The Effects of Intermittent Fasting on Asthma

Asthma is a disease of inflammation. Usually, inflammation is a response against something harmful like infections, toxins, and injuries. In asthma, the inflammation can be the result of the presence of excessive amounts of pro-inflammatory substances in the form of cytokines.

It is not surprising then that anti-inflammatory drugs in the form of steroids are necessary to control asthma symptoms, and higher steroid doses are needed during acute attacks.

Excess Visceral Fat and Inflammation

Visceral fat is contained inside the abdomen and envelops and infiltrates the visceral organs. One way to measure fat is by the Body Mass Index or BMI.

BMI is calculated using height and weight. A body mass index of 18.5 to 24.9 is considered normal. 25 – 29 is deemed to be overweight, and more than 30 is obese.

In the U.S.,  32.5% are overweight, and another 36.5% are obese. It is not surprising then that asthma is a common problem.

Asthma_attack-illustration_NIH
Inflammation of the airways in asthma

The current medical management of asthma only “controls” the condition but does not address the source of inflammation. In the process, asthma can persist and cause structural and irreversible changes in the respiratory tract that can severely impair lung function.

Intermittent Fasting and Asthma

Intermittent fasting is when the period of food consumption is limited to a certain number of hours or to certain days.  There are many ways to do intermittent fasting, and one way is called alternate daily fasting.

One study, from the National Institue of Aging, was done to assess if alternate-day fasting can benefit obese people with asthma. The study period was 2 months.

The study was done on ten subjects who are obese and asthmatic.

ADF was done by providing canned meal replacement shakes in the form of Atkins Advantage or Carb Solutions. The women were instructed to consume 320 calories, and the men consumed 380 calories every other day. That is less than 20% of their usual daily caloric intake.

Every other day, the subjects were able to eat to the point of satisfaction but not to intentionally overeat.

Ketone bodies in the form of β-hydroxybutyrate and leptin levels were monitored to measure dietary compliance.

During the whole study, their weights, levels of inflammatory substances in the blood, and lung functions were measured. The overall Quality of Life (QOL) was measured with questionnaires.

The Healthy Effects of Alternate Day Fasting on Asthma

Weight loss

9 of the 10 were able to follow the diet, and they lost 8% of their weight. The ketones became elevated. This means that the energy supplies during the fasting period were provided by fatty tissue, and thus fatty tissue was “burned” which explains the weight loss.

Leptin has been associated with inflammation. A lower level contributes to the anti-inflammatory effect of ADF. Lower leptin levels also lessen the overactivation of the hunger response, which is common in obesity.

Improved Quality of Life

All of the participants showed improvement in their overall quality of life. The QOL includes the emotional, social, and physical aspects of an individual’s life and is a measure of a person’s well being or lack thereof. A high QOL during intermittent fasting means better compliance and more positive outcomes.  

The quality of life (QOL) improvement in this study was actually better when compared to the QOL results in other studies using other asthma medications like montelukast and fluticasone proprionate.

Better Peak Expiratory Flow Rate and Forced Expiratory Volume

The Peak expiratory flow rate (PEFR) is the amount of air that can be forcefully breathed out, and it is measured by a peak flow meter.

In asthma, the PEFR is lower and worsens during an asthma attack. The smaller airways restrict the flow of expired air and manifest as prolonged and labored exhalation.

The improvement in PEFR is similar to using other “optimizing” controller medications in mild to moderate asthmatics.

The Forced Expiratory Volume-1 or FEV-1 also improved. FEV-1 is the volume of forced expired air in 1 second. In asthma, the FEV-1 is furthermore decreased.

Albuterol or salbutamol is frequently used during asthma attacks to increase the diameter of the airways. The subjects in this study also had better FEV-1 and faster relief after using albuterol.

Lower levels of Systemic Inflammation

There is a decrease in the level of systemic inflammation as evidenced by lower levels of  serum tumor necrosis factor-α (TNF- α) and brain-derived neurotrophic factor (BDNF)

Uric acid, commonly associated with gout, is increased after the study period. That’s because uric acid is an antioxidant and scavenges free radicals in the body. Free radicals are needed for cellular functions, but excess free-radicals cause damage. It should be noted that there was no reported increase in gout attacks among the subjects in this study.

Other markers of inflammation like 8-isoprostane, nitrotyrosine, protein carbonyls, and 4-hydroxynonenal adducts were also decreased.

Better Lipid Profiles

After the 8 week study period, total cholesterol and triglycerides were decreased, and HDL increased.

High cholesterol levels have been associated with diseases of chronic inflammation like heart diseases. Elevated triglycerides are one of the components of metabolic syndrome that is related to many other conditions.

That is why caloric restriction in the form of intermittent fasting can also improve other conditions associated with excess weight and metabolic syndrome.

Consistency with another Controlled Clinical Trial

In another study  of 16 subjects who are morbidly obese with an average BMI of 45.7. The average weight loss was 16.5 kgs or 36.3 lbs after a behavioral weight reduction program for 3 months.

The result also showed improvement in physical activity, airway hyperresponsiveness, asthma control, and lung functions. The participants also reported a better quality of life, just like in the other study.

Why does this matter?

Current treatment strategies for asthma are designed to mainly “control” the symptoms. It does not reverse the underlying inflammation. Just like other diseases, structural changes due to chronic inflammation can become permanent. That can mean having to carry an oxygen tank wherever you go in your old age.

This necessitates early intervention to prevent irreversible damage. As a bonus, other chronic conditions associated with inflammation can also get better with weight loss.

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Image Credit: Asthma By United States-National Institute of Health: National Heart, Lung, Blood Institute – http://www.nhlbi.nih.gov/health/health-topics/topics/asthma/, Public Domain, https://commons.wikimedia.org/w/index.php?curid=24760677

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