Herring and sardines are two types of fatty fish. As such, they derive a large percentage of calories, 50 percent or more, from fat. Some of this fat is in the form of omega-3 fatty acids, whose benefits include lowering triglyceride levels, blood pressure, and decreasing risk of abnormal heart beats, according to the American Heart Association, which recommends at least two servings of fatty fish per week. Both fish are good sources of protein and other nutrients, but certain key nutritional differences exist.
Vitamin D is a fat-soluble with hormone-like functions in the body. Its major role is in maintaining calcium balance. Calcium is necessary for strong bones. Additionally, vitamin D is important for proper immune function and blood pressure regulation. Sources include sunlight, fortified foods and animal products. Per 100 g, sardines contain nearly 200 international units, or IU, of vitamin D, which is about 30 percent of the daily recommended intake for adults. In contrast, herring does not contain vitamin D.
Calories, Fat and Cholesterol
Fish derive their calories from protein and from fat. As fatty fish, herring derive 65 percent of calories from fat. Per 100 g serving, which is equal to about 3.5 oz and contains 250 calories, herring contains about 18 g of fat and 100 mg of cholesterol. Sardines are lower in calories, derive fewer calories from fat, and contain less cholesterol. Per 100 g, sardines contain 185 calories, 10.5 g of fat, and roughly 60 mg of cholesterol. Sardines are therefore a better option if you are counting calories or watching cholesterol.
Vitamin B-12 is an essential water-soluble vitamin that plays a role in nerve tissue and blood cells. Deficiencies are common in older adults, notes the Linus Pauling Institute, and symptoms include anemia and memory loss. Adults should aim for 2.4 mcg per day of vitamin B-12. Sources include fortified foods, such as breakfast cereals and nutritional yeast, and animal products. Both sardines and herring are excellent sources of the vitamin. Per 100 g, sardines and herrings each contain about 9 mcg of B-12, or over 300 percent of the daily requirement. No health risks are associated with intakes of too much B-12.
Both sardines and herring are high in several other key nutrients. Sardines are higher in iron and calcium, though herring provide roughly 10 percent of the recommended intake of these minerals. Both are excellent sources of the mineral selenium, which functions as a free-radical scavenger, also known as an antioxidant, protecting your cells from the damage due to oxidative stress. Sardines contains nearly 1.4 mg of vitamin E, another antioxidant, while herring does not contain vitamin E. As mentioned, these fatty fish are rich in omega-3 fatty acids. Herring provides over 2 g per 100 g serving, while sardines offer over 1.2 g.