Green tea extract ineffective for reducing body weight for lowering prostate cancer risk

With more than one-third of U.S. adults considered to be obese and with the association between obesity and prostate cancer suggesting that obesity advances the disease, there is a need to find methods that can promote weight loss.  A recent randomized, double-blind, placebo controlled trial evaluated the effectiveness of decaffeinated green tea catechins (GTC) on reducing body weight or abdominal obesity but failed to produce any decrease in anthropometric variables, including change in weight, body mass index (BMI), and abdominal obesity. 

“The obesity epidemic is stronger than ever and that underscores the importance of identifying effective alternatives for men at risk of prostate cancer to help them reduce their body weight,” stated Dr. David Samadi.  “Even though green tea has numerous health benefits, as far as being an answer for effective weight management, there just doesn’t appear to be sufficient evidence to show this at this time.”

Several studies have suggested that men with high-grade prostatic intraepithelial neoplasia (HGPIN) and who are obese are more prone to experiencing advances in prostate carcinogenesis.  One study found men with metabolic syndrome (abdominal obesity, hypertension, and insulin resistance) and had HGPIN were at a higher risk for prostate cancer.  Both HGPIN and atypical small acinar proliferation (ASAP) are common histological findings on prostate biopsy and are considered to be precursor lesions and predictors of prostatic adenocarcinoma. 

“Americans are always looking for ways to lose weight and many turn to using nutrient supplements in a pill form as their answer,” exclaimed Dr. Samadi.  “Green tea is a popular beverage and has a couple of ingredients reported to be useful in weight management – caffeine and catechins.  Green tea catechins have been extensively studied on their anti-cancer mechanisms in prostate carcinogenesis but it has also been proposed that the green tea catechins may reduce body weight by increasing energy expenditure and fat oxidation, along with reducing lipogenesis and decreasing fat absorption.  And that is what this study wanted to find out – could green tea catechins not only reduce the progression of HGPIN and ASAP but also induce weight loss resulting in reduction of BMI, and waist to hip ratio.  If it could, it would be one method of helping the overall reduction of prostate cancer risk in men with HGPIN or ASAP.”

For the study 97 men diagnosed with HGPIN or ASAP were randomized to receive either 400 mg of bioactive catechins found in green tea or a placebo for one year.  Anthropometric data was collected at baseline, again at 6 and 12 months with the data then being analyzed to observe any changes in body weight, body mass index, and waist to hip ratio which is an indicator of abdominal obesity.  Results from the study at one year showed men randomized into the group receiving decaffeinated green tea catechins tolerated it well but it was not effective in reducing any of the biomarkers for obesity. 

“I believe the takeaway from this study is that men who are obese and at high risk for prostate cancer should avoid using nutritional supplements such as green tea in hopes of it effectively reducing their body weight,” advised Dr. Samadi.  “Green tea can still be enjoyed and used by these men but what really helps men most is screening for obesity. When we target those who are at a high risk for prostate cancer based on their risk factors such as their age, family history, or body weight, then we are making it a high priority to find interventions in helping them reach a healthier body weight.  Instead of using ineffective means such as taking supplements of green tea, rather we should focus on more effective weight management techniques such as improving food choices and helping them develop a regular, consistent exercise routine. This is what will be more advantageous in improving their odds of reducing their risk of prostate cancer in the long run.”

Patients newly diagnosed with prostate cancer can contact world renowned prostate cancer surgeon and urologic oncologist, Dr. David Samadi, for a free phone consultation and to learn more about prostate cancer risk call 212-365-5000.