Where's the beef?! Exploring the Impact of Plant-Based Meat Alternatives on Urinary Health: Insights from the SWAP-MEAT Pilot Trial

A study released by the Clinical Journal of the American Society of Nephrology looked and the urinary content of healthy individuals to determine whether eating plant based meat versus actual meat made a difference in the solutes excreted.

In recent years, the rise of plant-based meat alternatives has captured the attention of health-conscious consumers and researchers alike. Promoted for their environmental benefits and perceived health advantages, these alternatives have carved out a significant niche in the food industry. But how do they impact our health at a cellular level, particularly in terms of what is excreted through our urine?

Consuming excess animal meat may exacerbate kidney disorders such as urinary stone disease and chronic kidney disease. Plant-based meat alternatives imitate animal meat, and replace animal with vegetable protein, but it is unclear whether eating plant-meat confers similar health benefits as eating whole vegetables. This most study hypothesized that eating plant-meat when compared with animal meat decreases dietary acid load but increases dietary phosphorus and nitrogen. 1

The SWAP-MEAT Pilot Trial, an innovative study, delves into this very question. Its primary aim is to examine the urinary response to consuming plant-based meat alternatives in individuals with normal kidney function. Let’s dive into the details of this trial and what it reveals about our diet and urinary health.

What is the SWAP-MEAT Pilot Trial?

The SWAP-MEAT (Switching to Plant-Based Meat Alternatives: Assessing Urinary Parameters) Pilot Trial is a study designed to evaluate how consuming plant-based meat substitutes influences urinary biomarkers and overall kidney function in people who do not have pre-existing kidney conditions. This trial is significant because it targets a population with normal renal function, providing insights into how these dietary changes might impact those without kidney disease.

This recent SWAP-MEAT study was a randomized eight-week, crossover trial (NCT03718988) of participants consuming >2 servings/day of either plant-meat or animal meat for each eight-week phase. We measured urine sulfate, ammonium, pH, phosphorus, urea nitrogen, citrate, and creatinine concentrations, and serum creatinine and bicarbonate concentrations from stored participant samples from each phase. 1

Why Focus on Urinary Response?

Urinary biomarkers can provide valuable information about our metabolic and renal health. The kidneys play a crucial role in filtering waste products from the blood, which are then excreted in the urine. Changes in diet can influence this process, potentially affecting the composition of urine. By focusing on urinary responses, researchers can gauge how plant-based meat alternatives might influence kidney function, even in individuals with no pre-existing conditions.

Study Design and Methodology

Previous SWAP-MEAT studies have been performed with a controlled, randomized crossover design. Participants were initially placed on a standard omnivorous diet, then switched to a diet featuring plant-based meat alternatives for a set period. Urinary biomarkers, including protein levels, creatinine, and urea, were measured at various points throughout the study to assess any changes attributable to the dietary shift.

Participants were also asked about their overall well-being and any symptoms they might experience. This holistic approach ensures that researchers capture not just the physiological but also the subjective impacts of the dietary changes.

The methods of this current SWAP-MEAT study was a randomized eight-week, crossover trial (NCT03718988) of participants consuming >2 servings/day of either plant-meat or animal meat for each eight-week phase. We measured urine sulfate, ammonium, pH, phosphorus, urea nitrogen, citrate, and creatinine concentrations, and serum creatinine and bicarbonate concentrations from stored participant samples from each phase. 1

Key Findings

In previous SWAP-MEAT studies participants reported improvements in overall dietary quality, including higher intakes of fiber and lower intakes of saturated fats. These dietary benefits align with broader public health recommendations for reducing chronic disease risk.

Additionally some participants noted improvements in digestive health, including increased regularity and reduced bloating. While this is an indirect benefit, it highlights the broader impacts of plant-based diets on overall well-being.

Possibly most Important, no significant adverse effects on kidney function or other health markers were observed. This finding is reassuring for those considering plant-based diets, particularly individuals who may be concerned about potential negative impacts on their kidneys.

In this current study, 36 generally healthy participants were enrolled (mean±SD age 50.2 ± 13.8 years, 67% women, and 69% White). Eating the plant-meat diet vs. eating the animal meat diet was associated with lower mean concentration of urine sulfate (-6.7 mEq/L; 95% CI -11.0, -2.4), urine ammonium (-4.2 mmol/L; 95% CI -8.2, -0.1), urine phosphorus (-9.0 mg/dL; 95% CI -17.5, -0.5), and urine urea nitrogen (-124.8 mg/dL; 95% CI -226.9, -22.6). Eating plant-meat compared with eating animal meat was associated with higher mean urine pH (+0.3 units; 95% CI 0.2, 0.5) and mean urine citrate/creatinine ratio (+111.65; 95% CI 52.69-170.60). After participants consumed a plant-meat diet compared with when they consumed an animal meat diet, mean serum creatinine concentration was lower (-0.07 mg/dL, 95% CI -0.10, -0.04), whereas mean serum bicarbonate concentration was not different. 1

Implications for Consumers and Researchers

The SWAP-MEAT Pilot Trial offers valuable insights into the effects of plant-based meat alternatives on urinary health. With stable urinary biomarkers and reported benefits in dietary quality, the trial supports the notion that these alternatives can be a healthful choice for individuals with normal kidney function. As the food landscape continues to evolve, ongoing research will be key in helping us navigate the complex interplay between diet and health.

Eating plant-based meat products, compared with eating animal meat, in the most recent study was associated with lower urinary excretion of sulfate, ammonium, phosphorus, and urea nitrogen and higher urinary excretion of citrate. These findings provide rationale for examining whether plant-based meat will benefit patients with kidney disease. 1

For researchers, the trial underscores the need for further studies to explore long-term effects and to evaluate impacts in populations with varying health conditions. Understanding these dynamics will be crucial for making informed dietary recommendations and for advancing knowledge in nutritional science.

Stay tuned for more updates as further research sheds light on the broader implications of plant-based diets. Until then, the SWAP-MEAT studies provide a solid foundation for understanding how these innovative food products fit into our health and well-being.

1. Ward, Catherine P.1; Landry, Matthew J.1; Cunanan, Kristen M.1; Raphael, Kalani L.2; Dant, Christopher C.1; Gardner, Christopher D.1; Pao, Alan C.3,4,a. Urinary Response to Consuming Plant-Based Meat Alternatives in Persons with Normal Kidney Function: The SWAP-MEAT Pilot Trial. Clinical Journal of the American Society of Nephrology ():10.2215/CJN.0000000000000532, August 26, 2024. | DOI: 10.2215/CJN.0000000000000532