There is now a growing, and consistent body of evidence that eating fish has a memory-protective effect but how much fish should you eat and what's in fish that makes the difference? In an earlier Hoordaland Health study the best memory and cognition results occurred in those eating 75 grams of fish a day - a small serving that would fit in the palm of your hand. While it's often assumed that the reason is the omega 3 content of fish an analysis of all studies to date show that there's a more consistent association between eating fish per se and improved memory that between omega 3 intake and memory. Fish is also a good source of niacin, phospholipids, vitamin B12, vitamin D, selenium, zinc, iodine and taurine, all of which could potentially protect the brain from age-related memory decline. Omega 3 fats in fish provide both DHA, an essentially structural fat for the brain, and EPA, which is known to enhance mood.Both reduce oxidative stress and inflammation, two processes associated with dementia and Alzheimer's. Personally, I hedge my bets and both supplement omega 3s daily and eat fish three to four times a week. So, if you want to preserve your marbles make a cow happy - eat a fish today.