Are GMOs safe for patients with asthma? What about Chinese food? Or high fructose corn syrup? Before you shake your head, read this slideshow.
The products highlighted are categorized as either beneficial, neutral, or negative according to how they affect lung function and symptoms. In several cases new research has shifted an item from negative to neutral. In others, emerging evidence suggests asthma patients be far more selective in their consumption.
In a comprehensive review, Hyson and colleagues concluded that apples might be lung protective because of their antioxidant potential and phytochemical content.1 To date there has not been a specific study using objective data to measure the effects of apple consumption on asthma, but the idea is promising. When talking to patients about food choices and asthma, however, please do not include concentrated apple juice in the same category with the whole fruit. More on that later. (©valzan/Shutterstock.com)
Olive oil is a major component in the Mediterranean diet, which is one of the healthiest ways to eat in the world. New data based on consumption of the diet offer even more reinforcement. Cazzoletti and colleagues showed that high dietary intake of olive oil was associated with a lower risk of asthma in an Italian cohort.2 This data provides us with another reason to recommend the Mediterranean diet as a general eating plan for patients with asthma. (©DuÅ¡an Zidar/stock.adobe.com)
It is known that theophylline, the stimulant in tea, improves lung function. This compound has been used in prescription form for decades to treat COPD but has fallen out of favor secondary to its narrow therapeutic window. However, the dose in a cup of tea is safe and should be thought of as a way to help avoid or alleviate asthma symptoms. Practical advice to patients with asthma should include recommending tea when recovering from a simple upper respiratory infection. Patients can also feel good about incorporating a cup of their favorite tea into their daily routine. (©Vera Petruk/Shutterstock.com)
Sometimes research confirms exactly what we suspect. In 2017, a case-controlled study of 678 Puerto Rican children aged 6-17 years showed that frequent consumption of grains and vegetables and low consumption of dairy products and sweets was associated with higher lung function (as measured by FEV1 and FVC).3 Therefore, people with asthma who eat more grains and fresh vegetables and less dairy and sugary products will have less symptoms. These are fundamentals and could serve as the core of any supervised eating program. (©ElenaSchweitzer/Shutterstock.com)
GMOs can be animals, plants, or other organisms whose genetic makeup is modified in a laboratory. The fear surrounding their use is worldwide; in fact, dozens of nations prohibit the cultivation of GMO crops and animals. One of the worries is that there could be allergic potential in GMOs that could increase asthma symptoms if activated. A systemic review concluded that GMOs do not appear to be more allergenic vs their conventional counterparts as determined by IgE binding studies, case series of direct provocation and ingestion, and simulated digestion studies.4 Interestingly there is talk of GMOs having less allergic potential, but more work needs to be done. (©andriano_cz/stock.adobe.com)
MSG is a flavor enhancer commonly added to Chinese food, canned vegetables, soups, and processed meats. Many studies show conflicting results in relation to MSG’s effect on asthma symptoms. A now often cited single-blind, placebo-controlled study in 1999 used MSG challenges in subjects with asthma with and without a perceived sensitivity to MSG, found that MSG failed to induce signs or symptoms of asthma.5 “In view of the poorly conducted studies that proposed that MSG induced asthma and the subsequent studies that failed to confirm those findings, it is important to maintain a healthy skepticism about the existence of MSG sensitivity in individuals with asthma,” the researchers concluded. (©Lightspring/Shutterstock.com)
Tartrazine is a synthetic lemon yellow dye primarily used as a food coloring. It has often been implicated in allergic symptoms (urticaria, angioedema, asthma, atopic dermatitis) and as a potential lung pathogen. In a double-blind, placebo-controlled study of 26 adult atopic subjects with asthma, the administration of 35 mg of tartrazine dye did not precipitate any kind of significant cutaneous, respiratory, or cardiovascular reactions vs placebo.6 (©Alexander Ruiz Acevedo/Shutterstock.com)
There is growing evidence that intake of HFCS is associated with asthma. HFCS is used to sweeten soda and fruit drinks; fructose is also found in natural apple juice (so, go for the whole fruit instead). A link between high intake of the above drinks and increased asthma prevalence has been shown in large population studies such as the Framingham Offspring Study. According to the authors, the proposed mechanism is that high fructose-to-glucose ratios force the creation of enteral pro-inflammatory advanced glycation end products. These then bind receptors that potentiate asthma.7 For this reason, among others, patients with asthma should avoid products containing HFCS. This is critical advice for the general population as well. (©MaciejCzekajweski/Shutterstock.com)
Sulfur dioxide is a preservative found in wine and dried foods such as apricots, prunes, and raisins. Most studies report a 3% to 10% prevalence of sulfite sensitivity among subjects with asthma following ingestion of this additive. Therefore, people with asthma should use caution when drinking wine and eating dried fruit. Some wines carry the label “No added sulfites,” but it is important for anyone with asthma to know that no wine is truly sulfite-free because the fermentation produces sulfites as a byproduct of yeast metabolism. (©OlegDoroshin/Shutterstock.com)
1. Hyson, DA. A comprehensive review of apples and apple components and their relationship to human health. Adv Nutr. 2011;2:408–420.
2. Cazzoletti L, Zanolin ME, Spelta F, et al. Dietary fats, olive oil and respiratory diseases in Italian adults: A population-based study [published ahead of print January 28, 2019]. Clin Exp Allergy. doi: 10.1111/cea.13352.
3. Han YY, Forno E, Alvarez M, et al. Diet, lung function, and asthma exacerbations in Puerto Rican children. Pediatr Allergy Immunol Pulmonol. 2017;30:202-209.
4. Dunn SE, Vicini JL, Glenn KC, Fleischer DM, Greenhawt MJ. The allergenicity of genetically modified foods from genetically engineered crops: A narrative and systematic review. Ann Allergy Asthma Immunol. 2017;119:214-222.
5. Woessner KM, Simon RA, Stevenson DD. Monosodium glutamate sensitivity in asthma. J Allergy Clin Immunol. 1999;104:305-310.
6. Pestana S, Moreira M, Olej B. Safety of ingestion of yellow tartrazine by double-blind placebo controlled challenge in 26 atopic adults. Allergol Immunopathol (Madr). 2010;38:142-146.
7. DeChristopher LR, Tucker KL. Excess free fructose, high-fructose corn syrup and adult asthma: the Framingham Offspring Cohort. Br J Nutr. 2018;119:1157-1167.
A holistic approach to asthma includes managing nutrition. Some dietary choices will potentiate asthma symptoms while others help lung function and improve quality of life. This slideshow addresses the effect of several common foods, widely used food additives, and genetically modified organisms on asthma symptoms.Â Use this list as a handy reference when counseling your patients with asthma on dietary choices.Dr Schroeder is Clinical Instructor of Medicine at UCLA, David Geffen School of Medicine and Clinical Chief of Pulmonary and Critical Care Medicine, Emeritus, at Cedars-Sinai Medical Center.