The Association between Renal Hyperfiltration and the Sources of Habitual Protein Intake and Dietary Acid Load in a General Population with Preserved Renal Function: The KoGES Study

Abstract

Although the differential response of the kidney to the acute load of various sources of dietary protein in subjects with normal renal function is well known, the influence of habitual dietary protein intake and dietary acid load on renal function has not been tested well. The association between renal hyperfiltration (RHF), the earlier and possibly reversible stage of chronic kidney disease, and the sources of habitual dietary protein and dietary acid load was analyzed with the baseline data of 123,169 middle-aged healthy Koreans of a large prospective cohort study, who had a baseline estimated glomerular filtration rate (eGFR) >60 mL/min/m2 and no known history of diabetes and/or hypertension. eGFR was calculated with the Chronic Kidney Disease Epidemiology Collaboration equation using serum creatinine and RHF was defined as eGFR >95th percentile after adjustment for age, sex, height, and body weight. Dietary acid load was calculated with estimated net endogenous acid production (eNEAP). Although the level of habitual intake of animal protein was positively and vegetable protein was negatively associated with RHF, this association was significant only in women and younger participants (younger than sex-specific median age). The odds for RHF increased as the percentile rank of eNEAP increased until about the 50th percentile and then leveled off. The positive association between eNEAP and RHF was significant in both sexes and age groups. Dietary acid load was associated with RHF regardless of sex and age and rather than the amount of the total or the individual sources of habitual dietary protein, may be a better target for the dietary intervention of chronic kidney disease.

Insulin resistance underlies the elevated cardiovascular risk associated with kidney disease and glomerular hyperfiltration

“…Dietary acid load (estimated net endogenous acid production) was positively correlated with animal protein intake and inversely correlated with vegetable protein intake, as expected. Dietary acid load was positively associated with glomerular hyperfiltration in all participants, irrespective of sex and age (So et al, 2016). Consistently, an association between lower serum bicarbonate (reflecting increased dietary acid load due to animal protein intake) and higher odds of renal hyperfiltration has been observed in 41,886 adults with normal kidney function (estimated GFR > 60 ml/min/1.73 m 2 , calculated with the CKD-EPI-creatinine equation) from the general population (Park et al, 2016).…”

Association of renal hyperfiltration with incident proteinuria - A nationwide registry study

“…Proteinuria was defined as spot urine dipstick test for protein 1+ or higher and incident proteinuria as conversion of spot urine dipstick test, negative at the individual’s first health screening to 1+ or higher at any time during the follow-up period. RHF was defined as previously proposed with some modifications [ 11 , 27 ] by using initial health screening data of each participant. Briefly, the residuals were calculated from a multiple linear regression analysis, in which the logarithm-transformed eGFR was a dependent variable and sex, weight, height, known history of medication for diabetes and/or hypertension, and logarithm-transformed age were independent variables.…”

“…Renal hyperfiltration (RHF) has long been considered as one of the mechanisms of the progression of chronic renal diseases after a certain degree of renal injury has developed [ 1 ]. RHF has been associated with various clinical conditions including pre-diabetes and diabetes, pre-hypertension and hypertension, and metabolic syndrome [ 2 – 6 ], as well as lifestyle factors like obesity, smoking, lack of physical activity, lower cardiopulmonary fitness, and increased dietary acid load mainly due to a Western-style diet [ 7 – 11 ]. The clinical implications of RHF are not yet clear in conditions other than diabetes, in which RHF is considered as one of the initiating mechanisms of renal complications [ 12 ].…”

Dietary Influence on Body Fluid Acid-Base and Volume Balance: The Deleterious “Norm” Furthers and Cloaks Subclinical Pathophysiology

“…In two large population-based studies from community-dwelling elderly Koreans (KoGES), increasing NEAP and low-normal HCO 3 − is associated with subclinical acidosis and CKD [ 29 , 30 ]. Consistently, acid loading in a number of studies has been shown to be associated with proteinuria, progressive reduction of eGFR and development of CKD [ 31 , 32 , 33 , 34 ].…”