Nutrition interventions for asthma patients

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By Kellie Blake, RDN, LD, IFNCP

Difficulty breathing is one of the scariest conditions to live with and manage. The majority of my patients with asthma seek nutrition counseling for other concerns and most are surprised to learn the powerful impact food can have on their asthma symptoms. 

The exact cause of asthma is unknown, but it is characterized by an inappropriate immune response leading to chronic inflammation in the lung. This inflammation leads to swelling in the airways, mucus production, and bronchospasm making breathing difficult.

Asthma can affect anyone of any age, but typically develops in childhood. Environmental exposure from poor air quality, microbes, chemicals, and cigarette smoke can all cause asthma, as well as trigger asthma attacks. Genetics play a role as do obesity, allergies, and a history of respiratory infections.

Nutrition is often overlooked and can be a risk factor for the development of asthma and contribute to asthma exacerbation. As reported in the journal Medicina, 48 percent of asthma patients have at least one food allergy, yet nutrition therapy is still not routinely used for the prevention and management of asthma. 

Typical asthma treatment involves short-term relief medications and control medications, such as steroids, biologics, leukotriene modifiers, mast cell stabilizers, bronchodilators, and allergy shots. While these therapies are lifesaving for many, they can have unwanted long-term side effects.

Nutrition therapy is one cost-effective treatment option with minimal, if any, side effects. For asthma, nutrition interventions should ideally include an elimination diet, strategies to improve metabolic health, and nutritional supplementation.

Food allergy testing can be unreliable and confusing for patients, so I often prescribe an elimination diet to tease out any hidden food allergies or sensitivities. For a period of four to eight weeks, patients should exclude dairy, eggs, tree nuts, peanuts, fish and shellfish, wheat, soy, and corn. I also encourage patients to eliminate food dyes, additives, added sugar, and unhealthy fats.

After the elimination period, systematic reintroduction usually unearths at least one sensitive or allergic food. During the food reintroduction, there is a small risk of severe asthma attack, so I encourage patients to be appropriately prepared in the event asthma symptoms worsen. 

The systemic inflammation seen in asthma is associated with poor outcomes including poor lung function, more asthma exacerbations and more airway inflammation. As reported in The Journal of Allergy and Clinical Immunology, obese patients with asthma have higher levels of fat mass inflammation when compared to obese patients without asthma. In addition, obesity is a known asthma risk factor and contributes to asthma exacerbation. Improving the metabolic landscape and helping patients reach and maintain an ideal body weight can be important targets of nutrition therapy.

Improvements in metabolic health will begin during the elimination period, but one long-term meal plan to consider is the Mediterranean diet. As reported in the journal Nutrients, the typical Western diet, which is high in unhealthy fat and low in fiber, increases eosinophilic airway inflammation in those with asthma. The Mediterranean diet, on the other hand, is high in fruits and vegetables, which have been shown to improve both the systemic and airway inflammation found in those with asthma. I like the Mediterranean diet as it is easy to incorporate into any lifestyle, but any anti-inflammatory meal plan will likely be beneficial for improving metabolic health and thus asthma symptoms.  

In addition to a tailored meal plan, targeted nutritional supplementation with magnesium and vitamin C can be beneficial. Magnesium is an important cofactor for over 400 reactions in the body. In the case of asthma, magnesium relaxes bronchial smooth muscle and has an anti-inflammatory effect. Asthma patients have been shown to have lower magnesium status when compared to controls and low serum magnesium levels are associated with severe asthma. High magnesium foods to suggest include nuts, seeds, leafy greens, and dark chocolate. A magnesium supplement of up to 600 milligrams per day can also be helpful and I tailor the dosage based on dietary magnesium intake.  

Vitamin C is another supplement consideration for those with asthma. Vitamin C may act as a bronchodilator. Additionally, vitamin C concentration is lower in those with asthma when compared to controls. Asthma patients treated with one to two grams of vitamin C per day remained asthma free in one study and one gram of vitamin C per day decreased the frequency of asthma attacks in adults by 73 percent. Vitamin C supplementation is also helpful for improving exercise-induced asthma. Increasing the intake of fruits and vegetables will boost vitamin C intake. In addition to food sources, I often suggest 1,000 to 3,000 milligrams of vitamin C per day in divided doses.

Case Study

I recently had a patient who sought nutrition counseling for autoimmune disease, weight management, and fatigue. She was 63 inches tall and weighed 185 pounds, indicating obesity class one. During the initial assessment, she revealed lack of endurance and shortness of breath related to asthma.

The patient had recently started a leukotriene inhibitor for asthma and had to use a rescue inhaler at times. Her food intake was considered a typical Western diet.

My initial plan for this patient included:

1. A full elimination diet for at least four weeks with the goal of eight weeks
2. At least 85 ounces of water daily
3. A 10-minute walk after every meal
4. Daily meditation
5. Nutritional supplementation, including 200 milligrams of magnesium glycinate per day

After four weeks, the patient had lost seven pounds and reported having more energy. The patient said she was able to hike and swim with her grandkids where she previously would have been too out of breath and fatigued. She had also increased her daily activity from an average of 2,000 steps to 5,000 steps per day. She discontinued the leukotriene inhibitor and had not used her rescue inhaler since starting the elimination diet.

My patient continued the elimination diet for a total of eight weeks. She has lost twelve pounds and her energy level and stamina continue to improve.

The next step would be to include the food reintroduction to uncover her likely food sensitivities. She would be transitioned to a modified Mediterranean diet with sensitive foods excluded. Nutritional supplements and other lifestyle recommendations would be tailored to allow for continued improvement in metabolic health and symptom reversal.

While this patient did not seek nutritional counseling specifically for asthma, she had excellent improvement in her asthma symptoms.

References

Guilleminault, L., Williams, E., Scott, H., Berthon, B., Jensen, M., and Wood, L. (2017). Diet and Asthma: Is It Time to Adapt Our Message? Nutrients. https://www.mdpi.com/2072-6643/9/11/1227

National Heart, Lung, and Blood Institute (2020). Asthma. Health Topics. Retrieved from: https://www.nhlbi.nih.gov/health-topics/asthma

di Palmo, E., Gallucci, M., Cipriani, F., Bertelli, L., Giannetti, A., and Ricci, G. (2019) Asthma and Food Allergy: Which Risks?. Medicina (Kaunas). Retrieved from: https://www.mdpi.com/1010-660X/55/9/509

Peters, U., Dixon, A.E., and Forno E. (2018) Obesity and asthma. The Journal of Allergy and Clinical Immunology. Retrieved from: https://www.jacionline.org/article/S0091-6749(18)30282-3/abstract