Is it necessary to eat fish for a healthy diet?

December 4, 2025 •

4 min read

According to the American Heart Association, eating fish at least two times per week is recommended as part of a healthy diet. This often leads to the question: is it necessary to eat fish to be healthy, or can other sources provide the same nutrients?

Quick Summary

This article explores the nutritional benefits and health risks associated with fish consumption, examining essential nutrients like omega-3s and potential contaminants like mercury. It compares fish-based and plant-based diets, outlines viable alternatives, and concludes on whether eating fish is a mandatory component of a healthy diet.

Key Points

Omega-3s can be found in non-fish sources: While fish is rich in EPA and DHA, plant-based ALA from sources like flaxseed, chia seeds, and walnuts can provide omega-3s. Algae-based supplements offer a direct plant-based source of EPA and DHA.
Concerns exist about mercury in fish: Larger predatory fish like swordfish and shark contain higher levels of methylmercury, which can pose a risk to the nervous system, especially for pregnant women and young children.
Other nutrients from fish can be replaced: Nutrients such as protein, vitamin D, and vitamin B12 can be obtained from alternative sources like legumes, fortified cereals, and supplements on a plant-based diet.
Plant-based diets can also offer health benefits: Studies suggest that well-planned vegan diets are associated with a lower risk of chronic illnesses and can provide essential nutrients without the risks of aquatic contaminants.
Personal choice is key: The decision to eat fish is a personal one that involves weighing the nutritional benefits against potential risks and environmental factors. A healthy diet is achievable either way with proper planning.
Supplements can bridge nutrient gaps: For individuals who avoid fish, targeted supplements, especially for vitamin B12 and algae-based omega-3s, can help ensure a balanced nutrient intake.

The Nutritional Benefits of Fish

Fish is widely celebrated as a nutrient-dense food, packed with high-quality protein and a range of vitamins and minerals vital for human health. Fatty fish, such as salmon, mackerel, and sardines, are particularly prized for their omega-3 fatty acids, specifically eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These polyunsaturated fatty acids are crucial for brain development, heart health, and reducing inflammation. Fish also provides a good source of vitamin D, vitamin B12, iodine, and selenium, which play key roles in bone health, nerve function, metabolism, and thyroid regulation.

Heart Health: Omega-3s help lower blood pressure, reduce triglycerides, and decrease the risk of heart attack and stroke by slowing the growth of plaque in the arteries.
Brain Function: DHA, in particular, is essential for brain and eye development, and regular fish consumption has been linked to a slower rate of cognitive decline.
Vitamin D Source: Fatty fish is one of the best dietary sources of vitamin D, a nutrient that is deficient in many populations.
Rich in Minerals: Beyond fatty acids, fish provides essential minerals like iodine, zinc, and selenium that support various bodily functions.

The Potential Health Risks of Fish Consumption

While the benefits are significant, consuming fish also carries potential risks, primarily from environmental contaminants. Industrial and natural pollutants can accumulate in fish, with levels varying based on the species and its place in the food chain.

Mercury: A heavy metal, methylmercury, bioaccumulates in fish and can pose a risk to the nervous system, especially for developing fetuses and young children. High-mercury species include shark, swordfish, and king mackerel.
PCBs and Dioxins: Polychlorinated biphenyls (PCBs) and dioxins are industrial chemicals that persist in the environment and can accumulate in the fatty tissues of fish. Exposure has been linked to potential immune, reproductive, and nervous system problems.
Microplastics: The widespread presence of microplastics in aquatic environments means fish can ingest these particles, which may concentrate toxins. Human consumption of contaminated fish can lead to inflammatory and other health issues.
Foodborne Illness: Raw or undercooked fish, including sushi, carries a risk of foodborne pathogens like Listeria and Vibrio, which can be particularly dangerous for vulnerable groups like pregnant women.

Can a Healthy Diet Be Fish-Free?

It is absolutely possible to maintain a healthy diet without eating fish, provided that a well-planned diet addresses the key nutrients typically obtained from fish. The primary nutrient to replace is the long-chain omega-3 fatty acids, EPA and DHA, as the plant-based form, ALA, converts to EPA and DHA inefficiently.

Comparing Fish and Plant-Based Omega-3s


Feature	Fish-Based Omega-3s	Plant-Based Omega-3s
Types	Rich in EPA and DHA	Rich in ALA
Conversion	No conversion needed; highly bioavailable	Inefficiently converted to EPA and DHA by the body
Sources	Oily fish like salmon, sardines, and mackerel	Flaxseeds, chia seeds, walnuts, hemp seeds
Supplement Source	Fish oil capsules	Algae-based supplements (provide direct EPA/DHA)
Contaminants	Potential risk of mercury, PCBs, dioxins	Generally free of aquatic contaminants
Environmental Impact	Risks of overfishing and habitat destruction	Lower carbon footprint

Plant-Based Alternatives to Fill Nutrient Gaps

For those who do not eat fish, a variety of plant-based foods and supplements can provide the necessary nutrients.

Omega-3s (ALA, EPA, DHA)

ALA Sources: Flaxseeds, chia seeds, and walnuts are excellent sources of the omega-3 ALA. Grinding or milling flaxseeds improves absorption.
EPA and DHA Sources: Algae oil is a direct source of preformed EPA and DHA, making it the most effective plant-based alternative for these specific omega-3s. Seaweed and spirulina also provide smaller amounts.

Protein, Vitamins & Minerals

Protein: Legumes (beans, lentils), tofu, tempeh, nuts, and seeds provide high-quality plant-based protein.
Vitamin B12: Primarily found in animal products, B12 requires careful attention on a vegan diet. Sources include fortified cereals, fortified plant milks, nutritional yeast, and reliable supplements.
Iodine: While seafood is a primary source, iodine can be obtained from iodized salt, seaweed, and some fortified foods.
Vitamin D: Fortified foods (plant milks, cereals) and supplements are recommended, especially for those with limited sun exposure.
Iron and Zinc: These minerals are present in plant foods like legumes, nuts, and whole grains, though their absorption can be lower than from animal sources. Pairing them with vitamin C-rich foods can enhance absorption.

Conclusion: Informed Choices for Optimal Health

Ultimately, eating fish is not necessary for a healthy diet, but it does offer a convenient and highly bioavailable source of key nutrients, especially EPA and DHA omega-3s. The decision to include or exclude fish should be based on a personal assessment of its benefits versus the potential risks, such as mercury and PCB contamination, and the environmental impact. For those who choose not to eat fish due to taste preference, ethical reasons, or health concerns related to contaminants, it is entirely possible to obtain all necessary nutrients from alternative sources. A well-planned diet rich in diverse plant-based foods, potentially supplemented with algae oil for EPA/DHA and fortified products for B12, can provide a comprehensive nutritional profile. Consulting a healthcare provider or registered dietitian can ensure your dietary needs are fully met, regardless of your choice. A balanced approach focuses on variety and thoughtful nutritional planning to support long-term wellness.

Sources for a Balanced Diet

To get protein: Lentils, chickpeas, tofu, tempeh, edamame
To get omega-3s: Ground flaxseed, chia seeds, walnuts, algae-based supplements
To get vitamins and minerals: Fortified cereals, plant milks, leafy greens, nuts
To get iodine: Iodized salt, seaweed

Navigating Fish Consumption

Low-mercury options: Salmon, shrimp, canned light tuna
High-mercury options (to limit): Shark, swordfish, king mackerel
Cooking safety: Avoid raw or undercooked fish to prevent foodborne illness, especially for pregnant women and children.

Outbound Link

For more information on balancing the risks and benefits of fish consumption, the World Health Organization (WHO) provides comprehensive guidance that is updated regularly: WHO/FAO Expert Consultation on the Risks and Benefits of Fish Consumption.

Frequently Asked Questions

The most important nutrients in fish that are difficult to obtain in the same highly bioavailable form from plant sources are the long-chain omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).

Yes, children can get enough omega-3s without eating fish. Plant-based sources like walnuts, flaxseeds, and chia seeds contain ALA, and algae-based supplements provide EPA and DHA directly.

To minimize mercury intake, low-mercury fish options include salmon, shrimp, canned light tuna, tilapia, and catfish. These are considered safer choices for everyone, including vulnerable populations.

Fish oil supplements are not necessary if adequate EPA and DHA are obtained from other sources. Algae-based supplements are a suitable alternative for those who don't eat fish but want a direct source of EPA and DHA.

Vegans can obtain sufficient vitamin B12 through fortified foods such as plant-based milks and cereals, nutritional yeast, and through B12 supplements.

Not necessarily. Studies show that well-planned plant-based diets can offer significant health benefits, including a lower risk of certain chronic diseases. The health outcome depends more on the overall quality and balance of the diet than the inclusion or exclusion of fish.

Excellent plant-based protein sources include legumes (beans, lentils), soy products like tofu and tempeh, nuts, and seeds. These can be incorporated into a variety of meals to meet protein needs.