Effectiveness of Soya Bean Powder on Menopausal Symptoms Among Rural Women

Study design and setting

An interventional study was conducted in a selected rural area after seeking approval from the Institutional Ethics Committee of Krishna Vishwa Vidyapeeth (KVV/IEC/08/2023, dated 19.07.2023). Written informed consent was taken from all participants prior to data collection. Confidentiality and anonymity were maintained throughout the study.

The target population comprised post-menopausal women aged 40–55 years who had attained menopause naturally and were experiencing menopausal symptoms. Women were excluded if they had severe medical conditions such as hypertension, diabetes mellitus, heart disease, or thyroid disorders; were undergoing treatment for cancer or thyroid conditions; had gynaecological illnesses, including menopause induced by hysterectomy, or were receiving hormone therapy. Additionally, women with a history of drug or alcohol use, those suffering from mental illnesses, or those with known allergies to specific foods or drugs were also excluded from the study.

The sample size was calculated based on a previous study evaluating the effect of soy isoflavones on menopausal symptoms.^[14] The required sample size is estimated to be 48 participants per group using below formula.

$n=\frac{{(Z_{\frac{\alpha }{2}}+Z_{\beta })}^2\times 2{\sigma }^2}{{\left({\mu }_1\right|{\mu }_2)}^2}$

To account for attrition, the sample size was rounded to 50 in each group.

The sampling frame consisted of post-menopausal women residing in rural areas who met the inclusion criteria. A total of 100 subjects were selected from two public health centres and two villages and randomised to control (n = 50) and experimental group (n = 50) using a lottery method. Allocation concealment was ensured by preparing sequentially numbered opaque envelopes containing group assignments, which were opened only after baseline assessment. Due to the nature of the dietary intervention, participant blinding was not feasible.

A structured interview schedule was used, which included a socio-demographic profile and Menopause Rating Scale (MRS) to assess the severity of menopausal symptoms.

Intervention

The investigator provided 90 g of soya bean powder, supplying ∼49 g of protein per day to the subjects. The intervention was administered once daily for a study group for 20 days. During each home visit, the soya bean powder was carefully measured; each woman received 90 g of soya bean powder (30 g with a scoop divided into three parts) and was instructed to take 30 g in the morning with breakfast, mixing it with wheat flour for chapati preparation. In the afternoon, during lunch time, 30 g of soya bean powder was advised to be taken with cooked dal or vegetable. In the evening, 30 g of soya bean powder can be mixed with lukewarm water and consumed. This standardised preparation method was demonstrated during the education session. All participants in the experimental group received the same quantity (90 g/day) of soya bean powder, supplied by the investigator.

An educational session lasting 45 min was also conducted, which included information on the definition, phases, symptoms, and complications of menopause, and dietary strategies (particularly soya bean consumption) to reduce menopausal symptoms and improve QoL. Instructions regarding preparation and consumption were standardised and reinforced throughout the intervention period. The subjects were instructed to avoid the consumption of other soya-based products and dietary supplements throughout the intervention period to prevent interference with the effects of soya bean powder. Participants were advised to maintain their usual dietary habits and physical activity levels during the study period.

During data collection, investigators visited each subject at their home every day between 9 am and 12 pm to supervise consumption. The investigator was residing in the same village where the study was conducted, which made daily home visits practical and time-efficient. The powder was measured to meet the required quantity using a standardise scoop, dividing the daily dose into three equal portions of 30 g each. A diary was maintained to document the soya bean powder distribution and compliance daily. This daily home-based interaction ensured close monitoring of intake, adherence, and maintained consistency of the intervention across all participants.

The subjects were monitored daily until they completed the entire 20-day study period. There were no adverse effects, refusals, or dropouts observed during these 20 days. On the 21^st day following the completion of the intervention, a post-test assessment was conducted using the MRS.

Study variables

Independent variable: Educational intervention and daily intake of 90 g of soya bean powder.

Dependent variable: Severity of menopausal symptoms as measured by the MRS.

Data analysis

Data were coded and entered into SPSS version 21.0. Descriptive statistic was used to summarise baseline characteristics and symptom scores. An independent t-test was used to compare symptom scores between experimental and control groups. Paired t-tests were used to assess within group pre and post intervention changes. Chi-square test was used to examine the association. A p <0.05 was considered statistically significant.

Demographic characteristics of the study population

The study included 100 post-menopausal women equally divided into experimental and control groups. Most participants were aged 51-55 years, Hindu by religion, and had primary-level education. The majority were homemakers staying in nuclear families.

The menarche commonly occurs between the ages of 12–14, with regular menstrual cycles. Most participants were married and attained menopause between 40–50 years, within the past 8 years. A mixed dietary pattern was seen. In habits, tobacco chewing was more common in the experimental group, while tea/coffee consumption was higher in the control group. The demographic characteristics were comparable between the two groups [Table 1].

Levels of menopausal symptoms among postmenopausal women

The post-test assessment showed improvement in menopausal symptoms among women in the experimental group who received soya bean powder intervention. In the experimental group, 66% of women reported mild symptoms, while 34% experienced moderate symptoms. Notably, no participants in this group reported severe or very severe symptoms. In contrast, the control group showed a higher severity of symptoms, with only 56% (n = 28) reporting moderate symptoms, 40% (n = 20) reporting severe, and 4% (n = 2) reporting very severe symptoms. No participants from the control group showed mild symptoms [Table 2].

Pre-test menopausal symptom scores between the experimental and control groups

At baseline, there was no significant difference in the pre-test menopausal symptom scores between the experimental group, indicating that both groups were comparable before the intervention.

Comparison of the level of menopausal symptoms among postmenopausal women in the control group and experimental group

In the control group, there was no change in menopausal symptoms between pre-test and post-test. This suggests that without intervention, menopausal symptoms remained largely unchanged over the study period.

A comparison of pre-test and post-test scores in the experimental group showed a significant reduction in the level of menopausal symptoms following soya bean powder intervention. The mean menopausal symptom score decreased from 21.90 ± 6.57 in the pre-test to 9.92 ± 3.15 in the post-test and was statistically significant (p = 0.0001).

Comparison of post-test level of menopausal symptoms among postmenopausal women in experimental and control groups

A significant difference was observed in the post-test menopausal symptom scores between the experimental and control groups. The score in the experimental group was 9.92 ± 3.15, compared to 21.96 ± 6.27 in the control group, and was significant (p = 0.0001).

Association of pretest level of menopausal symptoms among postmenopausal women with demographic variables

There was no association between various demographic variables (such as age, religion, occupation, income, education level, type of family, dietary patterns, habits, menopausal age, years since last menstruation, and age at menarche) and the levels of menopausal symptoms during pre-test assessments among post-menopausal women.