Link Between Fructose and Asthma: Recent Study Findings

Overview of the Study

Recent research has explored the connection between fructose, particularly from high-fructose corn syrup (HFCS) found in sweetened sodas and apple juice, and respiratory issues such as asthma. The study indicates that consumption of HFCS through these beverages is associated with an increased risk of asthma and bronchitis.

Mechanisms Behind the Link

One potential explanation for these findings is that some individuals may not properly absorb HFCS in their intestines. This malabsorption can lead to the production of inflammatory substances that target receptors linked to asthma. Furthermore, many beverages contain fructose-to-glucose ratios exceeding the recommended safe level of 2:1, contributing to excessive fructose in the body.

Research Methodology

The study, published in the *British Journal of Nutrition*, specifically assessed the consumption of non-diet soda, apple juice, and fruit drinks in relation to asthma. It compared these with diet soda, which has not been associated with asthma, and orange juice, known for its balanced fructose-to-glucose ratio of 1:1.

The researchers utilized data from the Framingham Heart Study-Offspring cohort, which tracked the dietary habits of 5,013 individuals for over 30 years, starting in 1971—a period that coincides with the rise of HFCS use in sodas. Participants completed Food Frequency Questionnaires and underwent regular examinations, but those diagnosed with asthma in the first two examinations were excluded from the analysis. The cohort primarily consisted of Caucasian men and women with an average age of 47.9 years.

Key Findings on Asthma Risk

Throughout the study’s duration, 13.5% of participants developed asthma. Moderate consumers of non-diet soda (two to four times a week) showed a 59% increased risk of asthma. This risk escalated to 89% for those consuming non-diet soda five to seven times weekly, regardless of variations in age, body mass index (BMI), sex, and education.

Moreover, individuals who consumed fruit juice and apple juice two to four times per week exhibited 58% and 61% higher asthma risks, respectively. This is particularly significant given that apple juice is often viewed as a healthier choice compared to sodas. In contrast, orange juice and diet soda did not show any correlation with asthma development.

Implications and Limitations

The study’s outcomes suggest that consuming soda, fruit juice, and apple juice even moderately can enhance the risk of asthma, with more frequent consumption leading to greater risks. However, it is essential to note that the research did not consider other sources of HFCS, such as snack bars, ketchup, and desserts, which may also influence fructose levels and absorption issues.

Another limitation is the demographic makeup of the study sample, which was predominantly Caucasian, potentially affecting the generalizability of the findings to the diverse American population.

Conclusion

Given the identified associations with asthma even at moderate levels of HFCS intake, the researchers caution that merely recommending reductions in consumption of these beverages may be insufficient. They also observed a decline in juice consumption in the U.S., which coincided with a reduction in asthma prevalence from 2009 to 2013.

Written by Monica Naatey-Ahumah, BSc
Reference: DeChristopher, L.R., and Tucker, K.L. (2018). Excess free fructose, high-fructose corn syrup, and adult asthma: the Framingham Offspring Cohort. *The British Journal of Nutrition*, 1-11. https://doi.org/10.1017/S0007114518000417