Polycystic Ovary Syndrome (PCOS) is the most common endocrine disorder in women of reproductive age, impacting a significant percentage of this population. While there is currently no cure for PCOS, management of the syndrome mainly focuses on treating symptoms. Given the increasing interest in complementary therapies, this article explores the potential role of green tea in managing PCOS symptoms, examining the available research and evidence.
Understanding PCOS
PCOS is characterized by a range of symptoms, including menstrual irregularities, increased androgens, hirsutism, severe acne, obesity, insulin resistance, type 2 diabetes, cardiovascular disease (CVD), non-ovulation, and infertility. One of the major diagnostic criteria for PCOS is hyperandrogenism, an excess of androgen hormones (like testosterone or DHEA) in the body that may result in acne or hirsutism (irregular hair growth). It is important to note that not all individuals with PCOS will have high androgen levels.
Insulin resistance and hyperinsulinemia underlie metabolic changes and clinical signs in patients with PCOS. Insulin-resistant PCOS, the most common type, is often caused by a high intake of trans fat, high sugar intake, smoking, and pollution. High levels of insulin in the body trigger the ovaries to make testosterone and prevent ovulation. Inflammatory PCOS is caused by inflammation from toxins in the environment, stress, or a diet with gluten. This inflammation prevents ovulation, hormones become imbalanced, and the body starts to produce androgens.
Green Tea: A Potential Ally?
Green tea has been thought of as a health food for many years, with its main health-promoting effect being its high polyphenol content. Green tea is produced by drying Camellia sinensis leaves. The most well-known feature of this beverage is its antioxidant activities, which result from high concentrations of polyphenolic compounds, particularly catechins. The biological effects of green tea are mainly attributed to the tea polyphenols, including epigallocatechin-3-gallate (EGCG), epigallocatechin (EGC), epicatechin-3-gallate (ECG), and epicatechin (EC). Of these, EGCG is the most abundant and biologically active constituent.
Studies have shown that green tea extract (GTE), as a strong antioxidant compound, has anti-obesity, anti-diabetes, anti-cardiovascular, anti-angiogenesis, anticancer, and neuroprotective properties. Given these properties, researchers have explored the potential of green tea in managing PCOS symptoms, especially its anti-inflammatory properties and potential to have an anti-androgen effect.
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The Evidence: Green Tea and PCOS
The existing research presents a mixed picture of green tea's effectiveness in managing PCOS. Most studies looking at green tea and PCOS use a green tea extract capsule, rather than as a beverage. As a beverage, green tea doesn’t appear to have significant effects on PCOS symptoms directly.
A systematic review evaluated the potential roles of GTE on metabolic variables, hormone levels, and ovarian function in PCOS. This review included four human studies and four animal studies. All studies in humans showed the effects of GTE on weight loss. GTE’s effect on decreasing testosterone levels in humans and LH levels in animals were also reported. In addition, increases in FSH and progesterone levels in animal models were observed. Although GTE improved fasting blood sugar and insulin levels, the effect of GTE on inflammatory parameters, such as TNF-alpha and IL-6 and antioxidant status, was limited to animal studies.
Impact on Weight Loss
Weight gain is one of the clinical features of patients with PCOS who are both genetically predisposed and exposed to environmental risk factors. Changes in lifestyle, particularly weight loss, are important to improve infertility and PCOS-related metabolic disorders in women with PCOS.
Clinical trials conducted in women with PCOS have found significant positive effects of GTE on weight loss. Three out of four studies reported that 500 mg/day extract of GTE caused a decrease in weight in women with PCOS. In all four studies, the dosage of green tea extract was 500 mg per day, but the duration of the interventions ranged from 6 weeks to 3 months. However, one study found no significant effect of GTE was reported on body weight, fat percentage, and BMI in obese women with PCOS. The inconsistency between the results of this study and the other studies with significant effects of GTE on weight loss may be explained by the difference in the type of GTE and the process of tea extraction: in this study, PCOS women consumed 1.5 cups of 2% Lung Chen tea, which was equal to 540 mg EGCG. In addition to weight loss, one study demonstrated the effect of GTE on waist circumference and body fat percentage.
GTE is a thermogenic agent that reduces body weight by increasing energy expenditure and fat oxidation. This feature can be described by caffeine and catechin polyphenols in GTE, which inhibits catechol-0-methyltransferase (COMT) as norepinephrine degrading enzymes, leading to increased levels of norepinephrine and prolonged action of catecholamines. Decreased appetite and a reduction in the absorption of nutrients such as dietary lipids and glucose are other mechanisms that contribute to the weight loss effect of GTE.
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Effects on Glycemic Status
Insulin resistance and hyperglycemia are the most common features of patients with PCOS. GTE has also exhibited the potential to improve glycemic parameters in women with PCOS. Ameliorating insulin resistance and hence reducing circulating insulin levels leads to the improvement of hormonal imbalance and resumption of ovulation in PCOS subjects.
Two studies showed that GTE supplementation at 500 mg/day showed significant reductions in the FBS and insulin levels. In both studies, GTE supplementation was administrated for 3 months for overweight or obese women with PCOS. In another experimental study, the same results were observed in PCOS model rats after administration of GTE for 10 days. Studies suggest that GTE increases basal and insulin-stimulated glucose uptake from adipocytes and also inhibits glucose absorption in the small intestine.
Furthermore, GTE studies have demonstrated that insulin resistance (IR) is ameliorated by augmented expression of glucose transporter 4 (GLUT-4) in adipocytes. In addition, GTE’s antidiabetic activity suppresses gluconeogenesis in hepatic cells. There is evidence suggesting that GTE has insulin-like and insulin-enhancing activities.
Impact on Hormone Levels and Ovarian Function
PCOS is a metabolic disorder along with reproductive hormonal abnormality, including over-production of androgenic hormones such as testosterone, androstenedione, and progesterone, as well as increased secretion of LH to FSH. Insulin resistance is also more prevalent in patients with PCOS that leads to higher androgen levels and an increased LH/FSH ratio. GTE may reduce the adverse effects of hormonal disturbances in polycystic ovaries by regulating the secretion of gonadotropins or its receptors by regulating GnRH pulsatility.
Findings from a systematic review showed that GTE supplementation could lead to a reducing effect on serum levels of LH, free testosterone, and β-estradiol, but the serum levels of FSH and progesterone significantly increased in PCOS.
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One animal study found that GTE administration over 24 days led to a statistically significant decrease in serum levels of LH, β-estradiol, and testosterone in PCOS model rats, as well as improved ovarian function (Significant increase in the number of preantral, antral, prehavulatory and corpus luteum follicles and also caused a significant decrease in the number of cystic follicles), FSH, and progesterone levels, were also reported.
Effects on Inflammation and Oxidative Stress
One study found statistically significant reducing effects of GTE by injection on IL-6 and CRP biomarkers after 14 days’ treatment in PCOS model rats. However, in a clinical trial conducted in PCOS patients, it was found that 500-mg/day of GTE supplementation for over 6 weeks did not lead to statistically significant changes in levels of inflammatory factors (IL-6, hs-CRP, TNF-α). Another study reported that ingestion of GTE for 24 days in PCOS model rats statistically significantly increased serum levels of TNF-α, IL-1β, MDA, and IL-6 and increased SOD, CAT, and GPX in ovarian tissue.
Additional Research Findings
One study using rats, levels of LH and testosterone in PCOS group were increased while the level of FSH was decreased compared to the control group. In the groups treated with different doses of green tea for 10 days, it was observed that injection of green tea resulted in significant decrease in the level of LH and testosterone and no significant change in FSH in all three experimental groups compared to the PCOS control group. The results suggest that green tea reduces the amount of glucose in the experimental group compared to the PCOS control group. In addition, a non-significant decrease in the level of insulin in the treatment groups was observed. A significant decrease in the HOMA-calculated insulin resistance was observed at green tea extract-treated groups in a dose-dependent manner.
Examining the changes in the body weight in the experimental group compared to the PCOS control group showed that green tea extract reduced body weight in the experimental groups. The results obtained from changes in the ovarian weight showed that ovarian weight increased after induction of polycystic ovary syndrome. Then, green tea significantly reduced the large size of the polycystic ovaries compared to the PCOS control group ovaries.
Examining morphology of the tissue sections prepared from ovaries in the experimental group of follicles at different stages including graph showed that the follicles had thick granular layer and thin theca compared to the PCOS control group. Moreover, a significant number of corpus luteum, indicators of ovulation, was observed. However, greater number of cystic follicles was observed in the PCOS control group. They had thin granular layer and thick theca. Moreover, low number of corpus luteum was observed which indicated that injection of estradiol valerate induced polycystic ovaries reduced the number of active follicles as well as ovulation. Morphological studies of the treatment groups showed that injection of hydro-alcoholic green tea extract in 10 days increased the number of follicles at various stages. It also increased the number of corpus luteum and reduced the number of cystic follicles.
Measuring the diameter of the graph follicles in PCOS control group compared to the graph showed significant increase in diameter of the follicles; however, the diameter of the follicles significantly decreased in the experimental group compared to PCOS control group. The thickness of the granular layer in the PCOS control group significantly decreased compared to the control group while the thickness of the granulosa layer in the PCOS control group significantly increased compared the experimental group.
Potential Benefits of Green Tea for PCOS
- Insulin Resistance: Green tea can help reduce insulin resistance, a common issue for those with PCOS. Some human studies have observed a significant decrease in insulin resistance and fasting blood sugar levels after the consumption of green tea extract.
- Weight Management: Studies have also found that green tea can aid in weight loss, with women experiencing weight loss, reduced waist circumference, and reduced body fat, while taking green tea extract over 6 to 12 weeks.
- Hormone Balance: Some studies found that taking green tea extract helped lower testosterone levels in obese women with PCOS - compared to those taking a placebo
Considerations and Potential Side Effects
While green tea is known for its health benefits, it can also cause side effects if consumed in large amounts. Its caffeine content may lead to difficulty sleeping, headaches, anxiety, and stomach upset. It's important to enjoy green tea in moderation to avoid these issues. Additionally, excessive consumption of green tea can interfere with iron absorption, potentially leading to iron deficiency.
The Verdict
Green tea is a soothing and comforting warm drink for many, that is rich in polyphenols and antioxidants. Therefore, this review suggests that GTE could be considered a potential agent to attenuate PCOS complications mainly due to its effect on weight loss and glycemic levels. Although research to this point has not indicated it to be an effective treatment for PCOS symptoms, if it brings you comfort or relief, it is safe to consume in moderation.
Current research suggests that green tea, particularly in extract form, may offer some benefits for women with PCOS, specifically in the areas of weight management, insulin resistance, and hormone balance. However, it is important to note that not all studies show positive results, and more research is needed to fully understand the effects of green tea on PCOS.
Lifestyle Changes to Help Manage PCOS Symptoms
Like many other disorders, PCOS responds well to proactive lifestyle choices. This includes physical movement or exercise at a higher frequency. Physical activity is known for its ability to reduce insulin resistance. This is especially true when you integrate a healthy diet and limit your intake of carbohydrates. Experts note that exercise up to 150 minutes per week is ideal. This should be broken down into daily activity and be coupled with a diet that is low in inflammatory foods and low in sugar. With these changes, women can see an improvement in ovulation and weight loss.
Dietary Recommendations
Avoid the following foods:
- White Bread
- Muffins
- Sugary snacks
- Sugary desserts
- Sugary drinks
- Processed foods
These foods are known for their ability to exacerbate insulin resistance, so you want to avoid them entirely. Sugar should be avoided whenever possible, so this means you will have to really pay attention to your food labels. Avoid foods with the following names in the ingredient list: Sucrose Dextrose High Fructose corn syrup. Other foods to avoid or remove from your diet include margarine, fries, and processed meats.
Managing Stress
PCOS symptoms can cause stress. It is imperative for you to understand how to use stress reduction techniques to help you keep calm. These include meditation and yoga.