people over the course of 21 years, researchers found that those with high levels of C-reactive protein — an inflammation marker we discuss more in Chapter 7 — had a 12 percent steeper decline in thinking and memory skills than those with lower levels.
Though it’s the most common cause of dementia, Alzheimer’s disease isn’t a normal part of aging; only about 1 in 10 people over the age of 65 has Alzheimer’s, and about a third — 32 percent — of those over the age of 85 have the disease. There is no cure, but treatments are available.
Probing Parkinson’s disease
Parkinson’s disease is an attack on the nervous system that starts gradually, affecting your movement, your expressions, and even speech. Early symptoms can be as little as a barely detectable tremor in one hand, but they’re often accompanied by a stiffness in movement.
As the disease progresses, your face may stop showing signs of expression, and your arms may not swing when you walk. Speech will become difficult and slurred.
In the past, scientists didn’t see a connection between Parkinson’s disease and inflammation. Now, however, researchers are seeing chronic inflammation as a potential cause for the disease, and not a result. An abnormal accumulation of certain proteins is believed to trigger an inflammatory response, which then allows the disease to progress.
Early symptoms of Parkinson’s disease include the following:
Tremors
Slowed movement (bradykinesia)
Rigid muscles
Impaired posture and balance
Loss of automatic movements
Changes in speech
Changes in writing
Here are the risk factors for Parkinson’s disease:
Age: Parkinson’s disease generally starts in midlife, with the chances increasing as you get older. It rarely occurs in young adults.
Your genes: Having a close relative with Parkinson’s disease increases your chances of getting the disease as well. Still, unless you have several relatives with the disease, your chances don’t increase that much.
Gender: Parkinson’s occurs most often in men.
Environmental toxicity: Those regularly exposed to pesticides, herbicides, and insecticides have a greater likelihood of developing Parkinson’s disease.
Investigating amyotrophic lateral sclerosis (ALS)
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease, meaning it starts slowly and gradually worsens. Also called Lou Gehrig’s disease, ALS works against the nerves in your brain and spinal cord that control your muscles, inhibiting muscle movement and function.
As the disease progresses, it causes your muscles to continue to weaken, eventually leading to paralysis of your muscles — making not only walking and talking impossible, but also eating and breathing.
ALS happens when the motor neurons in your brain stop sending messages to your spinal cord, which then means your muscles aren’t getting the message, either. These messages control voluntary movements, like reaching for your phone or standing up, but also involuntary movements, like breathing and swallowing. The nerve cells stop communicating because they begin to break down and die. When your muscles stop working, they become weak and begin to atrophy.
There is no cure for ALS, and the typical lifespan post-diagnosis is three to five years, although some with the disease have lived ten years or longer.
Scientists are unsure what exactly causes ALS; only 5 to 10 percent of cases are genetic. Researchers have found links between ALS and the following:
Problems with the immune system: Though scientists stop short of calling ALS an autoimmune disease, some believe the brain’s main immune cells, the microglia, might be destroying healthy neurons.
Glutamate buildup: Glutamate is like a chemical transmitter, sending signals to and from the brain and nervous system. In people with ALS, glutamate builds up around the nerve cells and causes damage.
Oxidative stress: Some of the oxygen your body uses for energy may actually work against you and form free radicals (unstable molecules that have electrons that react with your tissues and can damage them).
Inflammation: In a 2017 study from Minzu University of China, researchers found that levels of pro-inflammatory molecules are increased in people with ALS, particularly in the central nervous system.
Assessing Huntington’s disease
Huntington’s disease is a fatal disorder that affects both physical and mental abilities and generally attacks right in the mid years — symptoms begin to appear between the ages of 30 and 50 and worsen over the next 10 to 25 years. It’s a genetic disease; if one parent has Huntington’s disease, each child has a 50 percent chance of inheriting the bad gene.
Huntington’s disease takes the worst features of Alzheimer’s, Parkinson’s, and ALS and brings them together into one disease. It causes depression and changes in personality, and it hampers the ability to walk and causes involuntary movements. Other symptoms include slurred speech and difficulty in swallowing.
The disease is incurable, and most who are diagnosed live 10 to 20 years after diagnosis, although some have lived 30 to 40 years.
Chronic inflammation has often been found in the nerve cells of those with Huntington’s disease, and researchers believe it may be one cause of the disease’s damage to the nervous system.
In fact, some studies have found that chronic inflammation plays a key role in how Huntington’s disease progresses. Inflammation occurs when there is injury or infection as the body’s way of protecting itself against infection. Your immune system attacks foreign systems in your body to get rid of them.
Some scientists believe the immune system sees an extended glutamine tract and interprets it as a foreign substance and tries to get rid of it.
Contributing to Cancer
Researchers continue to find connections between cancer and inflammation. For example, medical researchers have found that
Inflammation can cause DNA changes. A study conducted by the Massachusetts Institute of Technology (MIT) shows a correlation between the DNA damage caused by inflammation and colorectal cancer.
Recurring infections due to viruses, bacteria, and even overgrowth of yeast can set the body up so it’s prone to developing cancer cells. For example, certain strains of HPV (human papillomavirus)
