Prepregnancy Protein Source and BCAA Intake Are Associated with Gestational Diabetes Mellitus in the CARDIA Study

Plant foods, healthy plant-based diets, and type 2 diabetes: a review of the evidence

Type 2 diabetes (T2D) is a metabolic chronic disease in which insulin resistance and insufficient insulin production lead to elevated blood glucose levels. The prevalence of T2D is growing worldwide, mainly due to obesity and the adoption of Western diets. Replacing animal foods with healthy plant foods is associated with a lower risk of T2D in prospective studies. In randomized controlled trials, the consumption of healthy plant foods in place of animal foods led to cardiometabolic improvements in patients with T2D or who were at high risk of the disease. Dietary patterns that limit or exclude animal foods and focus on healthy plant foods (eg, fruits, vegetables, whole grains, nuts, legumes), known as healthy, plant-based diets, are consistently associated with a lower risk of T2D in cohort studies. The aim of this review is to examine the differential effects of plant foods and animal foods on T2D risk and to describe the existing literature about the role of healthy, plant-based diets, particularly healthy vegan diets, in T2D prevention and management. The evidence from cohort studies and randomized controlled trials will be reported, in addition to the potential biological mechanisms that seem to be involved.

Association between protein intake and risk of gestational diabetes mellitus: A systematic review and dose-response meta-analysis of cohort studies

BACKGROUND

Gestational diabetes mellitus (GDM) is a common condition in pregnancy, the prevalence of which has increased. Identifying modifiable risk factors for GDM, such as dietary factors, could prevent or delay the onset of the condition. Our goal was to perform a comprehensive meta-analysis of cohort studies, to summarize the current evidence on the relationship between total, animal, and plant protein intake during pregnancy, as well as pre-pregnancy protein intake, and the risk of GDM.

METHODS

A literature search was completed using Scopus, PubMed, Web of Science, and Google Scholar up to January 2023 and references of retrieved relevant articles. Observational studies examining the association between the consumption of dietary protein from different sources in pre-pregnancy or/and during pregnancy and the risk of GDM were included. To combine effect sizes for the comparison between the highest and lowest categories of protein intake, a random effects model was utilized. Dose-response relationships were investigated using a 1-stage random-effects model.

RESULTS

8 observational studies were included in the systematic review and 5 prospective cohort studies in the meta-analysis, involving a total of 24,160 participants and 2450 cases of GDM. The analysis revealed a significant association between total protein intake during pregnancy and an elevated risk of GDM (relative risk (RR): 2.24, 95 % confidence interval (CI): 1.67-3.00, P = 0.000). Conversely, no significant association was found between total protein intake before pregnancy and the risk of GDM. Both animal protein intake before pregnancy (RR: 1.47, 95 % CI: 1.06-2.03, P = 0.021) and during pregnancy (RR; 2.31, 95 % CI: 1.43-3.73, P = 0.001) showed a significant association with GDM. Interestingly, there was no significant association between the consumption of plant protein both before and during pregnancy and the risk of GDM. Further analysis revealed that an additional 5 % energy from total protein and animal protein per day was associated with a 24 % and 32 % before and 114 % and 67 % increased risk of GDM during pregnancy respectively.

CONCLUSION

In conclusion, consumption of animal protein and total protein before pregnancy is associated with an increased risk of GDM, although the association is not significant for total protein. Conversely, plant protein intake is linked to a decreased risk of GDM, however, the results are not significant. The intake of any protein type (plant/animal/total) during pregnancy is associated with an elevated risk of GDM, with this association being statistically insignificant for plant protein. Further cohort studies are required to validate the findings presented in this study.

REGISTRATION

PROSPERO (CRD42023396215).

The relation of dietary protein intake before and during the pregnancy with gestational diabetes mellitus (GDM): A GRADE-assessed systematic review and dose-response meta-analysis of epidemiologic studies

BACKGROUND

Although previous studies investigated the relation of protein intake and gestational diabetes mellitus (GDM), their findings were controversial. Therefore, we aimed to summarize this association, through a comprehensive systematic review and dose-response meta-analysis.

METHODS

Electronic databases including MEDLINE (PubMed), ISI Web of Science, Scopus and motor engineering of Google Scholar were systematically searched up to April 2023. Observational studies which investigated odds of GDM in relation to protein intake were included.

RESULTS

A total of 31,005 participants with 3451 cases of GDM from 13 eligible investigations were included in the systematic review and meta-analysis. Comparing the highest and lowest intakes of total, animal, and plant proteins revealed the summary RRs of 1.82 (95% CI: 1.42, 2.33), 1.79 (95% CI: 1.50, 2.14), and 0.98 (95% CI: 0.81, 1.20), respectively, indicating a significant positive association between total and animal protein intake and GDM. In the dose-response analyses, each 5% increment in energy intake from total protein during pregnancy was related to 20% increased odds of GDM (RR = 1.20; 95% CI: 1.09, 1.33). In the non-linear dose-response analyses, we found a non-linear association for animal protein intake during pregnancy (P for non-linearity <0.001); so that, a risk increase was seen from zero to 10% of energy intake from animal proteins, however, a risk reduction was seen after 10% of energy intake. However, there was not any significant non-linear trend between plant protein intake during pregnancy and risk of GDM. Based on the GRADE assessment, the quality of evidence for total, animal and plant protein was rated as "moderate", "moderate" and "very low", respectively.

CONCLUSION

We found a significant positive association between total protein intake and GDM; however, the associations of animal and plant protein intake with GDM were dose-dependent.

Maternal Pea Protein Intake Provides Sex-Specific Protection against Dyslipidemia in Offspring from Obese Pregnancies

Increased consumption of dietary pulse protein has been shown to assist in body weight regulation and improve a range of metabolic health outcomes. We investigated if the exchange of casein for yellow pea protein (YPPN) in an obese-inducing maternal diet throughout pregnancy and lactation offered protection against obesity and dyslipidemia in offspring. Sixty female Sprague Dawley rats were fed a low-calorie control diet (CON), a high-caloric obesity-inducing diet (with casein protein (CP), HC-CP), or an isocaloric/macronutrient-matched HC diet supplemented with YPPN isolate (HC-PPN) in pre-pregnancy, gestation, and lactation. Body weight (BW) and metabolic outcomes were assessed in male and female offspring at weaning and in adulthood after consuming the CON diet in the postnatal period. Consumption of the HC-PPN diet did not protect against maternal obesity but did improve reproductive success compared with the HC-CP group (72.7% versus 43.7%) and reduced total energy, fat, and protein in maternal milk. Male, but not female, offspring from mothers fed the HC-CP diet demonstrated hyperphagia, obesity, dyslipidemia, and hepatic triglyceride (TG) accumulation as adults compared with CON offspring. Isocaloric exchange of CP for YPPN in a high-calorie obese-inducing diet did not protect against obesity but did improve several aspects of lipid metabolism in adult male offspring including serum total cholesterol, LDL/VLDL cholesterol, triglycerides (TGs), and hepatic TG concentration. Our results suggest that the exchange of CP for YPPN in a maternal obese-inducing diet selectively protects male offspring from the malprogramming of lipid metabolism in adulthood.