Fish is an important part of a healthy diet for adults, children and developing babies. Yet most people likely don’t get enough fish in their diet, according to the U.S. Food and Drug Administration (FDA)[1]Questions & Answers from the FDA/EPA Advice about Eating Fish for Those Who Might Become or Are Pregnant or Breastfeeding and Children Ages 1 to 11 Years. U.S. Food and Drug Administration. Accessed 12/2/2023. . An excellent source of protein, fish also contain a variety of nutrients like omega-3 fatty acids, iron and zinc, making it an important component of a healthy eating pattern.
Continue reading to learn about the many health benefits of eating fish, the best types of fish to eat and considerations for including fish in your diet.
Health Benefits of Fish
Fish contain many essential vitamins and minerals that may benefit an individual’s overall health, according to Kimberly Gomer, a registered dietitian and nutritionist with a private practice in Miami. Consider the following nutrients commonly found in fish and their health benefits:
- Protein is essential to every cell in the body to build and maintain bones, muscles and skin.
- Vitamin A contributes to healthy eyesight, immune function, cellular communication, male and female reproduction and the formation and maintenance of the heart, lungs, eyes and other organs.
- B vitamins, including thiamine, riboflavin, niacin, folate and more, support cellular function, particularly in the brain and nervous system.
- Vitamin D helps the body absorb calcium to strengthen bones, enable muscle movement, carry messages (such as those important for the growth of neurons and creation of certain neurotransmitters) via nerves from the brain to the rest of the body and bolster your immune system. Vitamin D also helps fight viruses and bacteria.
- Omega-3 fatty acids contribute to energy and tissue growth in the heart, lungs, blood vessels, immune system and endocrine (hormone production) system.
- Calcium is crucial for strong bones, muscle movement, hormone release and blood flow.
- Iodine is necessary to make thyroid hormones needed for metabolism control as well as to support bone and brain development during pregnancy.
- Iron is needed to make hemoglobin (a protein in red blood cells that carries oxygen from the lungs to the rest of the body), myoglobin (a protein that provides oxygen to muscles) and certain hormones.
- Selenium contributes to reproduction, thyroid gland function, DNA production and protecting against infection.
- Zinc bolsters the immune system and contributes to DNA and protein production.
Fatty fish, such as salmon and mackerel, are better than leaner, white fish, such as mahi mahi or flounder, as fatty fish contain essential omega-3 fatty acids and fat-soluble nutrients the body can absorb, explains Gomer. Adults should eat at least 8 ounces of fish per week based on a 2,000-calorie diet, according to the FDA.
The healthiest fish to eat are those that contain plenty of nutrients while containing little to no mercury, a potential risk with certain types of fish.
“Think SMASH—sardines, mackerel, anchovies, salmon and herring—when choosing the healthiest fish to eat,” says Amanda Sauceda, a registered dietitian and founder of The Mindful Gut, a nutritional guidance company in Long Beach, California.
To help you choose, below are seven of the healthiest fish to eat, according to experts.
1. Sardines
“Sardines are one of the healthiest fish to eat because they’re very high in omega-3s,” says Gomer. “Sardines are eaten with the bone in, so they have calcium, and because they’re so little, they haven’t had a chance to acquire mercury,” she adds. Sardines are inexpensive and can be purchased in a tin in water or olive oil, with or without salt, says Gomer.
2. Mackerel
Mackerel is a good source of omega-3 fatty acids, says Sauceda. As an oily fish, mackerel is also a good source of vitamin D. Fried mackerel is higher in carbohydrates and sugars but lower in protein than canned, grilled, baked or broiled mackerel, according to data from the U.S. Department of Agriculture (USDA).
3. Anchovies
Anchovies are another type of fatty fish that are high in omega-3s. Anchovies provide large amounts of calcium, phosphorus (a mineral needed to make energy in the body) and potassium.
4. Salmon
A popular oily fish, salmon is chock-full of nutrients including omega-3s, protein, potassium, vitamin D, vitamin E and several B vitamins. Tinned salmon contains bones, which is an added source of calcium and phosphorus.
5. Herring
Herring is another oily fish that is an excellent source of omega-3s and vitamin D, as well as selenium and vitamin B12, a vitamin essential for the body’s central nervous system health and for making white blood cells, red blood cells and platelets. “The advantage of herring is that it is a wild caught fish (not farmed),” says Gomer. “The other huge advantage is that the issue of wild caught fish with mercury is much less of a problem in small fish (like sardines and herring).”
6. Trout
Trout is another oily fish that’s high in omega-3s and a good source of vitamin D, as well as potassium and phosphorous. Fried trout has higher levels of fat and carbohydrates and less protein than when grilled or steamed.
7. Tuna
Although not an oily fish, tuna is still a healthy choice thanks to the omega-3s, iodine and taurine (an amino acid that contributes to cellular structure, controls bleeding, reduces blood pressure and more) this fish contains.
The healthiest version of tuna is canned light, including skipjack tuna. Albacore and yellowfin tuna are also good choices, but it’s recommended to avoid bigeye tuna due to high mercury level risk, according to the FDA.
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How to Choose the Healthiest Fish
When choosing which fish to include in your diet, wild-caught fish over farm-raised fish is a healthier choice, says Gomer. “Not only do farm-raised fish have less nutrients than wild-caught, but they can have parasites and diseases due to the farm conditions.” What’s more, the water quality in which farmed fish are raised tends to be poor and causes fish stress, Gomer adds.
Poor water quality can affect the quality of fish through disease in the fish and exposure to excess production of phytoplankton, microscopic organisms that live in salty and freshwater environments. Large amounts of phytoplankton can lead to death or disease of marine life through the consumption of biotoxins or oxygen-depleting bacteria, low dissolved oxygen and toxic metabolite accumulation (such as ammonia, nitrite, carbon dioxide and hydrogen sulfide), explains Gomer. Phytoplankton-contaminated seafood can cause illness or death to individuals who consume it.
On the other hand, farmed fish may contain slightly higher omega-3 levels if they’re fed fortified food, according to the Colorado State University College of Health and Human Sciences.
When choosing between fresh and frozen fish, there’s “very little to no difference in nutrition” between the two, says Gomer, who notes that the main difference is in the way the fish tastes once cooked.
“Baked and air-fried fish are two of the healthiest ways to eat fish,” says Sauceda. Grilling is also a healthy option, but Sauceda notes that adding a marinade can help reduce the formation of certain carcinogenic chemicals. These chemicals include heterocyclic amines formed by amino acids, sugars and creatine reacting to high temperatures and polycyclic aromatic hydrocarbons created when the fish’s fats and juices drip onto the hot grilling surface or fire, causing flames and smoke.
“In general, the less that’s been done to [a fatty fish], the healthier it is, because it already has so much flavor and it doesn’t need extra fat,” says Gomer. She especially warns against cooking fish using seed oils like vegetable and canola oils, which raise our omega-6-to-omega-3 fatty acid ratios and can harm the heart and aggravate the gut by being pro-inflammatory and can be responsible for bloating/gas symptoms, says Gomer.
How to Incorporate Fish Into Your Diet
The best way to add more fish into your diet is to find the fish you like to eat and cook it in ways you like to eat them, say Gomer and Sauceda.
“Fish cooks very quickly, making it a perfect protein to include for a busy night’s dinner,” says Sauceda. “Frozen fish also works in a pinch and is a healthy option when fresh isn’t accessible.” Sauceda also suggests fish tacos (with cabbage and lime juice for added flavor and nutrition) and sticking to the Mediterranean diet as tasty ways to incorporate fish into your diet.
You can also sauté sardines and anchovies, which break down into small pieces, and add to sauces for a salty flavor. For an easy fish addition to your diet, use canned tuna or salmon to make tuna or salmon salad.
Potential Side Effects of Fish
Eating fish is generally safe for most healthy individuals. However, if you have a fish allergy, you may experience certain side effects, including:
- Hives or skin rash
- Nausea, stomach pain, vomiting or diarrhea
- Stuffy or runny nose and/or sneezing
- Headaches
- Anaphylaxis (a life-threatening shock response that impairs breathing)
Fish allergies may suddenly appear in adulthood, according to the American College of Allergy, Asthma and Immunology (ACAAI). Additionally, it’s possible for someone to be allergic to some types of fish but not others. For example, a person may have a (finned) fish allergy but not be allergic to shellfish, such as shrimp, crab and lobster.
Mercury contamination is a common concern when eating fish. A naturally occurring element, mercury can also be released into the environment via household or industrial waste and from the use of fossil fuels. When mercury settles into water or sediment, bacteria naturally converts it to methylmercury, a powerful neurotoxin that can be poisonous to nerve tissue. Small sea creatures may consume that bacteria and are then eaten by small fish, which are eaten by larger fish that humans tend to consume.
Larger, older fish tend to contain more mercury, which is why it’s recommended to avoid eating them due to their risk of mercury poisoning. Mercury buildup during pregnancy may lead to slow development and learning issues in babies and young children. In adults, mercury can harm the central nervous system as well as the cardiovascular system. Keep in mind that cooking fish does not eliminate mercury because it binds to proteins in fish tissue.
Pesticides and industrial chemicals may also be found in fish. However, it’s unlikely that levels of these contaminants are high enough to impact human health, according to the FDA.
Those who are pregnant or breastfeeding should eat two to three 4-ounce servings a week of what the FDA considers “best choices” fish, which includes fish like sardines, Atlantic mackerel, anchovy, salmon, herring and freshwater trout, or one serving of “good choices” fish, such as halibut, albacore/white tuna and yellowfin tuna. Additionally, the FDA recommends that children and individuals who are or may become pregnant in the next year should avoid eating raw fish.
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