Fifty two women, aged 18-40, will be recruited for the study. The investigators calculated
the sample size using G*Power software (RRID:SCR_013726); the sample size of the participants
was also determined. The effect size was calculated to be 1.04 on the basis of the
differences in body fat mass between baseline values and values after 6-weeks of application
of time-restricted eating by PCOS women. With an alpha value of 0.05, a sample size of eight
mice per group would yield a power of 0.95.
Women recruited for the study will be provided with detailed information regarding: the
purpose of the study, the study protocol, the measurements performed and the duration of the
study. Recruitment will take place via social networking sites, i.e. Facebook, where target
groups will be found, bringing together women with PCOS, and posts with an announcement and a
contact form will be placed there. After obtaining consent to participate in the study, a
group of qualified women will undergo a general medical interview by Jakub Noskiewicz, Ph.D.,
which will include a personal interview, including current medications and supplements taken,
medical history and a basic physical examination - examination, percussion. If the interview
reveals an existing infection, a chronic disease in the acute phase, a suspicion of e.g.
anemia, infectious skin diseases or malnutrition, or the intake of medications constituting
an exclusion criterion, the patient will not be qualified for the study. During this
interview, participants will be asked to provide medical documentation confirming they suffer
from PCOS.
Participants will be randomly assigned (using a specialized program) to two groups - control
and intervention. Research participants assigned to the control group will receive dietary
recommendations consistent with the healthy eating plate. Additionally, the recommended daily
energy intake will be individually determined for each patient. Participants assigned to the
TRF group will be instructed to continue eating their usual diet during the experiment
(without any qualitative or quantitative restrictions), but to eat it within a limited time
frame - from 9:00 a.m. to 5:00 p.m., and then fast until the next day ( protocol 8/16). The
duration of the study will be 3 months (12 weeks).
A nutritional assessment of the diet will be carried out (KomPAN questionnaire). The
nutritional assessment will be additionally supplemented by an interview from the last 24
hours. Then, the recruited women will be randomly assigned to the intervention group, using
time-restricted nutrition, or the control group, using the principles of the healthy eating
plate. The duration of the experiment will be 12 weeks, with follow-up visits scheduled at
4-week intervals. At the beginning of the experiment and at follow-up visits, women will have
blood drawn (per 18 ml) to assess biochemical parameters. Each time, a stool sample will also
be collected to assess the composition of the intestinal microbiota and short-chain fatty
acids, and an analysis of body composition, bone density and anthropometric parameters will
be carried out. During the last visit in week 12, women will be asked to fill out the KomPAN
questionnaire again, which will be supplemented by an interview from the last 24 hours. Each
time, an interview will be conducted regarding the women's well-being and adherence to the
recommendations provided. The level of adherence to the eating window will be verified using
a diary in which women will write down each day when they ate their first and last meals.
The following specific analyses are planned:
Assessment of anthropometric parameters (body weight, height, waist circumference, hip
circumference) as well as body composition and bone density.
Assessment of carbohydrate metabolism parameters (concentration of glucose, insulin,
calculation of HOMA-IR, HOMA-β, QUICKI), lipid metabolism (concentration of total
cholesterol (T-C), LDL cholesterol (LDL-C), HDL cholesterol (HDL-C) , non-HDL
cholesterol (non-HDL-C) and triglycerides)
Assessment of hormonal parameters (FSH, LH, testosterone, SHBG) and lipopolysaccharide
in the blood.
Assessment of neurohormonal parameters (kisspeptin, gamma-aminobutyric acid) in the
blood.
Assessment of the composition of intestinal microbiota and short-chain fatty acids in
women's feces.
Normality of the obtained data distribution will be tested using the Shapiro-Wilk test. The
Kruskal-Wallis test then will be used for nonnormally distributed data and the Tukey HSD test
will be used for normally distributed data. A p value of less than 0.05 was considered
statistically. The microbiota composition will be analyzed using RStudio (R version 4.0.3
(2020-10-10)) with packages including phyloseq, microbiome, and vegan. Taxa will be filtered
by removing all those not assigned to any phylum. Only taxa with abundances over 0.25% in at
least one sample will left in the dataset. All analyses of gut microbiota composition will be
performed on the basis of the relative abundances (RA) of the OTUs.
The data collected in the planned studies will include the results of measurements and their
statistical analyzes. All data will be collected directly by team members and coded. Detailed
instructions on data collection will be prepared by the team leader and each member will need
to read and receive appropriate training. All biochemical and anthropometric measurements
will be performed in at least two repetitions and will be checked by another team member. All
used specialized equipment will be properly calibrated before each use (scale, body
composition analyzer, Nanodrop spectrophotometer).
