Fish Oils and Omega-3s

For those of you of a certain age (are you looking at me?) you may remember that spoonful of awful tasting cod liver oil your mother used to force down you.  I always thought it was a punishment for something I did (or was likely to do).


Turns out, mom was right (who’d thought?).

Cod liver oil, like the oil from other cold-water, fatty fish such as mackerel, sardines and salmon, is chock full of beneficial omega-3 fatty acids.


So What Are Omega-3 Fatty Acids?

Omega-3 fatty acids (or omega-3s) are polyunsaturated fats (PUFAs) that are found in foods.  There are three primary types of omega-3 fatty acids: alpha-linoleic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA).  ALA is found primarily in plant oils, and EPA and DHA found primarily in fish or other seafood.  Omega-3s are very important for your overall health, and utilized by many parts of the body and in many biochemical processes.

ALA is considered an essential fat because our body cannot produce it naturally, so ALA must be obtained from food.  EPA and DHA can be produced within the body by conversion from ALA, so are not technically considered essential.  However, only a very small amount of EPA and DHA can be converted from ALA.  This process becomes less efficient as we age, and is almost non-existent in people with health issues or with people taking certain medications or eating a poor diet.  Therefore, it is necessary to obtain EPA and DHA from either food sources, or through supplementation, making EPA and DHA essential fats as well.


Why Do I Need Omega-3s?

Omega-3s are found in the cell membranes of every cell within the body and influence the function of receptors within those membranes such as heart, blood vessels, immune system, and respiratory system.

Omega-3s are also used for energy, and DHA is found in high concentrations in the retinas of the eyes, brain and sperm cells.

A study in 2009 looked at deaths in the United States in 2005 from modifiable dietary, lifestyle, and metabolic risk factors (things that can be changed).  The study found that smoking and high blood pressure were the number one cause of deaths in that category – about 5 out of every 6 deaths.  No big surprise there.  But, interestingly, low dietary omega-3 fatty acid intake was number 6 of the 12 risk factors investigated.


Here are some other reasons why you should pay attention to your omega-3 intake:

Cardiovascular Health

One of the best studied and proven benefits of omega-3s regards cardiovascular health and heart disease.  Clinical studies have shown that consumption of omega-3s – either from diet and/or supplementation – can prevent sudden cardiac death through control of a steady heart rate and avoidance of erratic rhythms, which can be fatal.  Such arrhythmias account for over 55,000 cardiac-related deaths in the United States every year.

Omega-3s also benefit cardiovascular health through lowering blood pressure, improving vascular function (blood vessels work better), and lowering heart rate.

Other studies have shown that higher doses of omega-3s can ease inflammation and reduce triglyceride levels.  Triglycerides are another type of fat (lipid), high levels of which are linked to atherosclerosis (a buildup of cholesterol plaque on the walls of the arteries).  High triglyceride levels with high bad cholesterol (LDL), or low good cholesterol (HDL) can lead to a buildup of fats on artery walls, which can lead to heart attacks or stroke.  Omega-3 supplementation can also increase good cholesterol levels.


Fish oil has many benefits for mental and cognitive health, and support for ADHD (attention deficit hyperactivity disorder) and its related disorders is an important advantage.

There is quite a bit of evidence to suggest that insufficient intake of PUFAs, primarily omega-3 DHA, contributes to various developmental and mental or cognitive disorders.  So, it is not unsurprising to see instances of certain disorders, such as ADHD, in children since the best source of DHA is from fish – and most children aren’t fans of fish (and no, frozen, breaded fish sticks don’t count).  To complicate matters, many children have a diet that consists of trans fats and omega-6 fatty acids, which can counteract the benefits of DHA, and only make matters worse.

Analysis of blood samples from children with ADHD or related symptoms (behavioral issues) in several studies showed significantly lower levels of DHA in plasma and red blood cells when compared to children of the same age without ADHD.

A study of children aged 6-12 years old treated with omega-3 fatty acids EPA and DHA showed improvement in restlessness, aggressiveness, work completion, and academic performance.  There was another clinical study that showed benefit in improving literacy and behavior in children with ADHD, especially with high doses of DHA.

Alzheimer’s Disease

Your brain is all fat!  No, that’s not an insult – it’s a fact (mostly).

About 60% of the brain consists of fats, especially DHA, so it makes sense that sufficient levels of supportive fats, such as PUFAs, would benefit brain health.

The loss of cognitive abilities – memory, reason, comprehension – concerns all of us, especially as we age.  The threat of dementia and related diseases such as Alzheimer’s is a concern not only for ourselves as we age, but also for our parents and loved ones as they age.

Analysis of the blood plasma levels of DHA in the brains of patients with Alzheimer’s Disease (AD) were found to be lower when compared to similar aged individuals without AD.  This study also concluded that low DHA levels in blood was a contributing factor to the development of AD.

Another study showed a link between an increase in the risk of dementia with diets high in saturated fat and cholesterol, and a lower risk in diets high in fish (with a low intake of saturate fat and cholesterol).

There are some clinical studies that show the benefit of omega-3 supplementation in those patients with Alzheimer’s Disease.  It was found that fish oil supplementation may act to slow age-related cognitive decline and Alzheimer’s as well as help to prevent brain atrophy.

Arthritis/Joint Support

There is significant evidence for the benefit of fish oil relative to symptoms of inflammatory joint disease such as rheumatoid arthritis and osteoarthritis.  These studied that fish oils higher in EPA than DHA or ALA seemed to provide better results in reducing inflammation and perceived joint pain.  The studied indicated that fish oil might be a safer alternative top NSAIDs for joint-related pain management.

Depression and Anxiety

Several studies have been performed on the benefit of PUFAs, primarily DHA on the symptoms of depression, anxiety, and mood.

Studies have shown a correlation between lowered omega-3s in and symptoms of depressed patients.  That study also showed an inverse correlation between fish consumption and depression – high fish consumption led to reduced incidences of depression, and vice versa.  Additional studies have supported that observation with analysis of blood samples showing low levels of omega-3s in blood plasma or cell membranes in depressed patients.

Another study showed that treatment of patients with bipolar disorder with a combination of omega-3s and usual treatments had significant beneficial effects.

There is also evidence the shows benefit for omega-3s for the development and function of the central nervous system through anti-inflammatory actions.

Early Childhood Development

Perhaps one the most intriguing, and important, benefits supporting sufficient omega-3 intake regards supporting child development.

There is quite a bit of clinical data to support the importance of omega-3s, especially DHA, in the development of the brain and central nervous system in children.  It has been found that maternal fatty acid levels are provided to the fetus in utero, and form the foundation for a healthy neural development from early on in pregnancy.

The science also shows that continued supplementation with DHA after birth either through breast milk, or through fortification of infant formulas and foods supports brain and neural network development as the child ages.  Studies have even shown an improvement in learning ability in children aged 7-9 years when supplemented with PUFAs from fish oil.

Skin and Hair

Skin can benefit from the intake of omega-3s, primarily EPA and DHA, which helps the skin maintain a smooth, elastic consistency, again likely through anti-inflammatory actions.

Several skin conditions such as acne, psoriasis, and eczema, have been shown to improve with high doses of EPA and/or DHA, up to 14 grams per day.

Also of interest is a connection between omega-3 supplementation and skin photo-protection from ultraviolet radiation.  Some studies have shown protection from sunburn, photo-aging (wrinkles), and skin cancer, though more research is needed.

According to a study, fermented fish oil from mackerel and DHA were evaluated for its effect on hair growth.  The study found that fermented fish oil and DHA promoted hair growth through activation of dermal papilla cells (cells in follicles which play an important role in hair growth).

Eye Health

Studies have shown that people who ate fish two or more times per week were less likely to develop age-related macular degeneration (AMD).  The studies, however, do not show an improvement in symptoms for someone who already has AMD.

Fish oil has also shown benefit against dry eye syndrome (DES).  DES occurs when the eyes don’t provide sufficient moisture in the form of tears, which causes vision problems and eye discomfort.  Studies show that either increased dietary intake of fish oil or supplementation can provide relief from these symptoms.


There has a been a change in the dietary ratio of omega-6 fatty acids – which are believed to contribute to increased inflammation – and omega-3 fatty acids (EPA and DHA) with the industrialization of the western world.  Current estimates of the dietary intake of omega-6 to omega-3 in the west is currently about 25:1, with a typical Japanese diet about 4:1.  Indeed, estimates of the western diet pre-industrialization was about 2:1.

This imbalance is believed to have led to increased systemic inflammation, which is tied to an increase incidence of a number of diseases as referenced above, but also include cancers.

Studies have evaluated the relationship between increased fish oil consumption (omega-3s) and these cancers.  Some studies have suggested that increased omega-3 intake may offer protective benefits against certain types of cancers such as breast, colon, prostate, and pancreatic cancers.


So, How Do I Get More Omega-3s?

First, and most obviously, you can increase your dietary intake of seafoods which are high in omega-3s, such as:

Type of Seafood Omega-3 Fatty Acids (EPA and DHA) mg/100g (3.5 ounces)
Anchovy 2,055
Catfish (farmed) 177
Cod (Atlantic) 158
Fish sticks (frozen) 214
Golden bass (tilefish, (Gulf of Mexico) 905
Halibut 465
Mahi mahi 139
Pollock (Alaskan) 468
Salmon (wild) 1043
Salmon (farmed) 2,648
Sardines 982
Swordfish 819
Trout 935
Tuna (albacore) 862
Tuna (light, skipjack) 270
Snapper 321
Clams 284
Crab 413
Lobster 84
Mussels 782
Oysters 688
Scallops 365
Shrimp 315

SOURCE: Mozaffarian D, Rimm EB. JAMA. 2006; 296(15):1885-1899

However, there may be a couple of challenges with obtaining higher doses of omega-3s strictly from the diet:

  • As shown in the chart above, you may have to consume a lot of fish on a daily basis in order to get high doses of omega-3s – not so great if you are not a fan of fish.
  • Many of these fish are at the top or high end of the food chain, and can concentrate high levels of pollutants and chemicals such as mercury. These compounds can have obvious negative effects with frequent (i.e. more than twice a week) consumption.  Smaller, infrequent consumption is usually safe, however.

There are multiple sources of marine oils: fish oil from various cold-water species, krill (a small marine crustacean), and even calamari (squid).  Krill oil is unique since it not only provides essential omega-3 (EPA & DHA), but also provides choline, phospholipids and astaxanthin with proven effects to improve human health.  Seaweed and algal oil is one of the few vegetable sources which is a good source of EPA and DHA.

There are other vegetarian and vegan sources of omega-3s, though these sources only provide ALA:  chia seeds, hemp seeds, flax seeds, and walnuts are good examples.

Avoid the following vegetable oils as they are usually over-refined, heated, solvent-extracted, or processed which may not only destroy the beneficial ALA, but can also introduce oxidation:

  • Corn oil
  • Safflower oil
  • Cottonseed oil
  • Soybean oil
  • Peanut oil

Good oils would be:

  • Olive oil
  • Flaxseed oil, flaxseed
  • Coconut oil, coconut butter
  • Avocado oil
  • Pumpkin seed oil


Why Use Supplements?

Taking supplements is a very popular way to increases your intake of omega-3s.

There are a number of quality fish oil supplements available on the market which provide varying amounts of fish oil and concentrations of EPA vs. DHA depending on your particular need.  In addition, you will find that the quality supplements will have been specifically processed and tested to confirm removal of harmful pollutants such as heavy metals, PCBs, herbicides, pesticides, and oil.

So, supplementation is usually the easiest, and safest, route to follow in order to obtain the necessary omega-3 intake.





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