Depression and Immunity

The sad fact is that one in five of us will suffer depression at some time in our lives. More than 20 million North Americans are afflicted with some form of depression, and it occurs twice as often in women as in men. The intensity may vary from mild to severe, and it may happen only once or recur throughout one’s lifetime.

While everyone feels down at some time or another, depression is a severe state of unhappiness that imposes itself on a person’s state of mind and affects his or her habits and normal conduct for at least two consecutive weeks. In some cases, depression can last months or even years before a diagnosis is made or treatment is sought. It often starts without a clear reason, is intense and can last for long periods.

Emotional trauma, the loss of a loved one and extreme stress are a few factors involved in the onset of depression. However, depression is more than sadness or the result of negative situations in our lives; it is a biochemical change in the brain. Depressed people have low levels of the neurotransmitter, serotonin. Food allergies, nutritional deficiencies and thyroid disease can have a profound effect on the biochemical activities in the brain. Depression has also been thought a consequence of serious and life-threatening diseases. Now the basis for depression will have to be rethought, as researchers are discovering that an overactive immune system may be the cause of severe depression.

Immune-Boosting Drugs and Depression

Over the last decade, reports have surfaced that those who have been prescribed powerful immune-boosting drugs such as interferon for hepatitis and cancer have experienced life-threatening depression with suicidal feelings. As a result, scientists have sought answers and, although the jury is still out, a hyper-stimulated immune system may just be the cause. This is the complete opposite of what was believed in the past. Depression was most often thought of as a symptom of weak immunity. Now, for many people with depression, treatments look at ways of regulating the immune system and controlling the inflammatory process that is involved in fighting viruses and other invaders. In other words, keeping the immune factors that regulate the immune system in balance.

See Treatments That Work

Overactive Immunity

Michael Maes, a psychiatrist at the University of Maastricht in the Netherlands, was one of the early researchers who thought that weak immunity was associated with depression. But he recently found that immune cells (including natural killer cells and macrophages) from those with depression were very overactive and secreted too many inflammatory immune factors. Other scientists are also making the connection between hyper-stimulated immunity and depression by looking at conditions affecting depressed individuals. Depressed people often have higher temperatures, suggesting they are fighting an infection, which results in an increase in inflammatory immune factors. As well, depressed people are three times more likely to die of heart disease. And as we now know, arteriosclerosis (blocked arteries) can be caused byinflammation in the arteries from bacterial infections.

So, what happens in the immune system to promote depression? We know that when the body is under attack, from a virus for example, immune cells secrete large amounts of inflammatory immune factors whose job is to destroy the virus. This boost in the immune system, when allowed to go on for too long, may be what affects mood and causes depression. Serotonin levels are known to be low in those with depression, and research has shown that immune-boosting substances can deplete tryptophan, a precursor used by the body to make serotonin. One third of people taking immune-boosting drugs get depressed. Nobody correlated this to an overactive immune system because it was just assumed that, if you were being treated for cancer or other serious diseases, the depression was a side-effect of the disease, not the treatment!

Stress, Cortisol and Inflammation

The stress/cortisol connection is important to preventing and treating depression. Cortisol is very important because we need it to regulate immune function. But a proper balance iscritical. When we are in a stressfulsituation, our adrenal glands secrete cortisol, causing an increase in inflammatory immune factors. This event is normally short lived and when the cortisol is no longer needed, our brain sends signals to stop it from being released. Cortisol levels then go back to normal, and the immune factors also revert back to balanced levels. But in depressed people, the brain fails to control cortisol and levels remain too high. Inflammatory immune factors secreted by our immune cells also cause an increase in cortisol secretion, adding to already excessive levels and thereby promoting depression.

Stressful events, high cortisol levels and the resulting inflammatory response, as well as viral infections, probably all play a role in altering mood. So what do we do if we have depression? See the accompanying chart for suggestions. Regulating or balancing immune function may turn out to be the best strategy.

Depression and Essential Fatty Acid
by Serenity Aberdour, ND

Research has shown a possible link between a deficiency of essential fatty acids (EFAs), particularly the “omega 3s,” and depression. It is an interesting story that goes something like this:

Cell Membranes

Our nerve cells (neurons) have a membrane, a sort of capsule that keeps all cellular bits and pieces inside where they belong. The makeup of this membrane is affected to a significant degree by diet. More EFAs in the diet means more EFAs are available for use in cell membranes. This can have a significant effect on the quality and function of a membrane.

EFAs help to keep a membrane “fluid.” Picture a bottle of flax oil and a tub of lard. Both are forms of fat, but their fatty acid contents give them very different qualities. Flax oil, high in unsaturated omega-3 fatty acids is fluid, flowing. Lard, full of saturated fatty acids, is hard and flows nowhere.

At the point where two neurons meet, a point known as a “synapse,” a fluid membrane becomes particularly important. Synapses are where neurons “talk.” The conversation is mostly an exchange of chemical messengers called neurotransmitters. Neurotransmitters, particularly serotonin, are a major focus in depression research. Serotonin is a “feel good” chemical and if levels are low and/or if serotonin does not pass properly between neurons, people may become depressed.

If a synaptic membrane in less fluid, neurotransmitters may not be transferred as efficiently as they should be. Increasing your omega-3 intake may help.

"Depressed" Blood

Studies show that red blood cells of depressed patients have low levels of certain omega-3 EFAs and that the degree of this deficiency may be correlated with the severity of the depression that is experienced. Depressed patients have also been found to have higher levels of inflammation-promoting substances called series two prostaglandins. A popular naturopathic approach to inflammatory conditions is to prescribe high doses of omega-3 fatty acids, usually in the form of flax or fish oils, to reduce the levels of these prostaglandins in the body. Now this time-honoured treatment may help to ease depression as well. Interestingly, some of the prescription drugs used to treat clinical depression are also known to manipulate prostaglandins levels.

Why Fish Oils?

The omega-3 EFA most effective in easing depression is likely to be fish oil. Cultural studies show a correlation between a population’s incidence of depression and its fish intake: more fish, less depression. Biochemistry offers more support for this argument. The type of omega-3 fatty acid incorporated into nerve tissue in greatest amounts is docosahexaenoic acid (DHA), the very EFA high in cold-water fish such as salmon and mackerel. The omega-3s in flax oil must first be converted to DHA before the brain can use them to build cell membranes. Rats are quite successful in accomplishing this conversion; humans have a harder time of it. So if you are targeting neurons and nerve function, supplementing with DHA or fish oil may be more efficient.One word of caution: when using fish oils, be sure to select supplements known for their purity and a policy of testing to ensure products are free of contaminants.

See Paxil antidepresant may up suicide risk

Source: Serenity Aberdour, ND has a particular interest in the natural treatment of depression and digestive disorders. She can be reached at docere@care2.com.