The scientific work
The study developed by Dr. Theodore M. Brasky, of the Fred Hutchinson Cancer Research Center in Seattle, in fact, gives no information on the importance of omega-3 dietary supplements or as the onset of prostate cancer. The same authors are very clear on this. Their research measured levels of various types of lipids in the blood of a subgroup of patients in the Prostate Cancer Prevention Trial, a large multicenter study, which lasted seven years and led to 18,800 people, designed to evaluate the effectiveness of fenestaride in preventing prostate cancer.
The data of blood tests
Dr. Brasky and his colleagues used blood samples taken during the seven years of 1.658 subjects in which the end of the study had been diagnosed with prostate cancer and 1800 controls whose cancer had not developed. In these 1658 patients with prostate cancer the authors have found that cancer of small degree (the majority of cases, which 1533 patients) there was no correlation between type of lipids present in serum and onset of prostate cancer. In subjects with a high prostate cancer grade, that is very advanced and aggressive (a minority, to be exact, 125 subjects) have noted with considerable surprise that these people had blood drawn at baseline, that is when they were not affected by tumor, a high level of DHA and a low level of trans fatty acids. Based on this evidence, the authors have calculated the weight of these two parameters in terms of increased risk of developing high prostate cancer grade.
The study did not include the intake of omega-3
As stated by the authors, this association has not been completely combined with a nutritional assessments. In fact, the study questionnaires to assess the diet of the subjects were not given and also the intake of omega-3 has not been evaluated. Among other things, the data relates only to DHA and not to EPA, which usually rises more in patients taking large amounts of fish or omega-3. What has particularly surprised the authors of the paper is that the anti-inflammatory action of DHA does not seem useful in preventing prostate cancer and that proinflammatory action of trans fatty acids appear to reduce the risk of aggressive prostate cancer. The same authors pointed out that the importance of taking omega-3 fatty acids and reduce those trans fatty acids have a fundamental value in the prevention of cardiovascular disease and therefore, their data, which also concerns a small number of cases does not alter the significance of this nutritional strategy, much more important in terms of public health.
Studies on omega-3
The authors also point out that many previous studies have found that intake of fish or omega-3 improves survival in patients with prostate cancer (Szymanski - 2010) and as research has demonstrated a reduction of metastasis of cancer prostate by the administration of omega-3. The same authors in a study that has yet to be published have found no increased risk of prostate cancer in subjects taking high-dose supplementation with omega-3 (Brasky TM, Kristal AR, Navarro SL, et al. - Specialty Supplements prostate cancer risk in the Vitamins and Lifestyle (VITAL) cohort. Nutr Cancer. In press - for now you can not read all but the study is cited by the authors in the work in question).
This evidence alone dampens any consideration on the use of omega-3 and risk of prostate cancer.
Other scientific works on omega-3 anti-inflammatory and anti-cancer action
On this view, previous studies have already shown that intake of polyunsaturated fatty acids omega-3 does not increase the risk of prostate cancer (Leitzman - 2004) and that large quantities of fat fish in the diet lowers the risk of prostate cancer (Terry - 2001); for an overview on the subject, the work of MacLean et al. published in JAMA in 2006 is interesting.
The conclusions of Prof. Scapagnini
The main message of the work consists in pointing out the role of lipids can be much more complex than we imagine in the regulation of pathological processes. It's important to note that the increase in the blood serum of DHA found in subjects who developed prostate cancer is not necessarily linked to their diet (genetic polymorphisms? environmental variations?) and there are still a lot of information to correctly interpret what has been shown in study .
These conclusions are necessary to contradict what was written in the article published on the science page of the newspaper “Il Giornale” entitled "Omega-3, a trend that could cause harm to health", which referred to the scientific work of Dr. Brasky. In general, the article on "Il Giornale" is misleading and not in line with the data from the study that inspired the above article.