Reduced likelihood for emphysema with plant-centered diet

Key takeaways:

• More adults with low vs. high A Priori Diet Quality Scores had emphysema.
• One researcher said diet can play a role in lung health despite not going directly into the organ.

Ever current and former adult smokers with a diet high in nutritionally rich, plant-centered foods had lower odds for emphysema, according to results published in Journal of the COPD Foundation.

“Our findings promote that continued adherence to a nutritionally rich, plant-based diet, focusing on whole grains, fruits and vegetables, but without having to fully exclude animal products, was able to decrease the risk of emphysema development in middle adulthood in those with a smoking history,” Mariah K. Jackson, PhD, MMN, RDN, LMNT, assistant professor in the medical nutrition program in the College of Allied Health Professions at the University of Nebraska Medical Center, told Healio.

“These findings suggest one’s food choices can be an accessible, complementary intervention for long-term lung health, as the diet scoring system we used allows for multiple real-world achievable pathways to healthy eating, instead of focusing on one particular food,” Jackson continued.

Using data from the Coronary Artery Risk Development in Young Adults (CARDIA) Lung Prospective Cohort Study, Jackson and colleagues assessed 1,351 ever-smokers to find out how a plant-centered diet impacts the likelihood for emphysema found on CT.

Researchers split up the total cohort into five groups based on the average A Priori Diet Quality Score (APDQS) from three different times (0, 7 and 20 years). Individuals who consumed more nutritionally rich plant-centered foods belonged to a higher quintile.

Dietary information was obtained at all three times for most adults (73.9%), leaving a smaller percentage of adults with only two measurements (22.9%) or one measurement (3.1%).

“The robust data [in the CARDIA Lung Study], including CT measurement of emphysema and repeated diet exposure with high retention across young to middle adulthood, a critical stage where smoking-related respiratory diseases typically begin to manifest, were vital to observing the relationship we found,” Jackson said.

After dividing up the cohort, 259 adults (mean age, 26.7 years; 73% women; 87.3% white; 12.7% Black) belonged to the highest APDQS quintile at baseline, with a mean score of 83.8, whereas 274 adults (mean age, 23.9 years; 51.8%; 30.7% white; 69.3% Black) belonged to the lowest APDQS quintile, with a mean score of 47.7.

The remaining adults fell into quintile two (n = 270), three (n = 277) or four (n = 271).

At a 25-year follow-up, 175 adults (13%; mean age, 50.4 years) had radiographic emphysema. Jackson highlighted that the age range of these individuals (42-56 years) was relatively young and called for more studies investigating the “critical windows where diet can have the greatest impact on lung health.”

More adults in the lowest APDQS quintile had emphysema than those in the highest quintile (25.4% vs. 4.5%), according to researchers.

Further, researchers found reduced odds for emphysema among those in the highest vs. lowest APDQS quintile (adjusted OR = 0.44; 95% CI, 0.19-0.99; P = .008) in a model adjusted for several covariates (age, sex, race, field center, maximal educational attainment, height at baseline, total energy intake, BMI and smoking). This finding suggests that adults who consume more plant-centered foods are less likely to develop emphysema.

“I think what will surprise most people about this study is the strength of the association between diet and lung health, with a 56% lower risk of emphysema, after adjustment, in those with the highest adherence to nutrient-rich plant-based diets,” Jackson said.

Notably, the odds for emphysema dropped by 34% (OR = 0.66; 95% CI, 0.49-0.9) with each increase in APDQS standard deviation by one.

Across three different pack-years of smoking (< 10, 10-20 and > 20), the odds for emphysema did not significantly differ between the highest and lowest APDQS quintiles.

According to Jackson, results from this study show that diet can play a role in lung health despite not going directly into the organ.

“Currently, you may not automatically think of diet as an intervention for lung health,” she said. “It doesn’t go directly into your lungs, like breathing in smoke or pollution exposure; so how could it help? Although exact mechanisms are unknown at this time, research is suggesting that our diet affects our microbiome in ways that ultimately can impact systemic inflammation.”

More research targeting lifestyle-based treatable traits could help protect the health of smokers struggling to quit, Jackson added.

“Smoking cessation is a hard road, and it is important to offer our patients other avenues to have a complementary intervention for their lung health,” she said.

Since this was an observational study, additional research on this topic is needed.

“Research should also continue to strive for increased diversity to help represent all those we care for,” Jackson said. “Additionally, understanding when dietary exposures have the greatest impact on lung health is essential to develop public health dietary recommendations for children and young adults with the goal of preventing future adverse respiratory outcomes.”

Reference:

• Plant-based diet decreases risk of developing emphysema. https://www.copdfoundation.org/About-Us/Press-Room/Press-Releases/Article/1939/Plant-based-Diet-Decreases-Risk-of-Developing-Emphysema.aspx. Published April 25, 2024. Accessed April 26, 2024.