Targeted Nutritional Interventions
Treatment of BPH with plant-derived compounds dates back to the 15th century BC in Egypt and natural therapies comprise approximately 50% of all treatments for BPH in Italy (Wilt 1998).
Saw Palmetto – Saw palmetto, also known as Seronoa repens (S. repens) or Sabal serrulata (S. serrulata), is the most widely used phytotherapeutic treatment for BPH (Wilt 1998; Gordon 2003). It has been documented as a treatment for swollen prostate glands since the 1800s (Wilt 1998). Saw palmetto has been found to be effective in treating the lower urinary tract symptoms of BPH. Evidence suggests that saw palmetto has similar efficacy to finasteride and tamsulosin, two medications used to treat BPH (Suter 2013). Saw palmetto extract appears to inhibit the activity of the 5α-reductase enzyme. It may also have anti-inflammatory properties and a tendency to promote apoptosis of prostate cells (Habib 2009; Suter 2013).
A pilot study examining the effects of 320 mg of saw palmetto extract found that this herbal treatment reduced BPH symptoms by over 50% after 8 weeks of treatment (Suter 2013). Another study found a combination of saw palmetto and stinging nettle root extract to be as effective as finasteride at treating BPH (Sokeland 2000). However, a review of studies found that saw palmetto was not significantly better than placebo (Tacklind 2012). But differences in methodological quality of the studies included in this review limit the interpretation of the results.
Saw palmetto has not been reported to cause any significant side effects. A study found no difference in the rate of serious and non-serious symptomatic adverse events between saw palmetto and placebo (Avins 2008). Most studies examining the benefits of saw palmetto for BPH have used doses of 320 mg daily (Dedhia 2008). Saw palmetto is rich in phytosterols, including beta-sitosterol (see below), and this may contribute to its therapeutic effects (Sorenson 2007).
Beta sitosterol – Beta-sitosterol belongs to a family of plant-derived compounds chemically similar to cholesterol. These compounds are called phytosterols. The impact of human intake of phytosterols has been studied in a variety of contexts, including cardiovascular disease and cancer (Jones 2009; Choudhary 2011; Rocha 2011; Genser 2012; Othman 2011). A beneficial role for phytosterols, and beta-sitosterol in particular, in prostate conditions is supported by a considerable body of research in both laboratory and clinical settings (Coleman 2002; Wilt 1999; Wilt 2000; Shi 2010; Shenouda 2007; Kobayashi 1998; Klippel 1997; Berges 1995).
A comprehensive review of 4 studies comprising data on 519 men with BPH showed that beta-sitosterol improved urinary symptoms and flow measures (Wilt 2000). A clinical trial in which men with symptomatic BPH consumed beta-sitosterol or placebo for 6 months, and were then followed for another 12 months, gave men the option to discontinue therapy after 6 months, or continue. Those men who chose to continue taking beta-sitosterol showed stable results on standardized prostate/urinary symptom and quality of life assessments at the 18-month follow-up, while men who chose not to continue therapy experienced a decline in some of the prostate/urinary scores (Berges 2000). In another clinical trial, 200 men with symptomatic BPH were randomized to receive either 20 mg of beta-sitosterol 3 times daily or placebo for 6 months. Men who took beta-sitosterol experienced greater improvements on 2 standardized assessments of prostate/urinary symptoms than men who took a placebo. Beta-sitosterol recipients also experienced improvements in peak urine flow rate and residual urinary volume; these parameters were unaffected by the placebo (Berges 1995). These results were corroborated in a later study of similar design, but which employed a higher dose of beta-sitosterol (130 mg daily). Men who took beta-sitosterol in this study not only experienced improvements in standardized prostate/urinary symptom assessments over placebo, but also in quality of life (Klippel 1997). In a clinical trial on 127 men with BPH, a combination of saw palmetto, beta-sitosterol, vitamin E, and rye flower pollen extract was superior to placebo in improving urinary frequency at night and during the day and also led to more significant improvements on a standardized prostate/urinary symptom assessment (Preuss 2001).
Pygeum Africanum – Pygeum africanum (P. africanum), also known as African plum, is used as a treatment for BPH in Europe (Lowe 1999). P. africanum may prevent the proliferation of cells within the prostate (Lowe 1999; Quiles 2010). A review of studies examining the effects of African plum on BPH found that it provides moderate relief from urinary symptoms (Wilt 2011; Dedhia 2008). The typical dose used in studies is between 75–200 mg daily (Dedhia 2008).
Rye Pollen – Rye pollen extract (also called Secale cereale) is made by first subjecting the pollen to bacterial degradation, followed by further extraction using organic and water solvents (Lowe 1999). It is commonly used in Japan, Argentina, and parts of Western Europe (Dedhia 2008). Laboratory studies have shown that the water-soluble portion of the extract inhibits growth of prostate cells (Lowe 1999). Studies of its efficacy have found that rye pollen extract reduces nighttime urination (Dedhia 2008). One study found that the use of 320 mg of honeybee-collected pollen extract improved urinary flow rate (Murakami 2008). Another study found that rye pollen extract reduced BPH symptoms, shrank prostate size, and increased urinary flow over the course of 4 years (Xu 2008).
Urtica Dioica (“stinging nettle”) – Stinging nettle root extracts have shown effectiveness as natural therapeutics for BPH (Alt Med Rev 2007; Nahara 2012). A study found that a combination of saw palmetto and 120 mg of stinging nettle extract was as effective as finasteride in the treatment of BPH; the herbal combination also had fewer side effects than finasteride (Sokeland 2000). Another study showed that stinging nettle alone had beneficial effects in patients with symptomatic BPH (Safarinejad 2005). This finding is supported by animal studies showing that stinging nettle extract reduced the size of the prostate, weekly urine output, and PSA levels, perhaps by disrupting prostate cell growth (Nahara 2012).
Isoflavones and Lignans – Plant-derived compounds called isoflavones, which are abundant in soybeans, and lignans, which are abundant in flax and Norway spruce, modulate estrogen signaling in the human body via interaction with estrogen receptors. Thus, these compounds are sometimes classified as “phytoestrogens”. Isoflavones and lignans have been investigated for their anti-cancer effects, but their ability to affect hormone-responsive tissues appears to influence the prostate (Kumar 2004).
Evidence suggests that isoflavones may inhibit testosterone-mediated prostate cell growth (Kumar 2004). These compounds were also shown to block the activity of 5α-reductase, the enzyme that converts testosterone to dihydrotestosterone (DHT), which promotes prostate growth (Evans 1995). One study suggested that men with BPH may have lower dietary intake of soy isoflavones than men with healthy prostates, as determined by lower prostate tissue concentrations of genistein, a potent isoflavone (Hong 2002). Genistein levels may also correlate with the size of the prostate in BPH: men with small-volume BPH have been found to have higher levels of genistein in their prostate tissue than men with large-volume BPH (Brossner 2004).
Supplementation with soy isoflavones has been found to reduce PSA levels in men with prostate cancer (Kumar 2004). In addition to preventing prostate cell proliferation, isoflavones may increase programmed cell death (ie, apoptosis) in low-to-moderate grade tumors from prostate cancer patients (Jared 2002). Another study found that isoflavones are very well tolerated (Wong 2012).
Lignans have also been evaluated as a treatment for BPH, and one study found that a flaxseed lignan extract reduced both BPH symptoms and the grade of lower urinary tract symptoms experienced by some patients (Zhang 2008).
Pumpkin Seed Oil – Pumpkin seeds (Curcurbita pepo) have been used in folk medicine as a treatment for urinary problems caused by an enlarged prostate (Tsai 2006). Compounds in pumpkin seeds may interfere with the action of dihydrotestosterone, which stimulates prostate cell growth (Gossell-Williams 2006). Studies in animal models of BPH have found that pumpkin seed oil blocks testosterone-mediated prostate growth (Gossell-Williams 2006, Abdel-Rahman 2006). Pumpkin seed oil’s effects were greater in animal models when the oil was combined with phytosterols (Tsai 2006).
Similar results have also been found in human studies. For example, one study found that pumpkin seed oil reduced BPH symptoms in Korean men and also improved their urinary flow rate. This study also found that a combination of pumpkin seed oil and saw palmetto reduced PSA levels (Hong 2009).
Lycopene – Lycopene is a carotenoid occurring abundantly in tomatoes. Men with higher lycopene levels in their blood, suggesting greater dietary lycopene consumption, are less likely to develop prostate cancer (Gann 1999). One laboratory experiment found that lycopene inhibited the growth of normal human prostate cells (Obermuller-Jevic 2003). Another study suggested that lycopene supplementation may decrease the growth of prostate cancer (Kucuk 2001).
Fatty Acids – Healthy fats, such as eicosapentaenoic acid (EPA), decosahexoaenoic acid (DHA), and gamma-linolenic acid (GLA), exhibit a wide range of beneficial effects on the human body and may support prostate health (Simopoulos 1999).
Flaxseed oil and fish oil are rich sources of essential fatty acids (Shaikh 2012; James 2000). A pilot study found that flaxseed supplementation, combined with a low-fat diet, lowered PSA levels in men who were scheduled to have a repeat prostate biopsy. This special diet also reduced the rate of prostate cell proliferation (Demark-Wahnefried 2004). Another study found that the essential fatty acids gamma-linolenic acid (GLA) and eicosapentaenoic acid (EPA), and their metabolites, suppressed the activity of 5α-reductase (Pham 2002).
Several other dietary constituents may also be able to protect against BPH, although more studies are needed.
Boswellia serrata - Boswellia serrata is an African tree whose bark yields an oily, resinous extract that has been used in traditional medicine (Alt Med Rev 2008). Compounds in Boswellia resin, particularly acetyl-11-keto-β-boswellic acid (AKBA), have potent anti-inflammatory properties (Abdel-Tawab 2011). Inflammation plays a role in the development of BPH and is associated with an increase in BPH symptoms (Altavilla 2012; Nickel 2008b). Several studies indicate that AKBA may slow growth of prostate cancer cells and induce apoptosis (Pang 2009; Yuan 2008; Lu 2008). Although studies have yet to formally evaluate the effect on Boswellia in men with BPH, its documented anti-inflammatory and cancer-fighting properties suggest it may deliver some benefits in this population.
Selenium - Selenium is a mineral the body needs in small quantities (Thomas 1999); however, increased selenium intake may help prevent BPH. A study found that a combination of selenium, lycopene, and saw palmetto was more effective than saw palmetto alone at preventing hormone-dependent prostate growth (Altavilla 2011). Another study found that higher serum levels of selenium were associated with a reduced risk of BPH (Eichholzer 2012).
Garlic - Garlic has anti-inflammatory, anti-cancer, and antioxidant effects, all of which may help prevent the development of BPH and prostate cancer. Although its mechanism of action is not clear, several animal and cell culture studies have suggested that garlic may be beneficial for BPH. In addition, combining garlic with other foods beneficial for the prostate, such as olive oil and tomatoes, may enhance its effects (Devrim 2007).
Beta-carotene and vitamin C - Increased intake of beta-carotene and vitamin C is associated with a decreased risk of having BPH requiring surgical treatment (Tavani 2006).