Prostate Cancer And Omega-3 Fats

Posted: 26/07/2013 in English, Paleo Diet, Science and stuff
Tags: , ,

by Robb Wolf (web)

Howdy folks!

This is going to be quick and likely full of type-o’s, I just want to get this posted and I’m not even going to pester Squatchy with a proof-read, so please accept it, warts and all. I’ve been hammering on the nutrition cert and the only way I get any work done on that is dropping off the map. Multi-tasking seems good for cortisol production and LOOKING busy, but not getting a damn thing done!

Ok, so lots of hub-bub about some recent papers implicating N-3 fats and increased prostate cancer risk. Here are two papers which largely cover the same material, which I will refer to here in a bit (serum fatty acids prostate cancer risk1plasma FAs and prostate cancer2). Luckily, some other folks have entered the fray, so I do not need to re-hash what type of study this is, and one of the main shortcomings of the research: this is correlation, not a demonstration of mechanistic causation. Check out this piece from which breaks all that down in a very accessible way. The main takeaway from this is typical of how the media runs wild with research: Headlines are saying fish oil gives you prostate cancer. As points out, even IF this is the case, the current batch of literature is not anywhere near sufficient to make that statement, just keep that in mind.

These papers involve a LOT of data analysis…I’m going to look a bit at some of the methodology that went into the fatty acid analysis, but this section from the Results section of paper 1 is worth looking at first:

“Table 1 gives baseline demographic and lifestyle characteristics of study cases and controls. Compared with controls, high-grade cases were significantly older and were more likely
to have been randomized to the finasteride treatment arm. Low-grade cases were less likely than controls to have a history of diabetes.”

I don’t have the time to go back trough this and re-crunch the data (perhaps a Denise Minger or Chris Masterjohn could tackle this?) to look at how these factors were addressed. What this is saying: the worst cancers happened in the oldest people, the less severe cancers occurred in people with less frequency of diabetes. We know age increases cancer risk, we also know insulin resistance and oxidative stress (like that seen in Type 2 DM) is a potent stimulus for endoderm derived epithelial cancers like those seen in breast, colon and prostate. So, I’m honestly scratching my head a bit about how these vectors were addressed in the whole picture. And again, as the piece from Examine makes clear, we do not know if elevated N-3 are: causing increased prostate cancer, a consequence OF prostate cancer, or simply correlative and have no dog in that fight at all. Given what we know about the effects of N-3′s (and N-6′s) and inflammation, oxidative stress and immune modulation, I’m not at all surprised if they do have some role in all this (be it positive or negative, depending on the situation) but these papers are at best preliminary work, necessitating more work.

Some thoughts and concerns in no particular order:

1-We do not seem to see the “negative” effects of N-3 consumption from whole foods. In fact consumption of N-3′s is called a “Cancer Reducing Diet” in other corners of the research world and interwebz. Again however, another correlative study.

2-Are additional N-3′s potentially harmful in a sick, inflamed, insulin resistant population? Seems a safe bet, and as to my point above, I’m not sure the researchers did a thorough job of accounting for those factors. Perhaps they did…I have not and will not have the time to crunch that data…hopefully someone else will. But this is a really important question.

3-It would appear no correlation with prostate cancer and saturated fats was found (sorry vegans). The headlines seem equally able to say “saturated fat does NOT increase prostate cancer risk.”

4-One thing that really concerns me is when the researchers were looking at trans fats (TFA’s) they lumped industrial, hydrogenated TFA’s in with those derived from the activity of ruminants, specifically the many isomers of conjugated linoleic acid (CLA). CLA has known anti-tumor activity, yet the researchers give it the same category as hydrogenated seed oils. CLA has been in our biosphere for a “looong time” and shows a variety of benefits…that the researchers missed this point makes me wonder a little about many other assumptions.

5-Is this the oxidative stress from rancid fish oil capsules? I never did get a sense from the literature how they delineated where the N-3 were coming from, but this could certainly be an issue. What the fish oil manufacturers do to mitigate this issue is add antioxidants like vitamin E to the capsules. But…all of these studies seem to implicate supplemental vitamin E as increasing cancer potential (beta carotene in smokers too).  Again, I’d really need to dig around in the data to see how or if any of this was accounted for.

6-The difference between the low vs high risk cancers seems to boil down to the equivalent of one vs 2 meals containing salmon per week. Is this a complete artifact of the data analysis? Only important in sick, inflamed individuals? We don’t know, but that seems an amazing razors edge to walk.

7-This whole story reminds me somewhat of the China Study. In that story, mice were fed casein protein, a piss-poor lab chow diet (already known to cause disease in our murine pals) and aflatoxin, a potent carcinogen. In other words, a diet completely divergent from what rodents would eat in the wold. Now, we wait and see what the cancer rates are in these critters relative to a low-protein control. What is reported is the high-protein group does not live as long, what is not reported, is the high protein group took longer to develop cancer, but once they did, it was off to the races. And from THIS we are told “animal protein causes cancer.” No, the aflatoxin caused the cancer, the protein intake protected against the cancer for a period of time but then when the critters HAD cancer, the higher protein intake appears to have accelerated the disease.

My point: How much does ANY of this have to do with “normal” healthy individuals? And by normal/healthy I’m talking about the tiny (but growing) percentage of people eating something that looks like a paleo diet, sleep well, exercise reasonably. What exactly do we get from looking at our population at large? I’d say one thing: Confused. Would this apply to the Okinawans? Kitavans?

Some take-aways

1-Reduce systemic inflammation (y’all know how), sleep, play, get sunlight, maintain your insulin sensitivity. These factors all seem to bode well for avoiding most cancers.

2-Supplement wisely, if at all. I made some pretty heavy handed fish oil recommendations in my book. I made those with the idea we could curb inflammation in sick, overweight people. I’d say my (and many other people’s) assumptions about that was/were wrong. I’ve had to modify recommendations down to the 2-4g level and have generally pushed getting as much of ones nutrition as possible from whole foods.

3-Maintain some perspective. For me life is about mitigating risks…trying to find the best ROI I can on happiness, meaningful work, etc. I’m pretty sure eating something akin to a paleo diet, smart exercise, community, lots of love are our best hedges against the unknowns of things like cancer. Is it a 100% “get out of Jail Free Card?” No, nothing is a guarantee, but there are better and worse bets.

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