Intermittent Fasting and... Asthma?!

On Sunday, my friend and assistant goalball coach was complaining about her current foray into intermittent fasting-the hunger aspect of it. Now, all I knew that time about intermittent fasting is that it allegedly amps up your metabolism/helps you lose weight by way of encouraging your body to go into brief periods of "starvation."

I read into intermittent fasting a little more because I get intrigued with such things and their actual scientific merit or if they're just, you know, a thing people do for some reason. (Plus, it turns out by some standards I actually accidentally intermittently fast at least a few times a week.)

And of course, apparently it helps with asthma and allergies. ¹

Like, um, is that even possible? Because it sounds ridiculous.

Intermittent fasting: What is it?

There are several methods for going about intermittent fasting. My friend is doing a method that means you can eat as desired for 8 hours a day, and fast for 16 hours-some sources recommend women instead eat as desired 10 hours a day and fast for 14. Others fast for a full 24 hours once or twice a week. And still others will eat 500-600 calories per day two days per week (not in a row) and eat normally the other five days. Intermittent fasting has several reported health benefits, with multiple studies linking it to improvements in brain health, reduction in cancer rates, reduced inflammation (a common feature of chronic disease like asthma and arthritis), reduced "bad cholesterol" and triglycerides, improved blood sugar, and improved insulin sensitivity. Oh and it can help you live longer. ²

What can't it do!?

And apparently, this article I read concluded that intermittent fasting could be helpful for asthma. ¹

Based on one study.

Hardly evidence. But let's explore that research as it must be useful since all the other studies cite it.

One study shows:

The study is titled Alternate Day Calorie Restriction Improves Clinical Findings and Reduces Markers of Oxidative Stress and Inflammation in Overweight Adults with Moderate Asthma. (Johnson et al., 2007) ³

What do we learn from the title alone? This targeted a very specific population: many of us are not also overweight adults with moderate asthma, so these findings may not relate to us. I will, however, humor myself and keep going…

Sample size: 10 participants, 9 of whom "adhered to the diet", which was eating normally every other day and restricting caloric intake to less than 20% of typical caloric intake the alternating days. In this very small sample study over eight weeks, compliance was high, "symptoms and pulmonary function" improved alongside a variety of other biomarkers, and "oxidative stress and inflammation declined in response to the dietary intervention". ³

I will add an important thing here: there was no control group. There was no healthy (non-asthmatic] control doing intermittent fasting to test their biomarkers independent of having asthma, and there was no asthmatic control group undergoing a different type of weight loss control to check their biomarkers and lung function. And this is why-like with the Andrew Wakefield study on vaccines causing autism, which they do not-research needs to have an adequate sample size, preferably multiple studies, and adequate controls in place so the research is not skewed.

This, my friends, is why it is important to read the primary source research, not just the articles or papers that cite it. Were the participants' improvements in asthma symptoms, blood tests, asthma control, quality of life, etc. related to an improvement in their asthma, or the improvement in their asthma from losing weight. In this study, I believe the improvement in asthma control is likely due to the fact that the participants lost 8% of their body weight over the course of the study. And there's plenty of evidence that obesity contributes to asthma severity (or non-asthma restricted breathing patterns that are misdiagnosed as asthma). ^3,4,5,6

Does intermittent fasting help with asthma?

The bottom line? Sure, there may be other benefits to trying intermittent fasting, but for asthma directly, the research supporting it is just not there. While intermittent fasting may be helpful for weight loss, and-in turn-helpful for asthma, it is not conclusive that it is helpful for asthma.