Dietary Fish Oils in Relation to the Incidence and Mortality of Prostate Cancer
Abstract
Abstract
Introduction: Prostate cancer is commonly diagnosed yet the precise incidence rates are not evenly distributed throughout the globe. Aside from obvious hereditary factors, there appears to be significant lifestyle or geographical input factoring into the incidence and mortality rates with diet at the forefront of the suspected variables. Cultural and geographic data support this notion in the absence of other known etiology for the apparent variances noted. Epidemiologically, North America and a “Western Diet” low in fish accounts for disproportionally high rates. It is argued that the limited treatment options such as radical prostatectomy and radiotherapy have not been tested enough and include uncertain prognoses with high side effects. Often unsupervised, patients seek alternative medicines and lifestyle changes in place of or in addition to established treatments without any legitimate evidence or guidelines for such. A novel, safe, and simple lifestyle modification is a worthwhile idea to be considered, however, pending the support of consistent scientific literature. This review seeks to discover whether fish oils have a role in medical advising for prostate cancer incidence/mortality reduction in American men over 40 years of age.
Methods: A search of both the latest and most relevant literature was conducted in November of 2018 utilizing EBSCOhost and Google Scholar. Articles were narrowed electronically, filtered via key words, then manually evaluated with specific criteria. Inclusion and exclusion criteria were utilized and articles were chosen by date of publication no earlier than 1999, or more recent in some searches, to maintain currency of the data, research practices, and medical knowledge base.
Results: Critical analysis of 6 articles revealed inconsistent yet hopeful findings that did include association of fish oils with reduction of prostate cancer (PCa) incidence in 3 of 4 articles and reduction of mortality in 2 articles. The single meta-analysis reviewed did show significance and non-significance for both incidence and mortality associations. Several additional health outcomes other than the primary endpoints were found to be associated in experimental intervention groups in some studies including weight loss, improved lipid profiles, reduced PCa proliferation, and decreased inflammatory markers. All applicable articles reported an intervention profile without significant adverse events and successful compliance rates between groups.
Discussion: In keeping with previous research there are still contradictions and gaps in the link between a possible association of dietary fish oils and improved PCa incidence, mortality, or progression. The consistently low-risk/high compliance rate of fish oil based interventions is additionally highlighted as a major factor in support of furthered research and potential clinical applications. Flaws in the research are pointed to as sources of the potential failure, however, the majority of selected studies include adequate levels of internal validity, data analysis, bias minimization, and adjustment of confounding variables.
Conclusion: Statistical significance is mixed, however, clinical significance seems to be promising if it can be supported by an augmented body of consistent evidence. Fish oil as a primary or secondary preventive recommendation regarding PCa incidence and/or mortality is not currently backed by enough data to be suggested at this time. New research is called upon with an emphasis on adequate duration of intervention, large representative sample sizes, isolation of the variables from confounders, and continued anticipation of bias and error sources.
Dietary Fish Oils in Relation to the Incidence and Mortality of Prostate Cancer
Abstract
Introduction: Prostate cancer is commonly diagnosed yet the precise incidence rates are not evenly distributed throughout the globe. Aside from obvious hereditary factors, there appears to be significant lifestyle or geographical input factoring into the incidence and mortality rates with diet at the forefront of the suspected variables. Cultural and geographic data support this notion in the absence of other known etiology for the apparent variances noted. Epidemiologically, North America and a “Western Diet” low in fish accounts for disproportionally high rates. It is argued that the limited treatment options such as radical prostatectomy and radiotherapy have not been tested enough and include uncertain prognoses with high side effects. Often unsupervised, patients seek alternative medicines and lifestyle changes in place of or in addition to established treatments without any legitimate evidence or guidelines for such. A novel, safe, and simple lifestyle modification is a worthwhile idea to be considered, however, pending the support of consistent scientific literature. This review seeks to discover whether fish oils have a role in medical advising for prostate cancer incidence/mortality reduction in American men over 40 years of age.
Methods: A search of both the latest and most relevant literature was conducted in November of 2018 utilizing EBSCOhost and Google Scholar. Articles were narrowed electronically, filtered via key words, then manually evaluated with specific criteria. Inclusion and exclusion criteria were utilized and articles were chosen by date of publication no earlier than 1999, or more recent in some searches, to maintain currency of the data, research practices, and medical knowledge base.
Results: Critical analysis of 6 articles revealed inconsistent yet hopeful findings that did include association of fish oils with reduction of prostate cancer (PCa) incidence in 3 of 4 articles and reduction of mortality in 2 articles. The single meta-analysis reviewed did show significance and non-significance for both incidence and mortality associations. Several additional health outcomes other than the primary endpoints were found to be associated in experimental intervention groups in some studies including weight loss, improved lipid profiles, reduced PCa proliferation, and decreased inflammatory markers. All applicable articles reported an intervention profile without significant adverse events and successful compliance rates between groups.
Discussion: In keeping with previous research there are still contradictions and gaps in the link between a possible association of dietary fish oils and improved PCa incidence, mortality, or progression. The consistently low-risk/high compliance rate of fish oil based interventions is additionally highlighted as a major factor in support of furthered research and potential clinical applications. Flaws in the research are pointed to as sources of the potential failure, however, the majority of selected studies include adequate levels of internal validity, data analysis, bias minimization, and adjustment of confounding variables.
Conclusion: Statistical significance is mixed, however, clinical significance seems to be promising if it can be supported by an augmented body of consistent evidence. Fish oil as a primary or secondary preventive recommendation regarding PCa incidence and/or mortality is not currently backed by enough data to be suggested at this time. New research is called upon with an emphasis on adequate duration of intervention, large representative sample sizes, isolation of the variables from confounders, and continued anticipation of bias and error sources.