Sardines, or pilchards, are common names used to refer to various small, oily fish within the herring family of Clupeidae. The term sardine was first used in English during the early 15th century and may come from the Mediterranean island of Sardinia, around which sardines were once abundant. Sardines are rich in vitamins and minerals. A small serving of sardines once a day can provide 13 percent of vitamin B2; roughly one-quarter of niacin; and about 150 percent of the recommended daily value of vitamin B12. All B vitamins help to support proper nervous system function and are used for energy metabolism, or converting food into energy. Also, sardines are high in the major minerals such as phosphorus, calcium, potassium, and some trace minerals like iron and selenium. Sardines are also a natural source of marine omega-3 fatty acids, which reduce the occurrence of cardiovascular disease. Recent studies suggest that regular consumption of omega-3 fatty acids reduces the likelihood of developing Alzheimer's disease. These fatty acids may also help lower blood sugar levels a small amount. They are also a good source of vitamin D, calcium, vitamin B12, and protein.