Effects of herbal and dietary supplements on cognition in menopause: a systematic review

From Menopause to Neurodegeneration-Molecular Basis and Potential Therapy

The impacts of menopause on neurodegenerative diseases, especially the changes in steroid hormones, have been well described in cell models, animal models, and humans. However, the therapeutic effects of hormone replacement therapy on postmenopausal women with neurodegenerative diseases remain controversial. The steroid hormones, steroid hormone receptors, and downstream signal pathways in the brain change with aging and contribute to disease progression. Estrogen and progesterone are two steroid hormones which decline in circulation and the brain during menopause. Insulin-like growth factor 1 (IGF-1), which plays an import role in neuroprotection, is rapidly decreased in serum after menopause. Here, we summarize the actions of estrogen, progesterone, and IGF-1 and their signaling pathways in the brain. Since the incidence of Alzheimer’s disease (AD) is higher in women than in men, the associations of steroid hormone changes and AD are emphasized. The signaling pathways and cellular mechanisms for how steroid hormones and IGF-1 provide neuroprotection are also addressed. Finally, the molecular mechanisms of potential estrogen modulation on N-methyl-d-aspartic acid receptors (NMDARs) are also addressed. We provide the viewpoint of why hormone therapy has inconclusive results based on signaling pathways considering their complex response to aging and hormone treatments. Nonetheless, while diagnosable AD may not be treatable by hormone therapy, its preceding stage of mild cognitive impairment may very well be treatable by hormone therapy.

Utilization of Isoflavones in Soybeans for Women with Menopausal Syndrome: An Overview

Based on their nutrient composition, soybeans and related foods have been considered to be nutritious and healthy for humans. Particularly, the biological activity and subsequent benefits of soy products may be associated with the presence of isoflavone in soybeans. As an alternative treatment for menopause-related symptoms, isoflavone has gained much popularity for postmenopausal women who have concerns related to undergoing hormone replacement therapy. However, current research has still not reached a consensus on the effects of isoflavone on humans. This overview is a summary of the current literature about the processing of soybeans and isoflavone types (daidzein, genistein, and S-equol) and supplements and their extraction and analysis as well as information about the utilization of isoflavones in soybeans. The processes of preparation (cleaning, drying, crushing and dehulling) and extraction of soybeans are implemented to produce refined soy oil, soy lecithin, free fatty acids, glycerol and soybean meal. The remaining components consist of inorganic constituents (minerals) and the minor components of biologically interesting small molecules. Regarding the preventive effects on diseases or cancers, a higher intake of isoflavones is associated with a moderately lower risk of developing coronary heart disease. It may also reduce the risks of breast and colorectal cancer as well as the incidence of breast cancer recurrence. Consumption of isoflavones or soy foods is associated with reduced risks of endometrial and bladder cancer. Regarding the therapeutic effects on menopausal syndrome or other diseases, isoflavones have been found to alleviate vasomotor syndromes even after considering placebo effects, reduce bone loss in the spine and ameliorate hypertension and in vitro glycemic control. They may also alleviate depressive symptoms during pregnancy. On the other hand, isoflavones have not shown definitive effects regarding improving cognition and urogenital symptoms. Because of lacking standardization in the study designs, such as the ingredients and doses of isoflavones and the durations and outcomes of trials, it currently remains difficult to draw overall conclusions for all aspects of isoflavones. These limitations warrant further investigations of isoflavone use for women's health.

The effects of phytoestrogens on postmenopausal health

Phytoestrogens are a group of non-steroidal polyphenolic plant-based substances, commonly used for the treatment of menopause-related conditions. They have both genomic and non-genomic effects, displaying weak affinity for estrogen receptors (ER) and preferentially binding to ER-B over ER-A. However, evidence for the benefits of phytoestrogen consumption has been limited. We conducted a review of recent literature, focusing on systematic reviews and meta-analyses reporting on postreproductive health effects of phytoestrogens. While many trials concerning dietary and supplementary phytoestrogens have been conducted, evidence of clinical efficacy is heterogeneous and inconclusive. There appears to be reduction in the vasomotor symptoms of menopause with phytoestrogen intake; however, it is likely small and slow in onset. Phytoestrogens also appear to improve bone mineral density and markers of cardiovascular risk; however, there is inadequate research regarding long-term outcomes. There appear to be no harmful effects of phytoestrogens on breast, endometrial cancer or colorectal cancer and phytoestrogens intake may in fact be protective. Research regarding the effect of phytoestrogens on cognition is mixed, with most studies reporting no significant association. Overall, individual variations in the metabolism of phytoestrogens and age-related genomic effects may account for the considerable variability in the measured effects of phytoestrogens.

Effects of soy isoflavones on cognitive function: a systematic review and meta-analysis of randomized controlled trials

CONTEXT

The results of preclinical and observational studies support the beneficial effect of soy isoflavones on cognition.

OBJECTIVE

This review aimed to evaluate the effects of soy isoflavones on cognition in adults.

DATA SOURCES

The PUBMED, EMBASE, Ovid Medline, Cochrane Library, and clinicaltrials.gov databases were searched.

STUDY SELECTION

Two researchers independently screened 1955 records, using the PICOS criteria: participants were adults; intervention was dietary sources with soy isoflavones or isolated soy isoflavones; comparator was any comparator; outcome was cognitive function; study type was randomized controlled trials (RCTs). A third researcher was consulted to resolve any discrepancies. Sixteen RCTs were included and their quality assessed.

DATA EXTRACTION

Information on study design, characteristics of participants, and outcomes was extracted. PRISMA guidelines were followed.

DATA ANALYSIS

A random-effects meta-analysis was used to pool estimates across studies. In the 16 RCTs (1386 participants, mean age = 60 y), soy isoflavones were found to improve overall cognitive function (standardized mean difference [SMD], 0.19; 95% confidence interval [CI], 0.07-0.32) and memory (SMD, 0.15; 95%CI, 0.03-0.26).

CONCLUSION

The results showed that soy isoflavones may improve cognitive function in adults.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42018082070.

Isoflavone Supplements for Menopausal Women: A Systematic Review

Isoflavones have gained popularity as an alternative treatment for menopausal symptoms for people who cannot or are unwilling to take hormone replacement therapy. However, there is still no consensus on the effects of isoflavones despite over two decades of vigorous research. This systematic review aims to summarize the current literature on isoflavone supplements, focusing on the active ingredients daidzein, genistein, and S-equol, and provide a framework to guide future research. We performed a literature search in Ovid Medline using the search terms “isoflavone” and “menopause”, which yielded 95 abstracts and 68 full-text articles. We found that isoflavones reduce hot flashes even accounting for placebo effect, attenuate lumbar spine bone mineral density (BMD) loss, show beneficial effects on systolic blood pressure during early menopause, and improve glycemic control in vitro. There are currently no conclusive benefits of isoflavones on urogenital symptoms and cognition. Due to the lack of standardized research protocols including isoflavone component and dosage, outcomes, and trial duration, it is difficult to reach a conclusion at this point in time. Despite these limitations, the evidence thus far favors the use of isoflavones due to their safety profile and benefit to overall health.

Therapeutic effect of Cnidium officinale Makino extract on ovariectomized hind-limb ischemic mice

BACKGROUND

Cnidium officinale Makino (COM) has been used traditionally to treat female sexual disorders, such as amenorrhea, hypomenorrhea and oligomenorrhea, by improving blood circulation.

METHODS

The present study aimed to investigate the alleviating effect of COM extracts on surgical injury-induced ischemia in the hind-limb of mice. In this study, female C57BL/6 mice were ovariectomized, and the vessels of the hind-limb were excised after ligation by surgical silk (6-0). The mice were orally administered with COM (150 or 300 mg/kg/day) for 3 weeks, and the blood flow rate of hind-limbs was evaluated by using a laser Doppler system after hind-limb ischemic surgery in an in vivo study. Additionally, the migration and tube formation of human umbilical vein endothelial cells (HUVECs) were evaluated in an in vitro study.

RESULTS

The blood flow rate was synchronized to the nonischemic lesion of the hind-limb, and its elevation compared to the vehicle was observed at 14 and 21 days after hind-limb ischemic surgery in COM-treated groups. The number of capillaries increase in a dose-dependent manner in the COM-treated groups (150 and 300 mg/kg). In HUVECs, the activities of cell migration were significantly increased by 50 and 75 μg/mL for the COM-treated groups. In addition, the number of tubule branches and junctions was also increased by doses of COM (50 and/or 75 μg/mL).

CONCLUSION

The results of our study suggested that the COM extract may have therapeutic application for the treatment of hind-limb ischemic damage, which is due to the improvement of the peripheral angiogenetic system.

Ameliorating effects of Cuscuta chinensis Lamak extract on hind‑limb ischemia, and angiogenic‑ or inflammatory associated factors in ovariectomized mice

Cuscuta chinensis Lamak (CCL) has traditionally been used in Korea to treat sexual disorders and skin problems. The aim of the present study was to investigate the effects of CCL extract on surgical injury‑induced ischemia in the hind limbs of mice. Specifically, female C57BL/6 mice were ovariectomized, and their hind‑limb vessels were ligated with surgical silk (6‑0) and excised. CCL (150 or 450 mg/kg/BW) was then administered to the mice for 3 weeks, and the blood flow rate was evaluated using a laser Doppler system at ‑7, 0, 7, 14 and 21 days following hind‑limb ischemia. The serum expression profiles of angiogenic and inflammatory mediators were measured using an antibody array, and the transcript levels were reverse transcription‑quantitative polymerase chain reaction. The rate of hind limb blood flow was normalized to non‑ischemic lesions and revealed to be markedly elevated at 14 and 21 days following ischemia when compared with the vehicle group. The density of capillaries in the hind limbs was also significantly increased following treatment with CCL in a dose‑dependent manner. In addition, the transcriptional expression of angiogenetic factors were upregulated, whereas that of inflammatory cytokines were downregulated. Finally, vascular endothelial cell migration and tube formation were evaluated in vitro using human umbilical vein endothelial cells (HUVECs) and identified to be significantly increased following treatment with CCL. Overall, the results of the present study indicate that CCL extract exhibits therapeutic potential for the treatment of hind‑limb ischemia as it promotes peripheral angiogenic and anti‑inflammatory effects in mice.

Overview of the Effect of Herbal Medicines and Isoflavones on the Treatment of Cognitive Function

Objectives

The current overview aimed to present the effect of herbal medicines on cognitive function among menopausal women.

Methods

Two separate authors performed systematic search of the 3 databases of (the MEDLINE Scopus and the Cochrane Central Register Trials) from inception to January 2018. Methodological quality of each study was assessed using the AMSTAR.

Results

According to 2 reviews, soy seems to be effective in enhancing summary cognitive function and visual memory. The effect of isoflavones on cognition was affected by treatment duration as six weeks of treatment improved some dimensions of cognitive parameters, including mental flexibility and planning, and longer treatment period (6 months) improved category digit span test, digit symbol test, and visual scanning test score. The effect of phytoestrogen on cognitive function of menopausal women might be altered age, gender, ethnicity, menopausal status, dosage, and length of treatment, types of cognitive test, location, types of soy, and types of phytoestrogen. Combination of Gingko with ginseng could not improve sustained attention, episode memory, category generation or frontal lobe function. Gingko biloba had no significant effect on planning, memory and sustained attention, except for its limited effect on mental flexibility in late menopause. In addition, other herbal medicines like black cohosh showed no effective beneficial.

Conclusions

Phytoestrogen, soy and isoflavones might have a limited beneficial effect on some aspects of cognition. The phytoestrogens affecting cognition might be modified by age, gender, ethnicity, menopausal status, dosage, and length of treatment, types of cognitive test, location, types of soy, and types of phytoestrogen.

Dietary Supplements: Foods, Medicines, or Both? A Controversial Designation with Unspecific Legislation

BACKGROUND

Dietary supplements have been widely used among the United States of America (USA) and the European Union (EU) population not only as a form of nutrition but also for medicinal purposes. Still, the legislation regulating these supplements remains unclear due to the fact that they can be considered as foodstuffs and/or medicinal products depending on various factors.

METHODS

The present review article intends to provide information concerning the variations on the definition of dietary supplements, the allowable substances on it, as well as the marketing and labelling requirements among the USA and the EU legislation.

RESULTS/CONCLUSIONS

In fact, several discrepancies can be found between regulations in the USA (mainly regulated by the Food and Drugs Administration) and in the EU (principally regulated by the Food Supplements Directive or by the Directive 2001/83/EC), and even between the different Member States of the EU, with the main differences observed in new products marketing requirements.

The relationship between phytoestrogens and speed of processing

OBJECTIVE

This study examined the cross-sectional association between phytoestrogens and speed of processing. We hypothesized that higher levels of phytoestrogens would be related to better cognitive performance among older women.

METHODS

Participants were from the National Health and Nutrition Examination Survey and consisted of 200 older women (M = 74.4 y). Stepwise regressions examined indicators of speed of processing, measured by the Digit Symbol Substitution Test. Isoflavones, lignans, and individual phytoestrogens were added to the regression after including covariates of age, education, race, smoking, and creatinine. Isoflavones were further broken into quartiles among the sample to further evaluate the nature of the curvilinear association.

RESULTS

Results showed a relationship between cognition and lignans, explaining 3.8% of the variance after including the covariates, indicating fewer lignans were associated with better speed of processing (P < 0.001). A significant curvilinear relationship with isoflavones explained 1.3% additional variance (P < 0.001). The moderate-high, low-moderate, and the lowest quartile of isoflavones were associated with better cognition, whereas the highest amount was associated with worse speed of processing. Among the individual phytoestrogens, only enterodiol accounted for 4.4% additional variance after taking into account covariates and indicated a negative association with cognition (P = 0.03).

CONCLUSIONS

Results suggest that moderate levels of isoflavones, but not lignans, may be associated with better speed of processing. Caution must remain for high isoflavone amounts due to the negative association with cognition. Given the results, phytoestrogens have the potential to be an intervention target for older females' cognition. To become a viable intervention, further research is needed.

Ginkgo biloba Extract (GbE) Stimulates the Hypothalamic Serotonergic System and Attenuates Obesity in Ovariectomized Rats

Menopause is associated with increased risk to develop obesity but the mechanisms involved are not fully understood. We have shown that Ginkgo biloba extract (GbE) improved diet-induced obesity. Since GbE might be effective in the treatment of obesity related to menopause, avoiding the side effects of hormone replacement therapy, we investigated the effect of GbE on hypothalamic systems controlling energy homeostasis. Wistar rats were either ovariectomized (OVX) or Sham-operated. After 2 months, either 500 mg.kg^-1 of GbE or vehicle were administered daily by gavage for 14 days. A subset of animals received an intracerebroventricular (i.c.v.) injection of serotonin (300 μg) or vehicle and food intake was measured after 12 and 24 h. Another subset was submitted to in vivo microdialysis and 5-HT levels of the medial hypothalamus were measured by high performance liquid chromatography, before and up to 2 h after the administration of 500 mg.kg^-1 of GbE. Additional animals were used for quantification of 5-HT_1A, 5-HT_1B, 5-HT_2C, 5-HTT, and pro-opiomelanocortin hypothalamic protein levels by Western blotting. OVX increased food intake and body weight and adiposity while GbE attenuated these alterations. i.c.v. serotonin significantly reduced food intake in Sham, Sham + GbE, and OVX + GbE groups while it failed to do so in the OVX group. In the OVX rats, GbE stimulated 5-HT microdialysate levels while it reduced hypothalamic 5-HTT protein levels. The results indicate that GbE improved the ovariectomy-induced resistance to serotonin hypophagia, at least in part through stimulation of the hypothalamic serotonergic activity. Since body weight gain is one of the most important consequences of menopause, the stimulation of the serotonergic transmission by GbE may represent a potential alternative therapy for menopause-related obesity.

Efficacy and side effects of chinese herbal medicine for menopausal symptoms: a critical review

This study evaluates 23 (9 Chinese and 14 non-Chinese) randomized controlled trials for efficacy and side effects of Chinese herbal medicine on menopausal symptoms. Menopause was diagnosed according to western medicine criteria in all studies while seven Chinese studies and one non-Chinese study further stratified the participants using traditional Chinese medical diagnosis "Zheng differentiation." Efficacy was reported by all 9 Chinese and 9/14 non-Chinese papers. Side effects and adverse events were generally mild and infrequent. Only ten severe adverse events were reported, two with possible association with the therapy. CHM did not increase the endometrial thickness, a common side effect of hormone therapy. None of the studies investigated long-term side effects. Critical analysis revealed that (1) high-quality studies on efficacy of Chinese herbal medicine for menopausal syndrome are rare and have the drawback of lacking traditional Chinese medicine diagnosis (Zheng-differentiation). (2) Chinese herbal medicine may be effective for at least some menopausal symptoms while side effects are likely less than hormone therapy. (3) All these findings need to be confirmed in further well-designed comprehensive studies meeting the standard of evidence-based medicine and including Zheng-differentiation of traditional Chinese medicine.

Menopausal symptoms: do life events predict severity of symptoms in peri- and post-menopause?

OBJECTIVE

Hormonal changes during menopausal transition are linked to physical and psychological symptoms' emergence. This study aims to explore if life events predict menopausal symptoms.

METHODS

This cross-sectional research encompasses a community sample of 992 women who answered to socio-demographic, health, menopause-related and lifestyle questionnaires; menopausal symptoms and life events were assessed with validated instruments. Structural equation modeling was used to build a causal model.

RESULTS

Menopausal status predicted only three symptoms: skin/facial hair changes (β=.136; p=.020), sexual (β=.157; p=.004) and, marginally, vasomotor symptoms (β=.094; p=.054). Life events predicted depressive mood (β=-.391; p=.002), anxiety (β=-.271; p=.003), perceived cognitive impairment (β=-.295; p=.003), body shape changes (β=-.136; p=.031), aches/pain (β=-.212; p=.007), skin/facial hair changes (β=-.171; p=.021), numbness (β=-.169; p=.015), perceived loss of control (β=-.234; p=.008), mouth, nails and hair changes (β=-.290; p=.004), vasomotor (β=-.113; p=.044) and sexual symptoms (β=-.208; p=.009).

CONCLUSIONS

Although women in peri- and post-menopausal manifested higher symptoms' severity than their pre-menopausal counterparts, only three of the menopausal symptoms assessed were predicted by menopausal status. Since the vast majority of menopausal symptoms' severity was significantly influenced by the way women perceived their recent life events, it is concluded that the symptomatology exacerbation, in peri- and post-menopausal women, might be due to life conditions and events, rather than hormonal changes (nonetheless, the inverse influence should be investigated in future studies). Therefore, these should be accounted for in menopause-related clinical and research settings.