Efficacy and Safety of Nutraceutical on Menopausal Symptoms in Post-Menopausal Women: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial

Abstract

Background

Menopausal symptoms severely reduce the quality of life of post-menopausal women worldwide. Nutraceuticals are widely prescribed as a viable and safer alternative and complementary approach to standard therapies. The aim of this study was to evaluate the clinical efficacy and safety of a nutraceutical in post-menopausal women.

Methods

The study was designed as a randomized, double-blinded, placebo-controlled clinical trial. Post-menopausal women aged 45–60 years old were enrolled and randomly assigned to either treatment (n = 50) or placebo group (n = 51). The intervention, a proprietary combination of soy isoflavone, black cohosh, chasteberry and evening primrose oil extracts, and the placebo, were administered to each group for total of 12 weeks. Menopausal symptoms, endocrine profiles, and blood chemistry were evaluated at baseline, 6 weeks, and 12 weeks of the study.

Results

Nutraceutical supplementation demonstrated a statistically significant reduction in hot flushes and sweating (p < 0.0001), sleep problems (p < 0.0005), depressed mood (p = 0.0004) and irritability symptoms (p < 0.0003) compared with the placebo group. There were no significant differences in hormonal levels between the test and placebo groups, however levels of C-reactive protein were significantly decreased. Moreover, serum LDL-C and triglyceride levels were significantly lower than baseline levels in the treatment group at 6- and 12-week timepoints. No adverse effects were reported during the treatment.

Conclusion

These data indicate that a nutraceutical containing a combination of four medicinal herbs effectively and safely improved menopausal symptoms, as well as general health indicators, in post-menopausal women.

Keywords:

• menopausal symptoms
• nutraceutical
• phytoestrogen
• post-menopausal women

Introduction

Menopause symptoms severely reduce the quality of life of women worldwide, with up to 80% of women experiencing symptoms. It is estimated that by 2030, the groups of post-menopausal women will reach 1.2 billion globally (Gold et al. 2006). The main symptoms are hot flushes and night sweats, collectively referred to vasomotor symptoms; with sleep disturbances, and secondary symptoms often present (Palacios et al. 2010), and which are either physical and psychological in nature. Menopause is further associated with increased risk of osteoporosis, cardiovascular disease (CVD), and negative changes to lipid profile (Alexander and Clearfield 2006; Finkelstein et al. 2008). Hormone replacement therapy containing estrogen is the current treatment of choice for menopausal symptoms. Research shows the synthetic hormone preparations vary clinically in safety and efficacy (Moskowitz 2006). However, there is considerable evidence suggesting an increased cancer risk in estrogen receptor (ER) α rich tissues (e.g. uterus and breast) (Ross-Innes et al. 2012; Zhou et al. 2008).

A nutraceutical approach to female complaints has increased during last years. Menopausal symptoms have been treated with soy isoflavones and other compounds (De Franciscis et al. 2019). Nutraceuticals with estrogenic activity, including herbal medicines with selective estrogen receptor modulator (SERM) effects, are promising alternative medicines used successfully over several decades for menopausal symptom relief, with the advantage that they do not pose a cancer risk. Extracts of soy (Glycine max) beans and germ are the best known and richest natural sources of isoflavones, such as genistin, with strong binding affinity to ERβ. Soy isoflavone extracts have been used worldwide to relieve menopausal symptoms (Chen et al. 2019). Black cohosh (Cimicifuga racemosa) is a perennial member of the buttercup family, native to North America. Black cohosh is well-recognized in Western herbal medicine for its beneficial effects on menopausal symptoms and contains a wide range of phytochemicals that have effect on the endocrine system (Seidlova-Wuttke et al. 2003). Chasteberry (Vitex agnus-castus) is native to Mediterranean regions has been used for centuries to treat several menstrual problems. It contains a wide variety of bioactive constituents, which include flavonoids and diterpenes, and is the most common treatment prescribed for menopausal symptoms amongst herbalists in the UK. (van Die et al. 2009). Evening primrose seed oil (EPO) is extracted from the seeds of evening primrose (Oenothera biennis). EPO has been used traditionally for women’s health issues, because it is a rich source of essential fatty acids, including gamma-linolenic acid and various phytosterols. In a previous study, supplementation with EPO significantly reduced the severity of symptoms in menopausal women (Farzaneh et al. 2013).

In this study, we aimed to evaluate the effects of a combination of each of these medicinal herbs in a single oral intervention to post-menopausal women as an alternative therapy, alongside a placebo control. While this specific formulation has positive anecdotal evidence in various Asian countries and in Australia, for the control of hormone-related symptoms in women, a controlled clinical evaluation of the formula has not previously been conducted.

Materials and methods

This clinical study was approved by the Dhurakij Pundit University College of Integrative Medicine Ethical Review Committee for Human Research (Approval number; 005/62EX) and was conducted in accordance with the Declaration of Helsinki for research involving human subjects. Also, the clinical trial was approved by the Thai Clinical Trials Registry (TCTR20190417001) and the WHO International Clinical Trials Registry Platform (WHO-ICTRP) dataset.

Sample size calculation

The power calculation was based on the ability to detect a 10% difference in menopausal symptoms in the primary analysis of the treatment versus the control, assuming a 10% standard deviation (SD) of effect (α = 0.05 and β-1 = 0.8) and an anticipated dropout rate of 10%. To satisfy these specifications, 110 subjects were required and were recruited.

Subjects

Post-menopausal women aged 45–60 years old were recruited at the Department of Nutrition, Faculty of Public Health, Mahidol University, Thailand. Women who had stopped menstruation for least 12 consecutive months and had reported menopausal symptoms were included in the trial. Women were excluded if they had gynecological disorders; if they had kidney or liver disease; a history of food allergy; were smokers; were pregnant or nursing, or who were using or had used any herbs, dietary supplements, medicines or hormonal therapy that contained estrogenic compounds.

Study design

This study was a randomized, double-blinded, placebo-controlled trial (Figure 1). It designed according to the CONSORT Statement (Schulz et al. 2010), available through the EQUATOR Network (http://www.equatornetwork.org/). A total of 110 post-menopausal women were randomly allocated to treatment or control groups based on a sequence provided by an independent researcher and computer-generated using a randomization plan from www.randomization.com. A list of consecutive study numbers was generated. Treatment groups were allocated by research assistant, but the allocation was concealed by assigning each participant with a unique number. Participants, principal investigators, and research assistant were blinded to group allocation. The treatment group (n = 55) was given the nutraceutical intervention containing 100 mg isoflavones, 520 mg black cohosh, 400 mg chasteberry, and 500 mg evening primrose oil per capsule (Estosalus®, Max Biocare Pty Ltd, Victoria, Australia). All the active ingredients used in the formulation were purchased as extracts from approved commercial suppliers. The suppliers undertake formal identification of the plant materials, performed by a qualified botanist and verified per batch against accepted herbarium or pharmacopeia standards (typically British or US pharmacopeias). Macroscopic and morphological identification methodology is compliant with Therapeutic Goods Administration (TGA) guidelines. The control group (n = 55) was provided with soybean oil capsules as the placebo, manufactured to match the nutraceutical capsules in terms of size, excipient content, color and appearance. The treatment group were asked to consume one 1,000 mg capsule of nutraceutical after breakfast daily for 12 weeks, during which time the subjects were asked to maintain their habitual diet and lifestyle. The control group followed the same dosage regimen with one daily placebo capsule. General physical examinations were conducted by physicians and research assistants. Dietary assessment was collected by dietitian using food intake records and nutrient intakes were calculated using the INMUCAL-nutrient computer program (Institute of Nutrition, Mahidol University, Nakhonpathom, Thailand). The clinical and biochemical outcome measures were assessed at baseline (0 weeks), during intervention (6 weeks) and upon completion (12 weeks). Compliance was also assessed at the final visit. In addition, the subjects were assessed for adverse effects by the physicians.

Figure 1. Flow chart for the study sample according to Consolidated Standards of Reporting Trials (CONSORT) guidelines.

Menopause symptom assessments

Menopause symptoms were assessed by physicians using the menopause rating scale (MRS) quality of life questionnaire. The MRS is an internationally recognized and validated 5-point Likert scale for the quantitative determination of the severity of physical and psychological menopausal symptoms. It consists of 11 items, including hot flashes/sweating, heart discomfort, sleep problems, joint or muscular discomfort, depressed mood, irritability, anxiety, physical and mental exhaustion, sexual problems, bladder problems, and dryness of vagina. MRS scores were taken at weeks 0, 6 and 12, a described previously (Heinemann et al. 2003, 2004).

Biochemical assessments

Blood samples were collected by a registered nurse after an overnight fast at baseline, half-way through the intervention (6 weeks) and at the end of treatment (12 weeks) for biochemical assessments. Parameters for evaluating the safety of the treatment included markers for kidney and liver function, as well as levels of serum hormones (FSH, LH, Estradiol, and SHBG). FSH was measured by an immunoradiometric assay (Arslan et al. 2003). LH was measured by radioimmunoassay (Wheeler 2013). Estradiol was measured by standard immunoassay (Rosner et al. 2013). SHBG was measured by chemiluminescent assay (Dittadi et al. 2013). Kidney function was assessed by determination of blood urea nitrogen (BUN) and creatinine (Cr). Liver function was assessed by determination of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels. Fasting blood glucose was determined by the glucose oxidase method (Duxbury 2004). Lipid profiles were determined by an enzymatically colorimetric assay (Thongoun et al. 2013). An anti-inflammatory marker, human serum C-reactive protein (hs-CRP) was determined by the latex immunoturbidimetry assay (Horiuchi et al. 2010). All biochemical analyses were carried out at N Health Asia Lab, Bangkok, Thailand, a medical laboratory with ISO15189:2007 certification.

Statistical analysis

Data were obtained at baseline, 6 and 12 weeks, for treatment and placebo groups. Endpoint measures of parameters and dietary intakes were assessed for normality using the Shapiro-Wilk test. The ROUT test was used to identify outliers, which were omitted at Q = 0.1%. For comparison of normally distributed groups, repeated measures ANOVA with Bonferroni correction was performed. The Kruskal-Wallis rank sum test was performed for multiple comparisons of non-normally distributed data between and within groups. Friedman’s test was performed for comparison of matched data within groups without missing datapoints. The chi-squared test was used to compare reported proportions of subject satisfaction scores. All statistical analyses were performed using Graphpad Prism version 8.3.0 and considered biologically significant for p-values < 0.05.

Results

Characteristics of subjects

A total of 180 participants were screened for eligibility and 110 participants were randomized and entered into the study (Figure 1). General characteristics are presented in Table 1. There were no significant differences in weight, BMI, body fat, blood pressure, or pulse rate between the treatment and control groups, before or after the intervention. There were also no significant differences in mean daily energy and nutrient intakes between the two groups, before or after the intervention (Table 2).

Table 1. General characteristics and blood chemistry of subjects.

Characteristics and blood chemistry	Treatment			Placebo			P1	P2	P3
	Baseline	Week 6	Week 12	Baseline	Week 6	Week 12
Age (year)	53.3 (47–57)	–	–	52.6 (45–58)	–	–	0.055	–	–
Weight (kg)	59.79 ± 10.18	59.41 ± 10.16	59.20 ± 10.17	62.13 ± 11.19	61.79 ± 11.17	60.45 ± 13.67	>0.999	>0.999	>0.999
BMI (kg/m^2)	23.94 ± 4.03	23.82 ± 4.01	23.08 ± 5.14	24.72 ± 4.28	24.58 ± 4.21	24.47 ± 4.33	>0.999	>0.999	>0.999
Body fat (%)	34.42 ± 6.27	34.18 ± 6.41	33.86 ± 6.52	36.21 ± 6.49	36.08 ± 6.54	36.00 ± 6.71	>0.999	>0.999	>0.999
Blood pressure (mmHg)
- Systolic	123.1 ± 19.32	122.0 ± 18.45	120.8 ± 16.30	126.5 ± 13.82	124.1 ± 11.63	124.7 ± 15.54	>0.999	>0.999	>0.999
- Diastolic	78.92 ± 11.27	78.78 ± 9.360	77.08 ± 12.15	82.36 ± 9.209	80.36 ± 10.07	78.62 ± 10.55	0.662	>0.999	>0.999
Pulse rate (bpm)	72.60 ± 9.52	72.92 ± 10.57	72.58 ± 9.47	73.96 ± 11.00	72.73 ± 10.18	75.94 ± 10.75	>0.999	>0.999	>0.999
FBG (mg/dL)	86.33 ± 8.66	85.35 ± 8.33	84.33 ± 8.92	84.80 ± 10.96	85.98 ± 11.71	84.00 ± 10.51	>0.999	>0.999	>0.999
Total Cholesterol (mg/dL)	209.2 ± 36.30	199.1 ± 37.99	200.6 ± 36.50	202.4 ± 34.52	202.4 ± 33.63	198.1 ± 31.35	>0.999	>0.999	>0.999
LDL-C (mg/dL)	143.5 ± 27.29	125.4 ± 22.84^a	122.1 ± 23.68^b	134.3 ± 22.68	133.2 ± 23.21	133.9 ± 23.67	>0.999	>0.999	0.2832
HDL-C (mg/dL)	62.26 ± 13.35	64.56 ± 13.64	63.36 ± 12.54	60.84 ± 15.93	62.63 ± 15.95	57.88 ± 13.87	>0.999	>0.999	0.49
Triglycerides (mg/dL)	108.6 ± 38.03	99.88 ± 34.03^c	96.57 ± 33.53^d	112.60 ± 32.10	112.80 ± 33.24	110.80 ± 34.52	>0.999	0.5397	0.4777
BUN (mg/dL)	12.58 ± 2.41	12.54 ± 2.44	12.94 ± 2.46	12.58 ± 1.73	13.79 ± 2.56	13.73 ± 2.59	>0.999	0.3576	>0.999
Cr (mg/dL)	0.71 ± 0.16	0.87 ± 0.17	0.66 ± 0.17	0.72 ± 0.22	0.82 ± 0.22	0.67 ± 0.17	>0.999	0.98	>0.999
AST (U/L)	21.89 ± 4.80	23.17 ± 4.71	21.76 ± 4.55	23.29 ± 5.44	23.84 ± 8.11	23.55 ± 6.37	>0.999	>0.999	>0.999
ALT (U/L)	20.59 ± 8.61	20.14 ± 6.98	21.80 ± 7.64	18.33 ± 5.37	18.96 ± 7.04	21.92 ± 9.59	>0.999	>0.999	>0.999
hs-CRP (mg/L)	1.67 ± 1.20	1.45 ± 0.97	1.25 ± 1.07^e,f	1.66 ± 1.02	1.87 ± 1.26	1.94 ± 1.16	>0.999	0.6054	0.0002

Note: Values are means ± SD. Means in a row with superscript letters without a common letter differ within group; Significant differences at p < 0.05. P1 = Comparison of mean between the two groups at baseline; P2 = Comparison of mean between the two groups at 6 wk; P3 = Comparison of mean between the two groups at 12 wk; Significant differences at p < 0.05; ^aP = 0.024 (Baseline vs Week 6); ^bP = 0.0018 (Baseline vs Week 12) based on ANOVA; ^cP = 0.046 (Baseline vs Week 6); ^dP = 0.0015 (Baseline vs Week 12) based on Friedman’s test within treatment group; ^eP = 0.0001 (Baseline vs Week 6) and ^fP = 0.0011 (Week 6 vs Week 12) based on Freidman’s test within treatment group. BMI, body mass index; FBG, fasting blood glucose; LDL-C, low density lipoprotein cholesterol; HDL-C, high density lipoprotein cholesterol; BUN, blood urea nitrogen; Cr, creatinine; AST, aspartate aminotransferase; ALT, alanine aminotransferase.

Table 2. Total energy and nutrients intake of the subjects.

Dietary assessment	Treatment		Placebo		P1	P2
	Baseline	Week 12	Baseline	Week 12
Energy (kcal/d)	1583 ± 448.10	1569 ± 477.40	1508 ± 455.90	1536 ± 409.10	>0.999	>0.999
Carbohydrate (% of energy)	57.17 ± 9.89	53.89 ± 8.14	57.90 ± 10.36	55.94 ± 12.47	>0.999	0.452
Protein (% of energy)	15.09 ± 4.31	17.79 ± 6.63	15.10 ± 4.76	15.67 ± 4.00	>0.999	>0.999
Fat (% of energy)	27.74 ± 8.56	28.32 ± 7.27	27.39 ± 8.83	28.39 ± 10.31	>0.999	>0.999
Cholesterol (mg/d)	295.30 ± 95.92	289.70 ± 83.81	292.4 ± 90.29	282.5 ± 62.09	>0.999	>0.999
Fiber (g/d)	11.21 ± 4.87	11.56 ± 5.85	12.26 ± 7.03	12.29 ± 6.26	>0.999	>0.999

Values are means ± SD. P1 = Comparison of mean between the two groups at baseline; P2 = Comparison of mean between the two groups at 12 wk; Significant differences at p < 0.05.

No subjects reported any adverse effects resulting from the supplementation of either the nutraceutical or placebo capsules throughout the whole trial period. Five subjects in the treatment group and four subjects in the control group dropped out, thus, a total of 101 subjects completed the study (Figure 1). According to the count of the recalled capsules at the end visit, compliance was almost complete, with rates of capsule intake of 98% and 96% in the nutraceutical and placebo group, respectively.

Effects of nutraceutical on biochemical markers

There were no significant differences in FBG and lipid profiles between the treatment and control groups before or after the intervention. Nutraceutical supplementation significantly decreased the inflammation marker, hs-CRP levels (p = 0.0002) compared with the placebo group. Furthermore, nutraceutical supplementation resulted in significantly decreased LDL-C and triglyceride levels after the intervention within treatment group at weeks 6 and 12, however these changes were not statistically different compared with the respective timepoints in the placebo group (Table 1).

Effects of nutraceutical on safety parameters

Biochemical markers related to kidney and liver function as well as sex hormone levels at baseline, 6 and 12 weeks are presented in Table 1 and Table 3. The baseline parameters of kidney and liver function as well as sex hormone levels did not differ significantly between the two groups. After 6 and 12 weeks of intervention, there were no statistically significant differences in BUN, Cr, AST, ALT, FSH, LH, Estradiol, and SHBG levels between the treatment and control groups.

Table 3. Hormone levels of subjects.

Parameters	Treatment			Placebo			P1	P2	P3
	Baseline	6 weeks	12 weeks	Baseline	6 weeks	12 weeks
FSH (mIU/mL)	60.27 ± 20.01	58.90 ± 19.07	57.98 ± 19.97	60.95 ± 19.32	61.12 ± 19.46	59.03 ± 18.71	>0.999	>0.999	>0.999
LH (mIU/mL)	20.50 ± 6.66	20.21 ± 5.75	19.56 ± 6.28	21.48 ± 8.69	22.49 ± 8.59	21.69 ± 8.55	>0.999	>0.999	>0.999
Estradiol (mIU/mL)	6.14 ± 2.42	5.18 ± 1.27	5.24 ± 1.70	7.52 ± 4.75	5.00 ± 4.72	5.00 ± 2.76	>0.999	>0.999	>0.999
SHBG (mIU/mL)	75.77 ± 37.26	74.76 ± 35.20	76.30 ± 34.76	69.96 ± 31.39	70.21 ± 33.73	72.76 ± 32.93	>0.999	>0.999	>0.999

Values are means ± SD. P1 = Comparison of mean between the two groups at baseline; P2 = Comparison of mean between the two groups at 6 wk; P3 = Comparison of mean between the two groups at 12 wk; Significant differences at p < 0.05. FSH, Follicle Stimulating Hormone; LH, Luteinizing Hormone; SHBG, Sex Hormone Binding Globulin.

Effects of nutraceutical on menopause symptoms

Menopause symptoms at baseline, 6 and 12 weeks are presented in Table 4. The baseline parameters of menopause symptoms did not differ significantly between the treatment and control groups. After intervention, nutraceutical supplementation had a significant improvement on hot flushes and sweating (p < 0.0001), sleep problems (p < 0.0005), depressed mood (p = 0.0004), and irritability (p = 0.0003) compared with the placebo. However, there were no statistically significant differences in heart discomfort, joint or muscular discomfort, anxiety, physical and mental exhaustion, sexual problems or bladder problems. Vaginal dryness showed a borderline significant (p = 0.051) decrease in severity between baseline and 12 weeks in the treatment group.

Table 4. Menopausal symptoms parameters of subjects.

Parameters	Treatment			Placebo			P
	Baseline	6 weeks	12 weeks	Baseline	6 weeks	12 weeks
Hot flushes and sweating							<0.0001
Not severe	30	42	48	28	31	30
Severe	23*	10*	3*	24	21	22
Heart discomfort							0.9694
Not severe	48	48	47	47	47	48
Severe	5	4	4	5	5	4
Sleep problems							<0.0005
Not severe	31	43	45	29	32	33
Severe	22	9*	6*	23	20	19
Joint or Muscular discomfort							0.8808
Not severe	29	33	34	32	32	33
Severe	24	19	17	20	20	19
Depressed mood							0.0004
Not severe	35	44	49	37	39	40
Severe	18	8	2*	15	13	12
Irritability							0.0003
Not severe	37	48	51	39	41	41
Severe	16	4*	0*	13	11	11
Anxiety							0.8368
Not severe	36	38	39	38	41	40
Severe	17	14	12	14	11	12
Physical and mental exhaustion							0.3139
Not severe	37	40	41	32	33	37
Severe	16	14	10	20	19	15
Sexual problems							0.7661
Not severe	46	50	50	47	48	48
Severe	7	2	1	5	4	4
Bladder problems							0.6264
Not severe	34	38	38	38	40	41
Severe	19	14	13	14	12	11
Dryness of vagina							0.0510
Not severe	38	47	47	40	42	41
Severe	15	5^a	4^a	12	10	11

P = Comparison of proportions between the two groups; P‐value assigned to group, with < 0.05, determined as significant value.

* Values responsible for the significant changes; ^avalues responsible for a borderline significant effect in the treatment group, which was not observed in the placebo group.

Discussion

In the present clinical study, a combination of soy isoflavones, black cohosh, chasteberry, and evening primrose oil extracts supplemented orally for a period of 12 weeks was found to improve menopause symptoms, inflammatory and cardiovascular status in post-menopausal women. The results show that the intervention did not affect anthropometric components such as weight, BMI, body fat, or safety parameters including biochemical markers related to kidney and liver function (Table 1) as well as sex hormonal changes (Table 3). Thus, this nutraceutical had no effects on body fat, body weight or adverse effects. The data demonstrate that supplementation with the commercial herbal preparation improved menopause symptoms including hot flushes and sweating, sleep problems, depressed mood, and irritability as a combination polyherbal product, in line with previous evidence for the effects of the individual ingredients.

In regard to soy isoflavones, a previous meta-analysis that demonstrated that supplementation with these compounds can significantly reduce hot flush frequency and severity greater than placebo in menopausal women (North American Menopause Society 2011; Taku et al. 2012), Soy isoflavones can also reduce night sweats (Upmalis et al. 2000), improve lipid balance (Han et al. 2002), quality of life (physical and psychological) (Basaria et al. 2009), and improve general menopause symptoms greater than placebo (Nahas et al. 2007). Moreover, soy isoflavone supplementation can improve sleep problems (Chen et al. 2019). Soy isoflavone is enriched for the key phytoestrogens daidzein and genistein with a relatively higher proportion of daidzein. While genistein has been recognized as the key isoflavone responsible for improving menopausal symptoms (Williamson-Hughes et al. 2006), due to its high ER binding affinity, daidzein is the main precursor of equol, a bioactive isoflavonoid gut flora metabolite that also shows ERβ binding affinity (Setchell et al. 2005). Hence both isoflavones result in ER-mediated effects similar to estradiol (Morito et al. 2001).

Isoflavones competitively bind to ERs, which are typically localized to the nucleus of target cells, but can also be present on the cell membrane. Binding of the receptor causes an increasein transcriptional activity of genes with ER response elements, although more complex secondary effects are now known to be involved. Isoflavones can be agonistic or antagonist, depending on estrodiol levels, exerting a mild estrogenic activity (∼35% of 17β-estradiol) which can normalize estrogen activity in either excess or deficiency states to treat symptoms. Genistein has the greatest affinity to estrogen receptors with a sevenfold greater preference toward ERβ than ERα. Daidzein is metabolized to form the isoflavone, equol, which also has potent ERβ affinity. These properties make soy isoflavones a safe and effective treatment option (Zhao et al. 2008). However, other nutraceutical compounds have been discovered in last years for treating menopausal complaints such as pollen extracts. Pollen extracts might achieve a better improvement of hot flushes, sleep disturbances and menopause-related symptoms than soy isoflavones (De Franciscis et al. 2020). Another study found that the pollen extract reduced significant menopausal symptoms showing a very low side effect profile. Hot flashes were reduced by 48.5%, and sleep disturbance by 50.1% (Fait et al. 2019).

Black Cohosh has several bioactive compounds including phytosterols, triterpenoid glycosides, actein, cimifugosides, cinnamic acid esters, alkaloids, ferulic acid, and salicylates. Previous studies have reported that black cohosh can significantly alleviate all symptoms of menopause including vasomotor effects, anxiety, depression, vaginal atrophy as well as other physical and psychological symptoms (Bai et al. 2007; Mohammad-Alizadeh-Charandabi et al. 2013; Osmers et al. 2005). Further benefits include improvement of sleep quality in post-menopausal women with disordered sleep patterns (Jiang et al. 2015), as well as improvement of vaginal maturity and increased osteoblast activity (Wuttke et al. 2006). A review of 21 randomized controlled studies revealed that black cohosh significantly improved menopause symptom greater than control or placebo (Beer et al. 2013). Though black cohosh extracts are generally not considered to contain analogs, they can show mild estrogenic effects (Seidlova-Wuttke et al. 2003) via hypothalamic control. Several of the constituents have serotonergic properties, which help to control thermoregulation, mood and the balance of LH and GnRH under estrogen withdrawal. Other components activate the central opioid system (binding to μ-opioid receptors) to provide pain and symptomatic relief during estrogen imbalance. Salicylates provide further relief of pain via COX enzyme inhibition. The triterpene glycosides exert antioxidant and anti-inflammatory properties, which help to reduce symptom severity (Burdette et al. 2003).

Chasteberry contains a wide variety of synergistic bioactive constituents which include flavonoids, diterpenes, iridoid glycosides. A review of randomized-controlled clinical studies revealed that chasteberry was effective in normalizing irregular cycles and relieving menopausal symptoms (van Die et al. 2013). On average, around 67% of irregular cycles returned to normal and symptoms were reduced by 25–50%. Chasteberry can improve a large variety of symptoms of moderate to severe menopausal symptoms (Ma et al. 2010). In the UK, chasteberry is the most common treatment prescribed for menopausal symptoms amongst herbalists (van Die et al. 2009). Chasteberry diterpenes have dopaminergic effects by binding and activating D2 receptors. This can improve several physical and psychological symptoms of menopausal symptoms. Flavonoids from chasteberry are agonists for μ- and δ-opioid receptors, able to provide relief from pain and may modify other opioid mediated symptoms (Słopień et al. 2015).

Evening primrose oil contains a high content of essential fatty acids, gamma-linolenic acid. In a recent double-blind, randomized, placebo-controlled trial, it was reported that supplementation with evening primrose oil significantly reduced the severity of hot flushes in menopausal women with additional improvements in quality-of-life indicators of social and sexual activity (Farzaneh et al. 2013). For premenstrual syndrome, there is some evidence that gamma-linolenic acid can regulate the severity of symptoms. This was demonstrated in one trial of an essential oil extract containing gamma linolenic acids in 120 PMS sufferers, aged in their 30’s. After 6 months of daily consumption, an approximately threefold reduction in self-reported indices of symptom severity was observed during both the follicular and luteal phases (Beer et al. 2013). The anti-inflammatory properties of gamma-linolenic acid are useful in supporting menopause symptoms, to help alleviate symptoms associated with vasomotor function and neurological stress responses. Gamma-linolenic acid is further broken down to form prostaglandins, which can mediate vascular inflammatory responses to enable control of vasomotor symptoms (Rocha Filho et al. 2011).

Regarding anti-inflammatory and cardiovascular effects, supplementation with the nutraceutical significantly reduced levels of hs-CRP, with trends toward reduced LDL-C and triglycerides, which are risk factors for cardiovascular disease. These data supported the results from previous studies showed the anti-inflammatory and cardioprotective properties of soy isoflavones (Chen et al. 2019), black cohosh (Burdette et al. 2003), chasteberry (van Die et al. 2009), and evening primrose oil (Rocha Filho et al. 2011). Similarly, previous studies have reported that soy isoflavones may produce a significant reduction in hs-CRP among postmenopausal women with elevated hs-CRP (Dong et al. 2011).

Based on our result and previously published data, we propose the following scenario by whicha combination of soy isoflavones, black cohosh, chasteberry, and evening primrose oil can act synergistically to improve menopausal symptoms and decrease inflammation markers. It contains the proprietary soy isoflavone, which provide estrogen analogs that can mediate the effects of insufficient estrogen for the relief of menopausal symptoms. Black cohosh, chasteberry and evening primrose oil also provide various support roles, with a combination of central endocrine, antioxidant and anti-inflammatory effects that can assist with managing the severity of both physical and psychological menopausal symptoms, decrease hs-CRP levels, and regulate metabolic changes associated with menopause that may increase cardiovascular risk in this subpopulation of women.

A limitation of our study was that the polyphenol metabolites derived from the formula were not quantified in plasma after oral intake. Future studies to detect these compounds would provide a clearer picture of the timing and individual variations of the observed physiological effects of these herbs. Moreover, the effects of reduction of LDL-C and triglycerides in the intervention group should be studied in more detail, considering that menopausal women are a risk group for cardiovascular disorders, such as hypertension and heart disease. Furthermore, the only safety biomarkers assessed were of liver and kidney function as well as sex hormone levels. However, there are more adverse events that could affect the safety profile of the treatment, such as neurological and cardiovascular outcomes. Thus, this should be studied in the future study.

Conclusions

Taken together, these data demonstrated that a combination of soy isoflavones, black cohosh, chasteberry, and evening primrose oil supplementation may be an alternative medicine for improving menopausal symptoms in post-menopausal women.

Acknowledgments

The authors thank all research assistants of the Department of Nutrition, Faculty of Public Health, Mahidol University, Thailand, for their invaluable assistance and site for study.

Declaration of interest

The authors declare that they have no competing interests.

Additional information

Funding

This research was supported by Max Biocare Pty Ltd, Australia.

Notes on contributors

Teerapong Rattanatantikul

Teerapong Rattanatantikul, MD, M.Sc. student in anti-aging and regenerative medicine program, College of Integrative Medicine, Dhurakij Pundit University, Bangkok, Thailand. He has experience in Chinese medicine. A special interest in studying the health benefits of nutraceuticals.

Mart Maiprasert

Mart Maiprasert, MD, Assistant Professor in anti-aging and regenerative medicine program, and a research scientist in research center of nutraceuticals and natural products for health & anti-aging, College of Integrative Medicine, Dhurakij Pundit University, Bangkok, Thailand. He has experience in anti-aging and aesthetic medicine. This expertise involute the hormone replacement therapy.

Pansak Sugkraroek

Pansak Sugkraroek, MD, Assistant Professor in anti-aging and regenerative medicine program, College of Integrative Medicine, Dhurakij Pundit University, Bangkok, Thailand. He also a physician at Women's Center and VitalLife Scientific Wellness Center, Bumrungrad International Hospital, Bangkok, Thailand. He has experience in obstetrics & gynecology and also anti-aging and regenerative medicine.

Akkarach Bumrungpert

Akkarach Bumrungpert, PhD, Assistant Professor in anti-aging and regenerative medicine program, and a manager of research center of nutraceuticals and natural products for health & anti-aging, College of Integrative Medicine, Dhurakij Pundit University, Bangkok, Thailand. He has experience in nutrition science. A special interest in studying the dietary supplements and functional foods.