Fresh tuna is a rich source of lean protein, omega-3 fatty acids and a wide variety of vitamins and minerals. A diet with a high intake of these nutrients can benefit your health by enhancing the function of your organs and by possibly lowering your risk of chronic medical conditions. According to the Monterey Bay Aquarium Seafood Watch, the safest, healthiest and most environmentally-friendly fresh tuna choice is albacore tuna that has been troll- or pole-caught in U.S. Pacific waters.