We know that nutrition research is less than ideal, by design. People living in the free world resist being confined to existing in a room with strangers, away from family and friends, for months on end to eat severely restricted diets in order to provide linear nutrition research results. I understand.
Below are comments on the recent omega-3 and prostate cancer study from Ohio State Univ and Fred Hutch Cancer Research Centers (Brasky TM, et al. JNCI, 2013):
- If long-chain (LC) omega-3s increased prostate cancer, wouldn’t we have more prostate cancer in countries that for centuries have eaten a lot of fish? We don’t.
- The LC omega-3 level in men with no cancer was 4.5% and in men with cancer was 4.7%. In a study designed to evaluate omega-3 nutrients and prostate cancer risk (which this study was not), a positive association with omega-3 is highly unlikely.
- The investigators measured plasma levels. Plasma levels change quickly, dependent on diet, and do not reflect consumption over the long-term (in example, this is like measuring someone’s blood sugar level and associating the one reading with disease risk – not good).
- In fact, early studies showed lower risk of prostate cancer in men who had higher levels of omega-3s from fish.
- It’s interesting that the press mentioned omega-6 levels in a positive light when the associations were not significant.
- We don’t know if the source of the omega-3, from fish or supplements. We absorb the omega-3s from supplements as well as we do from fish, but there are many other beneficial nutrients in fish, and sometimes there are some with fish oil supplements.
- This study also reported more cancer among non-smokers; this one finding contradicts nearly all that we know about cancer and smoking.
I defer to perspective and wisdom here.
Thank you, colleagues and friends, for seeking my thoughts.