Women who meet the criteria for inclusion in the study for a period of 4 weeks will be
randomly assigned to one of two groups: 1. The intervention group will follow the
principles of the healthy eating plate, which will be supplemented with elements of the
washoku diet (30 g of roasted black soybeans and 5 g of wakame); 2. The control group
will be covered only by the principles of the healthy eating plate.
All participants will receive a brochure with information on the recommended portion
sizes of individual product groups in the daily diet, recipes for dishes based on roasted
black soybeans and wakame. Before and after the study, in addition to anthropometric
measurements (body weight, waist circumference, hip circumference), body composition and
bone mineral density, an assessment of the diet (using a semi-quantitative questionnaire
of food frequency, as well as the current recording method from the last 4 days) and the
level of physical activity will be carried out. Additionally, the women will be asked to
collect a daily portion of urine to assess the concentration of soy isoflavones and to
determine the content of sodium, potassium and magnesium. Women will also have their
blood (18 ml) collected to assess selected biochemical parameters (glucose, insulin,
total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), high density
lipoprotein cholesterol (HDL-C), non-HDL cholesterol (non-HDL-C) and triglycerides). A
stool sample will also be collected to assess the composition of the intestinal
microbiota and its metabolites, i.e. short-chain fatty acids. Recruitment will take place
via social networking sites, i.e. Facebook.
The following specific analyses were planned:
Assessment of anthropometric parameters (height, body weight, hips and waist
circumference)
Analysis of body composition and bone mineral density
Assessment of nutritional status (selected metabolic parameters such as glucose
metabolism (glucose, insulin concentration), lipid metabolism (total cholesterol
(T-C), LDL cholesterol (LDL-C), HDL cholesterol (HDL-C), non-HDL cholesterol
(non-HDL-C) and triglycerides).
Assessment of dietary habits (a semi-quantitative questionnaire on the frequency of
food intake, additionally supplemented by the current recording method from the last
4 days.)
Assessment of intestinal microbiota composition
Assessment of fecal short-chain fatty acid concentration
Assessment of urine soy isoflavones concentration
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 (Operational Taxonomic Units).
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).