What have omega-3 fatty acids done for you lately?

The essential omega-3 fatty acid, the one that our bodies cannot synthesize, is alpha linolenic acid or ALA.  DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid) are other important omega-3's.    Being an essential fatty acid means we need to get ALA in our diets.   ALA can be converted into DHA and EPA in the body, however this process is very inefficient, and we really need a dietary source of these fatty acids as well.  You can get DHA and EPA by eating several servings of fatty types of fish each week.  You can eat anchovies, bluefish, carp, catfish, halibut, herring, lake trout, mackerel, pompano, salmon, striped sea bass, tuna (albacore) or whitefish to get your omega-3's.  Linolenic acid comes from plant sources such as tofu/soybeans, walnuts, flaxseed oil, and canola oil.  If you aren't such a big fish eater or don't want to take a chance on ingesting a lot of mercury or other toxins in the fish, there is a vast selection of omega-3 supplements available.

Omega-3 fatty acids at work.

DHA is found in very high concentrations in the membranes of the retina, and animal studies show it is necessary for the retina and other systems in the eye to function properly.  The phospho-lipids in the brain contain high proportions of DHA.  Animal studies show that when this level drops it can result in learning deficit.  DHA appears to be protective against Alzheimer's disease.  Epidemiological studies show high intake of fish is associated with decreased risk of impaired cognitive function and dementia.

EPA in cell membranes plays an important role in the body's response to inflammation and functioning of the immune system.  Omega-3's are involved in the expression of a number of genes.  Gene expression is the process by which the information coded in genes (DNA) is converted to proteins and other cellular structures, in other words, it is the instructions in the genes manifesting themselves in real cells. 

Studies have shown that groups of people who eat more fish and fish oils have a decreased risk of coronary heart disease and stroke.  Numerous clinical controlled studies in humans have shown that a high intake of EPA and DHA can lower serum triglycerides.  In fact, prescription levels of omega-3's are used for this condition.  Hypertriglyceridemia is a common condition for type 2 diabetics, and supplementing with fish oils can significantly lower serum triglycerides for these people.  In fact the American Diabetes Association recommends that diabetic individuals increase omega-3 fatty acid consumption by eating 2 or 3 servings of fish weekly.

Omega-3 fatty acids have also shown promise in studies as a treatment for rheumatoid arthritis, inflammatory bowel disease, asthma and mental illnesses such as depression, bi-polar disorder and schizophrenia.

Who dreamed up such a complicated name?

Fatty acids are lipids, fat-like compounds that are insoluble in water.  They are made up of only three elements – carbon, hydrogen and oxygen, arranged in a long chain.  They are polyunsaturated because the carbons in the chain are not completely saturated with hydrogen atoms.  The poly means they have more than one double bond in their structure.  The Greek alphabet is used to identify where the double bonds lie on the chain.  Omega is the last letter of the Greek alphabet, and represents the end of the chain with a methyl group attached.  The number three indicates the position of the first double bond, counted from the omega carbon.   Because the three double bonds are close to the end of the chain, and they cause the chain to bend slightly,  omega-3 molecules have the appearance of a  shepherds staff, or a fish hook, or if you like a candy cane.

Do omega-3's scour through the blood stream and "hook" cholesterol off blood vessels?

Not exactly.  In fact, we don't really know exactly how they work, but there are several mechanisms they use to lower cholesterol.  There is more and more evidence that omega-3's can lower your LDL cholesterol, significantly lower serum triglyceride levels, reduce inflammation, lower blood pressure, prevent arrhythmias, and slow the growth of atherosclerotic plaques, all of which decreases your risk of heart disease.

Getting omega-3's from food and supplements.

The Adequate Intake (AI) set for ALA is 1.1 grams for an adult female, and varies slightly for other age groups.  See a chart with recommended daily allowances for this and other nutrients.   Good sources for ALA include flax seeds and flax seed oil, walnut oil, canola oil, mustard seed oil, walnuts, soybean oil and tofu.

Since DHA and EPA are not considered essential nutrients, the US has not set daily allowances for them.  However several other countries and the WHO have, and the recommendations for a healthy person range from 300-500 mg per day.  Prescription strength DHA and EPA are used to treat a bunch of conditions from rheumatoid arthritis to high triglycerides, and these levels range from 2 to 6 grams per day of the omega-3's.  It's not a good idea to treat yourself with mega doses without checking with your doctor, as they can interfere with blood clotting and cause gastrointestinal problems.

When you are buying supplements of fish oil, make sure it is a brand that is screened for mercury and other toxins, which are common in fatty fish.  Also be aware that it may list the grams of fish oil in the supplement.  This is NOT the same as the amount of DHA and EPA.  A supplement may have 1000 mg (1 g) of fish oil and only 300 mg of omega-3's.  Read the label carefully to see what is in your product.  If you are taking several pills each day, spacing them out will decrease the risk of your having gastrointestinal side effects.  They are absorbed more efficiently if you take them with meals.  Flaxseed oil is a good way to supplement your diet with ALA, which can also be converted in the body to DHA and EPA.

If you would rather get DHA and EPA from food instead of supplements, eat 2 or 3 servings of fatty fish, like those mentioned in the beginning of this article, each week.  Stay away from fried fish and processed, packaged fish since these are high in trans fatty acids, and often low in omega-3's.

Another essential fatty acid is omega-6, or linoleic acid.  (LL)  But, that is a story for another day.

More on studies with omega-3 fatty acids

Structure of fatty acids

Read about omega-6 fatty acids