Do you dine on salmon regularly? Do you grab walnuts when you need a snack? Does your bread include flax seeds? If you answered yes to any – or all – of these questions, you may be protecting your brain from Alzheimer’s disease.

A new study out of Columbia University’s Taub Institute for Research in Alzheimer’s disease and the Aging Brain has found that omega-3 fatty acids may guard against this terrible disease. This research follows previous studies that found a possible association between diet and a lower risk of dementia, although scientists don’t understand what’s behind these findings

According to MedlinePlus, the Taub researchers looked at data from approximately 1,200 dementia-free participants who were over the age of 65. This group was asked to keep a record of what they ate for a year with a focus on 10 specific nutrients in foods that had been identified in previous research on brain healthy. These 10 nutrients were saturated fatty acids, omega-3 fatty acids, omega-6 fatty acids, mono-unsaturated fatty acids, vitamin E, vitamin C, beta carotene, vitamin B-12, folate and vitamin D.

At the end of the study, participants underwent blood tests to check the level of a key protein associated with Alzheimer’s.  The researchers found that participants who had consumed the highest amount of omega-3 fatty acids had the lowest amount of beta amyloid levels in their blood. The researchers noted that this finding held steady, no matter what the participant’s age, gender, ethnicity or educational background was.

So what exactly are omega-3 fatty acids? “Omega-3 fatty acids (also known as n-3 fatty acids) are polyunsaturated fatty acids that are essential nutrients for health,” wrote Dr. Frank Sacks, professor of cardiovascular disease prevention in Harvard School of Public Health’s Department of Nutrition. “We need omega-3 fatty acids for numerous normal body functions, such as controlling blood clotting and building cell membranes in the brain, and since our bodies cannot make omega-3 fats, we must get them through food.” There are two major types of this fatty acid. The first is alpha-linolenic acid (ALA), which is found in some vegetable oils and vegetables. The second type, which is found in fatty fish, contains eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Scientists do not know whether one type of omega-3 fatty acid is better than another, so you should try to eat both types.

So which foods have the most fatty acids? The George Mateljan Foundation reports that the highest concentration of omega-3 fats are in flax seeds (two tablespoons have 132.9 percent of the daily recommended value) and walnuts (one-quarter-cup has approximately 95 percent of the recommended daily value). Other very good sources of omega 3 fatty acids are salmon (a 4-ounce serving has 61 percent of the recommended daily value) and sardines (a 3.2-ounce serving has more than 55 percent of the recommended daily value).