Answer: Try eating turmeric spice, soy products and tomatoes (preferably cooked!), or take isoflavone, lycopene and curcumin supplements.
Combined inhibitory effects of soy isoflavones and curcumin on the production of prostate-specific antigen.
Abstract
BACKGROUND:
Sustained chronic inflammation in the prostate promotes prostate carcinogenesis. Since an elevated level of prostate-specific antigen (PSA) per se reflects the presence of inflammation in the prostate, intervention to improve the PSA value might potentially have beneficial effects for the prevention of the development of prostate cancer. Isoflavones and curcumin have anti-inflammatory and anti-oxidant properties. We examined the biological effects of soy isoflavones and curcumin on LNCaP cells. After that, we conducted a clinical trial for men who received prostate biopsies, but were not found to have prostate cancer, to evaluate the effects of soy isoflavones and curcumin on serum PSA levels.
METHODS:
The expression of androgen receptor and PSA were examined in LNCaP cells before and after treatment of isoflavones and/or curcumin. Eighty-five participants were randomized to take a supplement containing isoflavones and curcumin or placebo daily in a double-blind study. Subjects were subdivided by the cut-off of their baseline PSA value at 10 microg/ml. We evaluated values of PSA before and 6 months after treatment.
RESULTS:
The production of PSA were markedly decreased by the combined treatment of isoflavones and curcumin in prostate cancer cell line, LNCaP. The expression of the androgen receptor was also suppressed by the treatment. In clinical trials, PSA levels decreased in the patients group with PSA >or= 10 treated with supplement containing isoflavones and curcumin (P = 0.01).
CONCLUSIONS:
Our results indicated that isoflavones and curcumin could modulate serum PSA levels. Curcumin presumably synergizes with isoflavones to suppress PSA production in prostate cells through the anti-androgen effects.
A combination of tomato and soy products for men with recurring prostate cancer and rising prostate specific antigen.
Abstract
Tomato and soy products are hypothesized to reduce the risk of prostate cancer or enhance efficacy of therapy. A study was completed to determine if men with active prostate cancer will adhere to a dietary intervention rich in tomato products and a soy protein supplement men (n = 41) with recurrent, asymptomatic prostate cancer were randomized among 2 groups: Group A (n = 20) consumed tomato products (no soy) for Weeks 0 through 4, targeting a minimum of 25 mg of lycopene/day. Group B (n = 21) consumed soy (no tomatoes) for Weeks 0 through 4, providing 40 g of soy protein/day. For Weeks 4 through 8, all men consumed a combined tomato-rich diet and soy supplements. No grade II through IV toxicities were observed. During Weeks 0 through 4, mean daily lycopene intake for Group A was 43 mg (+/- 15 mg) and mean soy intake for Group B was 39 g (+/- 1 g), remaining similar during Weeks 4 through 8. Serum lycopene increased from 0.72 +/- 0.09 micromol/l to 1.21 +/- 0.10 micromol/l (P < 0.0001) and urinary isoflavone excretion increased from not detectable to 54.1 +/- 5.7 micromol/l (P < 0.05) with 8 wk of diet intervention. Serum prostate-specific antigen decreased between Weeks 0 and 8 for 14 / 41 men (34%). Mean serum vascular endothelial growth factor for the entire group was reduced from 87 to 51 ng/ml (P < 0.05) over 8 wk. In conclusion, prostate cancer patients will consume diets rich in tomato products and soy with excellent compliance and bioavailability of phytochemicals. Further studies combining tomato and soy foods to determine efficacy for prostate cancer prevention or management are encouraged.
Lycopene and soy isoflavones in the treatment of prostate cancer.
Abstract
Dietary intake of lycopene and soy has been associated with a lower risk of prostate cancer. In vitro studies with lycopene and genistein, a soy isoflavone, have shown induction of apoptosis and inhibition of cell growth in androgen-sensitive (LNCaP) and androgen-independent (PC3 and VeCaP) prostate cancer cell lines. In a previous Phase II clinical trial in prostate cancer patients, we observed prostate-specific antigen (PSA) stabilization with soy isoflavone intake. In this Phase II clinical trial, we investigated the efficacy of lycopene alone or in combination with soy isoflavones on serum PSA levels in men with prostate cancer. To be eligible for the study, men with prostate cancer had to have rising serum PSA following local therapy or while on hormone therapy. Study population included 71 eligible patients who had 3 successive rising PSA levels or a minimum PSA of 10 ng/ml at 2 successive evaluations prior to starting therapy. Subjects were randomly assigned to receive a tomato extract capsule containing 15 mg of lycopene alone (n = 38) or together with a capsule containing 40 mg of a soy isoflavone mixture (n = 33) twice daily orally for a maximum of 6 mo. One patient on the lycopene arm did not receive therapy due to his inability to ingest the study pill. There was no decline in serum PSA in either group qualifying for a partial or complete response. However, 35 of 37 (95%) evaluable patients in the lycopene group and 22 of 33 (67%) evaluable patients in the lycopene plus soy isoflavone group achieved stable disease described as stabilization in serum PSA level. The data suggest that lycopene and soy isoflavones have activity in prostate cancer patients with PSA relapse disease and may delay progression of both hormone-refractory and hormone-sensitive prostate cancer. However, there may not be an additive effect between the 2 compounds when taken together. Future studies are warranted to further investigate the efficacy of lycopene and soy isoflavones in prostate cancer as well as the mechanism of potential negative interaction between them.
An overview of the health effects of isoflavones with an emphasis on prostate cancer risk and prostate-specific antigen levels.
Abstract
Soybean isoflavones possess hormonal and nonhormonal properties that may reduce the risk of coronary heart disease, osteoporosis, and certain cancers, and alleviate hot flashes in menopausal women. Among the various cancers whose risk may be reduced by isoflavones, there is particular interest in prostate cancer. Eleven trials have examined the effects of isoflavones on serum prostate-specific antigen (PSA) levels. The dose of isoflavones in these trials from supplements or soy protein ranged from 60 to 900 mg/day (typical Japanese intake is 30-50 mg/day), subject number/group ranged from 8 to 62, and study duration from 20 days to 1 year. Isoflavones did not affect serum PSA in healthy subjects. In contrast, in 4 of 8 trials involving prostate cancer patients, isoflavones significantly favorably affected PSA although in no studies was there an absolute decrease in PSA concentrations. The mechanism by which isoflavones affect PSA could not be determined from the existing research, although hormonal changes do not seem to be a factor. The clinical evidence is sufficiently encouraging to justify considering additional Phase II and III clinical trials investigating the efficacy of soy isoflavones in different populations of prostate cancer patients alone and in combination with other treatments.
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