Fish-eating linked with a reduced risk of death from prostate cancer

Prostate cancer is the most common form of cancer in men in the Western world. However, many of these cancers are slow growing, and do not prove to be fatal. Many men, actually, will die with prostate cancer that never showed itself when they were alive. However, prostate cancer can and does kill with enough frequency to take this condition very seriously. And some men may want to do what they can to reduce the risk of developing this condition and ultimately succumbing to it.

I was interested to read a study published yesterday which assessed the relationship between one dietary factor – fish eating – and prostate cancer risk. There has been previous evidence linking higher fish consumption with lower prostate cancer risk. This latest study was a ‘meta-analysis’ of relevant studies (an amassing together of available data from more than one study) [1].

This review of the evidence did NOT find an association between fish consumption and risk of prostate cancer. However, and perhaps crucially, it DID find that higher fish consumption was associated with a reduced risk of death from prostate cancer. Overall, the protective effect associated with fish consumption was 63 per cent (a lot).

This finding is interesting and potentially relevant as one could argue that where prostate cancer is concerned, it is more important to reduce the risk of death of this condition rather than reduce more the incidence of this cancer. As mentioned above, a significant percentage of men will get the disease but not die from it. The suggestion is that higher fish consumption might protect against more aggressive tumours that are more likely to prove fatal.

Now, so-called ‘epidemiologica’l studies of this nature can only really be used to judge associations between things. They cannot be used to confirm ‘causality’ – in this case, the eating fish causes a reduced risk of prostate cancer. However, if the link does turn out to be causal, how might eating fish exert its protective effect?

Some species of fish (so-called ‘oily fish’, such as mackerel, herring, sardine, trout and salmon) contain an abundance of ‘omega-3’ fats, principally in the form of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). As the authors of the review point out, these fats have an anti-inflammatory effect within the body. The relevance of this is that inflammation is a potential underlying factor in the development of cancer, along with other pathogenic processes that can go alongside it such as cell proliferation and angiogenesis (the production of new blood vessels that can ‘feed’ cancer).

The authors also point to research which has found that in animal studies, omega-3 fats have some capacity to reduce the progression of cancer cells.

We don’t have all the answers regarding omega-3 and cancer, including prostate cancer. However, the fact that omega-3 fats have known anti-inflammatory effects helps explain their links with not just a reduced risk of cancer, but a reduced risk of other conditions including heart disease and dementia.

Another nutritional tactic worth considering to quell inflammation in the body is to cut back on carbohydrates that tend to disrupt blood sugar and insulin levels. For more on this, see here.

References:

1. Szymanski KM, et al. Fish consumption and prostate cancer risk: a review and meta-analysis. Am J Clin Nutr 15 September 2010 [epub ahead of print]

4 Responses to Fish-eating linked with a reduced risk of death from prostate cancer

  1. dennis 17 September 2010 at 12:36 am #

    Fish, at least wild fish from the sea, is the ultimate paleo food – nothing else compares apart possibly from wild game if one can get it. Everything else we normally eat – both plant and animal foods – has been farmed or otherwise modified by man. It is therefore not surprising that there are health benefits from wild fish. If one has to look in reductionist terms, yes it may be the omega 3′s which are beneficial – but perhaps it is more likely that it is just because our DNA is so well adapted to wild fish that it does not cause any inflammation. But all this is only applicable to wild fish and naturally farmed fish. It would be interesting to know if there is there is any distinction between wild and farmed fish – I bet the same result would not be observed for a diet with fish which has been intensively farmed with unnatural feed and more likely to cause inflammation.

  2. John 17 September 2010 at 4:06 pm #

    I don’t know if this may be linked to Professor Plant’s view that dairy products are heavily linked to prostate and breast cancers. Maybe the fish has some sort of protective effect from the milk growth factors.

  3. Jake 17 September 2010 at 6:57 pm #

    I believe one of the major functions of omega 3s is to neutralize the omega 6 fats that are highly inflammatory. This study confirms that prostate cancer is caused by inflammation.

    Many of the things you have outlined in the past to reduce inflammation will help prevent prostate cancer or many other cancers for that matter.

  4. dennis 19 September 2010 at 10:13 pm #

    Yes – and inflammation is caused by eating unnatural foods.

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