Health Risks of Eating Sardines

A can of sardines provides more than your total daily requirements for vitamin B12.
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The Food and Drug Administration recommends eating fish at least twice a week for optimal health. With growing concerns about toxins in the oceans, it's good to know that sardines are the safest choice of fish to eat. An added bonus is their wealth of nutrients, such as omega-3 fatty acids that contribute to sardines' health benefits, ranging from reducing inflammation, enhancing bone health and fighting depression.


Sardines can be a nutritious addition to your diet with health benefits that far outweigh any risks, even for pregnant women.

What Are Sardines?

Sardines, also referred to as pilchard or herring, are a type of small, silver-colored, oily fish that belongs to the Clupeidae family. Sardines were originally found in great abundance around the island of Sardinia, and now they thrive all over the world in the Mediterranean, Atlantic and Pacific oceans.

Sardines are larger than anchovies and can grow up to 7.9 inches in length. The flesh of sardines is white, and the fish has a slightly protruding lower jaw. With more than 20 varieties of fish that fall under the category of sardine, the most popular species include Sardina, Sardinops, sardinella and dussumieria.

Sardines Nutrition and Macronutrients

Sardines contain 191 calories per 3.75-ounce can, weighing 92 grams. The caloric ratio is split 50/50 with fats and protein. Supplying 45 percent of your recommended intake, a can of sardines is a good source of protein that provides the resources needed for the healthy functioning of your body.

Of the total fat content —10.5 grams, sardines contain mostly mono- and polyunsaturated fats, which include healthy omega-3 fatty acids. Sardines do not contain any carbohydrates.

The downside of eating sardines is their high cholesterol content — 131 milligrams or 44 percent daily value (DV) per can. Although Dietary Guidelines does not list a quantitative limit, they recommend people should eat as little dietary cholesterol as possible. The American Heart Association warns that high cholesterol is a risk factor for heart disease, heart attack and stroke.

Fresh Versus Canned Sardines

Both fresh and canned sardines provide similar nutritional benefits. Sardines can be grilled, pickled, salted or smoked, but fresh sardines are very perishable so most sardines are sold as canned for longer storage.

Sardines packed in water or olive oil are a healthier choice than those in soybean oil or other types of refined oils. Often flavoring is added, such as tomato or mustard sauce, which could add calories.

Canned Sardines' Health Risks

The only potential health risk of eating sardines may not come from the fish itself, but the can it's in. Cans can contain a toxic chemical, bisphenol A, known as BPA.

Despite concerns about its link to obesity, diabetes, heart disease and cancer, BPA is still used in food cans in America. According to the Center for Environmental Health (CEH), USDA warns that toxins in can linings can migrate to the food inside.

In the CEH study in 2017, 38 percent of cans tested used BPA, and another 19 percent contained toxic PVC in the linings. Lab studies found BPA exposure may cause reproductive disorders, genetic damage and possibly increase the risk of breast cancer.

Concern About Sardines' Mercury Content

Mercury is a heavy metal found in the form of methyl mercury in fish in varying amounts. The mercury originates from many sources, including the natural environment such as volcanic activity, or from pollutants from industrial activities. Large predator fish that are at the top of the food chain typically contain the highest levels of mercury accumulation.

Dietary Guidelines list sardines as one of the best fish choices lowest in methyl mercury content. The reason is that sardines are small and only eat plankton and not mercury-contaminated fish_._ They are short-lived, so mercury does not have time to build up in their flesh.

The Food and Drug Administration (FDA) recognizes the health benefits of eating fish, especially for pregnant women and young children. The FDA recommends a weekly intake of two to three servings of sardines, or 8 to 12 ounces for adults and 4 to 6 ounces for children age 4 to 7.

Omega-3 Fatty Acid Content

Fish is best known for its health benefits from its fatty-acid content. All types of sardines are oily fish and an excellent source of polyunsaturated omega-3 fatty acids. Per can, sardines packed in oil contain 1,362 milligrams of omega-3 fatty acids.

Of the omega-3 fatty acids in sardines, there are two dominant types: EPA, vital for the health of your heart, inflammatory and immune system; and DHA, required for the development of your brain, eyes and nervous system.

Read more: 17 Reasons Why You Probably Need More Omega-3s in Your Diet

Sardines for a Healthy Heart

Omega-3 fatty acid is a vital nutrient for reducing inflammation and your risk of dying from heart disease. Eating a can of sardines may lower your blood pressure, decrease triglycerides, reduce irregular heartbeats and slow the growth rate of atherosclerotic plaque, according to the Mayo Clinic.

Stroke is the number one cause of long-term disability and death in the U.S. Stroke can result from atherosclerosis, which could limit the flow of oxygen-rich blood to your heart and brain.

Results of three large cohorts in 2017, published by the American Heart Association's publication Stroke, found the group that was administered omega DHA had a reduction in the overall risk of stroke after an eight to 11-year follow-up.

Improve Your Mood

Eating sardines may help banish your feelings of depression. Your brain is 60 percent fat, and the 4.7 grams of healthy polyunsaturated fats in a can of sardines play an important role in normal brain function. Polyunsaturated fats are proven to have an association with many mood disorders.

A French study, published in Frontier in Physiology in 2018, found that low levels of omega-3 fatty acids had a negative effect on mood-related behavior, such as anxiety and depression. Findings suggested that polyunsaturated fats may be beneficial in the treatment of neuropsychiatric disorders.

Another controlled trial, published in Psychiatry Research in 2015, examined the association of omega-3 and depression on a group of undergraduates and found those who received omega-3 fatty acid had a 67 percent reduction in symptoms of depression after 21 days.

Boost Your Vitamin B12 Level

Another one of sardines health benefits is its high vitamin B12 content. One can of sardines provides a whopping 137 percent of your daily vitamin B12 requirement. Your body uses vitamin B12 for many functions, including making DNA, nerve and brain function and blood cell formation.

Vitamin B12 deficiency affects between 1.5 and 15 percent of people, especially among those who don't eat meat. A deficiency in vitamin B12 can cause symptoms including chronic fatigue, loss of appetite, constipation, nerve damage, impaired mental function and anemia.

Vitamin B12 is also important during pregnancy. A deficiency in women may cause problems in babies, including impaired movement and delays in typical developmental milestones, warns the National Institutes of Health.

Read more: Vitamin B12 Benefits & Side Effects

Selenium in Sardines

Selenium is a trace mineral that helps regulate metabolism and is important for DNA production and thyroid gland function. One can of sardines in oil provides 48.5 micrograms, or 69 percent of, your DV.

A report published in StatPearls in 2019, says a deficiency in selenium has been linked to cardiovascular disease, thyroid impairment, decreased immune function, hormonal imbalances, reproductive problems, deformity of bones, muscle weakness and mood disorders.

Protection for Your Bones

Each can of sardines provides a good source of four minerals essential for improving and maintaining bone density. These are:

With 85 percent of your body's phosphorus found in your bones as calcium phosphate, a deficiency of these minerals can cause serious bone disease. Getting too little potassium can deplete calcium in your bones, according to Institutes of Health.

About 50 to 60 percent of magnesium in your body resides in your bones. Magnesium can increase bone density and may reduce the risk of osteoporosis in women after menopause, says NIH. Other nutrients found in sardines that benefit your bones are copper, iron, zinc and vitamin D, according to American Bone Health.

Read more: What Is Healthy Bone Mass?

Benefits From B Vitamins

Sardines' nutrition includes B vitamins that help turn the food you eat into energy for proper functioning of heart, nerves, brain, muscles and blood cells. Each 3.75 ounce can of sardines contain most of the B vitamins including:

  • Niacin: 4.8 milligrams, 24 percent DV
  • Riboflavin: 0.2 milligrams, 12 percent DV
  • Vitamin B6: 0.2 milligrams, 8 percent DV
  • Pantothenic acid: 0.6 milligrams, 6 percent DV
  • Thiamine: 0.1 milligram, 5 percent DV
  • Folate: 11 micrograms, 3 percent DV
  • Vitamin B12: 8.2 micrograms, 137 percent DV

Read more: What Is the Function of Vitamin B Within the Human Body?

Antioxidants for Your Immune System

In addition to the antioxidant properties in omega-3, some other important nutrients in sardines also act as antioxidants that boost your immunity to help ward off disease. Antioxidants minimize free-radical damage. Free radicals are compounds that are byproducts of normal metabolic functions or introduced by the environment, such as by exposure to pollution.

The vitamins in sardines that act as antioxidants are vitamin E, vitamin A and riboflavin (vitamin B2). Minerals in sardines that function as antioxidants are copper, magnesium, zinc and selenium. A 2018 study, published in Frontiers in Pharmacology, concluded that antioxidants may have a role to replace conventional therapies in the combat against age-related diseases and oxidative stress.

A Good Source of Vitamin D

If you live in an area that doesn't get much sunshine or you spend most of your time indoors, eating sardines may help prevent a vitamin D deficiency. Sardines are one of the few foods that offer such a high amount — 250 IU or 63 percent of your daily requirements for vitamin D.

You need vitamin D for your muscles to move, for cellular communication and to help your immune system function properly. Along with calcium in sardines, vitamin D helps protect you from osteoporosis and bone disorders.

In addition, vitamin D may have a connection with medical conditions such as diabetes, hypertension, multiple sclerosis and autoimmune diseases.

Read more: Relationship Between Vitamin D & Calcium

Control Blood Glucose Levels

Fish such as sardines may help manage or prevent diabetes better than other types of meat. The protein in sardines doesn't impact blood sugar levels. Since they do not contain carbs, sardines don't have a GI ranking and won't create spikes and crashes, which is important to diabetics.

A 2015 study compared the effect of casein or sardine protein on secretion of insulin, using rats fed a high-fructose diet. Results, published in Molecular Medicine Reports, found the sardine diet prevented and reversed insulin resistance and oxidative stress.

Researchers concluded that sardines may have positive benefits on metabolic syndrome. Metabolic syndrome is a cluster of biochemical abnormalities associated with a high risk of developing Type 2 diabetes and cardiovascular disease.