For decades, concerns have circulated that high-protein diets may harm the kidneys — especially in people with type 2 diabetes (T2D), who are already predisposed to kidney disease. This belief has influenced many dietary guidelines, which often recommend a moderate-to-low intake of protein. But how solid is this advice?
A prospective study from the Netherlands followed 382 adults with T2D for a median of 6 years to assess whether higher dietary protein intake truly contributes to kidney function decline. Protein intake was measured objectively using 24-hour urinary urea excretion — a more accurate method than self-reported intake — and kidney outcomes were tracked over time.
Here’s what they found:
➡️ Higher protein intake was associated with a 38% lower risk of kidney function deterioration
➡️ Participants with protein intake <92 g/day—or <1.08 g/kg ideal body weight/day — had an increased risk of kidney decline
➡️ Those consuming >163 g of protein/day had a 58% lower risk of kidney decline
➡️ The findings were consistent across sensitivity analyses and did not differ by sex or baseline kidney function
While this study adds to a growing body of evidence suggesting that moderate-to-high protein intake does not harm kidney function, including in people with T2D who are not on dialysis, what constitutes “moderate to high” varies for many individuals. The study indicates that those with the highest protein intakes were linked to the lowest risk of decline. This directly challenges existing dietary guidelines, which recommend protein intake of 0.8 g/kg/day which is the accepted guide for the “average” person. Protein requirements change due to age, fitness, activity levels, pregnancy/breastfeeding and overall health.
This is one study which reinforces the safety — and potential benefit — of higher-protein diets in diabetes management. Protein-rich diets can support body composition, preserve muscle mass, and help regulate blood glucose, all while posing no increased risk to kidney health in this population.
While this one study found that a higher protein intake does not damage the kidneys — including among those with type 2 diabetes, you should always be assessed by a qualified professional as many factors influence kidney function other than protein alone.
Research:
Oosterwijk MM, Groothof D, Navis G, Bakker SJL, Laverman GD. High-Normal Protein Intake Is Not Associated With Faster Renal Function Deterioration in Patients With Type 2 Diabetes: A Prospective Analysis in the DIALECT Cohort. Diabetes Care. 2022 Jan 1;45(1):35-41. doi: 10.2337/dc21-1211. PMID: 34711636.