Renal Function Parameters of Thai Vegans Compared with Non-Vegans

Abstract

In Asia, vegetarianism is a well-established eating behavior. It appears that the adoption of a vegan diet leads to a lessening of several health risk factors. Although vegetarianism has some notable effects on the hematological system, the effect on the nephrological system has not been well clarified. The pattern of renal function parameters was studied in 25 Thai vegans compared with 25 non-vegetarians. Of the studied parameters, it was found that urine protein was significantly different (p < 0.05) in vegans and controls. Vegans had significantly lower urine protein level.

Keywords:

• vegetarianism
• renal function

INTRODUCTION

In Asia, vegetarianism is an old, classical eating behavior. The diet for the vegans is rich in fiber, has very little sodium, and contains no cholesterol.[1] It appears that the adoption of a vegan diet exemplified by the living food leads to a lessening of several health risk factors for cardiovascular diseases and cancer.[1],[2] However, there may be some risks with vegetarianism as well. The omission of meat and fish from the diet increases the risk of nutritional deficiencies.[3] The effect of vegetarianism on hematological system is clearly explained; however, the effect on the nephrological system has not been well clarified.

Wiseman et al.[4] said that the vegan diet is associated with glomerular and systemic hemodynamic changes that may be beneficial in the prevention of glomerular sclerotic changes in health and disease. They found that omnivores had significantly higher mean urinary albumin excretion rate than vegans.[4] Presently, it is accepted that a vegetarian diet might bring some usefulness to the patients with renal failure. In macroalbuminuria patients with type 2 diabetes, withdrawing red meat from the diet reduces the urine albumin excretion rate.[5] Barsotti et al. found that vegan diets exerted a favorable effect on proteinuria and hypercholesterolemia in nephrotic patients, without inducing clinical or laboratory signs of malnutrition.[6] However, there is no systematic case-control study on the effect of vegetarianism on renal function. Here, the author tries to study the important renal function parameter of Thai vegans comparing to non-vegetarians.

MATERIALS AND METHODS

A total of 25 Buddhist monks (all male, average age = 46.7 ± 10.1 years) who are strict vegetarianism according to religious regulations were examined. The diets of the subjects in this group contain no flesh or other animal products, including animal oils, cheese, and eggs. A control group comprising of 25 non-vegetarians Buddhist monks (all male, average age = 48.2 ± 9.4 years) is also included in this study. The controls are age-matched and have a similar lifestyle to the studied group but no practice. The subjects in both groups are healthy without a history of any previous known underlying diseases. After asking for informed consent, a blood and urine sample from each subject was collected for renal function parameter determination, including serum BUN, serum creatinine (Cr), and urine protein. Data were collected for further statistical analysis using SPSS 7.0 for Windows. A comparison of each renal function parameter between the vegetarians and non-vegetarians was performed using unpaired T-test. Statistical significant level was accepted at a p value ≤ 0.05.

RESULTS

The averages (mean ± SD) of the studied renal function parameters of those with and without vegetarianism are presented in Table 1. Of the studied parameters, it was found that urine protein was significantly different (p < 0.05) in vegans and controls.

Table 1 Average (mean ± SD) of renal function parameters in the subjects with and without low vegetarianism

Renal function parameters	Subjects withvegetarianism	Subjects withoutvegetarianism	p
Serum BUN (mg/dL)	9.8 ± 3.0	13.3 ± 2.0	> 0.05
Serum creatinine(mg/dL)	0.8 ± 0.3	0.9 ± 0.3	> 0.05
Urine protein (mg/dL)	1.4 ± 0.6	5.2 ± 1.8	< 0.05
BUN/creatinine ratio	12.7 ± 5.4	16.2 ± 6.9	> 0.05

*derived by calculation.

DISCUSSION

Although vegetarianism can bring several health advantages, several adverse effects on hematological system have been noted. The nutritional anemia is the major adverse effected of vegetarianism. There are some notable effects of vegetarianism on the hematological system; for example, megaloblastic anemia and mild iron deficiency anemia can be seen in the vegans. However, there are only limited reports on the renal function parameters in the vegans. Here, the author investigates the renal function parameters in Thai vegans compared to non-vegans.

Here, the author found that vegans had significantly lower urine protein level. This result is concordant with the trend in the previous studies[4],[5]; however, these previous studies' selection of the controls casts some doubt on the results. In this work, the author selects both the studied and control group as Buddhist monks who have to practice the similar lifestyle according to the principle of Buddhism. No significant difference in daily activity and practice can be expected. The only difference between the two is the practice of vegetarianism due to the difference of Buddhist sect. In addition, the vegetarianism in the studied group is a strict vegetarianism according to religious principles.

Concerning the other studied renal function parameters, although there is no significant difference, the trend of lower serum BUN and BUN/Cr ration can be observed. The higher BUN in the non-vegetarianism group might imply a higher protein load in their regular diet. Indeed, there are sufficient data from the literature to suggest that a low protein diet delays the progression of chronic renal failure.[6],[7] These results can confirm the usefulness of vegetanism here and support the use of a vegan diet for the patients with renal failure.

Some limitations on this study should be mentioned. First, the size of the subjects in both groups is small. However, the subjects of both groups are well-matched and confounding factors are managed. Second, the author did not take the 24 hour urine sample; therefore, assessment of 24-hour creatinine clearance could not be studied, and the question of if the creatine clearance differs between both groups cannot be answered. Further studies to answer this question should be performed.

ACKNOWLEDGMENT

The authors would like to thank all monks participating in this study. This study was granted by Rudchadapisake Sompote Fund and Educational Fund, Chulalongkorn University, 2002.