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 pattern. 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 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 extend 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.

The study compromises a randomized crossover fully controlled dietary
intervention at Wageningen University which compromises of 2x8 week
interventions separated by a 10 week washout period. Before the intervention
starts, a characterization of the participants will be performed in order to
describe them on anthropometrics, glucose tolerance and insulin sensitivity,
genetics, sleep patterns and stress levels. Prior to 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, throughout the dietary interventions systolic and diastolic blood
pressure will be monitored and a small quantity of parameters related to the
secondary objectives will measured.

Participants will follow both a 8-week completely controlled diet in which all
meats are of plant-based origin (PBMAs) and a 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 >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
own 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 prior to- 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.

The following burdens or risks may be associated with participation:

- The in-clinic and at-home blood pressure measurements are non-invasive.
However, the inflation of the arm cuff could potentially cause very mild
discomfort, but only for a very short amount of time (±20 seconds).
- Participants have to wear a continuous glucose monitor (CGM) twice. The
placement of the CGM, though minimally invasive, could be considered a burden
for the participants. We minimize this burden by using a continuous glucose
monitor that does not need regular calibration by finger pricks, and by using
it for only 2x ~14 days, instead of the full 16 weeks. The placement of the
Freestyle Libre will be done by experienced researchers.
- While wearing the CGM, participants will also wear an activity monitor; an
accelerometer. The ActiGraph placement is also not invasive, and has an
adjustable band to make wearing it as comfortable as possible.
- During test days, blood will be collected by venepuncture, which can
occasionally result in a local hematoma or bruise. Some participants report
pain during venepuncture. The blood collection will be done by experienced
nurses. A total of ~516 mL of blood will be drawn over the entire RCT (> 6
month period). For conventional blood donations, men donate ~500 mL blood every
2.5 months and women every 4 months.
- The collection of faecal and urine samples can be experienced as a burden
(collecting the samples and storing them at home). However, based on previous
experience, this procedure is quite feasible.
- In the DEXA scan, we use X-rays. In this examination, participants will
receive a total of about 0.002 mSv of radiation. In comparison, the "normal"
radiation that everyone in the Netherlands receives anyway is about ~2.5 mSv
per year. The radiation from the DEXA scan could cause damage to participants
health, but this risk is small. There is no harm if you have to undergo an
examination or treatment with radiation for a medical reason. If participants
have more frequent examinations with radiations, the doctor will check if it is
wise to undergo the DEXA scan and participants will be excluded from the scan
(but not the intervention) if determined so by the medical doctor.
- The blue coloured cakes are made from commercially available ingredients,
including a food-grade blue dye. No discomfort is to be expected from consuming
them, only small temporary staining of the tongue, which will not last >1 hour.

All food products in the intervention are commercially available. We do not
expect that either the composition of the diets or individual food products
will cause discomfort for the participants. Concerning the OGTT in the
characterization and the and HFMM in the intervention, there are no known
risks. These measurements are routinely applied in human biology research and
SOPS are available in the database of the Human Nutrition Department.

The study population exactly fits the population of interest, since middle-aged
and overweight/obese individuals are at risk of developing high blood pressure
and other cardiometabolic diseases. Additionally, we do not expect to find
effects in young people. A study evaluating the health impact of PBMAs
contributes to a better understanding of how these products fit into a healthy
diet and may be important in the current protein transition.