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Coffee Estrogen Link

September 29, 2010 Written by JP    [Font too small?]

A friend of the site recently posed an interesting question. She wondered whether drinking coffee adversely affects sex hormone levels in women. In particular she inquired about supposed estrogenic elements in coffee which may lead to an excess of estrogen or “estrogen dominance” in women. Ultimately, her concern was that regular coffee consumption could confer similar side effects as hormone replacement therapy.

Coffee does, in fact, contain phyto or plant estrogens. Studies dating back to the 1980’s have identified “weakly estrogenic” components in coffee. A paper published in the August 2008 issue of the Journal of Agricultural Food Chemistry found that coffee and tea contained up to 20 mcg/100 g of lignans, a type of phytoestrogen. While beer contained significantly more lignans – 71 mcg/100 g. These are obviously minute quantities of plant-derived estrogens. However, the authors of the study noted: “As these beverages are commonly consumed, they are a main source of dietary lignans”. Furthermore, emerging research is discovering previously unknown phytoestrogens in coffee which may alter “the actions of estradiol” and activate estrogen receptors. (1,2,3)

The best way to accurately assess the affects of coffee consumption and its impact on estrogen levels is to directly examine the medical literature. I’ve identified five studies that have scientifically evaluated this very topic. Here’s what they have to say:

  • The June 2009 issue of the journal Cancer examined the relationship between “caffeine, coffee, decaffeinated coffee and tea” and plasma concentrations of various sex hormones in 524 premenopausal and 713 postmenopausal women. In the premenopausal women, caffeine intake was associated with significantly lower levels of estradiol (a form of estrogen). The postmenopausal women demonstrated a positive association between caffeine and coffee intake and SHBG (sex hormone-binding globulin). However, this did not translate into any significant alteration in hormone levels. (4)
  • The October 2001 edition of the journal Fertility and Sterility investigated the hormonal influence of alcohol, coffee and tobacco in 498 women with ages ranging from 36 – 45 “who were not currently pregnant, breast feeding, or using exogenous hormones”. Coffee consumption of more than 1 cup per day was associated with higher estradiol levels. Up to a 70% increase in “early follicular phase E2 (estradiol)” was found in women consuming over 500 mg of caffeine/day vs. those consuming <100 mg/day. (5)
  • A 1998 publication in the journal Nutrition and Cancer studied the relationship between caffeine-containing beverages (black tea, coffee, cola, green tea and oolong tea) and serum estradiol and SHBG concentrations in 50 premenopausal women. Specifically, the researchers examined any hormonal alterations occurring on days 11 and 22 of the women’s menstrual cycles. Blood samples and food frequency questionnaires revealed that a higher intake of caffeine correlated to increased SHBG (sex hormone binding globulin). SHBG may inhibit estradiol-induced breast cancer cell growth and spread. Perhaps that’s why the conclusion of the study states that “consumption of caffeine-containing beverages appeared to favorably alter hormone levels associated with the risk of developing breast cancer”. (6,7)
  • A 1996 study involving 728 postmenopausal women noted “significant inverse associations between caffeine intake and bioavailable testosterone”. Two or more cups of coffee or > 4 cans of caffeinated soda per day was also correlated with higher estrone and SHBG levels. The downside of this examination (“The Rancho Bernardo Study”) is that it didn’t differentiate between coffee and soda intake. (8)
  • The May 1992 edition of the Annals of Epidemiology reported that “coffee intake, ascertained at the 26th week (of pregnancy), was found to be negatively related to pregnancy E2 (estradiol) levels”. This is believed to be one of the reasons why caffeinated coffee should be avoided during pregnancy as lower estrogen levels have been correlated with lower birth weight. (9,10,11)

Coffee Consumption May Decrease Cardiovascular Related Morbidity and Mortality

Source: American Journal of Clinical Nutrition, Vol. 83, No. 5, 1039-1046 (link)

There simply haven’t been enough well-designed studies to know with certainty what effect coffee is likely to have on estrogen concentrations in women during varying stages of life. But there is other information available which may assist in forming a more well-rounded perspective on this issue. Hormone replacement therapy (HRT) has been documented as increasing the incidence of breast cancer, endometrial cancer, heart attacks and strokes. If coffee truly provokes significant elevations in estrogen levels, it would seem likely that it too would increase the risk of the same health concerns.

A current review of the topic of coffee and cancer clearly states that, “There appears to be no association with breast, pancreatic, kidney, ovarian, prostate, or gastric cancer”. It goes on to reveal that, “For hepatocellular (liver) and endometrial cancers, there appears to be a strong and consistent protective association”. This summary point of view is largely supported by the latest population studies pertaining to both breast and endometrial cancer in relation to coffee consumption. But beware, adding sugar to coffee may negate the protective effect and even lead to a greater risk of endometrial cancer. (12,13,14,15,16,17,18)

The picture is even rosier when it comes to the coffee-cardiovascular issue. Three recent population studies involving approximately 200,000 participants have generally found a protective effect of moderate coffee consumption of between 12% to 55%. What’s most interesting is that some of the data points to gender-specific protection. For instance, a study carried out in the Netherlands concluded the following: “Coffee consumption was inversely associated with IHD (heart attack) mortality in women only”. A Japanese investigation came to a similar finding. “Our results suggest that coffee may have favorable effects on mortality due to all causes and CVD (cardiovascular disease), especially CVD, in women”. (19,20,21)

So what’s the answer to the question that originally inspired this column? It seems that caffeinated coffee can affect hormone levels, but it doesn’t do so in a predictable manner. If this is a concern for you, you might look at the studies above to determine which group of women you most closely resemble. Your hormonal response *may* be similar to theirs. However, I think what’s more important is to look at the end result of coffee consumption. The evidence that’s currently available suggests that coffee is unlikely to predispose women to the same health threats brought about by synthetic hormone replacement therapy. On the flip side, it’s also important to keep in mind that coffee is unlikely to yield the same health benefits of HRT as well.

Note: Please check out the “Comments & Updates” section of this blog – at the bottom of the page. You can find the latest research about this topic there!

Be well!


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Posted in Food and Drink, Nutrition, Women's Health

7 Comments & Updates to “Coffee Estrogen Link”

  1. Iggy Dalrymple Says:

    Coffee is also claimed to reduce the formation of kidney stones. I just had a large kidney stone removed surgically. Still have one, smaller, stone remaining.

  2. JP Says:


    The case of coffee vs. kidney stones is an interesting one:




    Be well!


  3. JP Says:

    Update 04/22/15:


    Clin Cancer Res April 15, 2015 21; 1877

    Caffeine and Caffeic Acid Inhibit Growth and Modify Estrogen Receptor and Insulin-like Growth Factor I Receptor Levels in Human Breast Cancer

    Purpose: Epidemiologic studies indicate that dietary factors, such as coffee, may influence breast cancer and modulate hormone receptor status. The purpose of this translational study was to investigate how coffee may affect breast cancer growth in relation to estrogen receptor-α (ER) status.

    Experimental Design: The influence of coffee consumption on patient and tumor characteristics and disease-free survival was assessed in a population-based cohort of 1,090 patients with invasive primary breast cancer in Sweden. Cellular and molecular effects by the coffee constituents caffeine and caffeic acid were evaluated in ER+ (MCF-7) and ER− (MDA-MB-231) breast cancer cells.

    Results: Moderate (2–4 cups/day) to high (≥5 cups/day) coffee intake was associated with smaller invasive primary tumors (Ptrend = 0.013) and lower proportion of ER+ tumors (Ptrend = 0.018), compared with patients with low consumption (≤1 cup/day). Moderate to high consumption was associated with lower risk for breast cancer events in tamoxifen-treated patients with ER+ tumors (adjusted HR, 0.51; 95% confidence interval, 0.26–0.97). Caffeine and caffeic acid suppressed the growth of ER+ (P ≤ 0.01) and ER− (P ≤ 0.03) cells. Caffeine significantly reduced ER and cyclin D1 abundance in ER+ cells. Caffeine also reduced the insulin-like growth factor-I receptor (IGFIR) and pAkt levels in both ER+ and ER− cells. Together, these effects resulted in impaired cell-cycle progression and enhanced cell death.

    Conclusions: The clinical and experimental findings demonstrate various anticancer properties of caffeine and caffeic acid against both ER+ and ER− breast cancer that may sensitize tumor cells to tamoxifen and reduce breast cancer growth. Clin Cancer Res; 21(8); 1877–87.

    Be well!


  4. JP Says:

    Update 05/23/15:


    Cancer Epidemiol Biomarkers Prev. 2015 May 21.

    Associations of coffee drinking with systemic immune and inflammatory markers.

    BACKGROUND: Coffee drinking has been inversely associated with mortality as well as cancers of the endometrium, colon, skin, prostate, and liver. Improved insulin sensitivity and reduced inflammation are among the hypothesized mechanisms by which coffee drinking may affect cancer risk; however, associations between coffee drinking and systemic levels of immune and inflammatory markers have not been well characterized.

    METHODS: We used Luminex bead-based assays to measure serum levels of 77 immune and inflammatory markers in 1,728 older non-Hispanic Whites. Usual coffee intake was self-reported using a food frequency questionnaire. We used weighted multivariable logistic regression models to examine associations between coffee and dichotomized marker levels. We conducted statistical trend tests by modeling the median value of each coffee category and applied a 20% false discovery rate criterion to P-values.

    RESULTS: Ten of the 77 markers were nominally associated (P-value for trend<0.05) with coffee drinking. Five markers withstood correction for multiple comparisons and included aspects of the host response namely chemotaxis of monocytes/macrophages (IFNγ, CX3CL1/fractalkine, CCL4/MIP-1β), pro-inflammatory cytokines (sTNFRII) and regulators of cell growth (FGF-2). Heavy coffee drinkers had lower circulating levels of IFNγ (OR=0.35; 95% CI 0.16-0.75), CX3CL1/fractalkine (OR=0.25; 95% CI 0.10-0.64), CCL4/MIP-1β (OR=0.48; 95% CI 0.24-0.99), FGF-2 (OR=0.62; 95% CI 0.28-1.38), and sTNFRII (OR=0.34; 95% CI 0.15-0.79) than non-coffee drinkers.

    CONCLUSIONS: Lower circulating levels of inflammatory markers among coffee drinkers may partially mediate previously observed associations of coffee with cancer and other chronic diseases.

    IMPACT: Validation studies, ideally controlled feeding trials, are needed to confirm these associations.

    Be well!


  5. JP Says:

    Update 06/15/15:


    Cancer Epidemiol Biomarkers Prev. 2015 Jun 10.

    Caffeine, coffee and tea intake and urinary estrogens and estrogen metabolites in premenopausal women.

    BACKGROUND: Prior studies have found weak inverse associations between breast cancer and caffeine and coffee intake, possibly mediated through their effects on sex hormones.

    METHODS: High-performance liquid chromatography/tandem mass spectrometry was used to quantify levels of 15 individual estrogens and estrogen metabolites (EM) among 587 premenopausal women in the Nurses’ Health Study II with mid-luteal phase urine samples and caffeine, coffee and/or tea intakes from self-reported food frequency questionnaires. Multivariate linear mixed models were used to estimate geometric means of individual EM, pathways and ratios by intake categories, and P-values for tests of linear trend.

    RESULTS: Compared to women in the lowest quartile of caffeine consumption, those in the top quartile had higher urinary concentrations of 16α-hydroxyestrone (28% difference; P-trend=0.01) and 16-epiestriol (13% difference; P-trend=0.04), and a decreased parent estrogens/2-, 4-, 16-pathway ratio (P-trend=0.03). Coffee intake was associated with higher 2-catechols, including 2-hydroxyestradiol (57% difference, ≥4 cups/day vs. ≤6 cups/week; P-trend=0.001) and 2-hydroxyestrone (52% difference; P-trend=0.001), and several ratio measures. Decaffeinated coffee was not associated with 2-pathway metabolism, but women in the highest (vs. lowest) category of intake (≥2 cups/day vs. ≤1-3 cups/month) had significantly lower levels of two 16-pathway metabolites, estriol (25% difference; P-trend=0.01) and 17-epiestriol (48% difference; Ptrend=0.0004). Tea intake was positively associated with 17-epiestriol (52% difference; Ptrend=0.01).

    CONCLUSION: Caffeine and coffee intake were both associated with profiles of estrogen metabolism in premenopausal women.

    IMPACT: Consumption of caffeine and coffee may alter patterns of premenopausal estrogen metabolism.

    Be well!


  6. JP Says:

    Update 06/15/15:


    Breast Cancer Res. 2015 Jan 31;17(1):15.

    Coffee and tea consumption and risk of pre- and postmenopausal breast cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort study.

    INTRODUCTION: Specific coffee subtypes and tea may impact risk of pre- and post-menopausal breast cancer differently. We investigated the association between coffee (total, caffeinated, decaffeinated) and tea intake and risk of breast cancer.

    METHODS: A total of 335,060 women participating in the European Prospective Investigation into Nutrition and Cancer (EPIC) Study, completed a dietary questionnaire from 1992 to 2000, and were followed-up until 2010 for incidence of breast cancer. Hazard ratios (HR) of breast cancer by country-specific, as well as cohort-wide categories of beverage intake were estimated.

    RESULTS: During an average follow-up of 11 years, 1064 premenopausal, and 9134 postmenopausal breast cancers were diagnosed. Caffeinated coffee intake was associated with lower risk of postmenopausal breast cancer: adjusted HR = 0.90, 95% confidence interval (CI): 0.82 to 0.98, for high versus low consumption; P trend = 0.029. While there was no significant effect modification by hormone receptor status (P = 0.711), linear trend for lower risk of breast cancer with increasing caffeinated coffee intake was clearest for estrogen and progesterone receptor negative (ER-PR-), postmenopausal breast cancer (P = 0.008). For every 100 ml increase in caffeinated coffee intake, the risk of ER-PR- breast cancer was lower by 4% (adjusted HR: 0.96, 95% CI: 0.93 to 1.00). Non-consumers of decaffeinated coffee had lower risk of postmenopausal breast cancer (adjusted HR = 0.89; 95% CI: 0.80 to 0.99) compared to low consumers, without evidence of dose-response relationship (P trend = 0.128). Exclusive decaffeinated coffee consumption was not related to postmenopausal breast cancer risk, compared to any decaffeinated-low caffeinated intake (adjusted HR = 0.97; 95% CI: 0.82 to 1.14), or to no intake of any coffee (HR: 0.96; 95%: 0.82 to 1.14). Caffeinated and decaffeinated coffee were not associated with premenopausal breast cancer. Tea intake was neither associated with pre- nor post-menopausal breast cancer.

    CONCLUSIONS: Higher caffeinated coffee intake may be associated with lower risk of postmenopausal breast cancer. Decaffeinated coffee intake does not seem to be associated with breast cancer.

    Be well!


  7. JP Says:

    Updated 07/02/17:


    Clin Endocrinol (Oxf). 2017 Jun 29.

    Cross-sectional association of coffee and caffeine consumption with sex hormone-binding globulin in healthy non-diabetic women.

    OBJECTIVE: Low sex hormone-binding globulin (SHBG) is a consistent risk factor for type 2 diabetes, particularly in women. Coffee consumption has been associated with a lower risk of type 2 diabetes but its effects on SHBG are less known.

    DESIGN AND METHODS: This was a cross-sectional study of 2,377 non-diabetic pre- and post-menopausal women from the E3N cohort study whose baseline SHBG was measured. Information on diet (including coffee and caffeine consumption), lifestyle, and medical conditions was collected through questionnaires. The relationship between coffee and caffeine consumption and SHBG was modeled, with adjustment for covariates and stratification by body mass index (BMI) categories (< or ≥25 kg/m2 ) and menopausal status. RESULTS: The mean age was 57.3 ± 6.4 years and 61% of the 2,453 women were postmenopausal. High coffee (≥3 cups/day) and caffeine (≥265 mg/day) intakes were associated with a reduced risk of being in the 1st quartile of the SHBG level distribution (<46.3 nmol∙L-1 ) in a multivariate adjusted model (OR: 0.69 [95% CI 0.52-0.92] and OR: 0.68 [95% CI 0.50-0.94] respectively). No association was found between tea consumption and SHBG levels. In multivariate models stratified on BMI categories and menopausal status, associations were restricted to women with a BMI ≥25 kg/m2 or being postmenopausal. The association with SHBG was consistently noted with both consumption of caffeinated coffee and caffeine, but not for decaffeinated coffee. CONCLUSIONS: High coffee and caffeine consumptions are associated with a reduced risk of low SHBG, an established risk marker for T2DM, which might contribute to the protective effects of coffee for type 2 diabetes. Be well! JP

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