Omega 3 fatty acids are a type of polyunsaturated fatty acid (PUFA). Fish oil capsules contain eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).
These compounds are known for their anti-inflammatory properties. EPA and DHA are used by the body to synthesize eicosanoids. Although fish oil is the most popular source of omega-3 fatty acids, there're plant-based sources available as well. Plant-based sources provide alpha-linolenic acid (ALA), which is converted into its active form inside the body.
Functions of Omega 3 Fatty Acid
These fatty acids are required in the synthesis of signaling molecules known as eicosanoids, which have important roles in the functioning of the immune, respiratory, cardiovascular, and endocrine systems.
Omega-3 fatty acids are also found in cell membranes and inside the brain. They play an important role in memory function, cognition, blood clotting, arterial contraction, and inflammation. EPA and DHA can prevent heart disease, strokes, and certain cancers.
Dietary Requirements and Deficiency of Omega 3 Fatty Acids
Ideally, 250–500 mg of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) per day needs to be consumed from animal sources.
According to the National Institutes of Health, the Adequate Intake (AI) from plant-based sources is 1,600 mg for adult males and 1,100 mg for adult females. Plant-based omega 3 fatty acids are not absorbed as easily as fish oils.
A deficiency in these fatty acids can cause:
- dryness of the eyes
- eye irritation
- chronic joint pain
- hair fall
- hair thinning
- dryness of hair
- chronic inflammation
- depression
- increased risk of Alzheimer’s disease
- increased risk of dementia
- increased symptoms of bipolar disorder
Read about the symptoms of omega-3 deficiency.
Sources of Omega 3 Fatty Acids
Omega-3 fatty acids can be found in both animal and plant-origin foods. EPA and DHA present in animal foods have more bioavailability than plant-based ALA. The following foods can be included in the diet:
- Anchovies
- Halibut
- Herring
- Mackerel
- Oysters
- Salmon
- Sardines
- Trout
- Tuna
- Bread
- Cereal
- Flaxseed
- Flour
- Fortified Pasta
- Peanut butter
- Oatmeal
- Pumpkin seeds
- Walnuts
Check out this list of plant-based omega-3-rich foods.
Types of Omega 3 Fish Oils
Commonly available fish oil capsules are of the following types:
1) Cod Liver Oil
It contains 2,438 mg of EPA and DHA per tablespoon and is available as capsules and syrups. Cod liver oil also contains vitamin A and vitamin D.
Learn more about the health benefits of cod liver oil.
2) Salmon Oil
Hundred grams of salmon contain 2,150 mg of EPA and DHA. It can reduce the risk of heart disease, dementia, and depression. Salmon oil is often mixed with anchovy oil.
Learn more about the benefits, side effects and safety of fish oils.
3) Krill Oil
Krill oil is extracted from Antarctic krill, a small shrimp-like animal. It contains omega 3 in two forms: triglyceride and phospholipid form. Krill oil is highly resistant to oxidation due to the presence of astaxanthin.
Learn more about the health benefits of krill oil.
4) Green-lipped mussel oil
This oil is usually in the form of triglycerides and free fatty acids. It also contains trace amounts of eicosatetraenoic acid (ETA). ETA is a rare type of omega 3 fatty acid that's more potent than EPA and DHA. Green-lipped mussel oil is considered to be an environmentally friendly choice.
Check out this list of foods that are rich in omega-3 fatty acids.
5) Mammalian oil
Mammalian omega 3 oil is made from seal blubber and contains triglycerides. It also contains high amounts of docosapentaenoic acid (DPA) apart from EPA and DHA. It does not contain significant amounts of omega-6 fatty acids.
Bottom Line
Omega 3 fatty acids can be obtained from fish oil as well as vegetarian and vegan oil capsules. Fish oils also contain naturally occurring vitamins A and D. For vegans and vegetarians, algal oil and flax seed oils are good options to include in the diet.
However, it has to be kept in mind that the bioavailability of vegan ALA differs from that of DHA and EPA. If you're not a vegan or vegetarian, it's advisable to consider fish oils while looking for omega-3 supplements. If you're allergic to seafood, check out for allergen advice on fish oil bottles.