Some food sources of omega-3 include seaweed, flaxseeds, chia seeds, and fatty fish. Examples of fish highest in omega-3 include mackerel, salmon, and sardines.

Omega-3s are a type of essential fatty acid, meaning people must obtain them from their diet.

There are three main types of omega-3 fatty acids: DHA, EPA, and ALA. Fish and seafood sources of omega-3 tend to be higher in DHA and EPA, while plant sources are typically higher in ALA. Eating a variety of omega-3 foods is important for optimal health.

This article discusses the health benefits of omega-3s, food sources, supplements, and more.

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There are three main types of omega-3 fatty acids:

  • alpha-linolenic acid (ALA)
  • eicosapentaenoic acid (EPA)
  • docosahexaenoic acid (DHA)

While ALA is present in plant oils, DHA and EPA are in fish, krill, and algae. The body can convert ALA to EPA and DHA, but the conversion rate is less than 15%. Therefore, people may need to consume more of these to get enough omega-3s.

Omega-3 fatty acids are essential for both physical and mental health.

Physical health benefits

Omega-3s are an integral component of cells and help them function effectively. They also help form signaling molecules called eicosanoids, which play a vital role in the:

  • Cardiovascular system: The cardiovascular system includes the heart, blood vessels, and blood.
  • Respiratory system: The respiratory system includes the lungs, airways, and blood vessels.
  • Immune system: The immune system includes the bone marrow, spleen, lymphatic system, and white blood cells.
  • Endocrine system: The endocrine system includes the pancreas, adrenal glands, thyroid gland, pituitary gland, and hormones.

Mental health benefits

According to a 2020 review, omega-3 also plays an important role in brain development, functioning, and aging. The review states that polyunsaturated fats (PUFAs) — including omega-3 and omega-6 — make up 20% of the brain’s overall weight.

The review also notes that an omega-3 deficiency has links to an increased risk of developing a range of mental health conditions. These include:

The authors add that increasing one’s intake of omega-3 may beneficially affect neurodegenerative disorders such as Alzheimer’s disease.

Fatty, oily fish is an excellent source of DHA and EPA.

The following types of fish are some of the best sources of these fatty acids. For each fish below, the serving size is 3 ounces (oz).

1. Mackerel

Mackerel is a small, fatty fish that people commonly eat smoked.

One serving of mackerel contains:

Along with omega-3s, mackerel is rich in selenium and vitamin B12.

2. Salmon

Salmon is a popular and nutritious fish. There are several differences between wild and farmed salmon, and their DHA and EPA content can vary.

One serving of farmed salmon contains:

  • 1.24 g of DHA
  • 0.59 g of EPA

One serving of wild salmon contains:

  • 1.22 g of DHA
  • 0.35 g of EPA

It also contains high levels of:

Learn more about the differences between wild and farmed salmon.

3. Seabass

Seabass is a mild white fish that is particularly popular in Japan.

One serving of seabass contains:

  • 0.47 g of DHA
  • 0.18 g of EPA

It also provides protein, selenium, calcium, and phosphorus.

4. Oysters

Oysters are a type of shellfish that restaurants tend to serve as an appetizer or snack. Unlike many other seafood sources, oysters contain all three major classes of omega-3s.

One serving of oysters contains:

  • 0.14 g of ALA
  • 0.23 g of DHA
  • 0.30 g of EPA

They are also rich in zinc and vitamin B12.

5. Sardines

Sardines are small, oily fish that are particularly dense and meaty. They are usually sold in cans.

One serving of canned sardines contains:

  • 0.74 g of DHA
  • 0.45 g of EPA

They are also a good source of selenium and vitamins B12 and D.

6. Shrimp

People around the world eat shrimp as both an appetizer and a component of many meals.

One serving of shrimp contains:

  • 0.12 g of DHA
  • 0.12 g of EPA

It is also rich in protein and potassium.

Below are some vegetarian and vegan food sources of omega-3.

1. Seaweed and algae

Seaweed, nori, spirulina, and chlorella are different forms of algae that many people eat for their health benefits.

Algae and seaweed are important sources of omega-3 for people on a vegetarian or vegan diet because they are one of the few plant foods containing both DHA and EPA.

The DHA and EPA content varies depending on the type of algae and the particular product.

There are many ways to include these foods in the diet. For example:

  • nori is the seaweed used in sushi
  • dried seaweed is a tasty, crispy snack
  • chlorella and spirulina make a nutritious addition to smoothies

Seaweed is also rich in protein, and it may have antidiabetic, antioxidant, and antihypertensive properties. People can find chlorella and spirulina in health-food stores or online.

2. Chia seeds

Chia seeds are an excellent plant-based source of ALA omega-3 fatty acids. They are also high in fiber and protein.

They contain 5.055 g of ALA per 1 oz serving.

People can use these seeds as an ingredient in granola, salads, or smoothies. They can also mix them with milk or yogurt to make chia pudding. Mixing chia seeds with water can also serve as an egg substitute.

3. Hemp seeds

Hemp seeds contain 2.605 g of ALA in every 3 tablespoons (tbsp).

They are also rich in many nutrients, including:

  • protein
  • magnesium
  • iron
  • zinc

4. Flaxseeds

Flaxseed oil contains 6.703 g of ALA per tbsp.

Flaxseeds are rich in many nutrients, including:

As with chia seeds, people can mix flaxseeds with water to create a vegan egg replacement. It is also easy to incorporate them into the diet by adding them to oatmeal, cereal, or salad.

5. Walnuts

Walnuts are an excellent source of healthful fats, including ALA omega-3 fatty acids. They contain 3.346 g of ALA per cup.

People can enjoy walnuts on their own, in granola, or in a trail mix, snack bar, yogurt, salad, or cooked dish.

6. Edamame

Edamame beans are immature soybeans that are particularly popular in Japan. They are rich in both omega-3s and protein.

A half-cup of frozen edamame beans contains 0.28 g of ALA.

Boiled or steamed edamame beans work well in a salad or as a side dish.

7. Kidney beans

Kidney beans are one of the most common beans to include in meals or eat as a side dish. People can add them to curries or stews or eat them with rice.

They contain 0.10 g of ALA per half-cup.

8. Soybean oil

Soybeans are popular legumes from Asia. Many people use soybean oil for cooking.

Soybean oil contains 0.92 g of ALA per tbsp. It is also a good source of:

9. Wheat germ

Wheat germ is the internal part of the wheat grain. It has a mild, nutty flavor, making it suitable as a topping for salads, cereals, or yogurt.

One cup of wheat germ contains 6.91 g of ALA.

Wheat germ is also high in Vitamin B1, Vitamin B6, and folate.

Some foods and beverages are not naturally high in omega-3s, so manufacturers may add the nutrient to the product. A person may be able to buy omega-3 fortified versions of:

  • fruit juices
  • bread
  • eggs
  • milk
  • yogurt
  • butter, margarine, and spreads
  • oils
  • baby food

People who cannot meet their omega-3 dietary requirements and those who experience high levels of inflammation may benefit from taking omega-3 supplements.

There are several types of omega-3 supplements to choose from, including:

  • Fish oil: Fish oil is the most common omega-3 supplement, and it offers the highest available dose. Fish oil supplements include both DHA and EPA.
  • Cod liver oil: Cod liver oil is rich in DHA and EPA omega-3s.
  • Krill oil: Krill oil is another seafood oil that is rich in DHA and EPA.
  • Algae oil: For people following a vegetarian or vegan diet, algae oils are an excellent source of omega-3s. However, they contain a lower dose than most fish oil supplements, so people may need to take more of them.
  • ALA supplements: Flaxseed, chia seed, and hemp seed supplements contain only the plant-based omega-3 ALA, which is not sufficient on its own. Although ALA supplements are not a substitute for fish or algae oil, they can be a good addition to the diet.

The amount of omega-3 in each of the above supplements depends on the type of supplement and the specific brand. Certain plant-based supplements, such as some algae and ALA supplements, include gelatin and are not suitable for vegetarians and vegans.

People should always read supplement labels carefully.

Omega-3 fatty acids are an essential dietary component and help to maintain proper cell functioning throughout the body. Research suggests they also play an important role in brain functioning and mental health.

A healthy diet is one that includes the three types of omega-3: DHA, EPA, and ALA. Fish and seafood tend to be high in DHA and EPA.

Plant sources are typically abundant in ALA, although seaweed and algae also contain EPA and DHA, making them a healthy option for people following a vegetarian or vegan diet.