The EXPLAIN Study: Exploring Plant-Based Meat Analogues for Their Impact on Health

Plant-based diets with little to no meat are considered healthy and sustainable by the general public. The increasingly popular plant-based meat analogues (PBMAs) allow consumers to easily decrease meat intake while maintaining their dietary patterns. However, scientific knowledge on the health impact of PBMAs on humans is currently very limited.

The primary objective of this clinical trial is to evaluate if and to what extent replacing all meat products in an average Dutch diet with currently commercially available PBMAs affects the systolic blood pressure of middle-aged men and women in a 2x8 week fully dietary controlled crossover intervention study. The secondary objectives are to assess the effect of this replacement of meat products with PBMAs on cardiometabolic health, gut microbiome, intestinal health, well-being, and underlying biological mechanisms.

114 men and women with a BMI of 23-40 kg/m2, aged 45-75 years will be included in the study. Participants will follow both an 8-week completely controlled diet in which all meats are of plant-based origin (PBMAs) and an 8-week diet in which all meats are of animal origin in randomized order with a 10-week wash-out period. Before the intervention starts, the participants will be characterized to describe them on anthropometrics, glucose tolerance and insulin sensitivity, genetics, sleep patterns, and stress levels. Before the start and at the end of each 8-week dietary intervention period, several measurements, including systolic blood pressure monitoring and secondary outcome measures will be done. Additionally, systolic and diastolic blood pressure will be monitored throughout the dietary interventions and a small quantity of parameters related to the secondary objectives will be measured.

Plant-based diets with little to no meat are considered healthy and sustainable by the general public. The increasingly popular plant-based meat analogues (PBMAs) allow consumers to easily decrease meat intake while maintaining their dietary patterns. PBMAs are designed to mimic the sensory and textural properties of meat and to replace animal protein with plant protein. Processing of plant-based ingredients is needed to achieve this, which potentially compromises the sustainability and health assets of PBMAs. One of the concerns with processing is that it results in relatively high salt levels in the products, which could affect the blood pressure of consumers. However, scientific knowledge on the health impact of PBMAs on humans is currently very limited. Therefore, a fully controlled dietary intervention with a standardized diet is needed to evaluate the health impact of commercially available PBMAs.

The primary objective is to evaluate if and to what extent replacing all meat products in an average Dutch diet with currently commercially available PBMAs affects the systolic blood pressure of middle-aged men and women in a 2x8 week fully dietary controlled crossover intervention study. The secondary objectives are to assess the effect of this replacement of meat products with PBMAs on cardiometabolic health, gut microbiome, and intestinal health, well-being, and underlying biological mechanisms. In addition, the investigators aim to study the relation between diet-specific responses (comparing PBMAs and meat products) and phenotype, including glucose responses and body composition.

The study compromises a randomized crossover fully controlled dietary intervention at Wageningen University which consists of 2x8 week interventions separated by a 10-week washout period. Before the intervention starts, the participants will be characterized to describe them on anthropometrics, glucose tolerance and insulin sensitivity, genetics, sleep patterns, and stress levels. Before the start and at the end of each 8-week dietary intervention period, several measurements, including systolic blood pressure monitoring and secondary outcome measures will be done. Additionally, systolic and diastolic blood pressure will be monitored throughout the dietary interventions and a small quantity of parameters related to the secondary objectives will be measured.

The study population consists of 114 men and women with a BMI of 23-40 kg/m2, aged 45-75 years, and weight stable (± \<3kg) for at least three months before inclusion. Participants will follow both an 8-week completely controlled diet in which all meats are of plant-based origin (PBMAs) and an 8-week diet in which all meats are of animal origin in randomized order with a 10-week wash-out period. Diets are fully controlled which implies that all foods and meals are provided to participants by the Human Nutrition Research Unit (HNRU) and are based on participants' habitual energy needs to maintain a stable body weight throughout the study. Except for PBMAs/meat, all other foods will be identical in both intervention diets. The composition of the diets is based on the Dutch National Food Consumption Survey. All food products provided, including the PBMAs, are commercially available.

The total study duration for a participant will be a little over \>6 months, including the 10-week washout. The total time that needs to be invested by participants in this study with visits and at-home measurements is 72 hours. Participants are restricted for a total of 16 weeks in their eating habits since they need to follow a fully standardized diet. Subjects will have their blood pressure measured at the HNRU and additionally will have to measure their blood pressure at home. In addition, subjects have to wear continuous glucose and physical activity monitors twice during the study for a total of approximately 28 days. During the characterization period, participants will visit the HNRU once or twice depending on participant preference. For the measurements before and at the end of each dietary intervention period, participants visit the HNRU three times per intervention period (one extra visit after for the HFMM), so six times total. Additionally, during the dietary intervention, participants will visit the Human Research Unit twice a week during dinner time.

Eligibility Criteria:
Inclusion Criteria:

* BMI of 23-40 kg/m2
* Age 45-75 years
* Willing to consume both meat and PBMAs
* Stable body weight (lost/gained ± \<3 kg over the last 3 months prior to inclusion)

Exclusion Criteria:

* Diseases or prior surgeries affecting the stomach, liver, kidneys or intestines (allowed i.e. appendectomy)
* Food allergies, intolerances (including lactose/gluten intolerance) for products used in the study design, and/or dietary restrictions interfering with the study (including special diets, vegetarians, and eating disorders)
* Cardiovascular diseases (e.g. heart failure. But hypertension up to 160 mmHg is allowed for inclusion as indicated by the research physician) or cancer (e.g. non-invasive skin cancer allowed)
* Anemia defined as Hb concentrations \<8.5 mmol/L for men and \<7.5 mmol/L for women
* Diagnosed with type 1 or type 2 diabetes
* Blood pressure \>160 mmHg\*
* Major mental disorders
* Drug-treated thyroid diseases (well-substituted hypothyroidism is allowed for inclusion)
* Diseases with a life expectation shorter than 5 years
* Regular use of/receiving medication interfering with research outcomes (as judged by research physician), such as the use of glucose-lowering drugs, insulin, use of medication that impacts gastric emptying, use of antipsychotics
* Starting or changing blood pressure medication type or dose during the study. (Continuation of blood pressure medication usage is allowed during the study)
* Use of anti-biotics over the last 3 months before the study start
* Dietary habits interfering with study design (vegan/vegetarian, ketogenic diet, etc.)
* Intention to change the intensity of exercise during the study period;
* Intention to lose weight during the study period
* Current smokers (including use of e-cigarettes)
* Use of soft and/or hard drugs (cannabis included)
* Abuse of alcohol (alcohol consumption defined as \>14 glasses (women) or \>21 glasses (men) of alcoholic beverages per week)
* Use of strong vitamins or other dietary supplements (e.g. iron- or B12-supplements, pre- or probiotics) expected to interfere with the study outcomes.
* Donated blood within 2 months prior to the screening
* Inability to comply with the study diet
* Being pregnant or lactating or planning to become pregnant
* Unable/unwilling to download a research application on the mobile phone
* Inability to understand study information and/or communicate with staff
* Inability/unwillingness to comply with staff instructions
* Displaying misbehavior towards other participants/staff
* Participation in another study that involves an intervention within two months prior to the intervention
* Working or doing a thesis/internship at the Division of Human Nutrition and Health or the Laboratory of Microbiology of Wageningen University.

\[\*Participants with a screening systolic blood pressure \>140 mmHg - ≤160 mmHg need written permission for participation without having (medical) treatment for the study period granted by their general practitioner after assessment of their cardiovascular risk. Participants within this screening range who cannot hand over written clearance from their general practitioner will be excluded from participation. Participants whose blood pressure has measured \>140 mmHg (systolic) or \>90 mmHg (diastolic) one or more times during the study, will receive a letter for referral to the general practitioner.\]