Alpha-linolenic acid (ALA), the most common omega-3 fatty acid in the Western diet, has no impact on prostate cancer, according to a large dietary study slated to appear in the August issue of Cancer Causes Control.

This study evaluated total intake of ALA from animal, fish, and plant sources in 29,592 men age 55-74 years in the screening arm of the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial. The men were followed for an average of 5.1 years.

During the study 1,898 men were found to have developed prostate cancer. Most of these men (1,631) were diagnosed with organ-confined disease, stage T1b to T3a and no nodal involvement. A small number, 285 , were diagnosed with advanced prostate cancer at a stage equal to or higher than T3b, with one or more nodes or one or more metastases.

The authors found “no association between total alpha-linolenic acid intake and overall risk of prostate cancer. “In addition, no relations were observed between ALA intake from any specific food source and the risks of total, organ-confined, or advanced grostate cancer.” ALA intake also bore no association with low grade tumors or high grade tumors.

They conclude: “In this prospective study of predominantly Caucasian men who were screened annually for newly incident prostate cancer, dietary intake of total ALA and ALA from specific food sources was not associated with risk of total prostate cancer or prostate tumors that were defined by stage and grade.”

Another study of diet questionaires filled in by men in the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial announced that antioxidant supplements have weak, mixed results for prostate cancer.

But methods and results are not consistent. Another study, from Brigham and Women’s Hospital and Harvard Medical School. reported that antioxidant blood levels are “key” to a gene-associated prostate cancer risk.

Source: A Prospective Study of Dietary Alpha-linolenic Acid and the Risk of Prostate Cancer (United States). Koralek DO, et al. Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Bethesda, MD, USA.