However, we asked and recorded the time of each subject's last meal. The present investigation on determinants of blood hormone levels included the first women who were at least 50 years of age, without any history of cancer and who had experienced a natural or a surgical menopause.

We also wanted to circumvent the problem of inherent cyclic variation in estrogen levels in premenoapaual women and thus limited our analysis to women who were 50 years of age or older and were postmenopausal by self-report; their postmenopausal status was subsequently confirmed by their circulating estrogen levels 5.

In addition, 19 of the women were excluded from the study for the following reasons; 4 were current users of replacement hormones, 1 had data missing for estrone, estradiol and androstenedione and 14 were regular drinkers of both green and black tea.

We excluded subjects who drank both types of tea regularly because we hypothesized that the two types of tea might have opposing effects on blood hormone levels; therefore, users of both types of tea would be non-informative in this study.

The Institutional Review Boards at the University of Southern California and the National University of Singapore have approved this study. Plasma aliquots from subjects under study were shipped in sealed containers on dry ice to one of us M. Y at the University of Southern California. These specimens were then delivered to the laboratory of Dr Frank Stanczyk who used radioimmunoassay, previously validated in his laboratory 9 , 10 , to measure plasma levels of estrone, estradiol and androstenedione.

Prior to quantification, the hormones were first extracted with hexane:ethyl acetate and then separated from interfering metabolites by the use of celite column partition chromatography. DNA was purified from buffy coats of peripheral blood samples using a PUREGENE Blood kit Gentra Systems, Minneapolis, MN or a QIAamp 96 DNA Blood Kit Qiagen, Valencia, CA.

This assay was performed using a TaqMan PCR Core Reagent kit Applied Biosystems, Foster City, CA according to the manufacturer's instructions. The fluorescence profile of each well was measured in an ABI HT Sequence Detection System and the results analyzed with Sequence Detection Software Applied Biosystems.

Any samples that were outside the parameters defined by the controls were considered as non-informative and were retested. We used the analysis of covariance methods to compare mean plasma levels of estrone, estradiol and androstenedione by the type of tea intake and by the type of tea in combination with soy intake and COMT genotype.

The time interval between last meal and blood drawn was also included as a covariate because the three hormones under study were higher among subjects who gave fasting samples 5.

We used linear contrasts 1 degree of freedom to test for trends by tea intake. Associations between tea intake and plasma estrogen levels were essentially identical with or without adjustment for intake of coffee, menstrual and reproductive factors.

Results shown in this report did not include coffee intake, and menstrual and reproductive factors as covariates. The distributions of the hormone levels were skewed, which were corrected to a large extent by transformation to logarithmic values.

Therefore, all statistical analyses were performed on logarithmically transformed values. We hypothesized that plasma estrogen levels will be lowest among regular green tea drinkers only, intermediate among non-regular tea drinkers and highest among regular drinkers of black tea only.

All P values quoted are two-tailed 2P. Calculations were performed using the SAS statistical software system SAS Institute, Cary, NC.

Analyses of estrone, estradiol and androstenedione were conducted on women, with the age ranging from 50 to 77 years mean Table I shows that Demographic characteristics e. However, regular black tea drinkers were less likely to be daily coffee drinkers and more likely to be higher soy consumers i.

highest quartile of soy protein intake compared to regular green tea drinkers and non-tea drinkers and irregular tea drinkers Table I. Adjusted for time interval between blood draw and last meal, age, body mass index and intake of soy protein.

Soy and tea appear to have independent effects on plasma estrone levels. Geometric mean hormone levels by tea intake, according to COMT genotype, are presented in Table III. Similarly, COMT genotype did not significantly influence plasma estradiol or androstenedione levels; and it did not modify the tea—estradiol or tea—androstenedione associations Table III.

After adjusting for tea intake and other covariates mentioned above, estrone, estradiol and androstenedione levels were The corresponding levels were In this cross-sectional study of postmenopausal Chinese women in Singapore, we found that tea drinking significantly influences plasma estrogen levels and that these levels are influenced differentially by the type of tea used.

Additionally, the COMT genotype, a measure of one's ability to eliminate tea polyphenols, did not influence the tea—blood hormone associations. We interpret these two findings to suggest that the differential effects of black and green tea on hormone levels are unlikely to be due to tea polyphenols, but rather due to some other, yet to be identified constituents of tea.

Before discussing our findings, some methodologic limitations of this investigation should be considered. An original intent of this cross-sectional study was to identify dietary and non-dietary determinants of blood estrogen levels in postmenopausal Chinese women 5.

When we started this project, we did not know that green tea and black tea would differentially influence blood hormone levels. In addition to including a larger sample size, future studies may be designed in a way to ensure that the numbers of non-tea drinkers, green tea drinkers only and black tea drinkers only are more balanced.

Despite the modest sample size of this study and the preliminary nature of its observations, the high degree of internal consistency of our findings, coupled with biological plausibility tend to strengthen the study hypothesis, that the type of tea may matter. A similar pattern of differences in androstenedione levels by tea intake was found.

It should be noted that we had previously reported no association between tea intake and blood estrogen levels and this was owing to ignoring the type of tea in our analysis 5. The present analysis shows that an association between tea intake and blood hormone levels may be missed if the type of tea and frequency of tea intake are not considered simultaneously.

Data in support of modulating effects of tea on plasma hormone levels lend credibility to observational findings of a tea—breast cancer association 2 since there is now compelling evidence that endogenous hormones, especially estrogens, play a critical role in the etiology of breast cancer The differing effects of green and black tea on circulating estrogen levels have corroborative support from human and non-human studies.

In a study of premenopausal women in Japan, Nagata et al. This level of EGCG intake is achievable in humans as one cup ml of green tea contains up to mg of EGCG Since levels of EGCG are substantially higher in green tea than in black tea 17 , it is plausible that the lower estrogen levels associated with green intake tea is explained partly by the inhibitory effects of EGCG on aromatase activity and hence the synthesis of estrogen.

However, black tea also contains EGCG and other tea catechins, though in lower levels and thus it is not obvious why estrogen levels are not lower in regular black tea drinkers compared with non-regular tea drinkers. In that study, serum prolactin levels increased significantly with increasing levels of black tea intake Although blood estrogen levels were not measured in this study, breast cancer risk was found to increase significantly with increasing prolactin levels in the Nurses Health Study Motivated by our previous finding that the inverse association between tea and breast cancer risk is found mainly among women who were heterozygous for the COMT L allele i.

those less efficient in eliminating tea polyphenols 4 , we investigated the tea—plasma hormone associations by COMT genotype.

Contrary to our findings in relation to breast cancer risk 4 , the COMT genotype did not significantly influence the tea—hormone associations in this analysis. Specifically, plasma estrone, estradiol and androstenedione levels were consistently lower among green tea drinkers while they were consistently higher among black tea drinkers irrespective of COMT genotype Table III.

We believe that our recent finding of an upregulatory effect of black tea and a downregulatory effect of green tea on circulating estrogen levels provides a cogent explanation for the paradoxical findings of our first two papers on tea 2 , 4.

These results suggest that tea polyphenols are not the constituents, in black tea and green tea, responsible for the hormonal effects of tea that we and others 6 , 14 , 15 , 18 have identified in human and rodent studies.

The differential effects on breast cancer protection between green tea versus black tea, despite comparable levels of antioxidative tea polyphenols between the two types of tea 20 , may lie in the possibility that they possess opposing effects on sex-steroid hormones.

Green tea may have strong beneficial effects on the breast through both its antioxidant properties and its downregulatory effects on estrogens. In contrast, while black tea possesses antioxidant effects, it nonetheless exhibits no downregulatory or may be upregulatory effects on blood estrogen levels.

These latter opposing effects of black tea, if confirmed, may help to explain the overall weaker effect of black tea on breast cancer risk. The sample size of this cross-sectional study is modest and thus we view these results as preliminary and requiring confirmation in larger studies.

Further investigations of possible hormonal effects of green tea and black tea should provide a better understanding of the role of these teas in the etiology of breast cancer and will complement epidemiologic investigations on the relationship between tea intake and breast cancer risk.

We thank Ms Siew-Hong Low of the National University of Singapore for supervising the field work of the Singapore Chinese Health Study. The Singapore Chinese Health Study has been supported by grants R01 CA, R35 CA and R01 CA from the National Cancer Institute, Bethesda, Maryland.

is supported, in part, by the California Breast Cancer Research Program 9PB and the Susan G. Komen Breast Cancer Foundation POP and Pike,M. Carcinogenesis , 23 , — Cancer , , — and Conney,A.

Drug Metab. and Yu,M. Cancer Res. Cancer Epidemiol. Biomarkers Prev. and Shimizu,H. Cancer , 30 , 21 — Cancer , 39 , — and Yu MC. Carcinogenesis , 26 , — and Mishell,D. and Lobo,R. and Yager,J. and Bloch,W. Nucleic Acids Res.

Cancer Inst. and Liao,S. Endocrinology , , — and Rosengren,R. and Ahmad,N. and Heber,D. Cancer , 45 , — and Pols,H. and Speizer,F. and Giri,A. Oxford University Press is a department of the University of Oxford. Esterone is synthesised from antrostenodione by aromatase in the ovaries and adipose tissue in peri and postmenopausal women.

As oestrogen levels drop, there is decreased circulating endorphin and cathecol-oestrogens [1] any 2-hydroxylated oestrogen derivative- the compound that oestrogen is converted to , which has a direct effect on the hypothalamus.

This is responsible for controlling appetite, sex hormones, sleep and body temperature. There is a resultant increased seratonin and norepinephrine release [2] and a lowering of the thermoregulatory set point.

Heat loss mechanisms are then triggered by subtle changes in body temperature with resultant hot flushes. Although a specific biochemical trigger for hot flushes has not been found, triggers such as hot and spicy foods, hot drinks, caffeine, alcohol, stress and external environmental temperature changes all lead to immediate changes in hormones and neurotransmitters, which may proceed or coincide with a hot flush.

We have collated some of this research together as you may find it useful. Studies have previously been done [4] using Sage and Alfalfa, in 30 out of 40 women in the study, the hot flushes completely disappeared and in the other 10 there was a decrease in symptoms, thus leading the researchers to conclude that the combination was an effective treatment, without side effects, for hot flushes.

This has been included in this evaluation as the EGCG in Green Tea has been shown to improve a menopause-induced overactive bladder. Post-menopausal women may experience an overactive bladder or stress incontinence.

Research [5] demonstrated that Green Tea extract could reverse bladder dysfunction in a dose-dependent fashion. Although high cholesterol itself does not cause symptoms, it is important to lower it to reduce the chance of heart attack or heart disease. Double blind, randomised, placebo-controlled studies in postmenopausal women suggest that EGCG has beneficial lowering effects on LDL cholesterol [6].

Marine Pine Bark has been shown to significantly reduce [7] signs and symptoms associated with menopausal transitions, notably hot flushes, night sweats, mood swings, irregular periods, loss of libido and vaginal dryness.

In studies done on peri-menopausal women [8], all menopausal transition symptoms improved. Alfalfa contains phytoestrogens and is rich in magnesium, calcium, vitamins A, B6, B12 and D and has traditionally been used for helping women with menopause symptoms for centuries.

It has been shown to be effective at reducing hot flushes and night sweats [9] when taken with sage. There are two important things to consider if you decide to take a supplement containing Alfalfa or introduce it into your diet.

Firstly, make sure you look for a non-GM source as so much alfalfa is grown with the Roundup resistant gene that is causing so much controversy in the USA. Secondly, Alfalfa contains large amounts of vitamin K, so give this careful consideration before introducing into your diet if you use warfarin or other anticoagulant medications.

Regular physical activity [10] has also been shown to decrease hot flushes and reduce night sweats. The menopause can be a difficult time for many reasons both from the physical symptoms and the mental impact.

That being said, as these studies have shown, there are a number of ways to ease some of the symptoms of menopause through diet and nutrition, which can have a significant effect on the way you feel.

Metabolics Menopause Support Formula contains each of the natural dietary substances mentioned in the above report and contains no binders or fillers, just the active ingredients and the capsule.

Should you have any further questions or queries about menopause, or any of the information covered here, please do get in touch or share your own experiences and tips with us on Twitter or Facebook. Are catechol oestrogens obligatory mediators of oestrogen action in the central nervous system?

Characterization of pharmacological probes with different receptor binding affinities and catechol oestrogen formation rates. Pfeiffer DG, MacLusky NJ, Barnea E, Naftolin F, Krey LC, Loriaux DL, Merriam GR. Biochemical, metabolic, and vascular mechanisms in menopausal hot flashes.

Freedman RR. Department of Obstetrics and Gynecology, Wayne State University, Detroit, Michigan, USA. First time proof of sage's tolerability and efficacy in menopausal women with hot flushes. Bommer S, Klein P, Suter A.

Vogel Bioforce AG, Roggwil, Switzerland. Treatment of neurovegetative menopausal symptoms with a phytotherapeutic agent. Istituto di Ginecologia e Ostetricia, Università degli Studi-Siena. Neuroprotection of green tea catechins on surgical menopause-induced overactive bladder in a rat model.

Juan YS, Chuang SM, Long CY, Chen CH, Levin RM, Liu KM, Huang CH. Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan. Effect of 2-month controlled green tea intervention on lipoprotein cholesterol, glucose, and hormone levels in healthy postmenopausal women.

Wu AH, Spicer D, Stanczyk FZ, Tseng CC, Yang CS, Pike MC. Department of Preventive Medicine, University of Southern California Keck School of Medicine, Los Angeles, California, USA. Case-control study of green tea consumption and the risk of endometrial endometrioid adenocarcinoma.

Surprisingly, green tea is obtained from the same plant as black tea, Camellia sinensis. The difference is, green tea leaves are dried and steamed, to optimise antioxidant content. Green tea has undergone minimal oxidation during processing.

The shorter processing provides green tea with a much lighter flavour. The season to which the leaves are picked are also vital to green teas health benefits. The plant originates from China and the Chinese have been consuming green tea for over 3, years, with first documented consumption being noted during the reign of Emperor Shennong.

Green tea seeds were first brought to Japan during the early 9 th Century by Buddhist Monks. The oldest tea producing region is Japan is Uji, located near Kyoto. All commercially produced tea in Japan, is green tea.

Most Japanese green teas are blended from leaves grown in different regions. Apart from having a very high antioxidant content, green tea contains an abundance of a chemical known as, Epigallocatechin gallate or, EGCG for short. EGCG has quite a strong anti-inflammatory and anti-microbial action.

In animal studies, it has been proved to inhibit the growth and progression of Helicobactor pylori, a common bacteria that has been linked to contributing to the development of gastritis and stomach ulcers.

Although these studies look at concentrated extracts of green tea, consuming up to 3 cups of this delicious tea per day, may assist in reducing inflammation and helping with gastritis. Given its lack of open discussion, menopause often remains shrouded in mystery, leaving many uninformed about its nuances and effects.

However, menopause is a significant […]. Read More. How many times have you Googled information about your menstrual cycle across your lifetime? Results shown in this report did not include coffee intake, and menstrual and reproductive factors as covariates.

The distributions of the hormone levels were skewed, which were corrected to a large extent by transformation to logarithmic values. Therefore, all statistical analyses were performed on logarithmically transformed values.

We hypothesized that plasma estrogen levels will be lowest among regular green tea drinkers only, intermediate among non-regular tea drinkers and highest among regular drinkers of black tea only. All P values quoted are two-tailed 2P. Calculations were performed using the SAS statistical software system SAS Institute, Cary, NC.

Analyses of estrone, estradiol and androstenedione were conducted on women, with the age ranging from 50 to 77 years mean Table I shows that Demographic characteristics e. However, regular black tea drinkers were less likely to be daily coffee drinkers and more likely to be higher soy consumers i.

highest quartile of soy protein intake compared to regular green tea drinkers and non-tea drinkers and irregular tea drinkers Table I. Adjusted for time interval between blood draw and last meal, age, body mass index and intake of soy protein. Soy and tea appear to have independent effects on plasma estrone levels.

Geometric mean hormone levels by tea intake, according to COMT genotype, are presented in Table III. Similarly, COMT genotype did not significantly influence plasma estradiol or androstenedione levels; and it did not modify the tea—estradiol or tea—androstenedione associations Table III.

After adjusting for tea intake and other covariates mentioned above, estrone, estradiol and androstenedione levels were The corresponding levels were In this cross-sectional study of postmenopausal Chinese women in Singapore, we found that tea drinking significantly influences plasma estrogen levels and that these levels are influenced differentially by the type of tea used.

Additionally, the COMT genotype, a measure of one's ability to eliminate tea polyphenols, did not influence the tea—blood hormone associations. We interpret these two findings to suggest that the differential effects of black and green tea on hormone levels are unlikely to be due to tea polyphenols, but rather due to some other, yet to be identified constituents of tea.

Before discussing our findings, some methodologic limitations of this investigation should be considered. An original intent of this cross-sectional study was to identify dietary and non-dietary determinants of blood estrogen levels in postmenopausal Chinese women 5. When we started this project, we did not know that green tea and black tea would differentially influence blood hormone levels.

In addition to including a larger sample size, future studies may be designed in a way to ensure that the numbers of non-tea drinkers, green tea drinkers only and black tea drinkers only are more balanced. Despite the modest sample size of this study and the preliminary nature of its observations, the high degree of internal consistency of our findings, coupled with biological plausibility tend to strengthen the study hypothesis, that the type of tea may matter.

A similar pattern of differences in androstenedione levels by tea intake was found. It should be noted that we had previously reported no association between tea intake and blood estrogen levels and this was owing to ignoring the type of tea in our analysis 5.

The present analysis shows that an association between tea intake and blood hormone levels may be missed if the type of tea and frequency of tea intake are not considered simultaneously. Data in support of modulating effects of tea on plasma hormone levels lend credibility to observational findings of a tea—breast cancer association 2 since there is now compelling evidence that endogenous hormones, especially estrogens, play a critical role in the etiology of breast cancer The differing effects of green and black tea on circulating estrogen levels have corroborative support from human and non-human studies.

In a study of premenopausal women in Japan, Nagata et al. This level of EGCG intake is achievable in humans as one cup ml of green tea contains up to mg of EGCG Since levels of EGCG are substantially higher in green tea than in black tea 17 , it is plausible that the lower estrogen levels associated with green intake tea is explained partly by the inhibitory effects of EGCG on aromatase activity and hence the synthesis of estrogen.

However, black tea also contains EGCG and other tea catechins, though in lower levels and thus it is not obvious why estrogen levels are not lower in regular black tea drinkers compared with non-regular tea drinkers.

In that study, serum prolactin levels increased significantly with increasing levels of black tea intake Although blood estrogen levels were not measured in this study, breast cancer risk was found to increase significantly with increasing prolactin levels in the Nurses Health Study Motivated by our previous finding that the inverse association between tea and breast cancer risk is found mainly among women who were heterozygous for the COMT L allele i.

those less efficient in eliminating tea polyphenols 4 , we investigated the tea—plasma hormone associations by COMT genotype. Contrary to our findings in relation to breast cancer risk 4 , the COMT genotype did not significantly influence the tea—hormone associations in this analysis.

Specifically, plasma estrone, estradiol and androstenedione levels were consistently lower among green tea drinkers while they were consistently higher among black tea drinkers irrespective of COMT genotype Table III. We believe that our recent finding of an upregulatory effect of black tea and a downregulatory effect of green tea on circulating estrogen levels provides a cogent explanation for the paradoxical findings of our first two papers on tea 2 , 4.

These results suggest that tea polyphenols are not the constituents, in black tea and green tea, responsible for the hormonal effects of tea that we and others 6 , 14 , 15 , 18 have identified in human and rodent studies.

The differential effects on breast cancer protection between green tea versus black tea, despite comparable levels of antioxidative tea polyphenols between the two types of tea 20 , may lie in the possibility that they possess opposing effects on sex-steroid hormones.

Green tea may have strong beneficial effects on the breast through both its antioxidant properties and its downregulatory effects on estrogens. In contrast, while black tea possesses antioxidant effects, it nonetheless exhibits no downregulatory or may be upregulatory effects on blood estrogen levels.

These latter opposing effects of black tea, if confirmed, may help to explain the overall weaker effect of black tea on breast cancer risk.

The sample size of this cross-sectional study is modest and thus we view these results as preliminary and requiring confirmation in larger studies.

Further investigations of possible hormonal effects of green tea and black tea should provide a better understanding of the role of these teas in the etiology of breast cancer and will complement epidemiologic investigations on the relationship between tea intake and breast cancer risk.

We thank Ms Siew-Hong Low of the National University of Singapore for supervising the field work of the Singapore Chinese Health Study. The Singapore Chinese Health Study has been supported by grants R01 CA, R35 CA and R01 CA from the National Cancer Institute, Bethesda, Maryland.

is supported, in part, by the California Breast Cancer Research Program 9PB and the Susan G. Komen Breast Cancer Foundation POP and Pike,M.

Carcinogenesis , 23 , — Cancer , , — and Conney,A. Drug Metab. and Yu,M. Cancer Res. Cancer Epidemiol. Biomarkers Prev. and Shimizu,H. Cancer , 30 , 21 — Cancer , 39 , — and Yu MC. Carcinogenesis , 26 , — and Mishell,D. and Lobo,R. and Yager,J. and Bloch,W. Nucleic Acids Res.

Cancer Inst. and Liao,S. Endocrinology , , — and Rosengren,R. and Ahmad,N. and Heber,D. Cancer , 45 , — and Pols,H. and Speizer,F. and Giri,A. Oxford University Press is a department of the University of Oxford.

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Subjects and methods. Journal Article. Tea and circulating estrogen levels in postmenopausal Chinese women in Singapore. Wu , Anna H. Oxford Academic. Google Scholar. Kazuko Arakawa.