Sardines are high in protein and fats (including omega-3) and do not contain sugars.
Avoid canned fish in flavored brines which might contain high FODMAP ingredients like Fructans.
Sardines are rich in vitamins and minerals. A small serving of sardines once a day can provide 13% of vitamin B2; roughly one-quarter of niacin; and about 150% 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, and potassium, and some trace minerals including iron and selenium.
Sardines are also a natural source of marine omega-3 fatty acids, which may reduce the occurrence of cardiovascular disease. Regular consumption of omega-3 fatty acids may reduce the likelihood of developing Alzheimer's disease. These fatty acids can also lower blood sugar levels. They are also a good source of vitamin D, calcium, vitamin B12, and protein.
Because they are low in the food chain, sardines are very low in contaminants, such as mercury, relative to other fish commonly eaten by humans.