What Causes COPD? Antioxidants Versus Oxidative Stress
So, we know COPD is chronic bronchitis and emphysema. We know it’s caused by inhaling irritants like cigarette smoke and toxins. Researchers now think they understand the link between airway irritants and COPD, and it lies in the relationship between antioxidants and oxidative stress. (1)
Here’s all you need to know.
What are free radicals? Electrons inside molecules like to be paired. When this happens a molecule is said to be stable. When a molecule has one or more unpaired electrons, it is said to be unstable. Such an unstable molecule is a free radical. They are “highly reactive” with other molecules. They are byproducts of “cellular and metabolic processes” inside your body, and they are normally stabilized by antioxidants (2-4)
What are antioxidants? These are molecules present in cells that donate electrons to free radicals without themselves becoming unstable. In this way they prevent free radicals from causing oxidative stress. (3-4)
What is oxidative stress? In our natural environment, it's what causes an apple to turn brown, or what causes iron or steel to rust. Inside our bodies, it causes cells to break down. It's when your body doesn’t have enough neutralizers like antioxidants to keep up with an excessive amount of free radicals. Free radicals start stealing electrons from molecules in nearby cells to obtain stability. They can steal electrons from any part of a cell, from the cell membrane to DNA. The molecule the electron is taken from becomes a free radical, and it steals an electron from another molecule. This sets off a series of chain reactions. This is oxidative stress, and it is very toxic or damaging to cells. It can even kill them. (2-4, 6)
What causes oxidative stress? Interestingly, many of the same things we are often told to avoid are the same things that can overwhelm the “antioxidant system and cause cell damage." (4) These include excessive drinking, smoking, drugs, ultraviolet light, radiation, pollution, toxins, chemicals, excessive exercise, inflammation (due to infections), very high levels of supplemental oxygen, and even illness. These are just some of the things that damage cells to cause chronic diseases such as hypertension, heart disease, diabetes, cancer, arthritis, pulmonary fibrosis, anxiety, depression, allergies, asthma, and aging. In our case, chronic inhalation of chemicals in the air at work or in wood or cigarette smoke are responsible for the development and progression of chronic bronchitis and emphysema, or COPD. (1-7)
How does oxidative stress cause damage to cells? To keep things simple here, let’s just consider the type of cell lining airways. Oxidative stress can cause them to abnormally trigger the same immune response they trigger when they are invaded by pathogens such as viruses. They release chemicals that mediate inflammation, and this in turn causes persistent airway inflammation. This inflammation is meant to trap pathogens, but there are no pathogens present. Plus, this inflammation doesn’t go away like it would if you had a cold, mainly because these chemicals would constantly be released. Long-term, this inflammation is damaging to cells, causing airway tissue to become scarred or thickened. This makes airways chronically narrow and leads to a diagnosis of COPD. These same chemicals may also cause inflammation of lung tissue, and long term this may damage lung tissue resulting in a diagnosis of emphysema. (1)
Can oxidative stress damage genes? Absolutely. It can cause gene mutations that turn genes responsible for the immune response into COPD genes. They may cause genes that make inflammatory chemicals to make too many of these chemicals, thereby resulting in airway and lung tissue inflammation. It can change the gene that make protease. Protease are enzymes that destroy dead and decaying lung tissue. These genes may now make too much protease. Or, anti protease genes may be make too little antiprotease. When protease is in excess, they may start to destroy healthy lung tissue resulting in a diagnosis of emphysema. (1, 5, 8)
Can oxidative stress due to inhaling pollutants cause other diseases too? The current thinking is that this is the case. While it’s a complicated process, they believe the oxidative stress caused by the over 4,000 chemicals in cigarette smoke, for instance, may impact the rest of your body too. The same is true for the inflammatory chemicals released in our example above, as they may also infiltrate your circulatory system and cause coronary artery disease. It is this revelation that has researchers now referring to COPD as a systemic disease more so than just a lung disease. (1)
Does oxidative stress affect COPD medicine? Actually, researchers seem to think that it may cause a decrease in the amount of receptors on cells for corticosteroids, especially during COPD flare-ups. This may explain why inhaled steroids, and even systemic steroids, don’t work as well for treating and controlling COPD as they do for asthma. Interventions may be needed to correct the imbalance so corticosteroids work better. A diet rich in antioxidants may prove helpful. This may also be another reason to continue the quest to finding better medicines for treating and controlling COPD. (1)
What can you do to stop oxidative stress? A good strategy may begin by teaching people about the importance of avoiding all of the things noted above that may contribute to oxidative stress and cause chronic diseases. In our case, it would involve educating children about the importance of never starting smoking. For those who already smoke, it’s important to educate them about the importance of quitting smoking. It’s also important to educate people in the workplace about creating strategies for avoiding airway irritants, such as wearing masks. These are just some examples. Another way to stop or slow damage due to oxidative stress is by eating a diet rich in antioxidants.
What foods are high in antioxidants? Antioxidants can be obtained through supplements that contain vitamin A, C, E, and beta-carotene. They can also be obtained through a diet rich in fruits, nuts, vegetables, chocolate, fruit juices, vegetable juices, tea, and red wine. You can learn more by reading the following articles: “Can a diet improve COPD control,” and “Supplements, Herbal Treatments, And Antioxidants”
What's our conclusion?
You could go crazy reading about this stuff, as it is a very confounding subject, even for researchers. However, they must continue to study this subject in an attempt to better understand our disease and to hopefully one day come up with better strategies for preventing it, treating it, and, ideally, curing it. In the meantime, their research is making us increasingly aware of the need to be mindful of what we eat, drink, and inhale.
Do you live with any sleep disorders (eg. insomnia, RLS, sleep apnea) in addition to COPD?