EPIC Norfolk food frequency questionnaire, daily food and drink diaries and food checklists.

Time frame: Baseline, Week 4

Biological markers of dietary intake

Absolute and change in biomarkers of dietary intake as measured via validated assays.

Time frame: Baseline, Week 4

Effects of Plant Foods on Gastrointestinal and Cardiometabolic Health

Overview

Conditions

Interventions

Eligibility

Locations (1)

Outcomes

Primary Outcomes

Secondary Outcomes