2025.01.20
[Doctor Supervised] The Relationship Between Oxidative Stress, Smoking, and Atherosclerosis: Points to Escape Free Radicals
Smoking promotes the production of free radicals and reactive oxygen species (ROS), leading to oxidative stress. When oxidative stress increases, reactive oxygen species attack healthy cells, and damage to blood vessel walls raises the risk of atherosclerosis.
Since diseases caused in part by oxidative stress are common, suppressing free radicals (reactive oxygen species) is crucial for maintaining health. This article explains the relationship between oxidative stress and atherosclerosis.
Smoking is said to lead to atherosclerosis, but oxidative stress plays a role in this connection. When harmful substances in cigarette smoke are absorbed into the body, they trigger oxidative stress.
When free radicals and reactive oxygen species increase in the body, disrupting the balance with the antioxidant system, excess free radicals and reactive oxygen species damage enzymes and cells. This damages blood vessel walls, leading to the accumulation of plaques and the development of atherosclerosis.
When smoking, acetaldehyde is secreted into saliva. Additionally, cigarette smoke contains harmful substances such as nitric oxide, carbon dioxide, and nicotine. These substances enter the body through saliva and breathing, generating free radicals and reactive oxygen species, which elevate oxidative stress.
Humans consume oxygen when using their brain and body. In the process of converting oxygen into energy, it changes into highly reactive substances called reactive oxygen species (ROS). While ROS are beneficial for functions like fighting bacteria and viruses or transmitting signals between cells, their strong oxidative power can harm healthy cells when produced in excess.
Among ROS, superoxide and hydroxyl radicals possess unpaired electrons, making them free radicals. These atoms or molecules with unpaired electrons are highly oxidative, capable of aggressively stealing electrons from surrounding substances.
Related Article: What Is Oxidative Stress? (Louis Pasteur Medical Research Center Antioxidant Laboratory)
Oxidative stress occurs when ROS production exceeds the capacity of the body’s antioxidant system. Excess ROS attack healthy cells, damaging organs, proteins, and DNA.
ROS include superoxide, hydroxyl radicals, hydrogen peroxide, and singlet oxygen. Among them, hydroxyl radicals—classified as free radicals—are highly reactive and bind to various substances like proteins, lipids, and carbohydrates.
Most damage caused by ROS to the human body is attributed to hydroxyl radicals. However, non-radical ROS like hydrogen peroxide can also generate hydroxyl radicals when reacting with metal ions or light. Therefore, caution is needed for both radicals and non-radicals.
In an oxidative stress state where ROS production is excessive, they damage proteins, lipids, DNA, and cells. When endothelial cells inside blood vessels are damaged, oxidized LDL cholesterol (oxidized LDL) penetrates the blood vessel walls, forming foam cells that accumulate cholesterol. LDL contains unsaturated fatty acids, which are highly susceptible to oxidation by ROS.
Oxidized LDL consumed by macrophages in white blood cells leaves residues that accumulate as plaques in blood vessel walls, leading to blockages and atherosclerosis.
Related Article: Smoking-Induced Oxidative Stress and Atherosclerosis (Louis Pasteur Medical Research Center Antioxidant Laboratory)
To reduce oxidative stress, suppressing free radicals and ROS is essential. This can be achieved by lowering oxidative stress levels or increasing antioxidant intake.
Quitting smoking is one effective way to lower oxidative stress. Smoking not only introduces ROS into the body through smoke but also promotes ROS production through acetaldehyde.
Limiting alcohol consumption is also essential since alcohol introduces large amounts of acetaldehyde into the body. Avoiding UV exposure is another key measure. UV rays stimulate ROS production in skin cells. Protect yourself with umbrellas, cardigans, or sunglasses to minimize exposure.
Consuming antioxidants can boost the body’s ability to neutralize ROS. Examples include vitamin C, vitamin E, polyphenols, and carotenoids.
Foods like blueberries (anthocyanins), green tea (catechins), and soy (isoflavones) are rich in polyphenols, while spinach and pumpkin contain carotenoids like beta-carotene, a key nutrient in antioxidant-rich green and yellow vegetables.
If daily antioxidant intake is challenging through food alone, consider supplements. While easily available at drugstores and online, it’s crucial to check their scientific basis before use.
Related Article: Diet Recommendations from the Perspective of Oxidative Stress (Louis Pasteur Medical Research Center Antioxidant Laboratory)
Smoking promotes free radical production, causing oxidative stress and contributing to atherosclerosis. Gradually reducing smoking and quitting altogether is ideal.
Combining lifestyle changes like reducing alcohol consumption, UV protection, moderate exercise, and antioxidant-rich diets or supplements can further reduce oxidative stress. Reviewing habits before oxidative stress severely impacts health is essential for a healthier future.
