Something smell fishy?  Probably isn't your breath if you've been taking your omega-3s.  Docosahexaenoic acid (DHA), a fatty acid found in algae and cold-water fish like salmon may help fight gum disease, according to new research from the Harvard School of Public Health.  The five-year study of nearly 10,000 adults showed people who regularly consumed polyunsaturated fatty acids were up to 20 percent less likely to have periodontitis, a condition when microorganisms in the mouth cause tooth loss, gum swelling, receding and bleeding-even heart disease and stroke.