I have been trying a few things related to the Man the Fisher idea. The first is iodine. I eat virtually no salt and also no seafood, so it seemed like a good idea to try some iodine. I have been supplementing with it for about a month. I haven't noticed any huge improvements, but there doesn't seem to be any negative side effects.
Next up are the Trace Minerals shown above. The idea is that there are critical elements that can only be provided by marine foods. Again, no big improvements but no side effects either.
I look at these two supplements as insurance policies. If the historical Paleo diet was heavily dependent on marine food, then I'm covered.