Plant-Based Diets Improve Maternal–Fetal Outcomes in CKD Pregnancies

Abstract

Reducing protein intake in patients with chronic kidney disease (CKD) limits glomerular stress induced by hyperfiltration and can prevent the progression of kidney disease; data in pregnancy are limited. The aim of this study is to analyze the results obtained in CKD patients who followed a plant-based moderately protein-restricted diet during pregnancy in comparison with a propensity-score-matched cohort of CKD pregnancies on unrestricted diets. A total of 52 CKD pregnancies followed up with a protein-restricted plant-based diet (Torino, Italy) were matched with a propensity score based on kidney function and proteinuria with CKD pregnancies with unrestricted protein intake (Cagliari Italy). Outcomes included preterm (<37 weeks) and very preterm (<34 weeks) delivery and giving birth to a small-for-gestational-age baby. The median age in our cohort was 34 years, 63.46% of women were primiparous, and the median body mass index (BMI) was 23.15 kg/m2 with 13.46% of obese subjects. No statistical differences were found between women on a plant-based diet and women who were not in terms of age, parity, BMI, obesity, CKD stage, timing of referral, or cause of CKD. No differences were found between the two groups regarding the week of delivery. However, the combined negative outcome (birth before 37 completed gestational weeks or birth-weight centile <10) occurred less frequently in women following the diet than in women in the control group (61.54% versus 80.77%; p = 0.03). The lower risk was confirmed in a multivariable analysis adjusted for renal function and proteinuria (OR: 0.260 [Q1:0.093–Q3:0.724]; p = 0.010), in which the increase in proteinuria from the first to the last check-up before delivery was lower in patients on plant-based diets (median from 0.80 to 1.87 g/24 h; p: ns) than in controls (0.63 to 2.39 g/24 h p < 0.0001). Plant-based, moderately protein-restricted diets in pregnancy in patients with CKD are associated with a lower risk of preterm delivery and small-for-gestational-age babies; the effect may be mediated by better stabilization of proteinuria.

Anemia in Pregnancy With CKD

“… 110 As in CKD in general, also in pregnant women with CKD, interest has shifted from macronutrient intake to micronutrient intake and the combination of micronutrient intake by types of diet (e.g., Mediterranean diet, whole foods plant-based diet). 111 , 112 , 113 , 114 , 115 In particular, pregnancy is a well-known physiological cause of hyperfiltration in which CKD is associated with an increase in proteinuria, but this increase could be diminished by diet. 112 , 116 The Italian Study Group on Kidney and Pregnancy has performed the largest study on a plant-based, moderately protein-restricted diet in pregnant women with CKD to counterbalance this proteinuria.…”

“… 111 , 112 , 113 , 114 , 115 In particular, pregnancy is a well-known physiological cause of hyperfiltration in which CKD is associated with an increase in proteinuria, but this increase could be diminished by diet. 112 , 116 The Italian Study Group on Kidney and Pregnancy has performed the largest study on a plant-based, moderately protein-restricted diet in pregnant women with CKD to counterbalance this proteinuria. 112 These 52 pregnant women with CKD receiving an intervention diet were compared with a propensity-score-matched cohort of CKD pregnancies on unrestricted diets.…”

“… 112 , 116 The Italian Study Group on Kidney and Pregnancy has performed the largest study on a plant-based, moderately protein-restricted diet in pregnant women with CKD to counterbalance this proteinuria. 112 These 52 pregnant women with CKD receiving an intervention diet were compared with a propensity-score-matched cohort of CKD pregnancies on unrestricted diets. The goal was to control protein intake to 0.8 g/kg/d, with over 80% coming from plant-derived sources.…”

“…Women in the control group had a significant increase in proteinuria during pregnancy, while the intervention group did not. 112 However, when not planned safely, risks of a plant-based diet include pregnancy complications such as low birthweight and anemia caused by deficiencies in vitamin B12 and/or iron, because these micronutrients are already often deficient in pregnancy. 117 , 118 , 119 , 120 Some, therefore, do not recommend a low-protein diet.…”

The Role of Plant-Based Diets in Preventing and Mitigating Chronic Kidney Disease: More Light than Shadows

“…Regarding the use of soy protein instead of animal protein, there is conflicting evidence on proteinuria [90]. Finally, Piccoli and colleagues found that pregnant CKD patients who followed a plant-based moderately protein-restricted diet had a lower increase in proteinuria from the first to the last check-up before delivery, as well as a lower risk of preterm delivery and small-for-gestational-age babies [91].…”