Toxins in food, like nitrosamines in cured and smoked meats, can stimulate the growth of cancer cells.
Chronic inflammation helps existing tumors grow and can encourage cancer stem cells to replicate. A study at the University of Michigan’s Comprehensive Cancer Center in 2010 suggested that the link between the stem cells of breast cancer and inflammation can promote recurrence of the cancer.
When inflammation persists, it creates a negative environment that can support the development of tumors, and pre-cancerous cells can become malignant. Researchers believe this happens because many of the processes that occur in chronic inflammation can contribute to tumor growth and disease progression.
Inflammation starts with the help of cytokines — chemicals that send signals to certain cells to either enhance or suppress the body’s immune system. These cytokines are proteins whose primary responsibility is to attack foreign bodies or damaged cells or to signal other parts of the immune system to get in gear and attack. Cancer cells are just the type of cells cytokines should be attacking. However, although cancer cells have somehow lost their ability to control their own growth, they are otherwise normal, healthy cells. Because of this, the immune system doesn’t recognize these cells as foreign, so it doesn’t attack.
Altering the Mind with Inflammation
Since the early 2000s, scientists have discovered that psychological stress is actually a trigger for certain kinds of inflammation — and that inflammation has been linked to the development of a variety of conditions, including depression, bipolar disorder, and schizophrenia, which we discuss more in the following section.
A new model of understanding mood disorders, such as anxiety and depression, identifies a link between inflammation and behavior. Neurotransmitter imbalances once believed to be the only causes of mood disorders are actually a response to inflammation in the brain, called neuroinflammation.
The inflammation in the human brain is also related to the gut through the gut-brain axis we discussed earlier.
Scientists has been investigating inflammation starting in the gut as playing an important role in mental health. The gut is no longer considered a simple organ designed for digestion, but rather a microbiome, an organization of living microorganisms. And when that organization experiences an imbalance, other organs, such as the brain, are affected.
A number of factors can cause gut imbalance, including the following:
Environmental toxins
Infections
Poor diet
Stress
Inflammation not only affects how the human body feels, but it also affects mood and mental health.
Examining depression
Depression is one of the leading causes of disability worldwide, according to the World Health Organization, with more than 264 million people globally suffering from the disorder.
Although inflammation can be healthy when the body is responding to injury or infection, it actually can lead to varying degrees of depression when it lingers. Typically, inflammation acts in concert with the immune system: when a person is sick, she becomes tired and experiences cognitive impairments and loss of appetite, so inflammation and the immune system helps the person sleep and get rest, gathering strength and balancing the brain.
But when an illness lasts for an extended period, the inflammation triggers depression and other illnesses. Researchers studying the link have found higher levels of inflammation markers in people who are depressed than in those who aren’t.
Here are a few of the several kinds of depression:
Major depressive disorder: This kind of depression is characterized by feelings of depression most days of the week. Other symptoms include loss of interest in things you used to enjoy, feeling of restlessness and agitation, unexplained weight loss or gain, difficulty making decisions, and thoughts of suicide.
Persistent depressive disorder: This depression lasts two years or longer, also known as chronic depression. Symptoms include low self-esteem, loss of appetite, difficulty concentrating, and feelings of hopelessness.
Psychotic depression: Psychotic depression is characterized by depression accompanied by hallucinations, delusions, or paranoia.
Although a great deal of emerging research has linked major depressive disorder and other chronic depressive conditions to inflammation, researchers know little about the role inflammation plays in acute depression.
Looking closer at bipolar disorder
Bipolar disorder, formerly called manic depressive disorder, is a disorder that causes shifts in mood, energy levels, concentration, and even the ability to complete daily tasks. Mood levels swing from very up — high energy, happy to near elation — to the very low — extremely sad, irritable, anxious, and hopeless.
Bipolar disorder is usually diagnosed during the teen years, though it can present in children as well. Some women may be diagnosed during or immediately after pregnancy. Although symptoms may no longer be present, bipolar disorder requires lifelong treatment.
The three kinds of bipolar disorder are as follows:
Bipolar I: This disorder is characterized by manic episodes that last at least a week or are so severe that they require hospitalization. The person is typically depressed as well, with depression lasting two weeks or more.
Bipolar II: Characterized by fewer and shorter episodes, this disorder doesn’t typically require hospitalization. Episodes can be manic, but they may only last a few days.
Cyclothymia: This disorder is defined as someone having hypomanic and depressive episodes that last about two years — one year in children and adolescents — but the symptoms aren’t severe enough to be actually diagnosed hypomanic or depressive. Hypomania is when your energy levels are higher than normal, but not as extreme as with mania.
A 2019 study from Brigham and Women’s Hospital showed a link between inflammation levels and the cognitive level of a person with bipolar disorder. Scientists found that those with higher levels of inflammation markers had poorer cognitive function — they had more trouble focusing, concentrating, and completing seemingly normal tasks.
Researchers viewed the findings as a treatment target for cognitive loss; by reducing the levels in inflammation markers, researchers believe the findings can improve cognitive function.
Eyeing schizophrenia
Schizophrenia is a very serious mental condition in which people have an abnormal or skewed perception of reality. Those with schizophrenia often experience hallucinations, delusions, and a cognitive impairment that hinders their ability to perform day-to-day functions. The disorder is typically diagnosed in men in their mid-20s and in women in their late 20s.
There is no known cause of schizophrenia, but
