Quercetin is a plant nutrient (phytonutrient) often found in supplements formulated for men, and for good reason: This potent antioxidant has qualities that make it a good candidate for supporting and promoting prostate health. If you enjoy apples, berries, red grapes, onions, tea and an occasional glass of red wine, then you’ve also been introduced to quercetin. Let’s extend that introduction a little further with a look at how quercetin can benefit prostate health, specifically its effects on prostatitis, prostate cancer and an enlarged prostate (benign prostatic hyperplasia, BPH).
Quercetin And Prostatitis
Quercetin has anti-inflammatory properties that make it a positive choice for managing prostatitis, an inflammatory condition of the prostate. The most common type of prostatitis is chronic nonbacterial prostatitis/chronic pelvic pain syndrome (CP/CPPS), characterized by pelvic pain, urinary tract symptoms (e.g., urinary urgency, dribbling, urinary frequency), blood in the urine or semen, and painful ejaculation. Quercetin blocks the production and release of histamine and other inflammatory factors.
In a double-blind, randomized study, 28 men who had CP/CPPS were assigned to take either placebo or 500 mg of quercetin twice daily for one month. An additional 17 men participated in an unblind arm of the study and took a supplement that contained quercetin along with saw palmetto, bromelain, cranberry and papain.
After one month, scores on the International Prostate Symptom Score (IPSS) declined from 21.0 to 13.1 among the men who took quercetin for prostatitis but only from 20.2 to 18.8 in the placebo group. Improvement in symptoms of at least 25 percent was reported by two-thirds of the men who took quercetin compared with only one of five who took the placebo. Most of the men in the unblind segment of the study said they had at least a 25 percent improvement in their symptom score. 
One hundred men who had CP/CPPS participated in a Cleveland Clinic study that used a multi-model therapy approach based on the UPOINT, which selects therapies (e.g., quercetin, physical therapy, alpha blockers) according to specific categories. The study lasted 26 weeks. At a median 50-week follow-up, 84 percent of the men had achieved at least a 6-point drop in chronic prostatitis scores. Quercetin was associated with the greatest decline in scores. 
Quercetin And Prostate Cancer
Based on a number of studies, quercetin has an ability to fight prostate cancer in several ways. For example, quercetin has shown that it can inhibit the activity of certain genes associated with the development of cancer as well as inhibit the spread of prostate cancer and help promote the death of cancer cells.   In the second study, the authors’ findings convinced them that quercetin could be developed “as a novel chemopreventive agent for metastatic prostate cancer.”
In a 2010 study, researchers at the University of Madras found that quercetin reduced the survival of certain prostate cancer cells by changing signaling between cells and causing cell death. They noted that quercetin could be a useful supplement in cancer patients. 
Quercetin And Enlarged Prostate
An enlarged prostate, or BPH, affects more than half of all men by age 60, and that number reaches 85 percent by the time men are 90, according to the American Urological Association.  A common treatment for BPH is a drug called finasteride (Proscar), and scientists evaluated the combination of finasteride and quercetin in rats with enlarged prostates. They found that the combination resulted in improved reduction in prostate weight that got better as the dose of quercetin was increased. 
For prostate health, quercetin supplements are available alone and in combination with other natural ingredients. A typical daily dose is 500 mg, and you should not take more than 1 gram daily without first talking to your healthcare provider. Possible side effects include headache and upset stomach.
For more on men’s health visit Prostate.net.
 Inhibition of prostate cancer cell colony formation by the flavonoid quercetin correlates with modulation of specific regulatory genes.
 Quercetin regulates insulin like growth factor signaling and induces intrinsic and extrinsic pathway mediated apoptosis in androgen independent prostate cancer cells (PC-3). http://www.ncbi.nlm.nih.gov/pubmed/20658310
 American Urological Association: http://www.urologyhealth.org/content/moreinfo/enlargedprostate.pdf
 Reduction of rat prostate weight by combined quercetin-finasteride treatment is associated with cell cycle deregulation. http://joe.endocrinology-journals.org/content/181/3/493.long