Caffeine May Block Estrogen
There has been an over whelming amount of research on the health benefits of coffee lately. In addition, to its performance enhancing effects, coffee also has been shown to reduce the risk of diabetes and may also prevent cancer. In recent years, mechanisms involved in mediating cancer protective effects of naturally derived plant polyphenols from green tea and coffee have been widely studied, most studies have have shown that coffee drinkers have lower risk of breast and prostate cancer. Prospective and retrospective epidemiological studies show an association between coffee consumption and a significantly reduced risk, delayed onset, and reduced growth of breast cancer. A study of women ages 18 to 44 found that drinking coffee and other caffeinated beverages can alter levels of estrogen. The study, which was published in The American Journal of Clinical Nutrition, analyzed data on more than 250 women who were examined one to three times a week over two menstrual cycles. They provided blood samples along with details about behaviors like exercise, eating and smoking. On average, they consumed about 90 milligrams of caffeine a day, equivalent to roughly one cup of coffee. At the end of the study, the results seemed to indicate depending on ethnicity, coffee effects women differently. In white women, for example, coffee appears to lower estrogen, while in Asian women it has the reverse effect, raising levels of the hormone. In white women, however, 200 milligrams or more of caffeine appeared to have a slight lowering effect on estrogen.This is important physiologically because it helps us understand how caffeine is metabolized by different genetic groups.
A new study published in the Journal of Clinical Cancer Research suggests that caffeine consumption may act like an anti-estrogen. Sweden is among the top coffee consuming countries worldwide, and less than 1% of the coffee consumed is decaffeinated. Coffee contains a mixture of bioactive components, and there are several plausible biologic pathways whereby coffee might alter breast cancer risk or progression. Caffeine and the polyphenol constituents have been suggested to contribute to its anticancer activities. Researchers examined the 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 estrogen receptor positive and negative breast cancer cells. At the end of the study, moderate (2-4 cups/day) to high (≥5 cups/day) coffee intake was associated with smaller invasive primary tumors and lower proportion of estrogen receptor positive tumors, 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 estrogen receptor positive tumors. Caffeine and caffeic acid suppressed the growth of estrogen receptor positive and ER negative cells. Caffeine also reduced the insulin-like growth factor-I receptor (IGFIR) and pAkt levels in both estrogen receptor positive and estrogen receptor negative cells. Together, these effects resulted in impaired cell-cycle progression and enhanced cell death. The clinical and experimental findings demonstrate various anticancer properties of caffeine and caffeic acid against both estrogen receptor(+) and estrogen receptor(-) breast cancer that may sensitize tumor cells to tamoxifen and reduce breast cancer growth. In summary, this study shows inhibitory effects by caffeine and caffeic acid on breast cancer cell growth. These results are in line with previous epidemiological reports demonstrating protective roles of coffee constituents and the risk or progression of breast cancer. The present findings enhance the general understanding of how modifiable factors present in our daily diet, such as coffee constituents, may alter estrogen receptor status, IGFIR levels, and contribute to reduced growth of breast cancer cells. In sum, the study showed that caffeine acted as an anti-estrogen and suppressed estrogen receptors.
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