EPA for Psychiatric and Neurodegenerative Diseases

A new review found controversial results from studies on the effects of eicosapentaenoic acid, a type of omega-3 fatty acid, on psychiatric and neurodegenerative diseases.

Neurodegenerative diseases are neurological disorders marked by the loss of nerve cells. Examples include Alzheimer's disease, Huntington's disease and Parkinson's disease.

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are both contained in fish oil. Oily fish, such as salmon, tuna, and herring, are good sources of EPA. Fish, liver, and egg yolks are good sources of DHA. In addition, the body converts alpha-linolenic acid, which is commonly found in nuts, seeds, and vegetable oils, into EPA and DHA.

There is evidence from multiple large-scale population (epidemiologic) studies and randomized controlled trials that intake of recommended amounts of DHA and EPA in the form of dietary fish or fish oil supplements lowers triglycerides, reduces the risk of death, heart attack, dangerous abnormal heart rhythms and stroke in people with known cardiovascular disease, slows the buildup of atherosclerotic plaques ("hardening of the arteries") and lowers blood pressure slightly. However, high doses may have harmful effects, such as an increased risk of bleeding.

Researchers from the University of Prince Edward Island in Canada explained that decreased n-3 fatty acid levels have been reported in patients with depression, schizophrenia or Alzheimer's disease.

The review reported that recently, EPA has been used to treat several psychiatric and neurodegenerative diseases due to its anti-inflammatory and neuroprotective effects. A total of six out of seven clinical trials have shown that EPA significantly improved symptoms of depression when compared with the placebo-treated populations.

Several investigations have also reported that EPA could effectively treat schizophrenia. A case report and a clinical trial have shown that EPA was beneficial for the management of most symptoms of Huntington's disease, while a more extensive clinical investigation has demonstrated that EPA could only improve motor functions.

The authors concluded that further clinical studies are required to fully explore the effects of EPA on other neurodegenerative diseases. The limitations of previous studies and further research directions were also discussed in the review.

The American Heart Association (AHA) recommends including fish in the diet for all individuals, and fish oil supplements in those with a history of cardiovascular disease.

Fish oil has been suggested as beneficial in conditions associated with low levels of omega-3 fatty acids (in plasma and/or membrane phospholipids) such as some psychiatric disorders. For mood disorders, Dr. Andrew Stoll of Harvard University has recommended 3-10 grams daily of EPA and DHA, in three divided doses with meals. Dr. Dean Ornish (creator of the Ornish diet ®) has recommended 2 grams per day of fish oil (MaxEPA®) for "cardiovascular improvement."

For more information on EPA and other omega-3 fatty acids, please visit Natural Standard's Foods, Herbs & Supplements database.

Comments

[W Thomas]

This is interesting. I know McClean's hospital has been studying EPAs for depression and other psychiatric disorders for a while now, but the doses found to be effective are quite high... beyond what one could possibly consume through diet alone. One of the issues with supplements is finding one that is pure and low in mercury. There was supposed to be a prescription, high-grade fish oil supplement approved for use for lowering trigylcerides... has anyone heard whether or not it has been approved?

[Pat]

This study is interesting. What types of fish are the best to eat? I've heard that some fish contain really high levels of mercury, which could be unsafe if you eat a lot of fish. Also, is this something you should be extra careful of during pregnancy?

[Stella]

Lovaza is a prescription omega-3 medication, and it is used to treat high triglycerides (over 500).

[Maryanne]

Because of the increased risk of bleeding, is it better to just get eicosapentaenoic acid through food rather than both food and supplements?

[Thom]

How much would have to be taken to cause thinning of the blood?

[Lynn]

This could certainly be promising if studied further. If consumed in moderation, are the positive effects still expressed? Does the risk of bleeding still significantly increase? I feel as if a balance of these foods might be the best option.

[asher]

Why open with the term, 'controversial'? ("A new review found controversial results from studies on the effects of eicosapentaenoic acid ...") I would have thought that "promising," 'hopeful," "encouraging," etc., would have been more appropriate.

By the way, in my country (Australia), commercial fish oils must be tested to ensure they're under a certain ppm level of mercury and other contaminants before the TGA will allow them onto the market. Generally, the bigger the fish, the higher the mercury content.

[Kelsey]

I read that the actual amount of omega-3 fatty acids in your body doesn't matter. What is important is the ratio of omega-6 fatty acids to omega-3s. Omega-6s are the kind of fatty acids found in sugary, processed foods. High levels of these have been strongly linked to depression and other psychological disorders. So it may not be so important to eat a lot of fish to counteract depression as it is to just eat less junk. Food for thought.

[Rihanna]

I think we should be weary of adding too many supplements. If we just eat very nutritious foods, we shouldn't have to supplement our diets. And I know that with fish, it's difficult to know how much is "safe" to eat because of mercury. And some studies really put an emphasis on how much fish you should eat because omega-3s are so important to health, and others tell you to watch it because of mercury. As long as you buy your fish from reputable sources, I think fish is a safe and important part of a healthy diet.

[Sherry]

I bet person behind the counter at your local fish market could tell you which fish contain the most mercury. I think where the fish was caught has a lot to do with the mercury content.

[Linds254]

Is it possible to consume high doses of EPA and DHA through food alone? The review doesn’t mention anything about the risks. Also, how do we know whether we got our fish from a good source and that it is safe?

[Mikaela]

Linds254,

Most cookbooks have tips on what to look for when buying fresh fish. In general, if you buy it from a busier store it's better because high demand means your fish hasn't been sitting around for a long time. Some other things to look for...

For a whole fish: full, clear, bright eyes, bright color, clean gills, mild odor (if it smells "fishy" it's no good!), shiny skin with tightly adhering scales and firm, elastic flesh.

For a fillet: glossy, fresh-cut look, firm texture, no browning or dried out edges and no discoloration.
Definitely take the time to look when you're shopping!

[Mitch]

Since low levels of n-3 fatty acid levels have been reported in patients with depression, schizophrenia and Alzheimer's disease, could supplements also help prevent these conditions?

[Daniel]

Do vegetarians need to have more amounts of EPA and DHA levels compared to non-vegetarians?

[Angel]

I'm really glad that researchers are studying possible treatments for neurodegenerative disorders. My aunt has Alzheimer's disease, and it's absolutely devastating. I hope that future research helps scientists develop newer, more effect drugs so that other people don't have to go through the pain of losing someone to such a debilitating illness.

[Lindsay]

Angel, I completely agree with you. My friend's father has Parkinson's disease, and it's hard on the whole family. Although it'll probably be many years before scientists find an effective treatment or cure, it's good to know that research is being done.

[Bonnie]

This study makes me feel fairly confident considering that many large-scale population studies with controlled trials have been done to study the effects of EPA (in fish form) on people in different ways. I always knew that eating fish was good for you, but now I really know the reasons why! I was shocked and amazed that there have been some investigations into EPA treating schizophrenia. This seems like something that should be studied right away because the benefits could prove to be unfathomable!

[Justine]

I’m glad that they mentioned not only the benefits of EPA and DHA, but also the fact that high doses may have harmful effects like bleeding. I do wish they went into more details about this though. How much is too much? I’m wondering if it’s the fish itself that might be harmful. I know that fish often contains mercury, but do the omega-3 fatty acids themselves cause harm as well?

[Andrew K.]

Are there any differences in taking omega-3 supplements, eating fish, or taking fish oil? Also, are there other nutrients in different types of fish that are beneficial? I’ve only ever really heard about the fatty acids. Since I don’t like fish I’d like to know what alternatives there are to it alone. It’s obvious that the benefits are worth it!

[Linds254]

Thank you so much for your answer Mikaela! I have been trying to cook my own meals lately and the tips you mentioned about buying fish will come in handy! I have been reading a lot about the benefits of eating fish and consuming foods with DPA and EPA lately, so this is great news!

[Greg]

I agree with Rihanna. I am also concerned about taking too many supplements. I definitely do not get enough fish in my diet, and I am considering taking fish oil in supplement form. Being a college student, it is difficult to buy and prepare fish the healthy way. Does anyone know more about taking different supplements at the same time? Is there a safe way to balance them?

[Justin A.]

Kelsey brings up a good point. Eating healthy always goes back to balance and avoiding junk foods. I didn’t know about the ratio of omega-6 fatty acids to omega-3s being an important factor, but this makes sense. As important as it is to incorporate nutritious foods into our diets, we also need to cut down on the not-so-nutritious foods we eat.

[JP]

To answer Daniel's question, a great source of omega-3s for vegetarians are nuts, especially walnuts. My aunt is a nutritionist, and she has said that a great snack is a nut mixture, aka peanuts, walnuts and almonds. They are all a great balance of protein, healthy fat and omega-3s.