Following the EAT-Lancet planetary health diet (PHD) is associated with reduced risk of developing incident chronic kidney disease (CKD), especially in patients who live in places with minimal green space, study findings suggested. Though PHD resembles other plant-based dietary approaches (eg, the dietary approaches to stop hypertension and Mediterranean diets) in terms of emphasizing vegetables, fruits, nuts, and whole grains, it also encourages a pattern of eating that promotes human health within a framework of environmental sustainability.

A unique aspect of the study was that the researchers analyzed molecular signatures (ie, metabolites and proteins) in participants’ blood samples to understand how PHD might confer protection against CKD.

“By constructing metabolic and proteomic signature scores, we were able to identify biological pathways that partially mediate the diet’s protective association with CKD,” coauthors Xianhui Qin, MD, nephrologist, and Fan Fan Hou, MD, PhD, chief of the renal division, both at the Nanfang Hospital in Guangzhou, China, told Medscape News Canada. Qin and Hou are also professors of medicine at Southern Medical University in Guangzhou, China.

“This approach allowed us to move beyond traditional dietary assessments and uncover potential mechanisms, such as modulation of inflammation or lipid metabolism, through which PHD might lower CKD risk.”

The study was published online on January 26 in CMAJ.

A Compensatory Role

Data were obtained from 179,508 participants (mean age, 55.9 years; 55% female; 96% White) from England, Scotland, and Wales who were enrolled in the UK Biobank between December 2006 and October 2010. Eligible participants completed at least one web-based dietary recall questionnaire and contributed biological samples. PHD adherence was calculated primarily using the Kesse-Guyot dietary score, which captures individual dietary variation, along with three other scoring methods.

The study outcome was incident CKD. During a median 12.1-year follow-up period, 2.7% (4819 of 179,508) participants developed CKD.

“A higher adherence to EAT-Lancet was consistently associated with a lower risk of incident CKD across four scoring methods,” said the researchers. Each SD increase in each diet index was associated with a lower risk for incident CKD (Kesse-Guyot: adjusted hazard ratio, 0.92). The Kesse-Guyot score showed a dose-response relationship when it was assessed by quartiles.

This protective association was more pronounced in participants with less access to residential green space, “indicating that the EAT-Lancet plays a compensatory role in settings where environmental supports for health are limited,” said the authors.

“Our findings suggest that the EAT-Lancet diet can be recommended as a feasible, evidence-based dietary strategy for CKD reduction and support personalized, stratified dietary guidance,” they added.

Adherence Is Key

PHD is based on the effect of diets on human health and was designed to improve or increase agricultural productivity and reduce food loss and waste. Achieving these outcomes could reduce environmental pressures on the climate, biodiversity, water, and pollution.

“It’s not very different from Canada’s Food Guide and the plate model,” said Jane Paterson, RD, registered dietician at University Health Network’s Toronto General Hospital, Toronto, who was not involved in the study. Though CKD incidence was not directly addressed during the development of the plate model, researchers considered obesity and diabetes, both of which place a person at high risk of developing CKD, Paterson said.

Common threads among plant-based diets include greater consumption of vegetables and nuts and reduced intake of red meat and saturated fats. Limiting added sugars and fats has been associated with the modulation of inflammation and oxidative stress pathways linked to CKD risk. In the study, the metabolic signature score significantly mediated 18.0% of the total effect of the EAT-Lancet index on CKD risk.

But a warning about the diet is appropriate. “Not all plant-based diets are healthy,” said Paterson. “By definition, a healthy plant-based diet includes whole grains, fruits, vegetables, legumes, nuts, and seeds and is low in sugary drinks and saturated fats. You can have someone following a plant-based diet that is low in whole grains and high in white, refined grains; low in fruits, vegetables, and legumes and nuts; and high in sugar, sweets, cereals, and juices.” Data demonstrate that British adults who consumed an unhealthy plant-based diet had as much as a 27% increased risk of developing kidney disease.

For clinicians, the primary message is that regardless of the plant-based diet recommended, the diet’s components and the patient’s adherence are key, said Paterson. Adopting such a diet is “a slow process, and it takes someone to value that change and see benefit it in it,” she said.

The study was supported by the National Natural Science Foundation of China, the Key Technologies R&D Program of Guangdong Province, the Guangdong Provincial Clinical Research Center for Kidney Disease, and the Program of Introducing Talents of Discipline to Universities (111 Plan). Qin, Hou, and Paterson reported having no relevant financial relationships.

Liz Scherer is an independent health and medical journalist who frequently reports on Canadian and EU health news.