Did you know about fatty versus lean fish?

I always thought all fish were similar. Well, I was wrong!

A recent Swedish study by Dr. Wolk and colleagues examined the impact of ingestion on fatty versus lean fish on the risk for Kidney cancer (renal cell carcinoma) in a cohort of 61,433 subjects. The study was published in JAMA (September 2006).

They found that fatty fish consumption was associated with reduced risk for renal cancer. However, there was no impact of lean fish or other seafood versus no consumption. Exclusion of the first two years of follow-up did not change the results.

Can you guess as to why the difference in outcome between the two kinds of fish? It is purely a matter of speculation at this time. It may be due to significant differences between lean and fatty fish in the content of omega-3 fatty acids and vitamin D. For example, fatty cold-water fish have up to a 20- to 30-times higher omega-3 polyunsaturated fatty acid, eicosapentaenoic acid, and docosahexanoic acid as compared to the lean fish. These are known to inhibit carcinogenesis. Similarly, low vitamin D levels have been linked to cancer development and the lean fish have lower vitamin D than their fatty counterparts.

Do you like or eat fish regularly? Do you consume fish more than red meat? Would the above report alter your eating habits?