Plant-centered diet consumption linked to less lung function decline

Key takeaways:

• Smaller decreases in FEV₁ and FVC were found in those with high adherence to a plant-centered diet vs. low adherence.
• More participants with a persistently poor lung health trajectory had poor diet.

WASHINGTON — Annual lung function decline rates were lower in individuals who had high adherence to a plant-centered diet, according to an abstract presented at the American Thoracic Society International Conference.

Robert Wharton

“This study adds to the body of evidence showing the healthful effects of pragmatic, plant-centered diet even in persons without disease,” Robert Wharton, MD, resident doctor at Icahn School of Medicine at Mount Sinai, told Healio. “The challenge now is implementation — how can we deploy public health initiatives that recognize the importance of diet in myriad disease states?”

In a longitudinal study, Wharton and colleagues analyzed 3,787 adults from the Coronary Artery Risk Development in Young Adults (CARDIA) study for 30 years to see how a plant-centered diet impacted lung function over early and middle adulthood.

Participants completed a diet history questionnaire at baseline, year 7 and year 20, and their FEV₁ and FVC were captured at baseline and at years 2, 5, 10, 20 and 30.

To assess participants’ adherence to the diet, researchers used the A Priori Diet Quality Score (APDQS), in which a healthier diet is represented by a higher score, according to the abstract. Individuals were then sorted into one of five groups based on their APDQS.

“We used ADPQS, which gives a score to each of 46 food groups,” Wharton told Healio. “Fruits, vegetables, whole grains, and nonfried fish and poultry are scored positively, whereas refined grains and red and processed meats are scored negatively. Some other foods with less certainty of evidence are rated as neutral.”

An adjusted linear regression model was used to see how APDQS was related to yearly lung function decline.

Compared with individuals grouped in quintile 1 (median APDQS score, 52), researchers found those in quintile 5 (median APDQS score, 82) had lower yearly reductions in FEV₁ (35 ml/year vs. 33.4 ml/year; P = .009) and FVC (37 ml/year vs. 34.6 ml/year; P < .001).

Notably, researchers did not find a significant relationship between APDQS and FEV₁/FVC.

“We already suspected that having a nutritionally rich, plant-centered diet was good for lung function, but our study showed that longitudinal adherence to this diet was important for everyone in a group of young to middle-aged adults who were otherwise reasonably healthy,” Wharton told Healio. “We wondered whether we would see a bigger or smaller effect in smokers, but that didn't seem to be the case, suggesting that the inflammatory pathways by which diet impacts lung function are unaffected by smoking.”

When participants were divided up according to trajectory of FEV₁ percent predicted derived from latent class analysis, 58 had persistently poor lung health, 173 had worsening lung health, 1,233 had preserved impaired lung health, 1,449 had preserved good lung health and 184 had preserved ideal lung health. Adults included in this categorization (n = 3,097) needed to have data for a minimum of two follow-ups, with one required to be taken at year 30.

Researchers found a higher prevalence of individuals in quintile 5 in the preserved good and ideal lung health categories than in the other lung health categories. On the other hand, having an APDQS in quintile 1 was more prevalent in those with persistently poor lung health than in categories of good or ideal lung health.

Even though this was an observational study, Wharton told Healio they thoroughly adjusted for smoking since it is a major confounder.

“We were very careful to adjust our analyses for the biggest confounder, smoking, with assessments of smoking status at each annual follow-up,” he said. “We even cross-checked participants’ self-report with serum cotinine measurements and found that they correlated well.”

Wharton added that findings from the study could make patients think more deeply about what they are eating and consider how food impacts their lung function.

“We already know so much about what diet can do for your health, particularly for cardiovascular disease,” Wharton told Healio. “I see this work as being a key piece of motivation for patients to improve their diet. As a resident, when I rotate in primary care clinic, I’m excited to relate to all of my patients who may need to lose weight or control their blood sugar that the benefits go beyond cardiovascular disease, weight loss or diabetes control and extend to lung function. I suspect this will be particularly encouraging in the patients who already have some respiratory disease.

“The other positive message is that this is a diet that’s easy to understand and attainable,” Wharton added. “[The A priori diet quality score] makes it easy to work with your patients to talk about a diet that makes sense for their lifestyle and cultural paradigm.”

For more information:

Robert Wharton, MD, can be reached at robert.wharton@mountsinai.org.