Flavonoids May Slow Lung Function Decline Specifically in Never, Ex-Smoker Population

Vanessa Garcia-Larsen, PhD, assistant professor, Human Nutrition Division of the Department of International Health, Johns Hopkins Bloomberg School of Public Health

Vanessa Garcia-Larsen, PhD

New research presented at the 2018 American Thoracic Society International Conference found that anthocyanin flavonoids found in dark-pigmented fruits like red grapes and blueberries is associated with slower rates of decline in lung function in the general population, specifically in never-and-ex-smokers but not among smokers.

Investigators studied the association between dietary intake of anthocyanins and lung function decline in 2 representative cohorts of adults in Europe, analyzing data from 463 adults, with an average age of 44, who participated in the second and third European Community Respiratory Health Surveys from 2002—2012.

“Our study suggests that the general population could benefit from consuming more fruits rich in these flavonoids like berries, particularly those who have given up smoking or have never smoked,” lead study author, Vanessa Garcia-Larsen, PhD, assistant professor, Human Nutrition Division of the Department of International Health, Johns Hopkins Bloomberg School of Public Health, said. “For smokers, quitting remains the best thing they can do to protect their health.”

Participants included in the current study answered a dietary questionnaire and underwent spirometry at enrollment, and again at follow-up. Researchers grouped participants into quartiles based on the amount of anthocyanins consumed.

Separate linear models were used with a random center and participant specific intercepts to investigate the effect of anthocyanin intake on forced vital capacity (FVC), forced expiratory volume in 1 second (FEV₁)​ ​​​​​​and the ratio FEV₁/FVC.

Anthocyanin intake was categorized into different quartiles—the lowest quartile of reference from baseline survey.

It was estimated that the adjusted difference in annual change in lung function over time was associated with anthocyanin intake due to interaction between each anthocyanin quartile and age.

Researchers found that the association between high consumption of the flavonoids and reduced lung function decline appeared to be stronger among those who never smoked and those who quit than in the general study population. However, among smokers, the study did not find an association between anthocyanin intake and lung function.

The models adjusted for factors including characteristics of age, gender, height, weight, body mass index, socioeconomic status, education, total fruit and vitamin C intakes, total energy intake and smoking habit in the 2 surveys. Additionally, researchers conducted stratified analyses by smoking status.

Individuals with lowest quartile of anthocyanin intake had an adjusted mean annual change of -18.9 mL/yr (standard error mean [SEM] ± 2.2) and -22.2 mL/yr (SEM ± 2.2) for FEV₁ and FVC, respectively, and those with greater anthocyanin intake had slower annual rates of decline in FEV₁ (-9.8 mL/yr; (95% CI, -15.5, -4.1) and FVC (-9.8 mL/yr; 95% CI -17.3, -2.3).

The ratio decline was slower (highest vs. lowest quartile of anthocyanin intake -0.02/yr; 95% CI -0.03, -0.01).

In conclusion, dietary intake of sources with anthocyanin is associated with significantly slower decline in lung function in the general population, specifically, however, in never-and-ex-smokers but not among smokers.

The study was limited by its small sample size and self-reported diets.

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