Benign Prostatic Hyperplasia (BPH): Saw Palmetto and Other Dietary Factors Can Help

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Originally published on by Michael Passwater

The prostate gland both produces a fluid component of semen and serves as a muscle-driven switch in men between urination and ejaculation. Like our ears and nose, the prostate continues to grow with age. The normal prostate growth rate is 2.2% per year, doubling in volume every 32.6 years. Unfortunately, the prostate's location just below the neck of the bladder, around the urethra and ejaculatory ducts, and near the rectum, affords little space for expansion. Although prostate cancer often produces similar symptoms of enlargement, Benign Prostatic Hyperplasia (BPH) is not cancerous. BPH appears to be an inevitable consequence of ageing, affecting half of men by age 50 and up to 80% of men by age 80. It is estimated that 14 million men in the United States and 210 million men worldwide have clinical symptoms of BPH.

However, in addition to age, other factors including family history, metabolic syndrome, obesity, hypertension, a sedentary lifestyle, consumption of fewer fruits and vegetables, and vitamin D and zinc deficiencies are also risk factors for BPH. [1-3] Attention to the modifiable risk factors of diet, activity, and stress reduction may delay onset and progression of symptoms. While BPH is "benign" in the sense that it is not a spreading life-threatening tumor or a precursor to prostate cancer, it can significantly impact quality of life. Frequent urination, urgent urination, nocturia, urinary retention, hesitancy, poor stream, incomplete voiding, urge incontinence, and overflow incontinence may all be symptoms of BPH. Surprisingly, the overall size of the prostate gland is not predictive of the symptoms experienced. Due to its location, growth of the middle lobe induces symptoms more immediately than growth of the lateral lobes.

Other conditions may cause symptoms similar to BPH. It is important to rule out prostate cancer, kidney, bladder, or blood pressure problems, and diabetes. Blood in urine or semen, or painful urination or ejaculation are not consistent with BPH, and should always be investigated. These situations may be symptoms of prostate cancer. Additionally, circulating Prostate Specific Antigen (PSA) is typically elevated in people with prostate cancer, and may also be elevated in BPH. The increased PSA in BPH is mostly free (unbound) whereas circulating PSA in the setting of prostate cancer is mostly protein bound. Determining the percentage of free PSA (%fPSA) in addition to the total PSA (tPSA) can be helpful to determine the need for more invasive evaluations. A low %fPSA increases concern for prostate cancer.

Brief History of BPH Management

Successful treatment of BPH is not new. Since at least the 1700s, Native Americans, in what is now the southeastern United States, used fruit of saw palmetto palms (Serenoa repens) to treat male urinary problems. Early European settlers in America used juice from saw palmetto berries to gain weight and improve general disposition. In April of 1879, Dr. J.B. Read of Savannah, GA, published the medicinal uses of the saw palmetto palm, including the treatment of prostate enlargement, in the American Journal of Pharmacy. A tea made from saw palmetto berries was commonly used to treat this condition and urinary tract infections. [4] Saw palmetto, along with pumpkin seeds continued to be used for these purposes through the 1940s. Various extracts of saw palmetto berries, and the berries themselves, remain available without a prescription. Extracts from the berries of the saw palmetto palm are still used in 50% of BPH treatment plans in Italy, and 90% of BPH treatment plans in Germany.

"Saw palmetto appears to have efficacy similar to that of medications like finasteride, but it is better tolerated and less expensive. There are no known drug interactions with saw palmetto, and reported side effects are minor and rare." (Andrea Gordon, MD and Allen Shaughnessy [5])

Saw Palmetto

The saw palmetto, also known as a "dwarf palm", is abundant throughout the coastal southeastern United States. Saw palmetto berries contain 70-90% free fatty acids, including oleic (>30%), lauric (30%), myristic, palmitic, linoleic, linolenic, stearic, caprylic, and capric acids. These berries also contain a smaller amount of phytosterols, mainly beta-sitosterol and small amounts of campesterol and stigmasterol, along with flavonoids. Pumpkin seeds also contain sterols. The mechanistic benefits of these natural compounds is unclear, however they appear to reduce inflammation and proliferation of prostate tissue. Saw palmetto appears to reduce of the active form of testosterone (DHT) without loss of libido, and to reduce the amount of an enzyme that controls proliferation of prostate cells.

There are many varieties of saw palmetto products on the market. The variability of product constitution is a likely source of the variability of clinical experiences and research results. The type of solvent used to prepare the extract impacts the composition of the product. Examination of commercially available saw palmetto extracts have shown a range of free fatty acids from 40% - 80% and from 8 mg to 1473 mg per manufacturer's recommended dose. N-hexane lipidosterolic extracts have been used in the majority of clinical studies of saw palmetto. Doses typically involve 160 mg twice per day or 320 mg once per day. Doses up to 480 mg per day have been shown to be safe. Whole berry doses of 1-2g per day have also been studied with favorable results. Those considering a saw palmetto supplement should check the label for indications of standardized contents with 85%-95% fatty acids and sterols. [6]

Approved Medications for BPH

Surgery (open reduction or several varieties of laser surgery) and four classes of medications are approved by the FDA for the treatment of BPH. The four classes of medications are:

  1. 5-alpha reductase inhibitors (5-ARI) which block the conversion of testosterone into dihydrotestosterone (DHT) within the prostate
  2. alpha-blockers which relax the muscles of the prostate and bladder neck
  3. phosphodiesterase inhibitors which relax muscles in the lower urinary tract
  4. anticholinergics which relax muscles in the bladder.

Unfortunately, these medications come with a spectrum of unwanted side effects. 5-alpha reductase medications have been shown to reduce PSA levels 41-50%, which may complicate evaluations for prostate cancer. Side effects of urinary tract muscle relaxants include postural hypotension (low blood pressure, sometimes fainting, upon standing up). Additionally, sexual dysfunction is a known side effect of all medications approved by the FDA for the treatment of BPH. Less common side effects include chest pain or tightness, confusion, and difficult or labored breathing. In 2011, the FDA issued a safety warning for 5-ARI medications due to an observed increased risk of being diagnosed with high grade prostate cancer. Off-label use of 5-ARIs by pregnant women is contraindicated due to the risk of birth defects in male offspring.

The FDA has denied requests for health claims associating saw palmetto with prevention or treatment of BPH symptoms. However, several clinical trials have demonstrated similar benefits with saw palmetto compared to 5-ARIs and alpha blockers with fewer side effects in the saw palmetto groups. [7-10] Gastrointestinal side effects are the most common complaints with saw palmetto extracts. Taking saw palmetto with food minimizes these discomforts. Unlike the approved pharmaceuticals, neither saw palmetto nor pumpkin seeds have the unwanted side effect of masking PSA levels. However, similar to the patented medications, those pregnant or taking hormone therapy should avoid saw palmetto products due to the potential interference with estrogen and testosterone metabolism.

Other Dietary Factors

Other dietary factors, including fruit and vegetable intake, may also contribute to the risk of developing and managing BPH symptoms. [11-17] In addition to pumpkin seeds, many other nuts and seeds contain phytosterols and zinc. Low zinc and vitamin D levels have been associated with an increased risk of BPH symptoms. A clinical trial involving 6000 IU vitamin D per day in subjects with BPH symptoms showed a significant reduction in prostate volume and symptoms. [18] Prostate cells contain vitamin D receptors and vitamin D appears to modify cell signaling down-regulating prostate stromal and epithelial cell proliferation. Epidemiology studies have shown an inverse relationship between vitamin D levels and prostate cancer mortality. Additionally, vitamin C is known to have anti-inflammatory properties and to inhibit HIF-1-alpha which can influence the growth of prostate cells. Vitamin C also has diuretic properties which offer many benefits (especially in brain injury and infections), but be aware that this, along with water intake near bedtime, may induce functional nocturia. Caffeine and alcohol also have diuretic properties and will increase urine volume and frequency.


BPH can be an irritating complication of aging for men, negatively affecting quality of life. Before assuming one's symptoms are due to BPH, prostate cancer and other causes should be excluded. In the setting of BPH, saw palmetto berries or hexane extracts of these berries along with pumpkin seeds, have demonstrated symptom relief comparable to FDA approved medications with fewer side effects and less expense.


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3. Lokeshwar SD, Harper BT, Webb E, et al. (2019) Epidemiology and treatment modalities for the management of benign prostatic hyperplasia. Transl Androl Urol. 8:529-539.

4. Florida Gulf Coast University Food Forest Plant Database (2015) Saw Palmetto (Serenoa repens)

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6. Mount Sinai Health Library Saw palmetto. Accessed July 8, 2023.

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10. Leibbrand M, Siefer S, Schon C, et al. (2019) Effects of an Oil-Free Hydroethanolic Pumpkin Seed Extract on Symptom Frequency and Severity in Men with Benign Prostatic Hyperplasia: A Pilot Study in Humans. J Med Food. 22:551-559.

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13. Espinosa G, Esposito R, Kazzazi A, Djavan B. (2013) Vitamin D and benign prostatic hyperplasia -- a review. Can J Urol. 20:6820-6825.

14. Zhang W, Zheng X, Wang Y, Xiao H (2016) Vitamin D Deficiency as a Potential Marker of Benign Prostatic Hyperplasia. Urology 97:212-218.

15. Crescioli C, et al. (2003) Inhibition of Spontaneous and Androgen-Induced Prostate Growth by a Nonhypercalcemic Calcitriol Analog. Endocrinology 144:3046-3057.

16. Rohrmann S, Giovanucci E, Willett WC, Platz EA (2007) Fruit and vegetable consumption, intake of micronutrients, and benign prostatic hyperplasia in US men, Am J Clin Nutr. 85:523-529.

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18. Zendehdel A, Ansari M, Khatami F, et al. (2021) The effect of vitamin D supplementation on the progression of benign prostatic hyperplasia: A randomized controlled trial. Clin Nutr. 40:3325-3331.

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