HOME
Dubious Link Between High Fat Diet And Risk Of Prostate Cancer?
In an article dated 16 July 2010 Medical News Today carried a report of a study which purported to show a link between a high-fat diet and prostate cancer.
Prostate cancer is an important cancer becuase it is the second leading cause of cancer-related deaths in men with an estimated 192,280 new cases diagnosed in the US in 2009 (1). Like many cancers, diet is considered one of the most important controllable risk factors for all the conditions that affect the prostate gland, including benign prostatic hyperplsia (BPH), prostatitis, and prostate cancer.
Sanjay Gupta, MS, PhD, Carter Kissell associate professor and research director in the Department of Urology and associate professor in the Department of Nutrition in the Case Western Reserve School of Medicine, and his team of post-doctoral fellows had previously demonstrated that nuclear factor kappa B (NF-B), a protein complex that controls DNA transcription which is activated as a result of inflammation and stress, is related to tumour progression (2) In the latest study, "High Fat Diet Increases NF-B Signaling in the Prostate of Reporter Mice", whose abstract is below, focused on the mechanisms by which a high fat diet might harm the prostate. They demonstrate that a high fat diet results in activation of NF-B in the abdominal cavity, thymus, spleen, and prostate.
Non obese NF-B reporter mice were fed a high fat diet for four, eight, and 12 weeks. Compared with mice fed a regular diet, the high fat diet group had significant increases in prostate weight, and in the prostate expression of markers of oxidative stress (such as NADPH), and inflammation (such as the downstream targets of NF-B: nitric oxide synthase, and cyclooxygenase [COX-2]) were increased. These studies, they say, provide direct evidence that a high fat diet causes proliferation, inflammation, and oxidative stress that can lead to benign prostatic hyperplasia, prostatitis, and cancer of the prostate. Dr. Gupta stated at interview that this study strengthens the possible 'link between a high-fat diet — typical of "Western style" high fat diet — as a potential cause of prostatic diseases including BPH and prostate cancer'.
But does it?
Firstly, this study was conducted on mice, not on humans. I am always wary of extrapolating the effects of diet in one species to another species, as the natural diets to which each are adapted can be quite different. Do mice naturally get prostate cancer? If they do (I suspect they don't), is the fat in their natural diet the cause?
The second concern I have about this study lies in the phrase used by Dr Gupta: ' Western style high fat diet'. The reason I am concerned about this is that all high-fat diets tend to be tarred with the same brush: A high-fat diet is a high-fat diet no matter which fats are in it, and this can be, and usually is, highly misleading. There is a huge difference as far as health and cancer are concerned, between the natural fats which we (and mice) are adapted to, and the modern, unnatural, processed commercial fats which western diets are composed of.
I think it extremely likely that 'Western style' fats are harmful; there is a wealth of evidence that they are. But so are low-fat diets. It is important to make these distinctions.
So has this study any value? In my estimation, if you are eating a natural high-fat diet, No!
Vykhovanets EV, Shankar E, Vykhovanets OV, Shukla S, Gupta S. High-fat diet increases NF-kappaB signaling in the prostate of reporter mice. Prostate. 2010 Jul 14. [Epub ahead of print] Department of Urology, Case Western Reserve University & University Hospitals Case Medical Center, Cleveland, Ohio. AbstractBACKGROUND: High-fat diet (HFD) is considered as a major risk factor for benign prostatic diseases and cancer in the Western world. Studies have shown an association between oxidative stress and prostatic diseases. NF-kappaB has been implicated in stress response and is deregulated in prostrate disorders; therefore, we sought to determine whether HFD could induce oxidative stress in the prostate which could contribute to prostatic diseases. METHODS: Transgenic NF-kappaB-Luc-Tag mice were either fed with regular diet (RD) or HFD for 12 weeks. Serial, non-invasive molecular imaging was performed to study NF-kappaB activation in the whole body, and in various organs including thymus, spleen, and prostate. Western blotting was used to determine the expression of NF-kappaB, its upstream and downstream targets in the prostate. RESULTS: Twofold increase in whole body NF-kappaB activity in vivo and two to threefold upregulated prostate NF-kappaB activity ex vivo were observed after HFD intake compared with RD controls. HFD-induced NF-kappaB activity was elevated remarkably in the abdominal cavity, thymus, spleen, and prostate with increase in prostrate weight. In the prostrate, an increase in the protein expression of gp91(phox), p22(phox), and p47(phox) NADPH oxidase subunits was observed suggesting the involvement of HFD in causing oxidative stress. Nuclear extracts from the prostrate tissue showed an increased expression of p65/RelA that corresponded with elevated cytosolic levels of p-IkappaBalpha, along with increased expression of downstream targets of NF-kappaB, nitric oxide synthase, and cyclooxygenase-2. CONCLUSIONS: Our findings suggest that HFD-mediated oxidative stress and deregulation of NADPH oxidase leads to NF-kappaB activation in the prostrate. Prostate (c) 2010 Wiley-Liss, Inc. |
References
1. Jemal A, Siegel R, Ward E, Hao Y, Xu J, Thun MJ. Cancer statistics, 2009. CA Cancer J Clin. 2009; ;59(4):225-49.
2. Shukla S, MacLennan GT, Fu P, Patel J, Marengo SR, Resnick MI, Gupta S. Nuclear factor-kappaB/p65 (Rel A) is constitutively activated in human prostate adenocarcinoma and correlates with disease progression. Neoplasia. 2004; 6(4):390-400.
Last updated 17 July 2010
Related Articles
