Can a high protein diet cause impaired renal function in healthy individuals?

From the Guidelines

In healthy individuals, a high protein diet is generally not associated with reduced renal function, as long as protein intake does not significantly exceed 2g/kg of body weight daily. Current evidence suggests that people with normal kidney function can safely consume higher amounts of protein without experiencing kidney damage or decline in renal function, as supported by the 2019 study on lifestyle management in diabetes care 1. The kidneys are designed to handle protein metabolism, and in those with healthy kidneys, they can adapt to process the increased nitrogen waste products that result from protein breakdown. However, it is essential to note that high-protein diets may impose significant health risks, including increased urinary calcium loss, which may facilitate osteoporosis, and increased uric acid levels, which may cause gout in susceptible individuals, as highlighted in the 2001 study on dietary protein and weight reduction 1.

Some key points to consider when evaluating the relationship between high protein diets and renal function include:

• The amount of protein recommended in high-protein diet regimens often exceeds established requirements, which may lead to adverse health effects, such as increased LDL cholesterol levels and reduced intake of essential nutrients 1.
• Protein intake goals should be individualized based on current eating patterns, and there is no evidence that adjusting daily protein intake will improve health in individuals without diabetic kidney disease 1.
• Those with diabetic kidney disease should aim to maintain dietary protein at the recommended daily allowance of 0.8 g/kg body weight/day, as reducing protein intake below this level is not recommended 1.
• Staying well-hydrated while consuming higher protein diets can help support kidney function by facilitating the elimination of waste products like urea, which must be filtered by the kidneys.

Overall, while high protein diets may not be directly associated with reduced renal function in healthy individuals, it is crucial to consider the potential health risks and individualize protein intake based on specific needs and health status.

From the Research

High Protein Diet and Renal Function in Healthy Individuals

• The relationship between high protein diets and renal function in healthy individuals is a topic of ongoing debate, with some studies suggesting that high protein intake may not affect renal function in healthy individuals 2.
• However, other studies have found that high dietary protein intake can cause intraglomerular hypertension, which may result in kidney hyperfiltration, glomerular injury, and proteinuria, potentially leading to worsening renal function 3.
• A study on the effects of a high-protein diet on kidney function in healthy adults found that a diet high in protein increased estimated glomerular filtration rate (eGFR) compared to carbohydrate and unsaturated fat diets, but the long-term consequences of this increase are uncertain 4.
• Another study found that long-term consumption of protein at 2 g per kg body weight per day is safe for healthy adults, but chronic high protein intake (>2 g per kg body weight per day) may result in digestive, renal, and vascular abnormalities and should be avoided 5.
• It is also worth noting that the quality of dietary protein may play a role in kidney health, with animal protein being associated with an increased risk of end-stage kidney disease (ESKD) compared to plant-based protein sources 3.

Key Findings

• High protein intake may not affect renal function in healthy individuals, but may cause intraglomerular hypertension and kidney hyperfiltration 2, 3.
• The effects of high protein diets on kidney function may be independent of changes in blood pressure 4.
• Long-term consumption of high amounts of protein may decrease food intake, body weight, and body adiposity, but may also have negative consequences for kidney and bone health 6.
• The quality and quantity of dietary protein are important determinants of its nutritional value and potential impact on kidney health 5.