News New research challenges restrictive diets for kidney disease

Australian researchers have found that eating more than 30 types of plant foods each week can dramatically improve gut health and reduce harmful toxins in people living with chronic kidney disease — challenging decades of dietary wisdom in the process.

Chronic kidney disease (CKD) affects hundreds of millions of people worldwide. For decades, dietary advice for those living with the condition has been surprisingly restrictive — with many patients told to limit specific high-potassium fruits and vegetables like bananas, oranges, and potatoes.

Now, a world-first study led by researchers at the University of Wollongong (UOW) is turning that conventional advice on its head. The findings point in a simple and exciting direction — that a more diverse, plant-rich diet may be far more beneficial for people with CKD than previously thought.

Published in the Clinical Journal of the American Society of Nephrology, the study is the first of its kind worldwide, demonstrating the positive effects of a plant-based diet in people with CKD. It was led by Dr Jordan Stanford of the University of Newcastle, with Associate Professor Kelly Lambert — a specialist kidney dietitian with more than two decades of clinical experience — as senior author.

So, what did the trial actually involve?

The participants, Australian adults living with moderate-to-advanced kidney disease, followed two different diets for six weeks each, with a break in between — a high-diversity plant-based diet (eating 30 or more unique plant foods per week) and a low-diversity plant-based diet (15 or fewer unique plant foods per week), all while continuing to follow personalised advice from their kidney care team. The high-diversity diet included a wide variety of fruits, vegetables, whole grains, nuts, and seeds.

And the results were compelling. Those following the high-diversity plant-based diet saw significant improvements in gut bacteria diversity, a reduction in harmful toxin levels in blood and urine, and a 47% reduction in the acid burden placed on the kidneys — a particularly significant finding for people managing CKD long-term.

The diet also shifted the gut microbiome toward increased production of beneficial metabolites, which play an important role in gut and overall health.

Notably, the low-diversity plant-based diet told a very different story. It depleted dozens of beneficial bacterial species and was associated with lower microbial diversity — a useful reminder that variety really is the spice of life when it comes to plant-based eating!

Perhaps most encouragingly, the most unwell participants appeared to benefit the most. Those with more advanced kidney disease and higher baseline toxin levels showed the greatest improvements — suggesting that a diverse plant-based diet could be especially valuable for people who need it most.

We were particularly excited to see that this relatively simple intervention could have such profound effects, especially for those with more advanced kidney disease.

Associate Professor Kelly Lambert, University of Wollongong

Challenging decades of dietary restriction

The research also challenges long-held assumptions about what a safe diet looks like for CKD patients. While historically advised to limit specific high-potassium foods out of caution, the study found that a more inclusive, plant-rich approach could, alternatively, actually be beneficial for these patients.

For years, dietary advice for kidney disease patients has been restrictive, often limiting fruit and vegetable intake due to concerns about certain minerals such as potassium. This potentially did more harm than good and led to unintended consequences. Our study shows that a more inclusive, plant-based approach is not only safe but potentially more beneficial, even for those with advanced kidney disease.

Associate Professor Kelly Lambert, University of Wollongong

By improving gut health and reducing circulating toxins, the researchers believe the high-diversity plant diet could potentially help slow disease progression and improve overall quality of life for people with CKD — outcomes that go well beyond what a restricted diet could achieve.

The beauty of simplicity

What makes this research particularly exciting is just how accessible the approach is. No expensive treatments, no complex procedures — just real food, plenty of plants, and lots of variety.

It’s about making straightforward changes to what people eat, focusing on variety and plant-based foods … It’s a major step forward in how we approach nutrition for people living with chronic kidney disease.

Associate Professor Kelly Lambert, University of Wollongong

Researchers hope the findings will also prompt a long-overdue shift in research and clinical practice, reassuring people with kidney disease that it’s not only safe but actively beneficial to embrace a wider, more colourful plate of plant foods.

This study adds to a growing body of evidence showing that what we eat has a profound impact on our health at every level — from gut health and chronic disease risk to brain function and even sleep quality.

Whether you’re managing a health condition or simply want to feel your best, the message from the science is clear: For most of us, the more variety and the more plants on our plate, the better!

Important note for people living with kidney disease: While this research is exciting and marks a genuine shift towards embracing more plant-based foods, it should not be considered a blanket green light to reintroduce previously limited foods — what’s right for one person with CKD may not be right for another. Individual needs still vary depending on disease stage and personal blood results, so please speak with your nephrologist or a specialist kidney dietitian before making any changes to your diet.