Effect of low- and high-protein maternal diets during gestation on reproductive outcomes in the rat: a systematic review and meta-analysis

Abstract Studies with animal models have consistently demonstrated adverse health outcomes in offspring born following nutritional manipulation during gestation. However, the effects of gestational dietary protein modification on reproductive outcomes at birth are less clear. We, therefore, conducted a systematic review and meta-analysis of controlled trials to determine whether high- or low-protein diets are associated with altered reproductive outcomes in a commonly studied species, the rat. Included studies were identified through a systematic search using electronic databases and manual literature review to identify randomized studies published between June 1972 and March 2019. Thirty-two studies were identified and used to analyze the effects of low- and high-protein gestational diets on litter size, litter weight, gestational weight gain, and gestational feed intake. The results indicate that low-protein diets significantly reduced litter weight (P < 0.00001) and gestational weight gain (P < 0.0006), but did not influence litter size (P = 0.62) or gestational feed intake (P = 0.25). In contrast, high-protein diets were found to reduce gestational feed intake (P = 0.004) but did not influence litter size (P = 0.56), litter weight (P = 0.22), or gestational weight gain (P = 0.35). The results suggest that low but not high-protein gestational diets alter reproductive outcomes at birth in rats.

Download Full-text

Diet quality during preconception or pregnancy and gestational weight gain: protocol for a systematic review and meta-analysis

BMJ Open ◽

10.1136/bmjopen-2019-033130 ◽

2020 ◽

Vol 10 (2) ◽

pp. e033130

Author(s):

Yamei Yu ◽

Isabelle Hardy ◽

Wenguang Sun ◽

Dean A Fergusson ◽

William Fraser ◽

...

Keyword(s):

Systematic Review ◽

Weight Gain ◽

Gestational Weight Gain ◽

Diet Quality ◽

Meta Analysis ◽

Random Effect ◽

Primary Data ◽

Gestational Weight ◽

Newcastle Ottawa Scale ◽

Scientific Meetings

IntroductionInappropriate gestational weight gain (GWG), including inadequate and excessive GWG, has become pandemic across nations and continents. This review aims to synthesise the evidence on the correlation between diet quality and GWG. If this association is confirmed, improving diet quality could become an intervention target in the efforts to reduce inappropriate GWG.Methods and analysisWe will conduct a systematic review of all prospective cohort studies on diet quality in preconception or pregnancy and GWG. Our secondary outcomes include gestational diabetes, pre-eclampsia and birth weight. A comprehensive search of all published articles in MEDLINE ALL (Ovid), Embase (Ovid), Food Science and Technology Abstracts (Ovid) and CINAHL (EBSCOHost), from database creation to 20 April 2019, will be conducted. Studies will be screened for eligibility by title, abstract and full text in duplicate by two independent reviewers. Study quality and risk of bias will be assessed using the adapted Newcastle–Ottawa Scale. Results will be reported following the meta-analysis of observational studies in epidemiology guidelines. If sufficient data are available, a meta-analysis will be conducted to synthesise the effect size reported as OR with 95% CI using both fixed-effect and random-effect models. I2 statistics and visual inspection of the forest plots will be used to assess heterogeneity and identify the potential sources of heterogeneity. Publication bias will be assessed by visual inspections of funnel plots and Egger’s test.Ethics and disseminationFormal ethical approval is not required as no primary data will be collected. We aim to publish the results of this study in a peer-reviewed journal and present them at conferences and scientific meetings to promote knowledge transfer.PROSPERO registration numberCRD42019128732

Download Full-text