September 27, 2025

expert reaction to unpublished conference abstract looking at the associated protective effect of eating fruit on the impact of air pollution on lung function

A conference abstract presented at the European Respiratory Society Congress (ERSC) looks at the effect of eating fruit on the impact of air pollution on lung function. 

Dr Samantha Walker, Director of Research, Asthma + Lung UK, said:  

“The statistical model the researchers have used is a snapshot (not looking at changes over time) – we should consider this a hypothesis-generating study, indicating this is an area of future interest to research.

“They are also only able to make inferences on associations, not causation – so we cannot say from this that fruit in women’s diet protects against air pollution.

“They have adjusted for lots of potential confounding variables, and used a large sample size, but there might still be other ways that haven’t been accounted for that the people in the high vs low fruit groups might differ (i.e. something else might be driving this difference in lung function).

“It’s not clear from the abstract how they have modelled the PM2.5 changes (i.e. have they just modelled this?) but we can probably say that higher fruit intake is associated with smaller declines in lung function with increasing PM2.5 exposure.

“Overall, I’d say the study design seems robust and appropriate for the question they are trying to ask, with a large dataset being used. But I would say that the authors conclusions might not be fully supported by the data (that we can see form abstract) and that they have uncovered an association between higher fruit intake and lung function that should be followed up with causative analyses.

“We know that a high fruit diet supports lung function, but it’s an interesting step forward in this study to see that it could also counteract the effects of air pollution on our lungs. Fruit and vegetables, particularly those high in vitamin C and K, can really help support our lungs to function well. While eating more fruit isn’t a replacement for taking your medication as prescribed, enjoying fruit as part of a balanced diet looks like it can help our lungs when they’re faced with external pressures like air pollution. It’s also encouraging to learn of simple things people can do to reduce the impact of air pollution on their health.  

“However, it is important to remember that there is unequal access to healthy foods, largely driven by cost. In addition, air pollution continues to hit people who are the poorest and from an ethnic minority background the hardest. The government must do more to address the disproportionate exposure to air pollution that contributes to worsening health inequalities, which is why Asthma + Lung UK is calling on the government to introduce stronger, legally binding air quality targets that align with World Health Organization guidelines.” 

Dr Mohammad Talaei, Lecturer in Life Course Epidemiology, Queen Mary University of London (QMUL), said:

Does the press release accurately reflect the science?

“Yes, to a great extent. However, a significant shortcoming is the lack of mention of the cross-sectional nature of this analysis in the press release. For example, the following phrase: “For every increase in exposure to PM2.5 of five micrograms per cubic metre of air, the team observed a 78.1ml reduction in FEV1 in the low fruit intake group, compared to only a 57.5ml reduction in the high fruit intake group in women” can mislead a reader as if the authors actually measured the reduction in lung function over time due to air pollution. In contrast, it was impossible due to the lack of a longitudinal design. What authors have found is, in fact, a weaker inverse association between PM2.5 and FEV1 in a subgroup of women with higher fruit intake. From this point, we cannot further claim that those who had a higher fruit intake had a lower reduction over a period. I think the press release should clarify that it was NOT “over a period”. 

Is this good quality research? Are the conclusions backed up by solid data?

“It is hard to comment based on an abstract, as many details are missing due to space limitations. 

“With this large sample available, I expect to find a sufficient number of men with an equivalent fruit intake to that of women in the highest intake group. A generally lower fruit intake in men should not stop authors from testing if such a signal is observed in men with comparable fruit intake. Therefore, I don’t think the lack of an association in men has been sufficiently investigated.

“I have also explained below that the authors have overestimated in the conclusions.

How does this work fit with the existing evidence?

“It is plausible to propose a protective effect for antioxidants that are high in fruits, as well as in vegetables. But the study found a signal for fruits, not vegetables. We still don’t know if those potential protective effects can be strong enough to mitigate the adverse effects of air pollution. 

Have the authors accounted for confounders? Are there important limitations to be aware of?

“The most significant limitation is the cross-sectional nature of this analysis, as explained above. Among the confounding factors the authors have considered are ethnicity, income, and education. There is room for better controlling the confounding effect of socioeconomic status, such as using more indicators, including area-based ones. The abstract also does not provide information on how sufficient income and education were controlled for. So a lot is still unknown.

What are the implications in the real world? Is there any overspeculation?  

“I cannot consider any in the real world other than suggesting further research. The phrase in the conclusion that says “seems to mitigate adverse effects of PM2.5 on lung function” is an overspeculation, as it implies a causal relationship. I also disagree that “this study confirms the potential respiratory health benefits of a healthy diet” (quote in press release); it suggests at most. However, I do agree that governments should continue their efforts to decrease air pollution.

Can we tell any correlation vs causation from this paper?

“We certainly cannot discuss causation; these are merely correlations.”

Prof Parveen Yaqoob, Pro-Vice Chancellor (Research & Innovation), University of Reading, said:

“Without seeing a full peer-reviewed publication it is hard to say how significant the finding is. Statements like this that are based on association should be interpreted with caution and not taken as evidence of a causal link.”

Prof Tom Sanders, Professor emeritus of Nutrition and Dietetics, King’s College London (KCL), said:

“This an observational study that is subject to confounding as the authors acknowledge. Low fruit and vegetable intake is characteristic of people in low socioeconomic groups who are more likely to live in areas where exposure to airborne pollution is greater. As far as I can ascertain no correction has been made for postcode, which would enable estimates of exposure to airborne pollution.”

‘Does diet modify the effects of air pollution on lung function? A large cross-sectional study’ by Kaewsri et al. was presented at the European Respiratory Society Conference (ERSC). The embargo lifted at 23:01 UK time on Saturday 27^th September 2025.

Declared interests

Dr Mohammad Talaei: I have no COI to declare

Prof Tom Sanders: No conflicts of interest in this case.

For all other experts, no reply to our request for DOIs was received.