Dietary Protein Intake and Renal Function

Abstract

Recent trends in weight loss diets have led to a substantial increase in protein intake by individuals. As a result, the safety of habitually consuming dietary protein in excess of recommended intakes has been questioned. In particular, there is concern that high protein intake may promote renal damage by chronically increasing glomerular pressure and hyperfiltration. There is, however, a serious question as to whether there is significant evidence to support this relationship in healthy individuals. In fact, some studies suggest that hyperfiltration, the purported mechanism for renal damage, is a normal adaptative mechanism that occurs in response to several physiological conditions. This paper reviews the available evidence that increased dietary protein intake is a health concern in terms of the potential to initiate or promote renal disease. While protein restriction may be appropriate for treatment of existing kidney disease, we find no significant evidence for a detrimental effect of high protein intakes on kidney function in healthy persons after centuries of a high protein Western diet.

Functional and Morphostructural Evaluation of the Kidneys of Wistar Rats after the Use of a Protein-Based Food Supplement

“…The results of this study corroborate the study of Martin et al who reported that the renal impact due to a highprotein diet for a short period of time is different from the impact caused by a chronic consumption of this type of diet; therefore, the supplementation period of 14 days was insufficient to cause a significant change in the protein metabolism and increased level of this metabolite [6]. The serum urea generally does not increase until more than 60% of nephrons do not function; therefore, this is a high specificity but low sensitivity marker [7].…”

Ultrastructural changes and nestin expression accompanying compensatory renal growth after unilateral nephrectomy in adult rats

“…44 The remaining kidney is, therefore, challenged to face prolonged hyperfiltration. 45 Hemodynamics and structural changes contribute to increased renal blood flow and decreased renal vascular resistance. 20,46 These changes were suggested to be mediated by nitric oxide and they continue for 1 week.…”

Effects of Nutritional and Dietary Supplements on Renal Function Among University Bodybuilders in Ghana

“…Nutritional contributions to these endogenous markers was not left out as some foods such as chicken, milk, egg, fish and other nutritional supplements such as protein, creatine, whey and amino acids have been implicated in most studies regarding kidney function especially among Bodybuilders (11) . Among bodybuilders in this study, very rich protein foods such as Chicken, egg, beans and fish were most consumed and in higher proportions.…”

“…At the centre of the controversy is the concern that habitual consumption of dietary protein in excess of recommended amounts promotes chronic renal disease through increased glomerular pressure and hyperfiltration (12) . The relationship between dietary protein and renal function has been studied for over half a century (11) . Addis and Drury (13) were among the first to observe a relationship between level of dietary protein and rates of urea excretion.…”

“…This could possibly result from the faster glomerular filtration rate (GFR) to remove waste products of protein and other supplement metabolism. A major cause of kidney impairment is the overconsumption of a particular dietary ingredient (11) and therefore the Recommended Daily Allowance (RDA) of such ingredient must be taken into consideration. In a study conducted by Harris et al (16) to ascertain what regimen of supplementation would produce the greatest increase in total creatine in the blood, they found out that 5 g of creatine, increased plasma concentration to 795 μmol/L, whereas a 1g dose only "produced a modest rise".…”