Healthy Low-Fat Diets Lower Death Risk in COPD, Study Finds

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Unhealthy low-fat diets (LFDs) were linked to higher odds of chronic obstructive pulmonary disease (COPD), while unhealthy low-carbohydrate diets (LCDs) were significantly associated with higher mortality risk. On the other hand, adopting a healthy LFD was linked to a lower risk of death in patients with COPD.

Diet is a proven beneficial modifiable lifestyle factor for patients with obesity and other chronic diseases. As obesity has a protective effect against death in patients with COPD, diet may play a role in the outcomes of this condition. This theory is strengthened by research that has backed the increased risk of the development and progression of COPD among those who adhere to a Western-style dietary pattern, which is defined by a high intake of processed red meat, saturated fat, sweets and refined grains.

Investigators used data from the National Health and Nutrition Examination Survey (NHANES) 2007–2012 cycle to explore the effects of LCDs and LFDs on COPD and mortality among people with the condition. Using statistical models, they compared how healthy and unhealthy versions of these diets influenced disease and survival outcomes.

Diet was evaluated using a 24-hour dietary recall, and nutrients were estimated using the US Department of Agriculture (USDA) Food and Nutrition Database for Dietary Studies (FNDDS). Using the percentage of energy derived from fats, proteins and carbohydrates, investigators calculated total LCD and LFD scores. Healthy and unhealthy scores were defined based on the percentage of energy from low-quality carbohydrates, high-quality carbohydrates, animal proteins, plant proteins, saturated fats and unsaturated fats.

“To the best of our knowledge, this study is the first to explore the association between different types of LCD and LFD scores with morbidity and mortality in COPD,” wrote an international team of investigators from the Department of Respiratory and Critical Care Medicine at The First Affiliated Hospital of Xi’an Jiaotong University in Shaanxi, China.

In total, 1,020 adults were involved in the analysis, including 456 patients with COPD. The median age of participants was 52 years, and 89 deaths occurred during the follow-up period. Those with a higher LCD score were more likely to be older and have a higher number of comorbidities, body mass index (BMI), education level and income level. Those with higher LFD scores had lower BMI, were nonsmokers, and had a lower education level and incidence of complications.

Results showed unhealthy LFDs increased the odds of developing COPD. Further, unhealthy LCDs were linked to a 21% higher risk of death with every 5-point increase in an “unhealthy score.” Conversely, healthier LFDs were associated with a 21% reduction in mortality risk with every 5-point increase in their “healthy score.”

Findings stressed that diet quality matters when it comes to managing COPD. Although unhealthy eating patterns can worsen outcomes, choosing a healthy LFD may reduce the risk of death in people with COPD.

Investigators noted using a nationally representative cohort coupled with validated measures to collect information on diet strengthened the study. However, limitations included using self-reported data to ascertain diet and other lifestyle factors, which may not be representative of long-term dietary habits. Additionally, the sample size of patients was limited due to missing information in the NHANES database. Lastly, the cross-sectional study design left investigators unable to identify any causal relationships.

“In individuals with COPD, an unhealthy LCD increases the risk of mortality, whereas a healthy LFD may improve the survival rate of patients,” investigators underscored. “Therefore, the importance of quality and food sources of macronutrients should be emphasized.”