I recently wrote a summary of the available scientific findings on how changing your diet can affect lung disease, primarily asthma and chronic obstructive pulmonary disease (COPD).
Currently, mainstream medicine has little to say about how nutrition impacts lung disease. But it is possible that following a low-carbohydrate diet could potentially result in clinical improvement for individuals with lung disease, both chronically as well as during an acute episode.
This is of interest to me as a medical professional, because of an experience I had early in my medical career. It had a profound impact on me, demonstrating the clinical power of a simple nutritional modification. It was during my residency training that I first became interested in the potential effects of nutrition on lung disease.
Here is the case history of a young male patient: A non-smoker, he had a history of recurrent chronic cough that started during upper respiratory infections (such as the common cold) and would linger for several months afterward.
Though his cough was unproductive and mostly just an annoyance, the fact that it would consistently last for months beyond resolution of the cold became concerning.
An allergist ultimately diagnosed him with cough-variant asthma and started him on a steroid inhaler. The inhaled steroid worked quite well, and he was able to reduce its use to several times a year, as needed when the cough recurred, usually with infections.
The same pattern persisted for years before he, for unrelated reasons, transitioned to a low-carb diet. Not long thereafter, he realized that he no longer required the inhaler and has not developed a post-infection cough since.
If, however, he consumed an uncharacteristically large amount of carbohydrates, the same dry cough that plagued him for years would return. Within a couple of days after resuming a low-carb diet, the cough disappeared again.
This pattern of re-emerging symptoms that followed carbohydrate ingestion was consistent. It seemed to be influenced more by the quantity of carbohydrate intake rather than by the kinds of carbohydrate consumed.
Confession: This male patient is, in fact, me. This personal experience alerted me to the potential adverse effect that carbohydrates can have on lung function, possibly having to do with inflammation.
Does carbohydrate restriction have an anti-inflammatory effect? Could this effect really be noticed within a few days of dietary carbohydrate restriction? Would carbohydrate restriction work for other individuals with asthma? Would it work in COPD, emphysema, or other respiratory system diseases?
Lung disease in the hospital setting
Years later, as a hospitalist managing countless patients with acute episodes of COPD, I have found certain patients who are incredibly slow to respond to conventional, aggressive treatment, such as oral steroids, nebulized bronchodilators, and often antibiotics.
Since gaining confidence with implementing carbohydrate restriction in the hospital setting, I have recommended carbohydrate restriction for several hospitalized patients. I chose patients who were not making significant progress with standard treatment.
Their hospital stays were longer than usual, with some initial improvement that then stalled for several days. At the time of admission, they did not have diabetes and were given a regular diet with no restrictions.
I recall these patients expressing frustration at the lack of continued improvement, including still dealing with coughing, wheezing, and shortness of breath. Thus, I offered the option of carbohydrate restriction and explained my rationale for doing so. I educated them on the carbohydrate content of foods and offered suggestions on how to order from the hospital menu.
However, I gave them the freedom to order as they pleased and did not put a specific carbohydrate limit on their diet orders. No changes were made to their medication.
Within a couple of days, these patients all experienced significant clinical improvement. With this subsequent improvement in their respiratory status, each of them was able to be discharged from the hospital soon thereafter.
Obviously, I cannot make the claim that my advice to restrict carbohydrate intake was the sole reason for their sudden clinical improvement. It may simply have been that they needed more time continuing the standard treatment.
Nevertheless, the evidence summarized in my overview article on low carb and lung disease gives me reason to believe that a low-carb diet may have at least contributed to improvement after their progress stalled with conventional treatment.
One of these patients contacted me several months later to inform me that she continued to eat low carb because it seemed to make a big difference for her COPD. She uses her inhalers much less than she did previously, and she was pleased with the way she felt overall with this dietary intervention. Nothing will change the fact that she has COPD from her many years of smoking, but she now has another tool to help manage her chronic lung disease and hopefully avoid future exacerbations.
Clinical application
The hands-on lessons I learned from my experience are striking and forced me to question why we do not routinely offer a low-carbohydrate diet to patients as an option in managing their lung disease. There appears to be a response to carbohydrate intake, possibly an inflammatory one, that triggers my asthma symptoms and resolves when I dramatically limit carbohydrates.
I have tested it in myself numerous times, and it seems possible that this trigger could be present in other people. The dramatic effect of carbohydrates on my lung function is enough to reinforce a lifelong low-carbohydrate lifestyle for me.
Though I have limited clinical experience with this situation, others (patients and physicians) have observed similar outcomes.
For example, in this video, Dr. Stephen Phinney, MD, PhD, responds to a question about the benefits of a low-carbohydrate diet for lung disease. The question comes from a gentleman living with severe COPD - his online identity is " COPD Athlete " - who has experienced profound improvements in his COPD with a low-carbohydrate, ketogenic lifestyle.
Carbohydrate restriction may be a powerful adjunct to current medical therapy for lung disease, in both the chronic state and in acute exacerbations. It is by no means meant to take the place of standard medical treatment, but it offers hope for better comprehensive disease management.
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