The new study inducing all the fuss shows an association between higher levels of omega-3 in the blood at baseline, and the development of prostate cancer during the study follow-up. However, those who went on to develop prostate cancer also had higher PSA levels at baseline, were more educated, and were more likely to have first degree relatives with prostate cancer. If any of these caused these men to increase their intake of omega-3s as a protective measure, the study could be evidence of causality opposite the claimed direction: Perhaps risk for prostate cancer, real or perceived, increased intake of omega-3s, rather than the other way around.
I was still in the reading and contemplation phase of my planned post on the fish oil and prostate cancer brouhaha (but not yet to the writing phase), when I came across this Huffington Post article “Fish Tales and Prostate Cancer” by Dr. David Katz. I thought, “Yes. Exactly.”
This is not an easy issue. The study, partly conducted via Seattle’s own Fred Hutchinson Cancer Research Center, was not the most well-constructed of studies, at least in terms of measuring the association between fish oil intake and prostate cancer (the base study looked at other things, too, and it may have been perfectly well constructed for those hypotheses, I haven’t read those research papers yet). The authors admit that the results, which suggest that fish oil intake is associated with a higher risk of prostate cancer, don’t make sense. Yet I watched an interview where one of the lead researchers said he feels confident that men of a certain age shouldn’t take fish oil. I, myself, don’t feel that confident.
If you are concerned, or at least interested, in this issue, I encourage you to read Dr. Katz’s well-reasoned article. I enjoyed all of it, but this paragraph in particular jumped out at me:
One might ask, is the dog wagging the tail, or is the tale wagging the dog? This makes me think of the current growing debate about whether obesity contributes to type 2 diabetes, or type 2 diabetes contributes to obesity.
In other news, yesterday I saw news of a very small study in Denmark indicating that the resveratrol in red wine may undo the benefits of cardiovascular exercise. In case you never made it past the headlines before shrieking and flinging your glass of red wine to the ground, keep this in mind: It was a very small study, it only involved men (average age = 65), and it specifically looked at resveratrol supplements. Not actual red wine
The takeaway: More and more studies are showing that supplements just don’t stack up to real food. In this case, it may be that ingesting too many antioxidants is as bad as not getting enough antioxidants. In other words, it’s important to get enough of a good thing, but more is not necessarily better. And then there’s the whole synergy thing. Who knows what compounds in red wine work in concert with resveratrol to produce health benefits. It’s know that ethanol (alcohol) itself, in moderation, is associated with better cardiovascular health in individuals for whom alcohol use is not contraindicated for other reasons.
Unless you have a known deficiency that can’t be corrected through food alone, I think the safe bet is always endeavor to get your nutrients from real foods.