Fatty Acids – more complex than we know…

My usual recommendation regarding fat in the diet is to consume a low fat diet. Seems logical, and in keeping with a great deal of research. For example, there are studies of men who completed dietary questions while being followed prospectively that have shown that “total fat consumption was directly related to risk of advanced prostate cancer…the association was due primarily to animal fat…” If you use Google Scholar and enter “low fat prostate”, you will see a page with 122,000 references, some of which show no effect of lo fat diets, but most of which claim that the low fat diets benefit mice at least, in terms of prostate cancer growth.

Then there is the observation that prostate cancer doesn’t take up much glucose, at least if we think about the relatively poor efficacy of FDG PET scans which rely on cancer cells taking up more glucose than normal cells. This relates directly to a question from a patient last week that I have heard over and over: I’m not eating any sugar, because sugar feeds cancer. In the first place, you can’t really change the glucose in your blood stream much by altering your sugar intake. Your brain relies exclusively on glucose to keep you alive, so your body fiercely defends the glucose level in a way that easily will nourish any cancer. Don’t eat any sugar at all, and your body will break down fat and muscle and make its own glucose to keep the brain alive.

So, what stimulated this blog was a report this morning in my ASCO news flash that refers to an article in the American Journal of Epidemiology. In it, researchers looking at more than 3400 men found that high levels of omega-3 fatty acids, the ones we all think are great for preventing heart disease, might produce an increased risk for developing aggressive prostate cancer. I haven’t had the time to look at the original article, but in the news report one of the authors states that he was “stunned”. Nothing stuns me anymore when it comes to dietary manipulations and findings of epidemiologists. I think our diets and bodies are so complex that it is really difficult to draw conclusions from large studies like this. Nevertheless, I DO continue to think that prostate cancer may be somewhat different from other cancers in lipid metabolism, and with some of the funds donated to us, I am supporting a research post-doctoral fellow to continue investigating this hypothesis in the lab. Stay tuned….and for now, don’t snarf down too many chicken macnuggets !