Tomato-based randomized controlled trial in prostate cancer patients: Effect on PSA

Clin Nutr. 2017 Jun;36(3):672-679. doi: 10.1016/j.clnu.2016.06.014. Epub 2016 Jun 30.

Abstract

Background & aims: The effect of lycopene-containing foods in prostate cancer development remains undetermined. We tested whether a lycopene-rich tomato intervention could reduce the levels of prostate specific antigen (PSA) in prostate cancer patients.

Methods: Prior to their curative treatment, 79 patients with prostate cancer were randomized to a nutritional intervention with either 1) tomato products containing 30 mg lycopene per day; 2) tomato products plus selenium, omega-3 fatty acids, soy isoflavones, grape/pomegranate juice, and green/black tea (tomato-plus); or 3) control diet for 3 weeks.

Results: The main analysis, which included patients in all risk categories, did not reveal differences in changes of PSA-values between the intervention and control groups. Post-hoc, exploratory analyses within intermediate risk (n = 41) patients based on tumor classification and Gleason score post-surgery, revealed that median PSA decreased significantly in the tomato group as compared to controls (-2.9% and +6.5% respectively, p = 0.016). In separate post-hoc analyses, we observed that median PSA-values decreased by 1% in patients with the highest increases in plasma lycopene, selenium and C20:5 n-3 fatty acid, compared to an 8.5% increase in the patients with the lowest increase in lycopene, selenium and C20:5 n-3 fatty acid (p = 0.003). Also, PSA decreased in patients with the highest increase in lycopene alone (p = 0.009).

Conclusions: Three week nutritional interventions with tomato-products alone or in combination with selenium and n-3 fatty acids lower PSA in patients with non-metastatic prostate cancer. Our observation suggests that the effect may depend on both aggressiveness of the disease and the blood levels of lycopene, selenium and omega-3 fatty acids.

Trial registration: ClinicalTrials.gov NCT00433797.

Keywords: Diet; Lycopene; Prostate cancer; Prostate specific antigen; Selenium; Tomato.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Aged
  • Carotenoids / administration & dosage*
  • Carotenoids / blood
  • Diet
  • Fatty Acids, Omega-3 / administration & dosage
  • Fatty Acids, Omega-3 / blood
  • Fruit and Vegetable Juices
  • Humans
  • Isoflavones / administration & dosage
  • Lycopene
  • Lycopersicon esculentum / chemistry*
  • Lythraceae / chemistry
  • Male
  • Middle Aged
  • Prostate-Specific Antigen / blood*
  • Prostatic Neoplasms / blood*
  • Prostatic Neoplasms / diet therapy*
  • Selenium / administration & dosage
  • Selenium / blood
  • Soybeans / chemistry
  • Vitis / chemistry

Substances

  • Fatty Acids, Omega-3
  • Isoflavones
  • Carotenoids
  • Prostate-Specific Antigen
  • Selenium
  • Lycopene

Associated data

  • ClinicalTrials.gov/NCT00433797