What You Eat Affects How You Breathe

For asthmatic children with allergies to food the statement that what you eat affects breathing is simple to understand.1 Allergic reactions to food that cause respiratory symptoms are also known in occupational asthma.2,3 The allergic response can affect not only the skin and gastrointestinal tract but can be a trigger for asthma resulting in symptoms such as shortness of breath, cough, wheeze and chest tightness. So for these individuals, the search then becomes imperative to discover those foods that trigger an asthma exacerbation. But what about children or adults with asthma who do not have food allergies? Can food have an impact on lung function?

McKeever and colleagues in their 2008 study4 showed that a high intake of several n-6 fatty acids was associated, particularly in smokers, with a significant reduction in FEV1. The table below shows a comparison of dietary patterns and what they found in their latest study of dietary factors and their effect on lung function.5

They noted that a high intake of refined foods was linked to an accelerated reduction in FEV1 over 5 years but did not draw any specific conclusions from this study.

A recent study published in the Journal of Allergy and Clinical Immunology6 offers evidence that with or without asthma, certain types of food can have an effect on lung function. The study involved

  • 37 non-obese individuals with a diagnosis of asthma
  • 14 obese individuals with asthma
  • 21 healthy individuals as controls
  • 5 individuals with asthma.

The study subjects were randomized to consume either a high-fat (HFM) or a low-fat meal. Researchers measured markers of inflammation, including percent neutrophils, C reactive protein (CRP) and IL6. [CRP is associated with reduced lung function.7] Lung function was assessed both pre- and post bronchodilator at 2, 3 and 4 hours. Four hours after the HFM the patients with asthma displayed increases in inflammatory markers and decreased FEV11 and FVC. The researchers concluded that a HFM also inhibits bronchodilator recovery in asthma.

A European study8 of 20 healthy adults without asthma, divided equally between men and women, was done to determine if a HFM would affect airway inflammation and pulmonary function. Prior to the meal exhaled nitric oxide (eNO) and pulmonary function tests (PFT) were performed. Tests done 2 hours after the HFM showed increased cholesterol and triglycerides but no effect on PFT measures including FEV1, FVC and FEV25-75. However, eNO increased by about 19%. The researchers suggested that a HFM may contribute to chronic inflammation in the airways and lung.

High consumption of fast foods and/or pop have been linked with an increased risk of asthma or wheeze.9 Data from children whose mothers drank high fructose corn syrup sweetened soft drinks during their first and third trimesters were analyzed at the 7 - 8 years of age. Children who drank juice, other than orange juice, were 34% more likely to develop asthma than children who did not. The researchers suggested that the possibility exists that early exposure to fructose may determine the development of asthma in children.10 A study found11 that mothers who consumed artificially-sweetened carbonated drinks were likely to report a diagnosis of asthma in their children during the first 7 years of follow-up (OR 1.30). Examining data of 1961 children, aged 2-9 years, from the National Health and Nutrition Examination Survey 2003-2006 it was noted that unlike orange juice, drinks (such as apple juice) with excess free fructose was significantly associated with asthma.12 Yet another study found that high soda (non-diet) intake was associated with asthma in high school students.13

High fat, sugar and salt are associated with asthma prevalence (OR1.13) and also with severity of current asthma (OR 0.84).14 A diet that includes candies, chips, chocolate, salty snacks, pastries, sweet desserts, fruit juices, soft drinks, and alcoholic beverages contribute to a dietary pattern that is associated with asthma.

A ten year cross-sectional study1 done in 20 countries analysed data from over 50,000 school children between the ages of 8 and 12 years, with more than half tested for allergies with skin prick testing. The study showed that the a low prevalence of current wheeze was associated with

  • fruit (OR 0.6)
  • fish (OR 0.85)
  • cooked green vegetables (OR 0.85)

Most impressive was the finding that while none of the food items was associated with allergic sensitization, frequent consumption of fruit, fish and vegetables was associated with a lower lifetime prevalence of asthma but high consumption of burgers was associated with a higher lifetime prevalence of asthma. The study concluded that diet is associated with wheeze and asthma but not with allergic sensitization in children.

Gender differences due to dietary salt intake was observed in an Italian study15 that involved 2459 children between the ages of 9 and 16. Questionnaires, urine samples, measures of lung function, methacholine and skin prick tests provided data. Analysis of the data showed that personal table salt use was associated with

  • cough and phlegm without colds (OR 1.87)
  • wheezing without colds (OR 2.19)
  • wheezing with dyspnoea (OR 1.45)
  • wheezing after exercise (OR 2,16)

The above associations were found mainly in boys. The researchers concluded that personal use of table salt is related to an increased prevalence of bronchial symptoms.

Burns and colleagues 16 designed a study to examine whether dietary factors such as fruit, vegetables, beta-carotene, retinol, and n-3 fatty acids affected the respiratory health of 2, 112 grade twelve students across the United States and Canada in the 1998-99 academic year. They found the following associations

  • low fruit intake with lower FEV1 and increased odds of chronic bronchitic symptoms (OR 1.36)
  • low n-3 fatty acids intake with increased odds of chronic bronchitic symptoms (OR 1.37), wheeze (OR 1,34) and asthma (OR 1.68).

Adolescents who smoked and had a lower dietary vitamin C intake had a higher risk (OR 1.69) of asthma and respiratory symptoms (OR 1.68) in a comparison with those who smoked but had a higher vitamin C intake.

A systematic review of studies 17 on the relationship with diet and asthma showed evidence of “beneficial effect of fresh fruits and antioxidant vitamins on asthma”. Diets high in fish, vegetables and fruit have been negatively associated with asthma. 14 The obvious conclusion is that a diet low in refined foods and high in fruit and vegetables, also known as the Mediterranean diet, is better for lung function than a diet high in fat, sugar and in refined foods.

Abbreviations

CRP C reactive protein, eNO exhaled nitric oxide, FEV 1 forced expiratory volume in one second, FEV 25-75 forced expiratory volume from 25% to 75% of vital capacity, FVC forced vital capacity, HFM high fat meal, OR odds ratio, PFT pulmonary function test.

References

  1. Nagel G, Weinmayr G, et al. Effect of diet on asthma and allergic sensitisation in the International Study on Allergies and Asthma in Childhood (ISAAC) phase two. Thorax 2010; 65:516–522.    
  2. Salvatori N, Reccardini F, et al. Asthma induced by inhalation of flour in adults with food allergy to wheat. Clin Exp Allergy 2008; 38:1349-1356.
  3. Gautrin D, Cartier A, et al. Occupational asthma and allergy in snow crab processing in Newfoundland and Labrador. Occup Environ Med 2010; 67:17-23.    
  4. McKeever TM, Lewis SA et al. The relation between dietary intake of individual fatty acids, FEV1 and respiratory disease in Dutch adults. Thorax. 2008;63(3):208-14.
  5. McKeever TM, Lewis SA et al. Patterns of dietary intake and relation to respiratory disease, forced expiratory volume in 1 s, and decline in 5-y forced expiratory volume. Am J Clin Nutr. 2010; 92(2): 408-15. doi: 10.3945/ajcn.2009.29021.
  6. Wood LG, Garg ML, Gibson PG. A high-fat challenge increases airway inflammation and impairs bronchodilator recovery in asthma. J Allergy Clin Immunol 2011; 127(5): 1133-40
  7. Rasmussen F, Mikkelsen D, et al. High-sensitive C-reactive protein is associated with reduced lung function in young adults. European Respiratory Journal. 2009;33(2):382–388
  8. Rosenkranz SK, Townsend DK, et al. Effects of a high-fat meal on pulmonary function in healthy subjects. European Journal of Applied Physiology. 2010;109(3):499–506.
  9. Lawson JA, Rennie DC, et al. Obesity, diet, and activity in relation to asthma and wheeze among rural dwelling children and adolescents. J Obes. 2013;2013:315096. doi: 10.1155/2013/315096.
  10. Wright, Lakiea S, Rifas-Shiman S et al. Maternal prenatal intake of fructose is associated with asthma in children. Journal of Allergy and Clinical Immunology, 2015; 135 (2) AB228.
  11. Maslova E, Strøm M, et al. Consumption of artificially-sweetened soft drinks in pregnancy and risk of child asthma and allergic rhinitis. PLoS One. 2013;8(2):e57261. doi: 10.1371/journal.pone.0057261.
  12. DeChristopher LR1 Uribarri J, Tucker KL. Intakes of apple juice, fruit drinks and soda are associated with prevalent asthma in US children aged 2-9 years. Public Health Nutr. 2016 Jan;19(1):123-30. doi: 10.1017/S1368980015000865. Abstract.
  13. Park S, Blanck HM, et al. Regular-soda intake independent of weight status is associated with asthma among US high school students. J Acad Nutr Diet. 2013 Jan;113(1):106-11. doi: 10.1016/j.jand.2012.09.020.
  14. Pistelli R, Forastiere F, et al. Respiratory symptoms and bronchial responsiveness are related to dietary salt intake and urinary potassium excretion in male children. Eur Respir J. 1993;6(4):517-22.
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  17. Barros R, Moreira A, et al. Dietary patterns and asthma prevalence, incidence and control. Clin Exp Allergy. 2015 Nov;45(11):1673-80. doi: 10.1111/cea.12544.