 foods most Americans infrequently consume. In fact, a recent survey found almost half of all Americans eat little or no seafood. That's a problem because our bodies don't manufacture DHA or EPA on their own. For those reasons, sources estimate up to 90% of all Americans have dangerously low levels of omega-3s. Number two, multivitamins. Why? A multivitamin for your brain is the dietary equivalent of a garage for your car.