Depression is a debilitating condition suffered by 121 million people worldwide. (1)
The rate of depression cases diagnosed has been increasing by approximately twenty percent each year. (2)
The World Health Organization estimates that major depression will be the leading cause of disability by 2030. (3)
It was once thought that clinical depression was the result of a chemical imbalance in the brain but that hypothesis has been disproven. In fact, there are many factors of depression.
Current research into the physiological factors of clinical depression has led to the theory of “cytokine-induced depression”, which is basically brain inflammation.
Cytokines are proteins secreted by cells as an immune response. There are inflammatory and anti-inflammatory cytokines. They can act on the cells that secrete them, neighboring cells, or cells in other parts of the body. Certain cytokines have been linked to pathologic pain. (4)
Cytokines Can Cause Brain Inflammation
Cytokines exist in the brain as in other parts of the body. Generally, chronic inflammation anywhere in the body can lead to illness and disease. One might even say that chronic inflammation WILL lead to illness and disease if left unaddressed.
Systemic inflammation of the brain can cause degeneration, manifesting in very distinct symptoms:
- obsessive-compulsive disorder (OCD) (5)
- brain fog
- impeded cognition and mental clarity
- memory loss
- attention deficit hyperactivity disorder (ADHD)
- suicidal ideation (6)
- bipolar disorder
- schizophrenia (7)
- lack of appetite
While inflammation is an appropriate immune system response to pathogens and injury, chronic inflammation occurs when the immune system is turned on but cannot shut off.
Microglia are immune cells in the brain; they serve to cleanse the brain of toxins, dead cells, and routine metabolic waste. Microglia are normally dormant, becoming active only when needed to fight infection or protect cells in the case of trauma.
Activated microglia produce several different chemicals as part of the immune response, including cytokines. (8) Appropriate activation of microglia will return to normal function with no damage done once the danger has been resolved.
Dysregulation of microglia receptors in the brain (caused by chronic inflammation) harms neuronal networks and changes microglia themselves. (9)
“The Immune-Cytokine Model of Depression (ICMD) is an entirely new concept for understanding the riddle of depression. This is the only model of depression to bridge the conceptual and diagnostic gap between physical and mental disorders. ICMD views depression to be any number of chronic physical-biological disorders that have mental-emotional symptoms. From the perspective of ICMD, depression isn’t really a disease, but rather a multifaceted sign of chronic immune system activation.” (10)
Immune Response and Inflammation
Dr. Datis Kharrazian, DHSc, DC, MNeuroSci has spent the last decade researching and teaching functional neurology, autoimmune disorders, chronic illness, and other related subjects.
In his book Why Isn’t My Brain Working?, Kharrazian posits that a weakened blood-brain barrier is the pathway toward brain inflammation.
When this thin sheath of tissue that protects the brain is compromised, it leads to “leaky brain”, similar to leaky gut. If the blood-brain barrier is breached, the way opens to pathogens.
With the introduction of pathogens comes the activation of microglia, which ultimately leads to brain inflammation. (11)
There are many conditions that can trigger microglia’s immune response activity in the brain, leading to inflammation, oxidative stress, neuron damage, and brain degeneration, including (12):
- Parkinson’s disease
- Alzheimer’s disease
- Huntington’s disease
- cerebral ischemia (stroke)
- multiple sclerosis
- AIDS dementia
- traumatic brain injury
- diabetic retinopathy
- glaucoma (13)
- zinc deficiency
- severe infection
- excess cortisol
- gut bacteria imbalance.
Brain Inflammation and Depression
In the past ten years, studies of patients with major depression have uncovered a common theme that initially surprised researchers: inflammation in the brain.
“Neuroimmune mechanisms are now viewed as central to the development of depressive symptoms and emerging evidence is beginning to identify the neural circuits involved in cytokine-induced depression.” (14)
The original theoretical basis for anti-depressant medications was based on the regulation of neurotransmitters that influence mood and emotion. (15) Low levels of serotonin or norepinephrine in particular are thought to be a significant factor in the incidence of anxiety and depression.
Selective serotonin re-uptake inhibitors (SSRI) act to stimulate the production of serotonin and norepinephrine (which are similar in structure to dopamine) in the brain and keep the levels up. (16)
Other types of anti-depressants tinker with other chemicals in the brain to stimulate communication between neurons and influence neural receptors. (17)
SSRI do stimulate the production of serotonin. They also counteract the actions of inflammatory cytokines. It may be the anti-inflammatory properties of these drugs that relieve the symptoms of depression and not the serotonin alone. (18)
Anti-depressants Don’t Work for Everyone
Because anti-depressants are formulated to change brain chemistry, they won’t help if the root problem is inflammation in the brain. (19) In fact, for most people anti-depressant drugs work no better than a placebo (and they come with serious side effects).
Natural Ways to Reduce and Avoid Inflammation
Inflammation is a natural phenomenon and is part of a healthy immune system response. Chronic inflammation is what you want to avoid. Knowing what lifestyle factors cause or increase the risk of systemic inflammation is the first step (source):
- refined sugars
- processed and refined flours (white bread, cookies, pasta, crackers, etc.)
- acidic foods
- dairy products
- animal fats
- food allergens (hidden food allergies cause body and brain inflammation)
- exposure to toxic metals (mercury, lead, cadmium, aluminum)
- chronic infections
- environmental toxins (pesticides, herbicides, food additives and preservatives)
- chronic stress
- lack of exercise, sedentary habits
- nutritional deficiencies: vitamins B12, C, and D; essential fatty acids
- overuse of antibiotics and acid blocking medications
- poor sleep habits.
Diet and Lifestyle to Avoid Chronic Inflammation
By reviewing some of the most common causes of inflammation, you can figure out how to avoid them.
- Exercise is always a good idea for every system in your body.
- Add anti-inflammatory foods to your regular diet—you can find some suggestions here.
- Regulate blood sugar—Alzheimer’s disease has been called “type 3 diabetes” due to the correlation of high blood glucose, insulin deficiency, and insulin resistance found with this neurodegenerative disease. (20)
- Use fruit oils (extra virgin olive, coconut, avocado) instead of vegetable oils and margarine (canola, corn, soy).
- Get enough omega-3 fatty acids.
- Ensure you regularly get enough quality sleep. (21)
- Restrict or eliminate processed foods, especially refined flour and sugar. Limit or eliminate wheat if you’re in the least bit sensitive to it.
- Increase fresh organic produce, herbs, and spices of all colors to get nutrients and antioxidants (which reduce inflammation).
- Especially consider adding these to your diet: green tea, ginseng, turmeric, ginger, nuts and seeds.
- Practice mindful meditation to relieve stress. (22)
Chronic inflammation anywhere in your body can be disastrous.
This is especially true for brain inflammation, which we now know to contribute to depression and neurodegenerative diseases.
To beat depression, you have to approach it holistically from both an emotional and a physiological approach.
Taking conscious steps to reduce systemic inflammation will help your psyche as well as your physique.