Can Fats Make You Happy?: Omega-3 Fatty Acids and Depression

Is all the discussion about Omega-3 fatty acids in health just a bunch of hype? The short answer is “no.”

Our best evidence on the effectiveness of Omega-3s is in the prevention of heart disease. They are particularly good at lowering triglycerides. And as I described in a previous blog, heart disease and depression and not only related, but likely share a similar underlying mechanism.So the fact that Omega-3s are helpful for both makes sense.

The long-chain Omega-3 fatty acids, EPA and DHA, have been used successfully to both prevent and treat depression. Both of these are found in fatty fish. EPA is the Omega-3 that actually treats depression because it specifically lowers inflammation and lowers the stress response. It has been used by itself or has been combined with medications. When it is used with medications, it makes medications work more effectively. The American Psychiatric Association recently recognized EPA as a promising treatment for mood disorders.

DHA helps prevent depression, but does not treat it by itself. It is usually combined with EPA. There is a vegetarian source of DHA, but no vegetarian source of EPA; fish oil is still the best source. Sources and dosages are listed on the side bar. Even in relatively large doses, EPA and DHA are safe for children, pregnant and breastfeeding women, and other populations. In addition, they provide a number of other health benefits for men and women, including lower their risk of heart disease and making them less vulnerable to stress.

For vegetarians, the bad news is that ALA, the Omega-3 in flax seed and other plant sources, such as walnuts and canola oil, does not prevent or treat depression. ALA is not harmful and can be helpful in other ways. But it is metabolically too far removed from EPA to aid in lessening depression.

What I like is that there really is no downside to using Omega-3s. And there is considerable upside. Even if they doesn’t lessen depression by themselves, they increase overall health. And that is a good thing.

Depression and Inflammation: The Surprising Link

Depression is risk factor for depression. Researchers have known that for many years but couldn't really explain why—until now.

In the past 10 years, researchers have firmly established that a lot of common diseases--such as diabetes, cancer, Alzheimer’s, and yes, even heart disease--are due to inflammation. For example, physicians have noted that elevated levels of an inflammatory marked called C-reactive protein is an early harbinger of heart disease.

But here’s where the plot really thickens. Depression is also caused by inflammation, and specifically by elevated levels of molecules called proinflammatory cytokines. In fact, by specifically treating people with cytokines, as they do for conditions such as MS, doctors have actually caused depression. The more cytokines patients received, the more depressed they got. When the patients started to taper off of the cytokines, the depression got better too.

Depressed people have significantly higher levels of the cytokines in their plasma than non-depressed people. And this is where the disease-depression link comes from. High levels of proinflammatory cytokines damage blood vessels, and elevate other factors in the blood that increases the risk of clots.

And in another interesting twist, we now know that most of the effective treatments for depression have one thing in common: they are also anti-inflammatory. In fact, that knowledge has fueled some very interesting discoveries. For example, antidepressants lower inflammation levels in cardiac patients. And they’ve been added to steroids for treating asthma, leading to the use of fewer steroids in these patients.

This discovery has also led to some novel ways of treating depression. For example, anti-inflammatory medications, such as ibuprofen, which is not an antidepressant, have been added to antidepressants to make them more effective. Adding Omega-3 fatty acids to a treatment regimen helps with depression for the same reason.

Knowing about the anti-inflammatory connection also gives us a framework for understanding why non-medication treatments for depression would also work.

Inflammation: The Key to the Link between Stress and Disease

Human beings are wired to respond to physical threat in some predetermined ways. This is our body’s way of preserving our lives. The problem is that our normal stress response is meant to be acute, not chronic. But the types of stressors modern humans encounter are often chronic, and so our stress response is out of sync with the realities of our world. When stressors are chronic, our stress response malfunctions and actually increases our risk of disease.

There are three main components of the stress response. When you understand these, you will understand the basic concepts underlying mind-body medicine.

Simply put, the human stress response has three basic components.

The first is the catecholamine, or fight-or-flight response, and it kicks in as soon as we are threatened.

The second is the response of the HPA axis. HPA stands for hypothalamic-pituitary-adrenal axis. When faced with a threat, the HPA axis responds with a cascade of chemicals, the final one being the stress hormone cortisol.

The third component is the immune system’s response. When faced with danger, the immune system increases inflammation by releasing molecules known as proinflammatory cytokines. Cytokines are basically messenger molecules of the immune system. Inflammation has a very important role in protecting your health. These molecules protect you against infection and heal wounds. But when levels of these cytokines continue to be high, they can actually damage your body.

A key finding in mind-body research is that psychological stress can trigger the inflammatory response.

You’ll notice that I’ve drawn this three-component response with arrows connecting each component. In a normally functioning system, these three components serve as checks and balances to each other. When one part gets too high, the others activate to lower it. The problem is that when this system is overloaded, as it is in stress and depression, the components no longer serve as checks and balances. Instead, they start actually enhancing the negative effects.

Fortunately, there are some steps you can take to lower your response to stress. And that is what we will talk about in the next few posts.