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Nutrition research review: Nutrition as a modifiable factor in the onset and progression of pulmonary function impairment in COPD: a systematic review.

For further information on this topic, you may be interested to learn more about the HealthCert Professional Diploma program in Medical Nutrition Management.

Chronic Obstructive Pulmonary Disease (COPD) is a progressive lung disease where airflow is persistently restricted, accompanied by respiratory symptoms including dyspnoea, cough, and mucous production. COPD is the third leading cause of death worldwide (World Health Organization, 2022)

Patients may experience exacerbations that can contribute to the decline of pulmonary function. Identified risk factors for both the onset and progression of COPD include smoking, air pollution exposure and, increasingly, there is evidence supporting the role of poor diet and malnutrition.

Research has suggested that healthy dietary patterns may be associated with lower levels of pulmonary and systemic inflammation and attenuation of oxidative stress associated with COPD. As such, van Iersel and colleagues undertook a systematic review of 89 studies to identify whether modification of dietary intake influenced COPD onset and progression.

The authors considered research comparing less healthy Western style dietary patterns, (i.e., high intake of red meat/processed meats, refined grains, sweets, desserts, and French fries), to health-promoting Mediterranean style dietary patterns (i.e., high in fruit, vegetables, legumes, fish, and wholegrains). Strong evidence was found for an increased risk of COPD onset with a Western-style diet, whereas increased adherence to the Mediterranean Style diet was associated with reduced COPD risk. No data was found exploring the long-term effect of these dietary patterns on COPD progression.

Processed meat intake was found to positively increase risk of COPD however no studies were found exploring the effect of processed meat intake on pulmonary function impairment.

Studies exploring the association of alcohol intake and COPD were inconsistent, however it does appear that when considering the general population, heavy drinking is associated with a decline in pulmonary function whereas mild-moderate consumption may be protective. No evidence was found that considered the effect of alcohol intake on pulmonary function in those already diagnosed with COPD.

Increased fruit and vegetable intake, as well as dietary fibre intake, is associated with reduced risk of COPD in the general population. Yet, no evidence was found relating the intake of fruits and vegetables and dietary fibre on pulmonary function decline in patients already diagnosed with COPD.

Similarly, strong evidence supports the benefits of polyphenols (e.g., catechins, flavanols, flavones, anthocyanins, resveratrol) on COPD risk. However, there is only limited evidence for the effect of polyphenols on COPD patient’s pulmonary functional impairment.

The influence of Vitamin D on COPD risk has been well studied. For the general population, there is no consistent evidence linking dietary intake of Vitamin D, serum levels and COPD risk. However, there is very strong evidence to support the benefit of Vitamin D supplementation on pulmonary function decline in COPD patients, especially in those who are Vitamin D deficient.

Whilst there is some evidence to support the benefit of Vitamins C, E, and beta-carotene on COPD risk in the general population, more research is needed to explore potential benefits associated with these micronutrients on pulmonary function decline in COPD patients.

Finally, research exploring the relationships of fatty acids and risk and progression of COPD has returned inconsistent findings.

Practice points:

• Evidence supports the role of nutrition in reducing risk of developing COPD:
  • Eating a Mediterranean style diet,
  • Reducing intake of processed meat,
  • Not exceeding a mild-moderate alcohol consumption,
  • Increasing intake of fruits and vegetables, polyphenols, dietary fibre, vitamins C, E, and beta-carotene

This systematic review confirms that nutrition is a modifiable factor for COPD development in the general population. However, more research is necessary to identify the role of nutrition on the progression of pulmonary function decline in COPD.

– Anna Millichamp APD, Bond University

Full paper

Lieke E J van Iersel, Rosanne J H C G Beijers, Harry R Gosker, Annemie M W J Schols, Nutrition as a modifiable factor in the onset and progression of pulmonary function impairment in COPD: a systematic review, Nutrition Reviews, Volume 80, Issue 6, June 2022, Pages 1434–1444.

Available: https://doi.org/10.1093/nutrit/nuab077

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