There is growing interest among the population in following diets and eating healthy foods that are compatible with respect for the environment in a scenario of climate change. For this reason, studies evaluating the impact of diets that provide benefits to both health and the planet are very timely. In this regard, the Planetary Health Diet (PHD) is an approach focused on mitigating the production of greenhouse gases associated with diet while promoting human health.

The present study addresses this issue from two perspectives. On the one hand, it studies the association between adherence to the PHD and the risk of mortality and chronic disease based on two large databases, the US National Health and Nutrition Examination Survey (US NHANES) and the UK Biobank. On the other hand, it performs a meta-analysis to jointly evaluate the association between the PHD and all-cause mortality, cancer, and cardiovascular disease.

The result of both approaches to the problem is that people who follow a diet more similar to the PHD have a lower risk of dying from chronic diseases, while reducing greenhouse gas emissions. The authors conclude that this type of diet should be promoted to improve public health and combat climate change.

The approach using official surveys has the advantage of providing access to a considerably large sample size. In fact, between the two databases used in the study, information from almost 170,000 people was accessed. However, it also has its limitations. First, the questions asked of respondents do not always have to be focused on the problem or hypothesis being addressed. In this study, for example, there are no direct questions about the PHD, which detracts from the value of the results. In addition, the surveys may not be up to date. For example, data from the US NHANES survey only goes up to 2018. In these surveys, dietary intake is assessed at baseline but may change during the follow-up period, so baseline measurements may not accurately reflect exposure levels throughout the study, which could introduce bias.

On the other hand, the meta-analysis approach allows for even larger sample sizes by combining all the studies included in the review. In this case, there are 37 studies, including more than 3,000,000 participants. The limitation is that the experimental designs are diverse, which may reduce the homogeneity of the results. Furthermore, as both approaches are observational in nature, they do not allow for the establishment of cause-and-effect relationships.

In any case, the combination of both approaches lends strength to the results and underscores the importance of considering the nutritional quality and environmental impact of foods and diets as a whole.

 

EN