The health benefits of sardines include the prevention of heart diseases, and age-related macular degeneration. They also help strengthen bones, boost the immune system, improve insulin resistance, and rejuvenate the skin.
What are Sardines?
Sardines are small, oily fish that belong to the family called Clupeidae. They are also known by the name pilchards in some places. They generally come in the form of canned fish and are commonly known as canned sardines. Although they are regarded as a single species, there are actually 21 types of fish that fall under the category of sardine.
The most popular species of sardines include Sardina, Sardinops, sardinella, and dussumieria. These fish are found mostly in the Atlantic and Pacific oceans, as well as in the Mediterranean Sea. According to a report, in the past, they were the most harvested fish around the world. 
Sardines were one of the easiest fish to obtain and they were known to man for a few millennia. However, they rose to popularity during the early 18th century in Europe after the introduction of the canned version. The craze of eating these fish slowly crept to America as well, where they became very popular by the late 19th and early 20th century. The concept of canned fish became an instant hit in the United States. People actually found it to be one of the best ways to store food.
Nutritional Value of Sardines
According to USDA, fish oil made from sardines contain energy and fats.  Vitamins include thiamin, riboflavin, niacin, vitamin B6, folate, vitamin B12, vitamin A, vitamin D, vitamin E, and vitamin K. The fatty acids found in them include total saturated fats, monounsaturated fats, polyunsaturated fats, and cholesterol. These fatty acids, vitamins, and trace mineral elements help in the prevention of many diseases and promote overall health.
Health Benefits of Sardines
The presence of macro and micro-nutrients, in these fish, without having a high-fat content makes them very useful for our body. Below are some of its most important benefits.
Prevention of Heart Diseases
Sardines are rich in omega-3 fatty acids, which are helpful in preventing heart diseases. Research by the Department of Food Science and Nutrition, University of Minnesota has shown that omega-3 fatty acids such as EPA (Eicosapentaenoic acid) and DHA (Docosahexaenoic acid) break down bad or LDL cholesterol in the body and thus help in preventing heart diseases. 
Omega-3 fatty acids are also known to break down arterial plaque, which blocks arteries and increases blood pressure. By clearing the plaque, these fatty acids help in controlling blood pressure as well.
Reduction in Blood Clots
Blood clots in the arteries can be dangerous for the cardiovascular system.  Regular intake of omega-3 fats found in fish like sardines is good for the heart because it helps in reducing cholesterol and blood pressure, thereby preventing stroke and atherosclerosis.
Reduced Risk of Macular Degeneration
A fact sheet released by the National Eye Institute (NEI) says that age-related macular degeneration (AMD) is a condition which is usually seen among people aged 50 or more.  Macular and retinal degeneration over the years results in loss of vision. Both NEI and the European Journal of Clinical Nutrition suggest that fish like sardines results in a reduced risk of developing AMD.  
A cancer research report published by Dr. Powel Brown and Dr. Corey Speers in the Journal of the National Cancer Institute, has shown that the intake of calcium and vitamin D can be very helpful in preventing certain types of cancers like breast cancer.  Sardines are one of the best sources of calcium and vitamin D. However, more research and clinical trials are required.
Sardines are a good source of calcium, and regular calcium helps in strengthening bones. A good amount of calcium, coupled with exercisecan strengthen bones and prevent diseases such as osteoporosis.
Healthy Immune System
Consuming sardines can help in building up the immune system. Research by The Journal of Nutrition suggests that sardine fish oil may improve the immune system by increasing the count of immune cells. 
The fats found in sardines play an essential role at the cellular level in skin cells. The book “Forever Young: The Science of Nutrigenomics for Glowing, Wrinkle-Free Skin and Radiant Health at Every Age” by Dr. Nicholas Perricone says that sardines (cold water fish) help in giving you a radiant skin. 
Insulin resistance is one of the major factors to look for in diabetes. In cases where there is insulin resistance, the insulin produced in the body is utilized less efficiently. This, in turn, means that there is more glucose in the blood than there usually should be. Studies have shown that insulin resistance can be reduced by consuming sardines, as the protein found in them is more effective in reducing insulin resistance as compared to casein protein.
Sardines contain selenium, which is helpful in neutralizing free radicals and protecting organs from damage. 
How to Buy & Store Sardines?
Sardines are available in many varieties and are cheap compared to some other fishes. They are best when consumed fresh. Canned ones come in a variety of flavors, such as mustard flavor, seasoned with sauce, with or without salt, and other versions and should be stored in a cool place. Depending on the taste, people make their own choice. Please do check the expiry date on the can.
Sardines can be baked or cooked quite easily and can be served as a main dish, a side dish, and can even be added to salads.
Fresh sardines can be prepared by applying a mixture of your favorite spices such as pepper, salt, garlic, lemon juice, condiments, and flavoring agents to the fresh sardines, which can then be grilled or barbecued.
Sardine and vegetable salad is yet another simple Greek recipe. Take sardines and sauté them in olive oil for a few minutes. Cut small pieces of tomato, cucumber, olives, and feta and add them to the sautéd sardines. Add lemon, vinegar, salt, and pepper, and sprinkle parsleyon the salad.