Dietary recommendations for obese pregnant women: current questions and controversies

Programming Skeletal Muscle Metabolic Flexibility in Offspring of Male Rats in Response to Maternal Consumption of Slow Digesting Carbohydrates during Pregnancy

Skeletal muscle plays a relevant role in metabolic flexibility and fuel usage and the associated muscle metabolic inflexibility due to high-fat diets contributing to obesity and type 2 diabetes. Previous research from our group indicates that a high-fat and rapid-digesting carbohydrate diet during pregnancy promotes an excessive adipogenesis and also increases the risk of non-alcoholic fatty liver disease in the offspring. This effect can be counteracted by diets containing carbohydrates with similar glycemic load but lower digestion rates. To address the role of the skeletal muscle in these experimental settings, pregnant rats were fed high-fat diets containing carbohydrates with similar glycemic load but different digestion rates, a high fat containing rapid-digesting carbohydrates diet (HF/RD diet) or a high fat containing slow-digesting carbohydrates diet (HF/SD diet). After weaning, male offspring were fed a standard diet for 3 weeks (weaning) or 10 weeks (adolescence) and the impact of the maternal HF/RD and HF/SD diets on the metabolism, signaling pathways and muscle transcriptome was analyzed. The HF/SD offspring displayed better muscle features compared with the HF/RD group, showing a higher muscle mass, myosin content and differentiation markers that translated into a greater grip strength. In the HF/SD group, metabolic changes such as a higher expression of fatty acids (FAT/CD36) and glucose (GLUT4) transporters, an enhanced glycogen content, as well as changes in regulatory enzymes such as muscle pyruvate kinase and pyruvate dehydrogenase kinase 4 were found, supporting an increased muscle metabolic flexibility and improved muscle performance. The analysis of signaling pathways was consistent with a better insulin sensitivity in the muscle of the HF/SD group. Furthermore, increased expression of genes involved in pathways leading to muscle differentiation, muscle mass regulation, extracellular matrix content and insulin sensitivity were detected in the HF/SD group when compared with HF/RD animals. In the HF/SD group, the upregulation of the ElaV1/HuR gene could be one of the main regulators in the positive effects of the diet in early programming on the offspring. The long-lasting programming effects of the HF/SD diet during pregnancy may depend on a coordinated gene regulation, modulation of signaling pathways and metabolic flexibility that lead to an improved muscle functionality. The dietary early programming associated to HF/SD diet has synergic and positive crosstalk effects in several tissues, mainly muscle, liver and adipose tissue, contributing to maintain the whole body homeostasis in the offspring.

Feeding a slowly digestible carbohydrate diet during pregnancy of insulin-resistant rats prevents the excess of adipogenesis in their offspring

An obesogenic environment during pregnancy has been shown to increase the risk of dysregulation on adipogenesis and insulin resistance in the offspring. Being essential for the growing fetus, glucose supply is guaranteed by a number of modifications in the mother's metabolism, and thus, glucose control during pregnancy especially among obese or diabetic women is paramount to prevent adverse consequences in their children. Besides the election of low-glycemic-index carbohydrates, the rate of carbohydrate digestion could be relevant to keep a good glucose control. In the present study, we compared the effects of two high-fat diets with similar glycemic load but different rates of carbohydrate digestion given to pregnant insulin-resistant rats. After birth, all animals were fed a standard diet until age 14 weeks. We analyzed offspring body composition, plasma and adipocyte lipidomics, lipid metabolism in adipose tissue and insulin sensitivity. Those animals whose mothers were fed the rapid-digesting carbohydrate diet exhibited an excessive adipogenesis. Thus, these animals showed a marked lipidemia, increased lipid synthesis in the adipose tissue and reduced glucose transporter amount in the adipose. On the contrary, those animals whose mothers were fed the slow-digesting carbohydrate diet showed a profile in the measured parameters closer to that of the offspring of healthy mothers. These results support the hypothesis that not only glycemic index but the rate of carbohydrate digestion during gestation may be critical to regulate the programming of adipogenesis in the offspring.

Gestational weight gain in obese pregnancy: impact on maternal and foetal metabolic parameters and birthweight

The aim of this prospective, observational study was to investigate the impact of gestational weight gain (GWG) among euglycaemic obese pregnant women on maternal and foetal metabolic parameters and neonatal outcome. Total GWG was recorded for 101 obese, non-diabetic women with a singleton pregnancy. At 28 weeks of gestation, fasting maternal blood samples were analysed for glucose, insulin, c-peptide and lipids. Cord bloods were collected at delivery for analysis of glucose, c-peptide and lipids. GWG (mean ± SD =10.9 ± 5.5 kg) was greatest among those of younger age and lower body mass index and 58% of women exceeded the Institute of Medicine GWG recommendations of 5-9 kg for obese pregnancy. GWG was significantly positively associated with increased risk of birthweight >4 kg, cord c-peptide levels and inversely associated with cord total cholesterol. This study identified that higher GWG in obese pregnancy may increase the risk of macrosomia and neonatal hyperinsulinaemia, within a euglycaemic maternal cohort. Impact statement Excess gestational weight gain (GWG) and maternal obesity frequently co-occur with adverse consequences for maternal and neonatal health; however, little is known of the underlying biological pathways which may be affected to contribute to adverse outcomes. Greater understanding of the biological mechanisms involved may help guide future studies to develop targeted interventions for more effective clinical outcomes. This study identified that higher GWG among obese pregnant women resulted in foetal hyperinsulinaemia even in the absence of maternal hyperglycaemia, potentially representing a biological pathway for larger birthweight babies. These results may highlight the need for more intensive dietary and lifestyle interventions among obese women who would not normally receive additional counselling beyond standard antenatal care if not diagnosed with glucose intolerance in pregnancy.

Dietary interventions in overweight and obese pregnant women: a systematic review of the content, delivery, and outcomes of randomized controlled trials

CONTEXT

Interventions targeting maternal obesity are a healthcare and public health priority.

OBJECTIVE

The objective of this review was to evaluate the adequacy and effectiveness of the methodological designs implemented in dietary intervention trials for obesity in pregnancy.

DATA SOURCES

A systematic review of the literature, consistent with PRISMA guidelines, was performed as part of the International Weight Management in Pregnancy collaboration.

STUDY SELECTION

Thirteen randomized controlled trials, which aimed to modify diet and physical activity in overweight and obese pregnant women, were identified.

DATA SYNTHESIS

There was significant variability in the content, delivery, and dietary assessment methods of the dietary interventions examined. A number of studies demonstrated improved dietary behavior in response to diet and/or lifestyle interventions. Nine studies reduced gestational weight gain.

CONCLUSION

This review reveals large methodological variability in dietary interventions to control gestational weight gain and improve clinical outcomes in overweight and obese pregnant women. This lack of consensus limits the ability to develop clinical guidelines and apply the evidence in clinical practice.

Healthy overweight/obese youth: early osteosarcopenic obesity features

BACKGROUND

Osteosarcopenic obesity was recently described as a variant phenotype of obesity, mainly observed in old age. This nested case-control study was performed to detect the differences in body composition between young, healthy overweight/obese and healthy lean populations of both genders. Our null hypothesis was that except for the fat mass, there would be absence of body composition differences, namely skeletal muscle and bone masses, between the groups.

METHODS

We used an advanced bio-impedance device to determine the body composition and measured circulating CRP (hsCRP) and diurnal salivary cortisol concentrations, as indices of inflammation and chronic stress, respectively. Overall, 2551 subjects aged 18-21 years participated in the study.

RESULTS

The healthy lean group included 1072 participants [900 males (84%) and 172 females (16%)], and the healthy overweight/obese group included 1479 participants [74 males (5%) and 1405 females (95%)]. Healthy overweight/obese participants presented with an increased fat mass (P < 0·001), as expected, but lower muscle (P < 0·001) and bone (P < 0·001) masses than lean controls. These findings were accompanied by increased extracellular water compartments, circulating hsCRP levels and evening salivary cortisol concentrations in the healthy overweight/obese group.

CONCLUSIONS

Our study suggests that 'osteosarcopenic' elements exist even in very young populations. These may represent a 'precursor' or forme fruste of the osteosarcopenic obesity phenotype in young healthy overweight/obese subjects, who may progressively develop osteosarcopenia in its full form at an older age. Our study highlights the significance of body composition analysis in medical practice, improving prevention and alleviating later health-related economic burden.

Role of probiotics in reducing the risk of gestational diabetes

Overweight and obesity currently constitute a major threat to human well-being. Almost half of the female population are currently overweight. Pregnant overweight women are at risk of gestational diabetes affecting the health of the mother and the child, in both the short and long term. Notwithstanding the extensive scientific interest centred on the problem, research efforts have thus far been unable to devise preventive strategies. Recent scientific advances point to a gut microbiota dysbiosis, with ensuing low-grade inflammation as a contributing element, in obesity and its comorbidities. Such findings would suggest a role for specific probiotics in the search for preventive and therapeutic adjunct applications in gestational diabetes. The aim of the present paper was to critically review recent demonstrations of the role of intestinal microbes in immune and metabolic regulation, which could be exploited in nutritional management of pregnant women by probiotic bacteria. By modulating specific target functions, probiotic dietary intervention may exert clinical effects beyond the nutritional impact of food. As this approach in pregnancy is new, an overview of the role of gut microbiota in shaping host metabolism, together with the definition of probiotics are presented, and finally, specific targets and potential mechanisms for probiotics in pregnancy are discussed. Pregnancy appears to be the most critical stage for interventions aiming to reduce the risk of non-communicable disease in future generations, beyond the immediate dangers attributable to the health of the mother, labour and the neonate. Specific probiotic interventions during pregnancy provide an opportunity, therefore, to promote the health not only of the mother but also of the child.

Risks associated with obesity in pregnancy, for the mother and baby: a systematic review of reviews

Maternal obesity is linked with adverse outcomes for mothers and babies. To get an overview of risks related to obesity in pregnant women, a systematic review of reviews was conducted. For inclusion, reviews had to compare pregnant women of healthy weight with women with obesity, and measure a health outcome for mother and/or baby. Authors conducted full-text screening, quality assurance using the AMSTAR tool and data extraction steps in pairs. Narrative analysis of the 22 reviews included show gestational diabetes, pre-eclampsia, gestational hypertension, depression, instrumental and caesarean birth, and surgical site infection to be more likely to occur in pregnant women with obesity compared with women with a healthy weight. Maternal obesity is also linked to greater risk of preterm birth, large-for-gestational-age babies, foetal defects, congenital anomalies and perinatal death. Furthermore, breastfeeding initiation rates are lower and there is greater risk of early breastfeeding cessation in women with obesity compared with healthy weight women. These adverse outcomes may result in longer duration of hospital stay, with concomitant resource implications. It is crucial to reduce the burden of adverse maternal and foetal/child outcomes caused by maternal obesity. Women with obesity need support to lose weight before they conceive, and to minimize their weight gain in pregnancy.