Optimising selenium intake for cancer prevention - a pilot study in Auckland.

Not Applicable

Completed

• Conditions: Prostate cancer prevention; Cancer - Prostate

• Registration Number: ACTRN12619001106123
• Lead Sponsor: niversity of Auckland

Brief Summary

Selenium is an important trace element for human health. Approximately 25 seleno proteins are known to man, and are involved in many pathways including that of the antioxidant defence systems. New Zealand soils are deficient in selenium; therefore, diets from crops produced in New Zealand are deficient in selenium. Meanwhile, New Zealand records the highest age standardised rates of prostate cancer incidence in the world. In 1996, Prof. Larry Clark and his group showed reduction in cancer rates including that of prostate cancer by a 200µg/day selenium as selenized yeast given for around 10 years. However, a large-scale study with 200µg/day selenium supplemented as selenomethionine, could not reproduce this finding. In our study, selenium supplementation by way of 200µg/day selenium as selenized yeast was given for six months to a male Caucasian group from Auckland to verify supplementation impacts measured through surrogate biomarkers (biologically measurable markers) as end points. These men were in the age group of 20-80y without known cancers other than non-melanoma skin cancers. A total of 571 men were recruited to the study and 481 completed the study. Beneficial effects monitored by way of biomarkers varied with demographic, lifestyle, diet, health and genetic data. In other words, selenium supplementation analysis indicates that 200µg/day selenium supplementation benefits are achieved only among stratified groups of men. Based on genetic differences, beneficial effects were realised between 120-150ng/ml serum selenium. As the duration of supplementation was only for six months, this study does not provide information on supplementation impacts for long-term use. It is important to extend this study to understand further interacting positive and negative benefits of selenium, before prophylactic selenium supplementation can be considered in stratified groups of New Zealand men.

Detailed Description

Not available

Study Timeline

• Results First Posted: 1900-01-01
• Study Completion: 2014-09-15
• Study Start: 2019-08-12
• Last Update Posted: 26 August 2019

Recruitment & Eligibility

• Status: Completed
• Sex: Male
• Target Recruitment: 571

Inclusion Criteria

Caucasian males in the age range 20-80y with no known cancers except for non-melanoma skin cancers, and not taking any dietary supplements containing >50 micrograms of selenium; (inherent serum selenium <200ng/ml added after recruitment), residents within the Auckland region, willing to attend the study centre based at the Faculty of Medical and Health Sciences, University of Auckland; willing to complete study questionnaires and keeping diet and activity diaries for four consecutive days.

Exclusion Criteria

Men taking any dietary supplements containing >50 micrograms of selenium.
With cancers excluding non-melanoma skin cancers
Men living outside Auckland region
Non-Caucasians.

Study & Design

• Study Type: Interventional
• Study Design: Not specified