Nutrition management in chronic lung disease

Nutrition is a modifiable factor that impacts on progression in lung disease, one of the biggest causes of death in the UK, says Sarah Airey.

Chronic respiratory disease and chronic lung disease (CLD) are terms used to describe diseases that affect the lungs and other parts of the respiratory system. They typically develop slowly and cause irreversible damage that worsens over time, making breathing more difficult. Most have no cure, so treatments focus on reducing symptoms and slowing disease progression. There are many different types of CLD:

• Asthma
• Chronic obstructive pulmonary disease
• Cystic fibrosis
• Bronchiectasis
• Interstitial lung disease ILD (includes asbestosis, pulmonary fibrosis, hypersensitivity pneumonitis, sarcoidosis)
• Pulmonary hypertension
• Tuberculosis

The two most common CLDs are asthma and chronic obstructive pulmonary disease (COPD). The latter is a group of lung conditions with the main types being emphysema and chronic bronchitis.

Interstitial lung disease (ILD) is a group of over 100 lung conditions that have a variety of causes (most common ones listed in Box 1). They are characterised by inflammation and scarring of lungs and most types are progressive. Although ILD is less common than COPD, some types progress rapidly and significantly reduce life expectancy (median survival of three-to-five years after diagnosis).¹

Tuberculosis (TB) is caused by bacteria and is a treatable condition but can cause long-term lung damage if not detected and treated early.

Nutrition impacts on CLD and vice versa

Those with CLD are at high risk of malnutrition as consequences of the disease (Box 2) impact on food choices and nutrient intakes. The reported prevalence of malnutrition varies depending on the CLD type, disease severity, population studied (inpatients/outpatients) and criteria used to diagnose malnutrition. Reported malnutrition rates range from 10% to 45%.^2,3

Studies show malnutrition increases CLD exacerbation rates, likelihood of needing hospital admission and recovery time from illness.² Although more difficult to clearly demonstrate, micronutrient deficiencies likely reduce immune function, increasing infection rates, and poor antioxidant intakes likely increase oxidative stress and free radical damage in the lungs. Malnutrition is known to increase with the severity of CLD and is likely both cause and consequence of worsening lung disease.

Poor diet could also contribute to worsening lung health in other ways. Emerging evidence shows links between the gut microbiome and lung microbiome.⁴ Gut dysbiosis is thought to influence COPD progression through a variety of mechanisms suggesting prebiotics and probiotics could be considered as treatment strategy in the future.

Factors impacting food choices and nutrient intakes in CLD

• Coughing
• Breathlessness
• Phlegm production/expectoration
• Dry mouth
• Fatigue
• Reduced functional ability
• Social isolation
• Reduced activity levels
• Medication side effects

Is malnutrition just an inevitable consequence of CLD?

In the past, weight loss was considered an inevitable consequence of CLD, but evidence showing the benefits of treating malnutrition is increasing. Previous Cochrane reviews on nutrition support in COPD concluded nutrition support had no significant benefit, but the 2012 Cochrane review supported treating malnutrition to promote weight gain, improve strength and improve quality of life.⁵

Guidance supporting assessment of nutrition status and nutrition interventions with specifically developed resources have since been developed.^6,7 However, screening and nutrition interventions still seem inconsistent.

The majority of dietitian resources are allocated to respiratory hospital inpatients.

Malnutrition can develop more rapidly during acute illness, but treating malnutrition is more challenging in severe disease, when hospital admission is required.

It is possible this late approach to nutrition treatments could reinforce the belief by respiratory health professionals that malnutrition is an inevitable consequence of the disease.

Obesity

A high proportion of those with CLD are classified as having obesity. An obesity paradox is seen in COPD because having a higher weight is shown to have a prognosis advantage, but not when BMI is very high (>40).⁸ The reason for this is not clear but it could possibly be due to having increased energy reserves during times when nutrition intake declines. However, BMI does not take into account the location of fat stores, known to influence health in different ways. Obesity can also mask malnutrition and/or muscle loss, which are both associated with poorer outcomes independent of BMI. Sarcopenic obesity is increasingly recognised as a health issue in many chronic diseases including CLD.

Muscle loss

Malnutrition can accelerate muscle loss. In CLD, muscle loss is common, increases with disease severity and is associated with worse outcomes. Muscle loss leads to reduced strength and physical function, which limits exercise capacity, impacting on respiratory muscle strength and lung function.⁹

In CLD, muscle loss is not just caused by poor dietary protein and energy intake. Chronic inflammation in the lungs increases systemic pro-inflammatory cytokines, which impact muscle metabolism and muscle wasting. In COPD, markers of systemic inflammation are shown to be inversely related to muscle strength, and systemic inflammation is thought to be present even in stable disease.¹⁰

In addition to muscle loss, structural muscle changes have been demonstrated in those with COPD that are not just down to the normal ageing process. These changes are sometimes referred to as muscle dysfunction and are thought to change muscle energy metabolism, causing increased muscle fatigue and reduced exercise capacity. The changes in muscle may be due to greater levels of oxidative stress resulting from hypoxemia, which can trigger or exacerbate inflammation.¹¹

The majority of UK CLD guidelines advise assessment of BMI on diagnosis and review. BMI does not give an accurate assessment of nutritional status and does not take into account muscle mass or muscle changes happening over time. Nutrition screening is a more accurate method of assessing nutritional status, but commonly used nutrition screening tools do not include assessment of muscle mass. The European Respiratory Society recommends assessment of muscle mass should be included in nutrition screening of those with CLD. The Global Initiative for Malnutrition (GLIM) includes reduced muscle mass as a criterion for diagnosing malnutrition but does not specify the method that should be used. Incorporation of hand grip strength measurements into malnutrition screening would identify muscle loss and screen for frailty and sarcopenia, increasingly recognised as negatively impacting health outcomes.

Pulmonary rehabilitation

There is strong evidence to show the benefits of pulmonary rehabilitation (PR), including improvements in exercise tolerance, quality of life and psychological status. PR includes exercise training together with an education element to support better self-management for long-term health benefits. PR is a cost-effective intervention and NICE COPD, ILD and IPF guidance includes recommendations for PR. The NHS Long Term Plan includes proposals to expand PR services to increase access for people with lung disease.

PR guidelines were developed in 2013 by the British Thoracic Society (BTS), with a follow-up clinical statement published in 2023.^12,13 They define PR as an interdisciplinary programme of care and agree nutritional deficiencies could restrict PR benefits but make no reference to dietitians or nutrition intervention apart from stating a referral to a dietitian should be considered for those with a low or high BMI. Additionally, no guidance on nutrition education is provided apart from the statement, “attendance at a PR course presents an ideal opportunity to screen and educate patients on nutrition”. PR quality standards have been developed but they do not include any nutrition-related standards or outcome measures. The BTS runs PR courses aimed at multidisciplinary audiences (Fundamentals of PR and Advanced Practice in PR) but neither includes any nutrition education.

Providing nutrition education during PR and assessing nutritional status is such a great opportunity to support people with CLD to improve their health. There is evidence that nutrition screening and interventions alongside PR appear to improve outcomes but further studies are needed. Some PR teams include nutrition education and nutritional screening and may have dietitians involved – but many do not.

Although evidence to support the influence nutrition has on lung health is increasing, nutrition education, community malnutrition screening and access to appropriate nutrition interventions seem to be lacking. Incorporating better nutrition guidance, quality standards and outcome measures into acute and community respiratory services is vital to ensure nutrition is included in the holistic care of people with respiratory disease.

Tips to get involved and highlight nutrition service gaps 

• Join the British Thoracic Society and/or the Primary Care Respiratory Society to give dietitians a voice and raise awareness of nutrition at the highest level
• Look for current gaps in respiratory dietetic services in your own area and opportunities for service development by improving links with:
  • Local pulmonary rehabilitation teams – find out the current approach to nutrition screening and what nutrition education is currently being provided
  • Hospital respiratory teams – audit inpatient and outpatient nutrition screening and promote nutrition screening and local treatment guidelines to ensure those at high risk of malnutrition are getting the nutrition interventions needed
  • Community respiratory teams – promote nutrition screening and local nutrition treatment guidelines
  • Lung disease groups – present at local support group meetings
• Promote self-screening for malnutrition in outpatients using posters, video presentations or information with outpatient letters
• Spotlight local respiratory nutrition services by presenting case studies and audits to stakeholders highlighting the benefits or missed opportunities due to gaps in service
• Get involved with respiratory team journal clubs and highlight new evidence for nutrition and interventions
• Collaborate with respiratory teams to raise awareness of nutrition as a modifiable factor
• Get involved with specific lung disease awareness days
• Explore nutrition outcomes that can be collected to present data and support service developments
• Network with dietitians working in this speciality to improve peer support and collaboration
• Use social media to help spread the word and raise awareness.

We could improve communication and peer support between dietitians working in this area to aid collaboration. Please get in touch.

References

1. Raghu G, Collard HR, Egan JJ, Martinez FJ, Behr J, Brown KK, Colby TV, Cordier JF, Flaherty KR, Lasky JA, Lynch DA. An official ATS/ERS/JRS/ALAT statement: idiopathic pulmonary fibrosis: evidence-based guidelines for diagnosis and management. American Journal of Respiratory and Critical Care Medicine. 2011;183(6):788-824.
2. Davalos-Yerovi V, Marco E, Sanchez-Rodriguez D, Duran X, Meza-Valderrama D, Rodriguez DA, Munoz E, Tejero-Sánchez M, Muns MD, Guillén-Solà A, Duarte E. Malnutrition according to GLIM criteria is associated with mortality and hospitalizations in rehabilitation patients with stable chronic obstructive pulmonary disease. Nutrients. 2021;13(2):369.
3. Faverio P, Fumagalli A, Conti S, Madotto F, Bini F, Harari S, Mondoni M, Oggionni T, Barisione E, Ceruti P, Papetti MC. Nutritional assessment in idiopathic pulmonary fibrosis: a prospective multicentre study. ERJ Open Research. 2022;8(1).
4. Spagnolo P, Molyneaux PL, Bernardinello N, Cocconcelli E, Biondini D, Fracasso F, Tiné M, Saetta M, Maher TM, Balestro E. The role of the lung’s microbiome in the pathogenesis and progression of idiopathic pulmonary fibrosis. International Journal of Molecular Sciences. 2019;20(22):5618.
5.  Ferreira IM, Brooks D, White J, Goldstein R. Nutritional supplementation for stable chronic obstructive pulmonary disease. Cochrane Database of Systematic Reviews. 2012(12).
6. Schols AM, Ferreira IM, Franssen FM, Gosker HR, Janssens W, Muscaritoli M, Pison C, Ruttenvan Mölken M, Slinde F, Steiner MC, Tkacova R. Nutritional assessment and therapy in COPD: a European Respiratory Society statement. European Respiratory Journal. 2014;44:1504–1520.
7. Anderson L, Banner J, Bostock B, et al. Managing malnutrition in COPD. 3rd edition. 2023. www.malnutritionpathway.co.uk/copd (accessed 11 April 2025).
8. Yao S, Zeng L, Wang F, Chen K. Obesity Paradox in Lung diseases: what explains it? Obesity Facts. 2023;16(5):411-26.
9. Luo Y, Zhou L, Li Y, Guo S, Li X, Zheng J, Zhu Z, Chen Y, Huang Y, Chen R, Chen X. Fat-free mass index for evaluating the nutritional status and disease severity in COPD. Respiratory Care. 2016;61(5):680-8.
10. Ferrari R, Caram LM, Faganello MM, Sanchez FF, Tanni SE, Godoy I. Relation between systemic inflammatory markers, peripheral muscle mass, and strength in limb muscles in stable COPD patients. International Journal of Chronic Obstructive Pulmonary Disease. 2015:1553-8.
11. Maltais F, Decramer M, Casaburi R, Barreiro E, Burelle Y, Debigare R, Dekhuijzen PR, Franssen F, Gayan-Ramirez G, Gea J, Gosker HR. An official American Thoracic Society/European Respiratory Society statement: update on limb muscle dysfunction in chronic obstructive pulmonary disease. American Journal of Respiratory and Critical Care Medicine. 2014;189(9):e15-62.
12. Bolton CE, Bevan-Smith EF, Blakey JD, Crowe P, Elkin SL, Garrod R, Greening NJ, Heslop K, Hull JH, Man WD, Morgan MD. British Thoracic Society guideline on pulmonary rehabilitation in adults: accredited by NICE. Thorax. 2013;68(S2):ii1-30.
13. Man W, Chaplin E, Daynes E, Drummond A, Evans RA, Greening NJ, Nolan C, Pavitt MJ, Roberts NJ, Vogiatzis I, Singh SJ. British thoracic society clinical statement on pulmonary rehabilitation. Thorax. 2023;78(5):s2-15.