(Image source from: Canva.com)
When considering the repercussions of smoking, many individuals primarily think of serious ailments such as heart disease or lung cancer. Although these conditions pose significant health risks, the effects of smoking on the immune system often go unnoticed. Smoking can compromise an individual's overall health and hinder recovery from relatively mild illnesses such as colds or the flu. Furthermore, it may elevate the risk of contracting pneumonia and tuberculosis. It is crucial to recognize that smoking undermines the body’s immune defenses, making it less proficient than that of non-smokers. A prime example of a harmful substance is cigarette smoke, which is packed with numerous toxic compounds. Among these toxicants are formaldehyde, lead, carbon monoxide, arsenic, and tar—elements that contribute to the over 7,000 harmful chemicals contained in cigarette smoke. Continuous exposure to these toxins can weaken the immune system, reducing its ability to combat infections.
Dr. Tushar Patil, a Senior Consultant and Medical Oncologist at Sahyadri Super Speciality Hospital in Deccan Gymkhana, Pune, elaborates on the dual components of the immune system: innate and adaptive immunity. The innate immune system serves as the body’s initial line of defense, responding promptly to invading pathogens, including bacteria and viruses.
Dr. Patil details several ways in which smoking affects this system:
Damage to Cilia – The lungs and airways contain minute, hair-like structures known as cilia that function to eliminate dust, mucus, and pathogens. Smoking inflicts harm and destruction on these cilia, allowing pathogens to linger in the lungs longer and potentially lead to infections.
Impaired Macrophages – Macrophages are specialized white blood cells responsible for engulfing and destroying harmful invaders. In smokers, these cells exhibit reduced efficacy, allowing infections to proliferate rapidly and escalate in severity.
Ongoing Inflammation – Smoking induces persistent, low-grade inflammation that can confuse the immune system, causing it to stay activated even in the absence of actual threats. This constant engagement drains the immune system’s resources, making it less prepared for real infections when they arise.
Effects of Smoking on Targeted Immune Defense
Dr. Patil explains that the adaptive immune system serves as the body's secondary line of defense. It formulates specific responses to infections that have occurred previously or those the person has been vaccinated against.
T-Cells – These crucial cells play a role in destroying infected body cells. Smoking leads to a decrease in both the quantity and potency of T-cells, which hinders the body’s ability to fend off viruses such as influenza or COVID-19.
B-Cells and Antibodies – B-cells are responsible for producing antibodies that assist the body in recognizing and combating infections. Smoking diminishes the number of these cells and weakens their performance. Consequently, the body’s response to infections becomes sluggish, and post-vaccine protection is reduced.
Delayed Healing – With a less responsive immune system, the body also experiences prolonged recovery periods after injuries, surgical procedures, or illness.
Individuals who smoke are more prone to illness and often face more serious health issues because smoking negatively impacts the immune system in various ways. Dr. Patil remarks that the likelihood of developing tuberculosis (TB)—a dangerous bacterial infection that is quite common in India—more than doubles for smokers, particularly those whose immune defenses are already weakened. Additionally, smoking increases the occurrence of pneumonia and bronchitis by harming the lung's protective functions, which leads to frequent respiratory infections.
Dr. Patil further comments that during the COVID-19 pandemic, it became evident that smokers who were infected with the virus had a greater chance of experiencing severe symptoms, needing intensive medical care or ventilation, and faced a higher mortality rate compared to non-smokers.
He explains that the ramifications of smoking are not limited to cancer; it also undermines the body's ability to defend against it. The immune system, especially the Natural Killer (NK) cells, is vital for identifying and eliminating abnormal or malignant cells before they proliferate. Smoking compromises these essential immune components, making it challenging for the body to ward off potential dangers.
For individuals already undergoing cancer treatment, the implications are even more concerning as smoking can diminish the efficacy of therapies such as chemotherapy and immunotherapy, both of which depend on a robust immune response to target and destroy cancer cells. This compounded effect—facilitating the onset of cancer while simultaneously impairing the body’s ability to combat it—renders smoking extremely hazardous.
On a positive note, cessation of smoking leads to a renewal of the immune system, often quicker than many anticipate. Dr. Patil clarifies that within weeks, the minute, hair-like structures in the lungs known as cilia commence regeneration, enabling them to efficiently clear mucus and harmful germs. In the subsequent months, vital immune cells like macrophages and T-cells gradually return to their normal functions, enhancing the body’s capability to fend off infections and recognize abnormal cells. Additionally, the responsiveness to vaccines improves—the particularly important benefit in the post-pandemic landscape. Consequently, individuals are likely to experience fewer illnesses and recover more swiftly when they do.
Smoking undermines immunity from various angles, increasing vulnerability to infections, diminishing vaccine effectiveness, impairing healing, and obstructing cancer-fighting abilities. Quitting smoking offers a much-needed and potent reset for your natural defenses.
