Research results: the MADIET clinical trial

November 2023

Can what people eat have an impact on the side effects of the antifibrotic medication, pirfenidone? Researchers in Europe explored this question further, read on to find out more about the MADIET clinical trial.

People affected by idiopathic pulmonary fibrosis (IPF), can be given an antifibrotic medication which can slow down the build up of scar tissue or fibrosis in the lungs. The medication is often taken with food, or directly after food, but it can make some people feel unwell with side effects. These can include:

  • Nausea
  • Vomiting
  • Loss of appetite
  • Indigestion
  • Photosensitivity
  • Fatigue

These side effects can have a huge impact on quality of life. There have been reports that there are differences in the frequency and severity of side effects depending on where people live within different parts of Europe, where diets can be contrasting. Researchers set up a study to find out if side effects are associated with what someone eats.

If you currently struggle with these side effects or malnutrition, you may find it helpful to speak to a dietitian.

What did the researchers do?

Patients were recruited from the UK, Germany, Netherlands, Italy, Greece and Spain. Everyone who took part had a diagnosis of IPF, were aged 40 years and over, and were about to start antifibrotic treatment of pirfenidone.

During the first assessment, patients were asked to complete a food frequency questionnaire. This looked at what people usually ate and how often. It focused specifically on the types of fats in foods and the methods used for cooking foods.

Depending on what the food frequency questionnaires showed, participants were put into one of two groups:

  • Group 1 – MUFA, people who had diet that is high in monounsaturated fat.

MUFA rich foods are mainly found in plant foods such as avocados, olive oil, rapeseed oil and nuts.

  • Group 2 – SFA, people who had a diet that is high in saturated fat.

SFA rich foods are mainly found in animal-based foods such as butter, lard, processed meat and dairy products. Foods that are made with these products such as biscuits, cakes and pastries are also considered to be high in SFA.

Patients were then asked to follow the same instructions for up to 16 weeks.

  1. Keep to their usual diet and not make any significant changes (same type of foods and cooking methods)
  2. When starting the pirfenidone, stick to the dose that they have been prescribed
  3. Use a patient diary to record daily food intake, pirfenidone dose and any side effects

What were the results?

89 patients took part in the study, 49 people were in the MUFA group and 37people were in the SFA group. The researchers looked at the frequency of side effects over the 16 weeks, according to which diet someone consumed. Those who were in the MUFA group had less side effects compared to the SFA group. For all those who did experience side effects, there was no difference found between the groups for the severity. The drug withdrawal was also higher in the SFA group.

There were some limitations to the study, including the short timeframe that the study took place and participants were not randomised to a group. There may have been other factors that accounted for the results, that were not looked at within the study.

What next?

This study was the first of its kind to look at the potential impact of diet on the side effects experienced by patients when taking pirfenidone. It showed that food intake could play an important role for helping to improve quality of life by reducing the side effects of pirfenidone. However, it does not show if changes to diet can help all patients. More nutritional research studies are needed to see what the most appropriate diet is for helping people affected by pulmonary fibrosis when taking antifibrotic medication.

At any given moment, people around the world are helping to further our understanding of pulmonary fibrosis, to find better and more effective treatment options. Studies such as this aim to help people affected by pulmonary fibrosis now, and improve quality of life during a time that is otherwise devastating.

Research would not be possible without amazing patients taking part in studies. If you are interested in taking part in research, please speak to your healthcare team to express your interest, and ask if there are any studies that you may be eligible to participate in.

If you would like to donate to pulmonary fibrosis research, please see our Hope for All Research Appeal.