Guide for Omega-3 fatty acids and their health benefits.
Omega-3s are ESSENTIAL FATTY ACIDS that the body must get from food. Foods that are high in Omega-3 mainly sourced from the sea like fish, seafood and certain types of algae. Another source includes vegetable oils, nuts, flax seeds and leafy vegetables. There is also a certain amount of omega 3 in eggs if they were fed on a diet containing omega-3 sources, for example, flaxseeds. 
In Western diets, omega-6, another type of fatty acid is very abundant. Omega-6 found in vegetable oils, nuts and seeds. The ratio is between omega-6 to omega-3 is 15/1-16.7/1. Western diets are deficient in omega-3 fatty acids and have excessive amounts of omega-6 fatty acids compared with the nutrition on which we have evolved. The recommendation is to consume more omega-3s to lower this ratio. 
In our the body
- Omega-3s are an integral part of cell membranes.
- Omega-3s regulate the nervous system, blood pressure, inflammatory processes and many other processes in the body.
- Omega-3s are also used by the body to maintain the health of the eyes, immune function and brain.
Omega−3 fatty acids are polyunsaturated fatty acids. The most researched ones are ALA, EPA, and DHA:
- ALA found in plant sources- walnuts, edible seeds, clary sage seed oil, algal oil, flaxseed oil, hemp oil.
- EPA and DHA found in animal sources- fish, fish oils, eggs from chickens fed EPA and DHA.
- Algae oils are a vegetarian source of DHA; some types of Alge also contain EPA.
The body can convert some ALA into EPA and then to DHA, but only in small amounts. Our ability to convert ALA may reduce with age.
Selected Food Sources of ALA, EPA, and DHA 
|Food||Grams per serving|
|Flaxseed oil, 1 tbsp||7.26|
|Chia seeds, 1 ounce||5.06|
|English walnuts, 1 ounce||2.57|
|Flaxseed, whole, 1 tbsp||2.35|
|Salmon, Atlantic, farmed cooked, 3 ounces||1.24||0.59|
|Salmon, Atlantic, wild, cooked, 3 ounces||1.22||0.35|
|Herring, Atlantic, cooked, 3 ounces*||0.94||0.77|
|Canola oil, 1 tbsp||1.28|
|Sardines, canned in tomato sauce, drained, 3 ounces*||0.74||0.45|
|Mackerel, Atlantic, cooked, 3 ounces*||0.59||0.43|
|Salmon, pink, canned, drained, 3 ounces*||0.04||0.63||0.28|
|Soybean oil, 1 tbsp||0.92|
|Trout, rainbow, wild, cooked, 3 ounces||0.44||0.40|
|Black walnuts, 1 ounce||0.76|
|Mayonnaise, 1 tbsp||0.74|
|Oysters, eastern, wild, cooked, 3 ounces||0.14||0.23||0.30|
|Sea bass, cooked, 3 ounces*||0.47||0.18|
|Edamame, frozen, prepared, ½ cup||0.28|
|Shrimp, cooked, 3 ounces*||0.12||0.12|
|Refried beans, canned, vegetarian, ½ cup||0.21|
|Lobster, cooked, 3 ounces*||0.04||0.07||0.10|
|Tuna, light, canned in water, drained, 3 ounces*||0.17||0.02|
|Tilapia, cooked, 3 ounces*||0.04||0.11|
|Scallops, cooked, 3 ounces*||0.09||0.06|
|Cod, Pacific, cooked, 3 ounces*||0.10||0.04|
|Tuna, yellowfin, cooked 3 ounces*||0.09||0.01|
|Kidney beans, canned ½ cup||0.10|
|Baked beans, canned, vegetarian, ½ cup||0.07|
|Ground beef, 85% lean, cooked, 3 ounces**||0.04|
|Bread, whole wheat, 1 slice||0.04|
|Egg, cooked, 1 egg||0.03|
|Chicken, breast, roasted, 3 ounces||0.02||0.01|
|Milk, low-fat (1%), 1 cup||0.01|
*Except as noted, the USDA database does not specify whether fish are farmed or wild caught.
**The USDA database does not specify whether beef is grass fed or grain fed.
Cold-water fatty fish, such as salmon, mackerel, tuna, herring, and sardines, contain higher amounts of omega-3s than fish with a lower fat content—such as bass and cod.
- Omega-3 supplements are tested to check that not containing heavy metals. Methyl mercury (a toxic heavy metal) removed during processing and purification, always buy a supplement from a company with a good reputation.
- Supplement usually contain 1 gram omega 3, taking daily it would correspond to eating three salmon meals per week. 
Who can benefit from taking omega 3 supplement or increasing omega 3 foods in the diet?
Higher concentrations of EPA and DHA than arachidonic acid (omega 6) shift the inflammation process toward less inflammatory activity. May be relevant in several diseases including rheumatoid arthritis, Crohn’s disease, ulcerative colitis, psoriasis, lupus, multiple sclerosis and migraine headaches. [3,9]
Heart and blood vessels:
Omega–3 fatty acids may decrease triglycerides, lower blood pressure slightly, reduce blood clotting, decrease stroke and heart failure risk and reduce irregular heartbeats.[3,4,6]
Anxiety & depression:
Omega-3s can readily go through the brain cell membrane and interact with mood-related molecules inside the brain. They also have anti-inflammatory actions that may help relieve depression. 
When comparing levels of omega-3 fatty acids in ADHD patients, studies found that ADHD patients have lower levels of omega-3 in their blood. Omega-3 are essential nutrients and necessary for a proper brain function and development. Additionally, there is strong evidence that omega-3 supplements could have beneficial effects on ADHD. Omega-3s may enhance dopamine; dopamine is a neurotransmitter that ADHD medications work to increase. 
Omega-3 fatty acids are also vital for the maintenance of normal brain function throughout life.
Pregnant and breastfeeding women:
A pure, high-quality omega–3 fish oil is recommended during pregnancy, as well as during breastfeeding.
DHA is the primary structural fatty acid of the grey matter of the brain and the retina. DHA may help to slow macular degeneration of the retina.
It appears that omega-3 fatty acids may reduce the symptoms of PMS, including depression, nervousness, anxiety, and lack of concentration and may also reduce the bloating, headache and breast tenderness.
These effects increased by more prolonged duration of treatment.
Animal studies have shown that a higher dietary omega–3/omega-6 fatty acids ratio is associated with beneficial effects on bone health.
How much should I eat?
Eat two portions of fish per week, one of which should be oily fish. For vegans and vegetarians – eat plant-based sources of omega 3 (flaxseeds, chia, walnuts) and consider taking Algae oil supplement.
In certain conditions, if you may suffer from a deficiency, it is recommended to take a supplement of omega 3.