Healthy adult vegetarians have better renal function than matched omnivores: a cross-sectional study in China

Effects of vegetarian diets on blood lipids, blood glucose, and blood pressure: a systematic review and meta-analysis

High blood lipids, blood glucose, or blood pressure ("3Bs") are established risk factors for cardiovascular diseases. However, the effects of vegetarian diets on these parameters were inconsistent in previous meta-analyses. We conducted a systematic review and meta-analysis with comprehensive subgroup analyses, quality assessment, and sensitivity analyses to confirm the effects of vegetarian diets on 3Bs. The literature was searched from PubMed, Cochrane, and Web of Science databases from the inception to February 2024. Human studies [both observational studies and randomized controlled trials (RCTs)] related to vegetarian diets and reporting 3Bs were included. The subjects were adults; the intervention/exposure was vegetarian diet which excludes the consumption of any meat, fish, and seafood and the control was an omnivorous diet; the minimum study length was two weeks. The results showed that the vegetarian diets significantly reduced the blood total cholesterol [WMD: -0.54 (95% CI: -0.60, -0.48) mmol L-1, p < 0.001 for observational studies; WMD: -0.24 (95% CI -0.37, -0.10) mmol L-1, p < 0.001 for RCTs], low-density lipoprotein cholesterol [WMD: -0.41 (95% CI: -0.48, -0.34) mmol L-1, p < 0.001 for observational studies; WMD: -0.25 (95% CI: -0.38, -0.12) mmol L-1, p < 0.001 for RCTs], and high-density lipoprotein cholesterol [WMD: -0.07 (95% CI: -0.09, -0.05) mmol L-1, p < 0.001 for observational studies; WMD: -0.07 (95% CI: -0.11, -0.04) mmol L-1, p < 0.001 for RCTs] level compared with the omnivorous diet in both healthy subjects and subjects with chronic diseases, while it had a null effect on the blood triglyceride level. In addition, the vegetarian diets significantly reduced the fasting blood glucose (FBG) [WMD: -0.35 (95% CI: -0.50, -0.21) mmol L-1, p < 0.001], glycated hemoglobin [WMD: -0.15 (95% CI: -0.28, -0.01) %, p = 0.034], and HOMA-IR [WMD: -0.98 (95% CI: -1.46, -0.51), p < 0.001] compared with the omnivorous diet, particularly when the duration was more than 12 weeks. The reduction effect on FBG was particularly significant by a vegan diet and/or in subjects with chronic diseases. The effects of the vegetarian and omnivorous diets on systolic and diastolic blood pressure were not significantly different.

Plant-based diets for kidney disease prevention and treatment

PURPOSE OF REVIEW

Plant-based diets are associated with a lower risk of hypertension, diabetes, cardiovascular disease, and mortality. Using the most recent evidence, we critically appraised the role of plant-based diets in primary and secondary prevention of chronic kidney disease (CKD) with a focus on key nutritional factors (dietary acid load, phosphorus, potassium, sodium, and fiber).

RECENT FINDINGS

In healthy individuals, observational studies found that greater intake of plant protein and higher adherence to plant-based diets (overall, healthful, and provegetarian) was associated with a lower risk of CKD. In those with CKD, plant-based diets were associated with a lower risk of mortality, improved kidney function, and favorable metabolic profiles (fibroblast growth factor-23, uremic toxins, insulin sensitivity, inflammatory biomarkers). Only few studies reported nutrient content of plant-based diets. These studies found that plant-based diets had lower dietary acid load, lower or no significant difference in phosphorus and sodium, and higher potassium and fiber. One study reported that vegetarian diets were associated with severe vitamin D deficiency compared to nonvegetarian diets.

SUMMARY

Plant-based diets provide several benefits for prevention and management of CKD, with little risk for individuals with CKD. Incorporation of vitamin D rich foods in plant-based diets may be helpful.

Nutritional and Dietary Management of Chronic Kidney Disease Under Conservative and Preservative Kidney Care Without Dialysis

While dialysis has been the prevailing treatment paradigm for patients with advanced chronic kidney disease (CKD), emphasis on conservative and preservative management in which dietary interventions are a major cornerstone have emerged. Based on high-quality evidence, international guidelines support the utilization of low-protein diets as an intervention to reduce CKD progression and mortality risk, although the precise thresholds (if any) for dietary protein intake vary across recommendations. There is also increasing evidence demonstrating that plant-dominant low-protein diets reduce the risk of developing incident CKD, CKD progression, and its related complications including cardiometabolic disease, metabolic acidosis, mineral and bone disorders, and uremic toxin generation. In this review, we discuss the premise for conservative and preservative dietary interventions, specific dietary approaches used in conservative and preservative care, potential benefits of a plant-dominant low-protein diet, and practical implementation of these nutritional strategies without dialysis.

Low Serum Creatinine Levels in Early Pregnancy Are Associated with a Higher Incidence of Postpartum Abnormal Glucose Metabolism among Women with Gestational Diabetes Mellitus: A Retrospective Cohort Study

The predictive factors for the progression from gestational diabetes mellitus (GDM) to type 2 diabetes remain incompletely elucidated. Our objective was to investigate the link between serum creatinine, a proxy for skeletal muscle mass, and the development of postpartum abnormal glucose metabolism (AGM).

METHODS

A retrospective review of the medical records of 501 women with GDM was conducted, all of whom underwent a 75 g oral glucose tolerance test (OGTT) between 4 and 12 weeks postpartum. Women were grouped based on quartiles of serum creatinine at the first antenatal visit to estimate the association between serum creatinine and postpartum AGM incidence.

RESULTS

Compared with the highest quartile of creatinine, lower quartiles were substantially linked to an increased incidence of postpartum AGM (adjusted odds ratios 3.37 [95% CI 1.77-6.42], 2.42 [95% CI 1.29-4.51] and 2.27 [95% CI 1.23-4.18], respectively). The generalized additive model suggested a linear relationship between serum creatinine levels and the risk of postpartum AGM below 68 µmol/L of serum creatinine levels. A decrease of 2 μmol/L in serum creatinine levels was found to be associated with a 10% increase in the odds of developing postpartum AGM. Linear regression revealed that a low serum creatinine level was linked to a higher postpartum 2-h glucose level and a decreased insulinogenic index (p = 0.007 and p = 0.027, respectively).

CONCLUSIONS

An association was observed between lower serum creatinine levels in early pregnancy and an increased risk of postpartum AGM and poorer β-cell function in women with a recent history of GDM. Further research is needed to understand the mechanisms underlying our findings, as well as the role of skeletal muscle mass or nutritional status in early pregnancy on later glucose metabolism.

Fibre Intake in Chronic Kidney Disease: What Fibre Should We Recommend?

Chronic kidney disease (CKD) is a major global health problem that challenges all patients' healthcare needs. Fibre consumption benefits kidney patients by acting preventively on associated risk factors, improving intestinal microbiota composition or reducing metabolic acidosis and inflammation. In this review, we focus on increasing fibre consumption and the quality of fibre to recommend, in addition to increasing the consumption of foods that naturally have it in their design, that can resort to fortified foods or fibre supplements. The Western nutritional practice, which is low in fibre and rich in animal proteins, saturated fats, sodium, and sugar, increases the risk of mortality in these patients. On the contrary, patterns with higher consumption of fibre and vegetable proteins, such as the Mediterranean, vegetarian, or Plant dominant low protein diet (PLADO), seem to have a preventive effect on the associated risk factors and influence CKD progression. Until now, the use of fibre supplements has not achieved an evident impact on clinical results. Fibre-rich foods contain other nutrients that reduce cardiovascular risk. Promoting diets richer in vegetables and guaranteeing adequate energy and protein intake is a challenge for the multidisciplinary teams involved in the standard of care for CKD.

Serum creatinine as an indicator of lean body mass in vegetarians and omnivores

Growing numbers of Americans are adopting vegetarian or vegan diets. While risk for some chronic conditions may be lower when following these diets, concern remains over the ability to consume adequate amounts of various nutrients, notably, protein. Knowing that serum creatinine is a reliable marker of muscle mass, this study examined the relationships between serum creatinine, lean body mass (LBM), handgrip strength, and protein intake in healthy vegetarian (n = 55) and omnivorous (n = 27) adults. Significantly higher protein intakes (+31%), LBM (+7%), serum creatinine (+12%) and handgrip strength (+14%) were observed for the omnivore participants compared to vegetarian participants. Positive correlations (p < 0.001) were noted between creatinine and LBM (R² = 0.42), creatinine and handgrip strength (R² = 0.41), protein intake and LBM (R² = 0.29), and handgrip strength and LBM (R² = 0.69). These data show that serum creatinine concentrations were lower in vegetarian women and men in comparison to their omnivorous counterparts and that serum creatinine concentrations correlate with LBM and strength in healthy adults, regardless of diet.

COULD PROTEINURIA PREDICT THE RENAL PROGNOSES OF PATIENTS WITH TYPE 2 DIABETES MELLITUS AND DIABETIC NEPHROPATHY?

AIMS

This study investigated the relationship between proteinuria levels, clinicopathological features, and renal prognoses in Chinese patients with type 2 diabetes mellitus (T2DM) and diabetic nephropathy (DN).

METHODS

Three hundred patients with T2DM and biopsy-proven DN were enrolled. Patients were stratified by 24-h proteinuria levels: Group 1:≤1g/24h); Group 2:1-3g/24h; and Group 3:≥3g/24h. Renal outcomes were defined as having reached end-stage renal disease (ESRD). The proteinuria level's influence on the renal outcomes was evaluated using Cox regression analysis.

RESULTS

Among subgroups stratified by proteinuria levels, systolic blood pressure, serum creatinine, BUN, cholesterol, DR and hypertension incidence, the incidences of patients who progressed to ESRD were the lowest in group 1 (P<0.05). However, eGFR, serum albumin and hemoglobin were highest in group 1. Patients with higher proteinuria levels had much lower five-year renal survival rates. Univariate analyses revealed that higher proteinuria levels were significant clinical predictors of renal prognosis (P<0.05), although they were not independent risk factors for progression to ESRD in the multivariate Cox proportional hazard analysis (P>0.05).

CONCLUSIONS

The higher the level of proteinuria, the lower the 5-year renal survival rate of DN patients, but there was no significant correlation between proteinuria level and 5-year renal survival rate. Other factors in the proteinuria group may have more significant effects on the 5-year renal survival rate, such as lower baseline eGFR, serum albumin, hemoglobin and higher cholesterol, higher incidences of DR and more severe lesions.

Biomarker Concentrations in White and British Indian Vegetarians and Nonvegetarians in the UK Biobank

BACKGROUND

Prospective studies have shown differences in some disease risks between vegetarians and nonvegetarians, but the potential biological pathways are not well understood.

OBJECTIVES

We aimed to assess differences in concentrations of biomarkers related to disease pathways in people with varying degrees of animal foods exclusion.

METHODS

The UK Biobank recruited 500,000 participants aged 40-69 y (54.4% women) throughout the United Kingdom in 2006-2010. Blood and urine were collected at recruitment and assayed for more than 30 biomarkers related to cardiovascular diseases, bone and joint health, cancer, diabetes, renal disease, and liver health. In cross-sectional analyses, we estimated adjusted geometric means of these biomarkers by 6 diet groups (regular meat eaters, low meat eaters, poultry eaters, fish eaters, vegetarians, vegans) in 466,058 white British participants and 2 diet groups (meat eaters, vegetarians) in 5535 British Indian participants.

RESULTS

We observed differences in the concentrations of most biomarkers, with many biomarkers showing a gradient effect from meat eaters to vegetarians/vegans. Of the largest differences, compared with white British regular meat eaters, white British vegans had lower C-reactive protein [adjusted geometric mean (95% CI): 1.13 (1.03, 1.25) compared with 1.43 (1.42, 1.43) mg/L], lower low-density lipoprotein cholesterol [3.13 (3.07, 3.20) compared with 3.65 (3.65, 3.65) mmol/L], lower vitamin D [34.4 (33.1, 35.9) compared with 44.5 (44.4, 44.5) nmol/L], lower serum urea [4.21 (4.11, 4.30) compared with 5.36 (5.36, 5.37) mmol/L], lower urinary creatinine [5440 (5120, 5770) compared with 7280 (7260, 7300) μmol/L], and lower γ-glutamyltransferase [23.5 (22.2, 24.8) compared with 29.6 (29.6, 29.7) U/L]. Patterns were mostly similar in British Indians, and results were consistent between women and men.

CONCLUSIONS

The observed differences in biomarker concentrations, including lower C-reactive protein, lower LDL cholesterol, lower vitamin D, lower creatinine, and lower γ-glutamyltransferase, in vegetarians and vegans may relate to differences in future disease risk.

Dietary patterns and risk for hyperuricemia in the general population: Results from the TCLSIH cohort study

OBJECTIVE

Prospective cohort studies linking dietary patterns and hyperuricemia (HUA) are limited, especially in Asian populations. The aim of this study was to prospectively investigate the association between various dietary patterns and risk for HUA in a general adult population.

METHOD

We used data from the TCLSIH (Tianjin Chronic Low-grade Systemic Inflammation and Health) cohort study of 20 766 men and women who were free from HUA, cancer, and cardiovascular disease at baseline. Dietary patterns at baseline were identified with factor analysis based on responses to a validated 81-item food frequency questionnaire. HUA was defined as serum uric acid levels >420 μmol/L in men and >350 μmol/L in women. Cox proportional hazards regression models were used to examine the association of dietary patterns with incident HUA.

RESULTS

In all, 4389 first incident cases of HUA occurred during 73 822 person-years of follow-up (median follow-up of 4.2 y). Three main dietary patterns were extracted. They were the vegetable, sweet food, and animal food patterns. After adjusting for demographic characteristics, lifestyle factors, other dietary pattern scores, and inflammatory markers, comparing the highest with the lowest quartiles of dietary pattern scores, the multivariable hazard ratios (95% confidence interval) of HUA were 0.79 (0.72-0.87; P_trend < 0.0001) for the vegetable pattern, 1.22 (1.12-1.33; P_trend < 0.0001) for the sweet food pattern, and 1.24 (1.13-1.37; P_trend < 0.0001) for the animal food pattern.

CONCLUSIONS

Dietary patterns rich in animal or sweet foods were positively associated with a higher risk for HUA, whereas the vegetable pattern was negatively associated.

Effects of vegetarian versus Mediterranean diet on kidney function: Findings from the CARDIVEG study

BACKGROUND

The aim of the present study was to assess the effects of a lacto-ovo-vegetarian diet (VD), compared to a Mediterranean diet (MD), on kidney function in a group of subjects with medium-to-low cardiovascular risk profile.

METHODS

We analysed 107 subjects (82 women, 25 men; median age 52) who followed a VD (n = 54) and a MD (n = 53) for 3 months in the CARDIVEG study, a randomized, open, crossover trial that compared the effects of these 2 diets on cardiovascular disease risk.

RESULTS

The effect of the two diets on kidney function markers was evaluated by conducting a general linear model for repeated measurements adjusted for possible confounding factors such as age, sex, physical activity, alcohol, smoking, hypertension, LDL cholesterol, glucose and body weight change. A significant reduction in creatinine (-5.3%; P < .001), urea nitrogen levels (-9%; P = .001), blood urea nitrogen (BUN) (-8.7%; P = .001) and BUN/creatinine ratio (-5.8%; P < .001), and an increase in estimated glomerular filtration rate (eGFR) (+3.5%; P = .001) was observed during the VD period. On the contrary, no significant changes were noted in the MD group. Variations obtained in the two dietary interventions were significantly different (P < .0001) for creatinine levels, BUN/creatinine and eGFR, for which opposite trends were observed in the VD and MD groups.

CONCLUSIONS

In a selected group of subjects with medium-to-low cardiovascular risk profile, a 3 month VD period determined significant improvements in kidney function markers. Further trials are needed to confirm these results.

Constitutions of Deficiency and Stasis of Traditional Chinese Medicine and Related Factors among Middle-Aged Women in Taiwan

Background

Traditional Chinese medicine (TCM) appears to be the common therapy in middle-aged women. The constitution serves as a guide for TCM treatment. However, little is known about the constitution and related factors in middle-aged women. The objectives of this study were to describe the yang-deficiency, yin-deficiency, and stasis constitutions in middle-aged women. Demographic and health factors related to yang deficiency, yin deficiency, and stasis were also examined.

Methods

A total of 1,000 women aged 40–65 years were selected from 2009 through 2018 using random sampling from the Taiwan Biobank Research Database in Taiwan. Yang-deficiency, yin-deficiency, and stasis were assessed using the body constitution questionnaire. Multiple logistic regression analysis was used to identify factors associated with constitution in deficiency or stasis.

Results

The proportions of middle-aged women who had the constitution in yang-deficiency, yin-deficiency, and stasis were 29.7%, 21.7%, and 17.7%, respectively. The result of binary logistic regression showed that current menstruation, abnormal spirometry, and education level were predictive factors of yang deficiency. Women with younger age, abnormal spirometry, or a vegetarian diet had a significantly associated yin deficiency. Younger age, abnormal spirometry, and coffee habit were predictors of stasis.

Conclusions

Middle-aged women in Taiwan with abnormal spirometry had a higher risk for deficiency or stasis constitutions, especially for those younger than 56 years. Healthcare providers should learn patients' constitutions and provide appropriate advice, referring them to safe providers of their desired method.