Shellfish include any sea-creature that has its skeleton on the outside – oysters, clams, lobster, shrimp, scallops, crabs and others. Shellfish are a good source of omega-3 polyunsaturated fatty acids that are associated with reduced inflammation, heart disease, and certain cancers. Studies also suggest that shellfish may reduce age-related eye diseases, such as retinopathy and macular degeneration. Latest research showed that omega-3 fats are important for cognitive function, especially in children (see more). Additionally shellfish may lower elevated blood pressure. Shellfish are low in total fats compare to animal protein, and has fewer calories, ounce-for-ounce, than other sources of animal protein. Furthermore shellfish, same as in animal proteins, are high in vitamin B12, which were shown to be extremely low in the elderly population. Vitamin B12 is known for its heart protective benefits.