Low Carbohydrate-Diet Scores and Long-term Risk of Type 2 Diabetes Among Women With a History of Gestational Diabetes Mellitus: A Prospective Cohort Study

Association between low-carbohydrate-diet score, glycemia and cardiovascular risk factors in adults with type 1 diabetes

BACKGROUND AND AIMS

Low-carbohydrate-diets (LCDs) are gaining popularity in individuals with type 1 diabetes (T1D). However, the impact of such diets on glycemia and cardiovascular risk factors is debated. This study aims to evaluate associations between low-carbohydrate intakes using LCD score with glycemia and cardiovascular risk factors (lipid profile) in adults with T1D or LADA in Québec, Canada.

METHODS AND RESULTS

This is a cross-sectional study using data collected in the BETTER registry (02/2019 and 04/2021) including self-reported 24-h dietary recalls to calculate LCD scores, waist circumference, level-2 and level-3 hypoglycemic episodes and measured biochemical data (HbA1c, LDL-cholesterol and non-HDL-cholesterol). Participants were divided into quartiles (Q) based on LCD scores. Two hundred eighty-five adults (aged 48.2 ± 15.0 years; T1D duration 25.9 ± 16.2 years) were included. Categorical variables underwent Chi-squared/Fisher's Exact tests, while continuous variables underwent ANOVA tests. Mean carbohydrate intake ranged from 31.2 ± 6.9% (Q1) to 56.5 ± 6.8% (Q4) of total daily energy. Compared to Q4, more people in Q1 reported HbA1c ≤ 7% [≤53.0 mmol/mol] (Q1: 53.4% vs. Q4: 29.4%; P = 0.011). The same results were found in the models adjusted for age, sex and T1D duration. A greater proportion of participants in Q1 never experienced level-3 hypoglycemia compared to Q3 (Q1: 60.0% vs. Q3: 31.0%; P = 0.004). There were no differences across quartiles for frequency of level-2 hypoglycemia events and lipid profile (LDL-cholesterol and non-HDL-cholesterol).

CONCLUSIONS

Low-carbohydrate intakes are associated with higher probabilities of reaching HbA1c target and of never having experienced level-3 hypoglycemia. No associations with level-2 hypoglycemia frequency, nor cardiovascular risk factors were observed.

Maternal Dietary Carbohydrate and Pregnancy Outcomes: Quality over Quantity

Dietary nutrition plays a crucial role in determining pregnancy outcomes, with poor diet being a major contributor to pregnancy metabolic syndrome and metabolic disorders in offspring. While carbohydrates are essential for fetal development, the excessive consumption of low-quality carbohydrates can increase the risk of pregnancy complications and have lasting negative effects on offspring development. Recent studies not only highlighted the link between carbohydrate intake during pregnancy, maternal health, and offspring well-being, but also suggested that the quality of carbohydrate foods consumed is more critical. This article reviews the impacts of low-carbohydrate and high-carbohydrate diets on pregnancy complications and offspring health, introduces the varied physiological effects of different types of carbohydrate consumption during pregnancy, and emphasizes the importance of both the quantity and quality of carbohydrates in nutritional interventions during pregnancy. These findings may offer valuable insights for guiding dietary interventions during pregnancy and shaping the future development of carbohydrate-rich foods.

Association of low-carbohydrate diet scores and type 2 diabetes in Chinese rural adults: The Henan Rural Cohort Study

PURPOSE

To investigate the association between low-carbohydrate diet scores (LCDs) and the risk of type 2 diabetes in rural China.

METHODS

A total of 38,100 adults were included in the Henan Rural Cohort Study. Macronutrient intake was assessed via a validated food-frequency questionnaire to create low-carbohydrate diet (LCD) scores. Multivariate logistic regression models and subgroup analysis were performed to estimate the odds ratio (OR) and 95% confidence interval (95% CI).

RESULTS

After multivariable adjustment, participants with a high total low-carbohydrate diet score have a high risk of T2D (extreme-quartile OR = 1.23, 95% CI: 1.04-1.41; P = 0.007), whereas plant-based LCD score is not related to T2D risk. Among individuals with a BMI < 24 (extreme-quartile OR = 1.22, 95% CI: 1.01-1.47; P < 0.001) or high levels of physical activity (extreme-quartile OR = 1.42, 95% CI: 1.17-1.72; P < 0.001), the animal-based LCD score is positively correlated with the risk of T2D.

CONCLUSION

Among Chinese rural populations, high-fat-low carbohydrate diet is associated with an increased risk of type 2 diabetes. High intake of animal protein and fat also increases T2D risk in those who are overweight or have high physical activity.

The Role of the Glycemic Index and Glycemic Load in the Dietary Approach of Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is a common metabolic disorder that often develops during pregnancy, characterized by glucose intolerance and insulin resistance (IR). To ensure the well-being of both the mother and the fetus, the body undergoes multiple metabolic and immunological changes that result in peripheral IR and, under certain hereditary or acquired abnormalities, GDM in predisposed women. The adverse short- and long-term effects of GDM impact both the mother and the fetus. Nutrition seems to play an important role to prevent GDM or improve its evolution. An emphasis has been given to the proportion of carbohydrates (CHO) relative to protein and lipids, as well as dietary patterns, in GDM. The effects of CHO on postprandial glucose concentrations are reflected in the glycemic index (GI) and glycemic load (GL). Diets rich in GI and GL may induce or exacerbate IR, whereas diets low in GI and GL appear to enhance insulin sensitivity and improve glycemic control. These positive outcomes may be attributed to direct interactions with insulin and glucose homeostasis or indirect effects through improved body composition and weight management. This comprehensive narrative review aims to explore the significance of nutrition, with a focus on the critical evaluation of GI and GL in the dietary management of women with GDM.

Precision stratification of prognostic risk factors associated with outcomes in gestational diabetes mellitus: a systematic review

BACKGROUND

The objective of this systematic review is to identify prognostic factors among women and their offspring affected by gestational diabetes mellitus (GDM), focusing on endpoints of cardiovascular disease (CVD) and type 2 diabetes (T2D) for women, and cardiometabolic profile for offspring.

METHODS

This review included studies published in English language from January 1st, 1990, through September 30th, 2021, that focused on the above outcomes of interest with respect to sociodemographic factors, lifestyle and behavioral characteristics, traditional clinical traits, and 'omics biomarkers in the mothers and offspring during the perinatal/postpartum periods and across the lifecourse. Studies that did not report associations of prognostic factors with outcomes of interest among GDM-exposed women or children were excluded.

RESULTS

Here, we identified 109 publications comprising 98 observational studies and 11 randomized-controlled trials. Findings indicate that GDM severity, maternal obesity, race/ethnicity, and unhealthy diet and physical activity levels predict T2D and CVD in women, and greater cardiometabolic risk in offspring. However, using the Diabetes Canada 2018 Clinical Practice Guidelines for studies, the level of evidence was low due to potential for confounding, reverse causation, and selection biases.

CONCLUSIONS

GDM pregnancies with greater severity, as well as those accompanied by maternal obesity, unhealthy diet, and low physical activity, as well as cases that occur among women who identify as racial/ethnic minorities are associated with worse cardiometabolic prognosis in mothers and offspring. However, given the low quality of evidence, prospective studies with detailed covariate data collection and high fidelity of follow-up are warranted.

Comparison of the Ketogenic Ratio of Macronutrients With the Low-Carbohydrate Diet Score and Their Association With Risk of Type 2 Diabetes in Postmenopausal Women: A Secondary Analysis of the Women's Health Initiative

BACKGROUND

Previous attempts to identify low-carbohydrate diets (LCDs) in epidemiological studies relied on the LCD Score, which is unable to identify ketogenic dieters. Ketogenic ratios of macronutrients are clinical equations proposed to predict ketogenic diets; however, their utility in epidemiological studies is unknown.

OBJECTIVE

To determine the number of participants consuming a ketogenic diet, compare ketogenic ratios to the LCD Score, and evaluate their association with type 2 diabetes mellitus (T2DM).

DESIGN

Secondary analysis of the Women's Health Initiative with 17.9 ± 6.03 years of follow-up. Baseline food frequency questionnaires were used to calculate the ketogenic ratio as follows: (0.9 × grams fat + 0.46 × grams protein) / (0.1 × grams fat + 0.58 × grams protein + grams net carbohydrate), a value ≥1.5 is the minimum threshold for a ketogenic diet.

PARTICIPANTS/SETTING

One hundred twenty-five nine hundred eighty-two postmenopausal women without diabetes (aged 50 to 79 years) enrolled in the multicenter Women's Health Initiative observational study and clinical trials were included.

MAIN OUTCOME MEASURES

Risk of self-reported incident T2DM.

STATISTICAL ANALYSES PERFORMED

Cox proportional hazards models, adjusted for age, race, ethnicity, education, income, health insurance, relationship status, geographic region, Women's Health Initiative study component, female hormone use, smoking status, alcohol use, recreational physical activity, total energy intake, diet quality, body mass index, hyperlipidemia, and hypertension, were used to compare hazard ratios and 95% CIs for T2DM among quintiles of the ketogenic ratio.

RESULTS

A total of 18,775 incident cases of T2DM occurred. The median ketogenic ratio was 0.35 (interquartile range 0.28 to 0.42) and 15 individuals (0.01%) exceeded the threshold for a ketogenic diet. Higher ketogenic ratio quintiles were associated with increased risk of T2DM in a dose-dependent manner. Comparing extreme quintiles of the ketogenic ratio, the hazard ratio for diabetes was 1.24 (95% CI 1.18 to 1.31; Ptrend < 0.001) in fully adjusted models. Similarly, comparing extreme quintiles, the hazard ratio for diabetes was 1.36 (95% CI 1.29 to 1.43; Ptrend < 0.001) for the LCD Score and 1.13 (95% CI 1.07 to 1.19; Ptrend < 0.001) for the simplified ketogenic ratio in fully adjusted models.

CONCLUSIONS

Increasing ketogenic ratio values are associated with increased risk of T2DM and align well with LCD Scores; however, too few participants consumed a ketogenic diet to determine its association with T2DM.

Dietary Patterns Associated with Abnormal Glucose Tolerance following Gestational Diabetes Mellitus: The MyNutritype Study

Abnormal glucose tolerance (AGT), which includes type 2 diabetes and pre-diabetes, is highly prevalent in women post gestational diabetes mellitus (post-GDM). Dietary patterns have been associated with the risk of developing AGT in women post-GDM, but evidence in Asian populations is sparse. This study aimed to determine the association between a posteriori dietary patterns and AGT in women post-GDM. This cross-sectional study recruited 157 women post-GDM (mean age 34.8 years) from Seri Kembangan Health Clinic and Universiti Putra Malaysia. AGT was diagnosed according to the Malaysian Clinical Practice Guidelines using a 75 g 2 h oral glucose tolerance test or HbA1c. Food intake was assessed using the 2014 Malaysian Adult Nutrition Survey food frequency questionnaire. Five dietary patterns were derived using principal component analysis: 'Unhealthy', 'Fish-eggs-fruits-vegetables', 'Cereals-confectionaries', 'Legumes-dairy', and 'Meat-sugar-sweetened-beverages'. After adjusting for sociodemographic characteristics and total energy intake, the 'Cereals-confectionaries' dietary pattern was significantly associated with AGT (adjusted odds ratio 1.536, p = 0.049). Targeted lifestyle modification, including dietary intervention, for women post-GDM is warranted to reduce their risk of AGT and its complications.

Association between adherence to a low carbohydrate dietary (LCD) pattern with breast milk characteristics and oxidative markers in infants' urine: a cross-sectional study

BACKGROUND

Breast milk (BM) is a dynamic fluid that varies over time and between women. The variations in BM components are most likely associated with maternal diet quality. This study aimed to assess adherence to a low carbohydrate dietary (LCD) pattern with oxidative stress markers of BM characteristics and infants' urine.

MATERIALS AND METHODS

In this cross-sectional study 350 breastfeeding mothers and their infants were recruited. BM samples were collected from mothers, and urine specimens were obtained from each infant. To evaluate LCD scores, subjects were divided into 10 deciles according to the percent of energy obtained from carbohydrates, proteins, and fats. Determination of total antioxidant activity was conducted using the ferric reducing antioxidant power (FRAP), 2, 2'-diphenyl-1-picrylhydrazyl (DPPH), thiobarbituric acid reactive substances (TBARs), and Ellman's assay. Biochemical assays of samples including calcium, total protein, and triglyceride level were also performed using commercial kits.

RESULTS

Participants with the greatest LCD pattern adherence were placed into the last quartile (Q4), and those with the minimum LCD were in the first quartile (Q1). Individuals in the highest LCD quartile had significantly higher levels of milk FRAP, thiol, and protein, as well as infant urinary FRAP and lower milk MDA levels than those in the lowest quartile. Multivariate linear regression analyses indicated that higher score of the LCD pattern was associated with a higher level of milk thiol, protein, and lower level of milk MDA (p < 0.05).

CONCLUSION

Our findings show that adherence to a LCD, as defined by a low level of carbohydrates in daily food intake, is linked with improved BM quality and markers of oxidative stress in infant urine.

Predictors and risk factors of short-term and long-term outcomes among women with gestational diabetes mellitus (GDM) and their offspring: Moving toward precision prognosis?

As part of the American Diabetes Association Precision Medicine in Diabetes Initiative (PMDI) - a partnership with the European Association for the Study of Diabetes (EASD) - this systematic review is part of a comprehensive evidence evaluation in support of the 2 ^nd International Consensus Report on Precision Diabetes Medicine. Here, we sought to synthesize evidence from empirical research papers published through September 1 ^st , 2021 to evaluate and identify prognostic conditions, risk factors, and biomarkers among women and children affected by gestational diabetes mellitus (GDM), focusing on clinical endpoints of cardiovascular disease (CVD) and type 2 diabetes (T2D) among women with a history of GDM; and adiposity and cardiometabolic profile among offspring exposed to GDM in utero. We identified a total of 107 observational studies and 12 randomized controlled trials testing the effect of pharmaceutical and/or lifestyle interventions. Broadly, current literature indicates that greater GDM severity, higher maternal body mass index, belonging to racial/ethnic minority group; and unhealthy lifestyle behaviors would predict a woman's risk of incident T2D and CVD, and an unfavorable cardiometabolic profile among offspring. However, the level of evidence is low (Level 4 according to the Diabetes Canada 2018 Clinical Practice Guidelines for diabetes prognosis) largely because most studies leveraged retrospective data from large registries that are vulnerable to residual confounding and reverse causation bias; and prospective cohort studies that may suffer selection and attrition bias. Moreover, for the offspring outcomes, we identified a relatively small body of literature on prognostic factors indicative of future adiposity and cardiometabolic risk. Future high-quality prospective cohort studies in diverse populations with granular data collection on prognostic factors, clinical and subclinical outcomes, high fidelity of follow-up, and appropriate analytical approaches to deal with structural biases are warranted.

Quality of low-carbohydrate diets among Australian post-partum women: Cross-sectional analysis of a national population-based cohort study

Low-carbohydrate diets (LCDs) are popular among people attempting weight loss and recommended for pregnant women with gestational diabetes (GDM), but they may increase health risks if nutritionally inadequate. We aimed to describe the dietary intake of post-partum women according to their relative carbohydrate intake, overall, and among women attempting weight loss or diagnosed with GDM in their recent pregnancy. This cross-sectional population-based cohort study included 2093 post-partum women aged 25-36 years who participated in the Australian Longitudinal Study on Women's Health. Dietary intake was assessed using a validated food frequency questionnaire. Relative carbohydrate intake was determined using a previously developed LCD score. Data were weighted to account for oversampling of women from rural/remote areas. More than half of women (n[weighted] = 1362, 66.3%) were trying to lose weight, and 4.6% (n[weighted]=88) had GDM in their recent pregnancy. Women with the lowest relative carbohydrate intake (LCD score quartile 4) consumed 36.8% of total energy intake from carbohydrates, and had a lower intake of refined grains, whole grains, fruit and fruit juice, and a higher intake of red and processed meat, compared with women with the highest relative carbohydrate intake (quartile 1). Different food groups, both healthy and unhealthy, were restricted depending on whether women were attempting weight loss and had recent GDM. These findings may reflect a lack of knowledge among post-partum women on carbohydrates and dietary guidelines. Health professionals may have an important role in providing advice and support for post-partum women who wish to restrict their carbohydrate intake, to ensure optimal diet quality.

Association between low-carbohydrate diet score and incidence of type 2 diabetes among Japanese adults: the JACC Study

We prospectively examined the association between low-carbohydrate diet (LCD) score and incidence of type 2 diabetes (T2D) in Japanese adults using Japan Collaborative Cohort Study for Evaluation of Cancer Risk (JACC Study) data. A total of 19 084 (7052 men and 12 032 women) Japanese non-diabetic participants aged 40-79 years, who enrolled in the JACC study between 1988 and 1990, were included in our analysis. Dietary intake was evaluated using a validated food-frequency questionnaire. The overall, animal and vegetable LCD scores were calculated by dividing the study participants into eleven categories based on the percentages of energy from carbohydrates, protein and fat. The incidence of T2D was assessed using a self-administered questionnaire. We used multivariable logistic regression analysis to estimate the odds ratios (ORs) and 95 % confidence intervals (CIs) of incident T2D across the quintile of each LCD score, with adjustment for potential confounders. During the 5-year study period, 490 adults (247 men and 243 women) developed T2D. The multivariable-adjusted OR of incident T2D for the highest v. lowest quintiles of overall and animal LCD scores, respectively, were 0·64 (95 % CI 0·42, 0·99) and 0·83 (95 % CI 0·55, 1·27) for men, 0·78 (95 % CI 0·51, 1·18) and 0·84 (95 % CI 0·57, 1·24) for women. The vegetable LCD score was associated with a lower risk of T2D in men (OR 0·51; 95 % CI 0·33, 0·77). Our results suggest that diets lower in carbohydrates and higher in fat and protein are unlikely to higher the T2D risk among Japanese individuals.

Current Evidence Concerning Effects of Ketogenic Diet and Intermittent Fasting in Patients with Nonalcoholic Fatty Liver

Nonalcoholic fatty liver disease (NAFLD) is emerging globally, while no therapeutic medication has been approved as an effective treatment to date, lifestyle intervention through dietary modification and physical exercise plays a critical role in NAFLD management. In terms of dietary modification, Mediterranean diet is the most studied dietary pattern and is recommended in many guidelines, however, it may not be feasible and affordable for many patients. Recently, a ketogenic diet and intermittent fasting have gained public attention and have been studied in the role of weight management. This article reviews specifically whether these trendy dietary patterns have an effect on NAFLD outcomes regarding intrahepatic fat content, fibrosis, and liver enzymes, the scientific rationales behind these particular dietary patterns, as well as the safety concerns in some certain patient groups.

Associations of Moderate Low-Carbohydrate Diets With Mortality Among Patients With Type 2 Diabetes: A Prospective Cohort Study

CONTEXT

A statement of context for the abstract was added in Objective as follows: Lower-carbohydrate-diet (LCD) has been reported to have beneficial effects on cardiovascular risk factor profile in general population. However, whether adherence to an LCD could benefit long-term survival among individuals with diabetes is unclear.

OBJECTIVE

This work aimed to investigate the associations of different types of lower-carbohydrate diets with mortality among individuals with type 2 diabetes (T2D).

METHODS

This prospective study included 5677 patients with T2D. The overall, unhealthy, and healthy lower-carbohydrate-diet (LCD) scores were calculated based on the percentage of energy from total and subtypes of carbohydrate, protein, and fat. Deaths were determined via linkage to the National Death Index records until December 31, 2015. Cox proportional hazards models were used to estimate the hazard ratios (HRs) and 95% CIs of mortality.

RESULTS

During a median of 6.3 years of follow-up (39 401 person-years), 1432 deaths were documented. After multivariable adjustment including lifestyle factors, diabetes duration, and glycated hemoglobin A1c, patients in the third quartile of overall LCD score had the lowest risk of mortality (HR: 0.65; 95% CI, 0.50-0.85), compared with the first quartile. The multivariable-adjusted HRs (95% CIs) of mortality across quartiles of healthy lower-carbohydrate-diet score were 1.00 (reference), 0.78 (0.64-0.96), 0.73 (0.58-0.91), and 0.74 (0.58-0.95) (Ptrend = .01). Isocalorically replacing 2% of energy from carbohydrates with plant-based protein or polyunsaturated fatty acids was associated with 23% to approximately 37% lower total mortality. Similar results were observed when analyses were stratified by age, sex, race/ethnicity, smoking status, body mass index, physical activity, and diabetes duration.

CONCLUSION

Healthy LCD score was significantly associated with a lower risk of mortality in adults with T2D. Adherence to a well-balanced moderate lower-carbohydrate diet that emphasizes healthy carbohydrates, plant-based protein, and polyunsaturated fat may prevent premature death among patients with T2D.

A Scoping Review on Gestational Diabetes in Hawai'i: A "Window of Opportunity" to Address Intergenerational Risk for Type 2 Diabetes Mellitus

The health of women over the entire span of their reproductive years is crucial - beginning in adolescence and extending through the postpartum period. This paper provides a scoping review of the relevant literature on risk factors for gestational diabetes mellitus (GDM) and progression from GDM to type 2 diabetes mellitus (T2DM), particularly among women of Native Hawaiian and Pacific Islander (NHPI) and Asian racial/ethnic backgrounds in Hawai'i, using the PubMed database (July 2010 to July 2020). NHPI and Asian populations have a greater likelihood of developing GDM compared to their White counterparts. Risk factors such as advanced maternal age, high maternal body mass index, and lack of education about GDM have varying levels of impact on GDM diagnosis between ethnic populations. Mothers who have a history of GDM are also at higher risk of developing T2DM. Common risk factors include greater increase in postpartum body mass index and use of diabetes medications during pregnancy. However, few studies investigate the progression from GDM to T2DM in Hawai'i's Asian and NHPI populations, and no studies present upstream preconception care programs to prevent an initial GDM diagnosis among Hawai'i's women. Thus, updated reports are necessary for optimal early interventions to prevent the onset of GDM and break the intergenerational cycle of increased susceptibility to T2DM and GDM in both mother and child. Further attention to the development of culturally sensitive interventions may reduce disparities in GDM and improve the health for all affected by this condition.

Dietary carbohydrate and the risk of type 2 diabetes: an updated systematic review and dose-response meta-analysis of prospective cohort studies

We did this study to clarify the association between carbohydrate intake and the risk of type 2 diabetes (T2D) and potential effect modification by geographical location. PubMed, Scopus and Web of Science were searched to find prospective cohort studies of dietary carbohydrate intake and T2D risk. A random-effects dose-response meta-analysis was performed to calculate the summary hazard ratios (HRs) and 95%CIs. The quality of cohort studies and the certainty of evidence was rated using the Newcastle-Ottawa Scale and GRADE tool, respectively. Eighteen prospective cohort studies with 29,229 cases among 607,882 participants were included. Thirteen studies were rated to have high quality, and five as moderate quality. The HR for the highest compared with the lowest category of carbohydrate intake was 1.02 (95%CI: 0.91, 1.15; I2 = 67%, GRADE = low certainty). The HRs were 0.93 (95%CI: 0.82, 1.05; I2 = 58%, n = 7) and 1.26 (95%CI: 1.11, 1.44; I2 = 6%, n = 6) in Western and Asian countries, respectively. Dose-response analysis indicated a J shaped association, with the lowest risk at 50% carbohydrate intake (HR50%: 0.95, 95%CI: 0.90, 0.99) and with risk increasing significantly at 70% carbohydrate intake (HR70%: 1.18, 95%CI: 1.03, 1.35). There was no association between low carbohydrate diet score and the risk of T2D (HR: 1.14, 95%CI: 0.89, 1.47; I2 = 90%, n = 5). Carbohydrate intake within the recommended 45-65% of calorie intake was not associated with an increased risk of T2D. Carbohydrate intake more than 70% calorie intake might be associated with a higher risk.

Consistently Low Levels of Osteocalcin From Late Pregnancy to Postpartum Are Related to Postpartum Abnormal Glucose Metabolism in GDM Patients

OBJECTIVE

Increasing evidence suggests that osteocalcin (OC), a marker of bone formation, plays an important role in glucose homoeostasis. Few studies have investigated the relationship between OC levels in gestational diabetes mellitus (GDM) patients and their postpartum glucose metabolism. This study evaluated the relationship between OC levels in late pregnancy, their longitudinal changes, and postpartum glucose metabolism among GDM patients.

MEASURES

Serum OC was measured in late pregnancy and the postpartum period for 721 GDM patients. All patients underwent a 75-g oral glucose tolerance test (OGTT) at 6-8 weeks postpartum. According to postpartum OGTT outcomes, patients were categorized into abnormal glucose metabolism (AGM) (n=255) and normal glucose tolerance (NGT) groups (n=466). Glucose metabolism-related indices were measured and calculated. Logistic regression analysis and linear mixed-effects model were used to assess the association between OC and postpartum AGM.

RESULTS

In late pregnancy, OC levels were lower in the AGM group than in the NGT group (13.93 ± 6.90 vs 15.33 ± 7.63 ng/ml, P=0.015). After delivery, OC levels increased in both groups. However, OC levels remained lower in the AGM group than in the NGT group (23.48 ± 7.84 vs 25.65 ± 8.37 ng/ml, P=0.001). Higher OC levels in late pregnancy were associated with decreased risk of progressing to postpartum AGM (OR:0.96, 95%CI:0.94-0.99). Linear mixed-effects analysis showed that postpartum AGM patients exhibited consistently lower OC levels than NGT group from late pregnancy to the postpartum period after adjustment for cofactors (β=-1.70, 95% CI: -2.78- -0.62).

CONCLUSIONS

In GDM patients, consistently low levels of OC from late pregnancy to postpartum were associated with increased postpartum AGM risk. The increase in serum OC may act as a protective factor to curb the progression of AGM at postpartum for GDM patients.

The low-carbohydrate-diet score is associated with resting metabolic rate: an epidemiologic study among Iranian adults

Purpose

Low-carbohydrate diet (LCD) has been used for weight loss and preventing obesity, but the association of adherence to LCD and resting metabolic rate (RMR) has not been investigated. This study aimed to investigate the association between the low-carbohydrate-diet score (LCDS) and RMR among Iranian adults.

Methods

This cross-sectional study was conducted on 270 Iranian adults 18-70 y of age. To assess dietary intakes, participants completed a validated food frequency questionnaire. The LCDS was calculated based on carbohydrate, protein and fat intake, expressed as a percentage of energy. The higher score indicates the lower carbohydrate and the higher protein and fat intake. RMR was measured by indirect calorimetry after an overnight fast.

Results

Multivariate-adjusted means showed that RMR significantly increased across tertiles (p = 0.041). However, there were no significant differences in the mean of fat mass (FM) and fat-free mass (FFM) across tertiles of LCDS (p = 0.986 and p = 0.621, respectively). Also LCDS and RMR (r = 0.14, p = 0.021) were found to be correlated, but LCDS and FFM (r = 0.06, p = 0.323), FM (r = -0.05, p = 0.412), had no statistically significant correlation. RMR had a significant positive association with LCDs in the crude model (β = 18.81, 95% CI: 2.55, 35.07, P = 0.024). Moreover, after controlling for covariates this association changed to non-significant (β = -0.14, 95% CI: -7.05, 19.25, P = 0.03).

Conclusion

Adherence to diets lower in carbohydrates and higher in fat and protein were associated with higher RMR. Further studies with a larger sample size are needed to confirm these findings.

Low-carbohydrate diet and maternal glucose metabolism in Chinese pregnant women

Few studies have suggested that long-term adherence to low-carbohydrate diets (LCD) may affect maternal glucose metabolism in Western countries. We aimed to investigate the association between LCD during pregnancy and glucose metabolism in a Chinese population. A total of 1018 women in mid-pregnancy were recruited in 2017-2018. Participants underwent a 75 g oral glucose tolerance test (OGTT). Daily dietary intakes over the past month were accessed using a validated FFQ. The overall, animal and vegetable LCD scores which represent adherence to different low-carbohydrate dietary patterns were calculated. Mixed linear regression and generalised linear mixed regression were conducted to evaluate the associations between LCD scores and maternal glucose metabolism. Of the 1018 subjects, 194 (19·1 %) were diagnosed with gestational diabetes mellitus (GDM). The overall LCD score (β: 0·024, se 0·008, PFDR = 0·02) and animal LCD score (β: 0·023, se 0·008, PFDR = 0·02) were positively associated with OGTT 1-h glucose. No significant associations were found between the three different LCD scores with fasting plasma glucose, OGTT 2-h glucose, or insulin resistance, respectively. Compared with the lowest quartile, the crude OR of GDM for the highest quartile were 1·84 (95 % CI 1·14, 2·95) for overall LCD score (Pfor trend = 0·02) and 1·56 (95 % CI 1·00, 2·45) for animal LCD score (Pfor trend = 0·02). However, these associations became non-significant after adjustment for covariates. In conclusion, a low-carbohydrate dietary pattern with high animal protein and fat is associated with higher postprandial 1-h glucose levels in Chinese pregnant women.

Association between postpartum low-carbohydrate-diet scores and glucose levels in Chinese women

OBJECTIVES

Views on the relationship between a low-carbohydrate diet (LCD) and glucose levels are controversial, and no study, to our knowledge, has examined this association in postpartum women. We aimed to explore the association between postpartum LCD scores and glucose levels.

METHODS

We included 500 postpartum women from a prospective cohort study in Guangzhou, China, during 2017 and 2018. Dietary information during the first month after delivery was assessed via a validated food frequency questionnaire. The overall, animal, and plant LCD scores were determined based on percentages of energy from carbohydrate, protein, and fat. Higher scores reflected higher intakes of fat and protein and lower intakes of carbohydrate. At 6 to 8 wk postpartum, women with previous gestational diabetes mellitus underwent oral glucose tolerance tests (n = 104), and the others had fasting plasma glucose (FPG) tests (n = 396). Multivariable linear, quantile, and logistic regressions were conducted.

RESULTS

Of the 500 participants, 71 (14.20%) developed impaired fasting glucose. Animal LCD score was positively associated with FPG levels (β = 0.007, P = 0.017), but quantile regression showed that LCD scores were related to FPG only in women with lower FPG levels; they had no significant association in those with higher FPG levels. No significant interaction effect on FPG was found between LCD scores and history of gestational diabetes mellitus (P_interaction > 0.40). Furthermore, the relationships between the three LCD scores and risk of developing impaired fasting glucose were not statistically significant.

CONCLUSIONS

Animal LCD score during puerperium may be positively associated with FPG levels in the early postpartum period in Chinese women, but no interactions with history of gestational diabetes mellitus were observed. Stronger associations were observed in women with lower FPG levels.

Impact of dietary counseling on the perception of diet in patients with gestational diabetes mellitus

AIMS/INTRODUCTION

Medical nutrition therapy is the cornerstone of gestational diabetes mellitus (GDM) treatment. Patients with GDM should receive dietary counseling regarding diet and exercise.

MATERIALS AND METHODS

To study patients' perception level of diet and their level of understanding after dietary counseling, we analyzed 225 reports of dietary counseling of patients with GDM prepared by dieticians. We also assessed the patients' level of understanding after dietary counseling by asking questions regarding the counseling content. The answers to the questions were aggregated, and substantially similar answers were grouped and categorized.

RESULTS

The dieticians' suggestions were well understood by the patients. Moreover, the patients also identified their previous incorrect eating habits, such as excessive carbohydrate restriction or inappropriate fruit intake. Although distributed frequent meals were recommended by the dieticians, few patients actually practiced this for various reasons. Some patients were apparently influenced by dietary information from the mass media.

CONCLUSION

Dietary counseling was regarded as helpful and acceptable to most patients with GDM in our hospital, and many suggestions were recognized as informative for modification of previous dietary habits. By providing the results of the questionnaire survey to the dieticians, they can improve the quality of their counseling, which is expected to result in better individual care of the patients.

Beyond protein intake: does dietary fat intake in the year preceding pregnancy and during pregnancy have an impact on gestational diabetes mellitus?

Purpose

Studies regarding the association between dietary fat intake and gestational diabetes mellitus (GDM) are limited and provide conflicting findings. Thus, the study aims to examine the association of dietary fat intake in the year preceding pregnancy and during pregnancy with the risk of GDM, taking the relevance of dietary protein intake on GDM into consideration.

Methods

A prospective study was conducted in 6299 singleton pregnancies, using the data from the Nutrition in Pregnancy and Growth in Southwest China (NPGSC). A validated food frequency questionnaire was used to assess dietary fat intake in the year preceding pregnancy and during the first and second trimesters of pregnancy. Logistic regression analysis was used to assess the prospective associations of dietary fat intake and the type and source of dietary fats in different time windows with GDM risk.

Results

Higher intake of total fat [OR (95% CI): 2.21 (1.19–4.20), P = 0.02] during 12–22 weeks of gestation was associated with higher GDM risk. However, adjustment for animal protein intake greatly attenuated this association [OR (95% CI): 1.81 (0.93, 3.64), P = 0.11]. Total fat intake neither in the year preceding pregnancy nor during the early pregnancy was associated with GDM risk. Moreover, insignificant associations were observed between intakes of vegetable fat, animal fat, cholesterol, saturated fatty acid, monounsaturated fatty acid and polyunsaturated fatty acid one year before pregnancy and during the first and second trimesters and GDM risk.

Conclusion

Our study indicated that dietary fat intake one year before pregnancy and across the two pregnancy trimesters preceding the diagnosis of GDM has no relevance on GDM risk among Chinese women, particularly those with normal BMI, low, or normal calorie intake.

Western Dietary Patterns, Foods, and Risk of Gestational Diabetes Mellitus: A Systematic Review and Meta-Analysis of Prospective Cohort Studies

An increasing number of epidemiological studies suggest that adherence to Western dietary patterns (WDPs) is associated with risk of gestational diabetes mellitus (GDM), but results remain inconsistent. Therefore, we conducted a systematic review and meta-analysis of the effect of WDPs and typical Western dietary foods on GDM. A literature search was performed in PubMed, Embase, Web of Knowledge, and the Cochrane Library up to December 2019. Cohort studies investigating the combined associations of WDPs with incidence of GDM were included. Reviewers were paired, and they independently reviewed and assessed studies, extracted data, and evaluated study quality. Pooled HRs were calculated using random-effects models. Heterogeneity and publication bias tests were also conducted. Twenty-one prospective cohort studies with 191,589 participants, including 12,331 women with GDM, were included in our analysis. The pooled risk ratio (RR) of WDPs was 1.52 (95% CI: 1.21, 1.91), indicating a significant association with GDM risk in Western countries. Potatoes (pooled RR: 1.12; 95% CI: 0.93, 1.35) showed a nonsignificant (P > 0.05) relation to GDM risk. However, consumption of animal meat (pooled RR: 1.35; 95% CI: 1.16, 1.57) and fast food (pooled RR: 1.75; 95% CI: 1.41, 2.19) showed a positive association with the risk of developing GDM. Subgroup analysis demonstrated that the consumption of red meat and processed red meat increased the risk of GDM more than either poultry or fish intake. Our study provides further evidence for understanding the relation between dietary factors and increased GDM risk and contributes to reducing the incidence of GDM through healthy diets.

Dietary patterns and associations between air pollution and gestational diabetes mellitus

The prevalence of gestational diabetes mellitus (GDM) has been increasing worldwide. Dietary patterns and air pollution are closely related to the occurrence of GDM. No previous study has explored the interaction effect of air pollution exposure and dietary patterns on GDM. We explored the interaction effect between main dietary patterns and pre-pregnancy exposure to air pollution on the development of GDM based on a prospective birth cohort in Northeast China. A total of 2244 participants were included in this study. Factor analysis was used to identify dietary patterns. We found that long-term exposure to nitrogen dioxide (NO₂) and carbon monoxide (CO) before pregnancy was significantly associated with an increased risk of GDM; the animal foods pattern significantly modified these associations. The sub-group analysis showed that compared with a lower intake in the animal foods pattern (NO₂, odds ratio [OR] = 1.07, 95% confidence interval [CI]: 0.84, 1.35; CO, OR = 1.05, 95% CI: 0.81, 1.34), higher intake in the animal foods pattern (NO₂, OR = 1.41, 95% CI: 1.09, 1.83; CO, OR = 1.36, 95% CI: 1.05, 1.76) before pregnancy increased the hazardous effects of NO₂ and CO on GDM development. The intake of animal blood, animal organs, preserved eggs, and processed meat products in animal food pattern could all aggravate the effect of exposure to air pollution due to NO₂ and CO on GDM. Our study demonstrated that there was a significant interaction effect between animal foods pattern and exposure to air pollution on GDM. These results provide further scientific evidence of the associations among air pollution, dietary intake, and GDM, and may help as well as the prevention of GDM.

Low-carbohydrate diets and the risk of pancreatic cancer: a large prospective cohort study

Low-carbohydrate diets have become a popular approach for weight loss in recent years. However, whether low-carbohydrate diets are associated with the risk of pancreatic cancer remains to be elucidated. Hence, we examined the association of low-carbohydrate diets with the risk of pancreatic cancer in a US population. A population-based cohort of 95 962 individuals was identified. A low-carbohydrate-diet score was calculated to quantify adherence to this dietary pattern, with higher scores indicating greater adherence. Cox regression was used to calculate risk estimate for the association of the low-carbohydrate-diet score with the risk of pancreatic cancer. Subgroup analysis was used to identify the potential effect modifiers. After an average follow-up of 8.87 years (875856.9 person-years), we documented a total of 351 pancreatic cancer cases. In the fully adjusted model, the highest versus the lowest quartiles of the overall low-carbohydrate-diet score were found to be associated with a reduced risk of pancreatic cancer (hazard ratioquartile 4 versus 1: 0.61; 95% confidence interval: 0.45, 0.82; Ptrend < 0.001). Subgroup analysis found that the inverse association of low-carbohydrate diets with the risk of pancreatic cancer was more pronounced in individuals aged ≥65 years than in those aged <65 years (Pinteraction = 0.015). Similar results were obtained for animal and vegetable low-carbohydrate-diet scores. In conclusion, low-carbohydrate diets, regardless of the type of protein and fat, are associated with a lower risk of pancreatic cancer in the US population, suggesting that adherence to low-carbohydrate diets may be beneficial for pancreatic cancer prevention. Future studies should validate our findings in other populations.

Lower carbohydrate and higher fat intakes are associated with higher hemoglobin A1c: findings from the UK National Diet and Nutrition Survey 2008-2016

PURPOSE

Evidence of low-carbohydrate, high-fat diets (LCHF) for type 2 diabetes (T2DM) prevention is scarce. We investigated how carbohydrate intake relates to HbA1c and T2DM prevalence in a nationally representative survey dataset.

METHODS

We analyzed dietary information (4-day food diaries) from 3234 individuals aged ≥ 16 years, in eight waves of the UK National Diet and Nutrition Survey (2008-2016). We calculated LCHF scores (0-20, higher score indicating lower  %food energy from carbohydrate, with reciprocal higher contribution from fat) and UK Dietary Reference Value (DRV) scores (0-16, based on UK dietary recommendations). Associations between macronutrients and diet scores and diabetes prevalence were analyzed (in the whole sample) using multivariate logistic regression. Among those without diabetes, analyses between exposures and %HbA1c (continuous) were analyzed using multivariate linear regression. All analyses were adjusted for age, sex, body mass index, ethnicity, smoking status, total energy intake, socioeconomic status and survey years.

RESULTS

In the overall study sample, 194 (6.0%) had diabetes. Mean intake was 48.0%E for carbohydrates, and 34.9%E for total fat. Every 5%E decrease in carbohydrate, and every 5%E increase in fat, was associated with 12% (95% CI 0.78-0.99; P = 0.03) and 17% (95% CI 1.02-1.33; P = 0.02) higher odds of diabetes, respectively. Each two-point increase in LCHF score is related to 8% (95% CI 1.02-1.14; P = 0.006) higher odds of diabetes, while there was no evidence for association between DRV score and diabetes. Among the participants without diagnosed diabetes (n = 3130), every 5%E decrease in carbohydrate was associated with higher %HbA1c by + 0.016% (95% CI 0.004-0.029; P = 0.012), whereas every 5%E increase in fat was associated with higher  %HbA1c by + 0.029% (95% CI 0.015-0.043; P < 0.001). Each two-point increase in LCHF score is related to higher  %HbA1c by + 0.010% (0.1 mmol/mol), while each two-point increase in the DRV score is related to lower  %HbA1c by - 0.023% (0.23 mmol/mol).

CONCLUSIONS

Lower carbohydrate and higher fat intakes were associated with higher HbA1c and greater odds of having diabetes. These data do not support low(er) carbohydrate diets for diabetes prevention.

A moderate-carbohydrate diet with plant protein is inversely associated with cardiovascular risk factors: the Korea National Health and Nutrition Examination Survey 2013-2017

Background

Because a moderate-carbohydrate diet reportedly has minimal risks, the substitution of carbohydrate for protein has been emphasized. Few studies have explored the effect of moderate-carbohydrate diets with higher protein intake in Asians, who typically consume a high-carbohydrate low-fat diet. Therefore, this study evaluated the associations of moderate- versus high- carbohydrate diets with cardiovascular risk factors among Korean adults by protein source.

Methods

This study included 7965 adults (3196 men, 4769 women) aged ≥ 19 years who participated in the 2013–2017 Korea National Health and Nutrition Examination Survey. Dietary intake was assessed by a 24-h recall method and four types of diet were defined: a moderate-carbohydrate diet with plant protein (MCP) or animal protein (MCA) and a high-carbohydrate diet with plant protein (HCP) or animal protein (HCA).

Results

Compared with the MCP group, men in the other three groups had significantly higher odds ratios (ORs) for elevated total cholesterol, reduced high-density lipoprotein (HDL)-cholesterol, and metabolic syndrome. Among women, only the HCP group had an increased OR for reduced HDL-cholesterol, compared with the MCP group. Similar associations were observed in younger adults (19–49 years). In addition, younger adults in the MCA group exhibited higher ORs for elevated triglycerides in men and elevated total cholesterol in women, compared with those in the MCP group.

Conclusions

A moderate-carbohydrate diet with a high intake of plant protein was inversely associated with cardiovascular risk factors, especially among younger Korean adults. Further intervention studies are required to confirm this relationship and develop the optimal diet for cardiovascular health in the Korean population.

Associations of dietary protein intake with all-cause, cardiovascular disease, and cancer mortality: A systematic review and meta-analysis of cohort studies

BACKGROUND AND AIMS

The relationships between dietary protein intake and risk of all-cause, cardiovascular disease (CVD), and cancer mortality are still unclear. We conducted a systematic review with meta-analysis of cohort studies to summarize the evidence.

METHODS AND RESULTS

We searched PubMed and Web of Science for relevant studies through February 2020. The associations of total, animal, and plant proteins with all-cause, CVD, and cancer mortality were evaluated. Study-specific relative risks (RR) were pooled using the fixed effect model when no significant heterogeneity was detected; otherwise the random effect model was employed. Twelve cohort studies were eligible for the study. Increased total protein showed no clear association with risk of all-cause, CVD, and cancer mortality. In the stratified analysis by protein sources, higher plant protein intake was associated with a reduced risk of all-cause mortality (highest vs lowest intake: RR = 0.92; 95% CI: 0.88, 0.96; each 3% increment of intake: RR = 0.97; 95% CI: 0.94, 0.99), and may be associated with a reduced risk of CVD mortality (highest vs lowest intake: RR = 0.90; 95% CI: 0.80, 1.01; each 3% increment of intake: RR = 0.95; 95% CI: 0.91, 0.99). Moreover, higher intake of animal protein may be associated with an increased risk of CVD mortality (highest vs lowest intake: RR = 1.11; 95% CI: 1.01, 1.22; each 3% increment of intake: RR = 1.02; 95% CI: 0.98, 1.06).

CONCLUSION

This study demonstrates that higher plant protein intake is associated with a reduced risk of all-cause and CVD-related mortality. Persons should be encouraged to increase their plant protein intake to potentially decrease their risk of death.

Carbohydrate restriction in midlife is associated with higher risk of type 2 diabetes among Australian women: A cohort study

BACKGROUND AND AIMS

Low-carbohydrate diets (LCDs) are increasingly popular but may be nutritionally inadequate. We aimed to examine if carbohydrate restriction in midlife is associated with risk of developing type 2 diabetes (T2DM), and if this association differs by previous gestational diabetes (GDM) diagnosis.

METHODS AND RESULTS

Dietary intake was assessed for 9689 women from the Australian Longitudinal Study on Women's Health in 2001 (aged 50-55) and 2013 (aged 62-67) via validated food frequency questionnaires. Average long-term carbohydrate restriction was assessed using a low-carbohydrate diet score (highest quartile (Q4) indicating lowest proportion of energy from carbohydrates). Incidence of T2DM between 2001 and 2016 was self-reported at 3-yearly surveys. Log-binomial regression was used to estimate relative risks (RR) and 95% CIs. During 15 years of follow-up, 959 women (9.9%) developed T2DM. Carbohydrate restriction was associated with T2DM after adjustment for sociodemographic factors, history of GDM diagnosis and physical activity (Q4 vs Q1: RR 1.27 [95% CI 1.10, 1.48]), and this was attenuated when additionally adjusted for BMI (1.10 [0.95, 1.27]). Carbohydrate restriction was associated with lower consumption of fruit, cereals and high-fibre bread, and lower intakes of these food groups were associated with higher T2DM risk. Associations did not differ by history of GDM (P for interaction >0.15).

CONCLUSION

Carbohydrate restriction was associated with higher T2DM incidence in middle-aged women, regardless of GDM history. Health professionals should advise women to avoid LCDs that are low in fruit and grains, and to consume a diet in line with current dietary recommendations.

Low and reduced carbohydrate diets: challenges and opportunities for type 2 diabetes management and prevention

Low-carbohydrate diets (LCD) have been promoted for weight control and type 2 diabetes (T2D) management, based on an emerging body of evidence, including meta-analyses with an indication of publication bias. Proposed definitions vary between 50 and 130 g/d, or <10 and <40 % of energy from carbohydrate, with no consensus on LCD compositional criteria. LCD are usually followed with limited consideration for other macronutrients in the overall diet composition, introducing variance in the constituent foods and in metabolic responses. For weight management, extensive evidence supports LCD as a valid weight loss treatment, up to 1-2 years. Solely lowering carbohydrate intake does not, in the medium/long term, reduce HbA1c for T2D prevention or treatment, as many mechanisms interplay. Under controlled feeding conditions, LCD are not physiologically or clinically superior to diets with higher carbohydrates for weight-loss, fat loss, energy expenditure or glycaemic outcomes; indeed, all metabolic improvements require weight loss. Long-term evidence also links the LCD pattern to increased CVD risks and mortality. LCD can lead to micronutrient deficiencies and increased LDL-cholesterol, depending on food selection to replace carbohydrates. Evidence is limited but promising regarding food choices/sources to replace high-carbohydrate foods that may alleviate the negative effects of LCD, demanding further insight into the dietary practice of medium to long term LCD followers. Long-term, high-quality studies of LCD with different food sources (animal and/or plant origins) are needed, aiming for clinical endpoints (T2D incidence and remission, cardiovascular events, mortality). Ensuring micronutrient adequacy by food selection or supplementation should be considered for people who wish to pursue long-term LCD.

Animal based low carbohydrate diet is associated with increased risk of type 2 diabetes in Tehranian adults

BACKGROUND

To investigate the association of low carbohydrate diet (LCD) score with the risk of type 2 diabetes among adults.

METHODS

This cohort study was conducted on 4356 healthy participants aged ≥ 19 years old, who were followed-up for a mean duration of 3 years within the framework of the Tehran Lipid and Glucose Study. LCD score was calculated using a food frequency questionnaire according to intake of carbohydrate, protein, and fat at baseline. Diabetes was defined according to the criteria of the American Diabetes Association. Multivariable logistic regression models, adjusted for potential confounders, were used to estimate risk of diabetes across quartiles of LCD score.

RESULTS

Mean ± SD age of the study participants (44.4% men) was 40.5 ± 13.0 years. The median (25-75 interquartile range) of LCD score was 17.0 (12.0-21.0) and after a 3 year follow-up period, 123 (2.8%) incident cases of diabetes were ascertained. After adjustment for confounding variables, including age, sex, smoking status, physical activity, total calorie intake, saturated fatty acid, waist circumference, educational level, and family history of diabetes, the multivariable-adjusted ORs (95% CIs) of type 2 diabetes, comparing the highest with the lowest quartiles, were 2.16 (1.16-4.04) for total LCD score (P-value = 0.015), 1.81 (1.06-3.11) for animal-based LCD score (P-value = 0.029), and 1.47 (0.85-2.52) for plant-based LCD score (P-value = 0.160).

CONCLUSION

Our findings suggest that a higher adherence to LCD, mostly with higher intakes of protein and fat from animal-source foods, can increase the incidence of diabetes; however, a plant-based low-carbohydrate dietary pattern is not significantly associated with risk of type 2 diabetes.

The Role of Diet in the Prevention of Diabetes among Women with Prior Gestational Diabetes: A Systematic Review of Intervention and Observational Studies

BACKGROUND

Women with prior gestational diabetes (GDM) have an increased lifetime risk of developing type 2 diabetes mellitus (T2DM). There are no up-to-date systematic reviews analyzing the relationship of diet with risk of developing T2DM following GDM.

OBJECTIVE

To systematically review the evidence from intervention and observational studies on effects of dietary interventions and associations of dietary intake with T2DM outcomes in women with a GDM history.

METHODS

Six electronic databases were searched (Cumulative Index to Nursing and Allied Health Literature, Embase, Medline, Cochrane Central, Proquest, and Scopus) for articles published until May 2019. This review includes intervention and observational studies among women of any age with a history of GDM that reported on the effects of dietary interventions or association of dietary intake (energy, nutrients, foods, dietary patterns) with T2DM, impaired glucose tolerance, impaired fasting glucose, or prediabetes.

RESULTS

The systematic review identified five articles reporting results from four intervention studies, and seven articles reporting results from four observational studies. Findings from intervention studies indicated trends toward beneficial effects of a low-glycemic index diet, a low-carbohydrate diet, and a diet in line with general population dietary guidelines, but studies had unclear or high risk of bias. Findings from two cross-sectional and one prospective study indicated poorer diabetes outcomes for women with higher intakes of branched-chain amino acids, total and heme iron, and a diet relatively low in carbohydrates and high in animal fat and protein, and better outcomes among those consuming diets rich in fruit, vegetables, nuts, fish, and legumes, and low in red and processed meats and sugar-sweetened beverages, after adjustment for confounders, including body mass index.

CONCLUSIONS

Findings from observational studies support current dietary guidelines for the prevention of T2DM. Further dietary intervention studies are needed to confirm whether or not dietary modification following a GDM pregnancy reduces women's risk of developing T2DM.

Low-Carbohydrate Diets for Gestational Diabetes

Nutrition therapy provides the foundation for treatment of gestational diabetes (GDM), and has historically been based on restricting carbohydrate (CHO) intake. In this paper, randomized controlled trials (RCTs) are reviewed to assess the effects of both low- and higher CHO nutrition approaches in GDM. The prevailing pattern across the evidence underscores that although CHO restriction improves glycemia at least in the short-term, similar outcomes could be achievable using less restrictive approaches that may not exacerbate IR. The quality of existing studies is limited, in part due to dietary non-adherence and confounding effects of treatment with insulin or oral medication. Recent evidence suggests that modified nutritional manipulation in GDM from usual intake, including but not limited to CHO restriction, improves maternal glucose and lowers infant birthweight. This creates a platform for future studies to further clarify the impact of multiple nutritional patterns in GDM on both maternal and infant outcomes.

Diabetes & Women's Health (DWH) Study: an observational study of long-term health consequences of gestational diabetes, their determinants and underlying mechanisms in the USA and Denmark

PURPOSE

Women who experience gestational diabetes mellitus (GDM) are at exceptionally high-risk of developing type 2 diabetes (T2DM) later in life. However, limited information is available about genetic and environmental factors that are implicated in the progression from GDM to T2DM.

PARTICIPANTS

The Diabetes & Women's Health (DWH) Study applied a hybrid design, which combined new prospective data collection with existing data in two prospective cohorts, the Danish National Birth Cohort (DNBC) and the Nurses' Health Study II (NHS II). In total, the DWH Study identified 7759 women with a GDM diagnosis from both cohorts; 4457 women participated in the DWH Study data collection, which included two cycles of follow-up from 2012 to 2014 and 2014 to 2016.

FINDINGS TO DATE

Progression from GDM to T2DM was high. In the NHS II group, by 2013, 23.1% (n=846/3667) developed T2DM. In the DNBC group, at cycle 1 (2012-2014), the progression rate was even higher: 27.2% (n=215/790) had developed T2DM. Furthermore, we have shown that women who had GDM experienced a significantly greater risk of hypertension and cardiovascular diseases, as well as early stages of glomerular hyperfiltration and renal damage. Moreover, the DWH Study findings have shown that healthful diet and lifestyle factors and weight control were related to a lower risk of T2DM, hypertension and cardiovascular diseases.

FUTURE PLANS

Primary data collection for the DWH Study is complete and investigators are currently investigating interactions of the abovementioned modifiable factors with T2DM genetic susceptibility in determining the risk of progression from GDM to T2DM. Findings from ongoing work will provide further insights for identifying more precise prevention strategies for T2DM and comorbidities in this high-risk population. Future work will examine novel biomarkers of health and disease in this cohort.

Low-carbohydrate diets for overweight and obesity: a systematic review of the systematic reviews

Low-carbohydrate diets are being widely recommended, but with apparently conflicting evidence. We have conducted a formal systematic review of the published systematic reviews of RCTs between low-carbohydrate vs. control (low-fat/energy-restricted) diets in adults with overweight and obesity. In MEDLINE, Embase, Web of Knowledge and Cochrane Database of Systematic Reviews, searched from inception to September 2017, we identified 12 systematic reviews, 10 with meta-analyses. Differences in methods, study quality, weight change and citations of published systematic reviews were assessed by AMSTAR-2. Review methods varied in definitions of low-carbohydrate diet, databases searched and bias assessment. Overall review quality was high in two, moderate in three, critically low in seven. Among meta-analyses, 4/5 with critically low quality showed low-carbohydrate diet superiority for weight loss (0.7-4.0 kg), while high quality meta-analyses reported little or no difference between diets. Greater numbers of participants correlated with smaller differences in weight loss (r = 0.73, p = 0.03). More citations correlated with lower review quality (rho = -0.9, p = 0.037), with larger differences in weight loss (rho = -0.9, p = 0.037), and with journal impact factor (rho = 1.0, p = 0.01). In conclusion, publication acceptance and citations appear to favour apparently larger effect sizes above methodological quality. Better quality reviews and RCTs are needed, before recommending low-carbohydrate diets as preferred to other approaches for energy restriction.

Dietary Intakes and Circulating Concentrations of Branched-Chain Amino Acids in Relation to Incident Type 2 Diabetes Risk Among High-Risk Women with a History of Gestational Diabetes Mellitus

BACKGROUND

Circulating branched-chain amino acids (BCAAs; isoleucine, leucine, valine) are consistently associated with increased type 2 diabetes (T2D) risk, but the relationship with dietary intake of BCAAs is less clear.

METHODS

The longitudinal Nurses' Health Study II cohort conducted a blood collection from 1996 to 1999. We profiled plasma metabolites among 172 incident T2D cases and 175 age-matched controls from women reporting a history of gestational diabetes before blood draw. We estimated dietary energy-adjusted BCAAs from food frequency questionnaires. We used conditional logistic regression models to estimate odds ratios (OR) and 95% CI of T2D risk across quartiles (Q1-Q4) of BCAAs, adjusting for age, body mass index (BMI), physical activity, family history, and other established risk factors. We also assessed joint exposure to below/above medians of diet and plasma concentrations, with lower diet/lower plasma as reference.

RESULTS

Dietary and plasma BCAA concentrations were positively associated with incident T2D (diet Q4 vs Q1 OR = 4.6, CI = 1.6, 13.4; plasma Q4 vs Q1 OR = 4.4, CI = 1.4, 13.4). Modeling the joint association indicated that higher diet BCAAs were associated with T2D when plasma concentrations were also higher (OR = 6.0, CI = 2.1, 17.2) but not when concentrations were lower (OR = 1.6, CI = 0.61, 4.1). Conversely, higher plasma BCAAs were associated with increased T2D for either lower or higher diet.

CONCLUSIONS

Independent of BMI and other risk factors, higher diet and plasma BCAA concentrations were associated with an increased incident T2D risk among high-risk women with a history of gestational diabetes, supporting impaired BCAA metabolism as conferring T2D risk.

Associations of Diet and Physical Activity with Risk for Gestational Diabetes Mellitus: A Systematic Review and Meta-Analysis

Rising rates of gestational diabetes mellitus (GDM) and related complications have prompted calls to identify potentially modifiable risk factors that are associated with gestational diabetes mellitus (GDM). We systematically reviewed the scientific literature for observational studies examining specific dietary and/or physical activity (PA) factors and risk of GDM. Our search included PubMed, Medline, CINAHL/EBSCO, Science Direct and EMBASE, and identified 1167 articles, of which 40 met our inclusion criteria (e.g., singleton pregnancy, reported diet or PA data during pre-pregnancy/early pregnancy and GDM as an outcome measure). Studies were assessed for quality using a modified Quality Criteria Checklist from American Dietetic Association. Of the final 40 studies, 72% obtained a positive quality rating and 28% were rated neutral. The final analysis incorporated data on 30,871 pregnant women. Dietary studies were categorised into either caffeine, carbohydrate, fat, protein, calcium, fast food and recognized dietary patterns. Diets such as Mediterranean Diet (MedDiet), Dietary Approaches to Stop Hypertension (DASH) diet and Alternate Healthy Eating Index diet (AHEI) were associated with 15–38% reduced relative risk of GDM. In contrast, frequent consumption of potato, meat/processed meats, and protein (% energy) derived from animal sources was associated with an increased risk of GDM. Compared to no PA, any pre-pregnancy or early pregnancy PA was associated with 30% and 21% reduced odds of GDM, respectively. Engaging in >90 min/week of leisure time PA before pregnancy was associated with 46% decreased odds of GDM. We conclude that diets resembling MedDiet/DASH diet as well as higher PA levels before or in early pregnancy were associated with lower risks or odds of GDM respectively. The systematic review was registered at PROSPERO (www.crd.york.ac.uk/PROSPERO) as CRD42016027795.

Unsatisfactory Glucose Management and Adverse Pregnancy Outcomes of Gestational Diabetes Mellitus in the Real World of Clinical Practice: A Retrospective Study

BACKGROUND

Facing the increasing prevalence of gestational diabetes mellitus (GDM), this study aimed to evaluate the management of GDM and its association with adverse pregnancy outcomes.

METHODS

The data of 996 inpatients with GDM who terminated pregnancies in our hospital from January 2011 to December 2015 were collected. Treatments during pregnancy and the last hospital admission before delivery were analyzed. Pregnancy outcomes of the GDM patients were compared with 996 nondiabetic subjects matched by delivery year and gestational age. The association between fasting plasma glucose (FPG) and adverse pregnancy outcomes was examined by logistic regression analyses.

RESULTS

The average prevalence of GDM over the 5 years was 4.4% (1330/30,191). Within the GDM patients, 42.8% (426/996) received dietary intervention, whereas 19.1% (190/996) received insulin treatment. Adverse outcomes were more likely to occur in patients with unsatisfactory control of blood glucose such as respiratory distress syndrome (RDS, χ2 = 13.373, P < 0.01). Elevated FPG was identified as an independent risk factor for premature birth (odds ratio [OR] = 1.460, P < 0.001), neonatal care unit admission (OR = 1.284, P < 0.001), RDS (OR = 1.322, P = 0.001), and stillbirth (OR = 1.427, P < 0.001).

CONCLUSIONS

Management of GDM in the real world of clinical practice was unsatisfactory, which might have contributed to adverse pregnancy outcomes.

Improving cardiometabolic and mental health in women with gestational diabetes mellitus and their offspring: study protocol for MySweetHeart Trial, a randomised controlled trial

INTRODUCTION

Gestational diabetes mellitus (GDM) carries prenatal and perinatal risk for the mother and her offspring as well as longer-term risks for both the mother (obesity, diabetes, cardiovascular disease) and her child (obesity, type 2 diabetes). Compared with women without GDM, women with GDM are twice as likely to develop perinatal or postpartum depression. Lifestyle interventions for GDM are generally limited to physical activity and/or nutrition, often focus separately on the mother or the child and take place either during or after pregnancy, while their results are inconsistent. To increase efficacy of intervention, the multifactorial origins of GDM and the tight link between mental and metabolic as well as maternal and child health need to be heeded. This calls for an interdisciplinary transgenerational approach starting in, but continuing beyond pregnancy.

METHODS AND ANALYSIS

This randomised controlled trial will assess the effect of a multidimensional interdisciplinary lifestyle and psychosocial intervention aimed at improving the metabolic and mental health of 200 women with GDM and their offspring. Women with GDM at 24-32 weeks gestational age who understand French or English, and their offspring and partners can participate. The intervention components will be delivered on top of usual care during pregnancy and the first year postpartum. Metabolic and mental health outcomes will be measured at 24-32 weeks of pregnancy, shortly after birth and at 6-8 weeks and 1 year after childbirth. Data will be analysed using intention-to-treat analyses. The MySweetHeart Trial is linked to the MySweetHeart Cohort (clinicaltrials.gov/ct2/show/NCT02872974).

ETHICS AND DISSEMINATION

We will disseminate the findings through regional, national and international conferences and through peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT02890693; Pre-results.

Impact of Dietary Fiber Consumption on Insulin Resistance and the Prevention of Type 2 Diabetes

Large prospective cohort studies consistently show associations of a high dietary fiber intake (>25 g/d in women and >38 g/d in men) with a 20-30% reduced risk of developing type 2 diabetes (T2D), after correction for confounders. It is less well recognized that these effects appear to be mainly driven by high intakes of whole grains and insoluble cereal fibers, which typically are nonviscous and do not relevantly influence postprandial glucose responses [i.e., glycemic index (GI)] or are strongly fermented by the gut microbiota in the colon. In contrast, a dietary focus on soluble, viscous, gel-forming, more readily fermentable fiber intakes derived from fruit and certain vegetables yields mixed results and generally does not appear to reduce T2D risk. Although disentangling types of fiber-rich foods and separating these from possible effects related to the GI is an obvious challenge, the common conclusion that key metabolic effects of high-fiber intake are explained by mechanisms that should mainly apply to the soluble, viscous type can be challenged. More recently, studies in humans and animal models focused on gaining mechanistic insights into why especially high-cereal-fiber (HCF) diets appear to improve insulin resistance (IR) and diabetes risk. Although effects of HCF diets on weight loss are only moderate and comparable to other types of dietary fibers, possible novel mechanisms have emerged, which include the prevention of the absorption of dietary protein and modulation of the amino acid metabolic signature. Here we provide an update of our previous review from 2008, with a focus on mechanistic insights of how HCF diets may improve IR and the risk of developing T2D.

Carbohydrate craving: not everything is sweet

PURPOSE OF REVIEW

Cravings for carbohydrates have been known about for hundreds of years but the mechanisms behind it were unclear. This review will highlight recent advances in our knowledge of mechanisms to detect carbohydrates in the diet.

RECENT FINDINGS

Recent work has begun to identify the physiological mechanisms by which carbohydrates and glucose are detected and how this drives their intake. Recently, evidence has been found for systems that regulate carbohydrate and glucose intake via taste, hedonic, and homeostatic pathways.

SUMMARY

Identification of the physiological mechanisms that regulate carbohydrate intake will allow a better understanding of how their intake is regulated and responds to changes in dietary intake. Such an understanding will be a key for developing a more rational approach to the development of successful weight loss diets.

Gestational Diabetes Mellitus:current knowledge and unmet needs

Gestational diabetes mellitus (GDM) is a global health concern, not only because its prevalence is high and on the increase, but also because of the potential implications for the health of mothers and their offspring. Unfortunately, there is considerable controversy in the literature surrounding the diagnosis and treatment of GDM, as well as the possible long-term consequences for the offspring. As a result, worldwide there is a lack of uniformly accepted diagnostic criteria and the advice regarding the treatment of GDM, including diet, insulin therapy, and the use of oral blood glucose-lowering agents, is highly variable. In this review we provide an overview of the important issues in the field of GDM, including diagnostic criteria, different treatment regimens available, and the long-term consequences of GDM in the offspring.

Contributions of the Nurses' Health Studies to Reproductive Health Research

OBJECTIVES

To review the Nurses' Health Study's (NHS's) contribution to identifying risk factors and long-term health consequences of reproductive events.

METHODS

We performed a narrative review of the NHS I, NHS II, NHS3, and Growing Up Today Study (GUTS) publications between 1976 and 2016.

RESULTS

Collection of detailed reproductive history to identify breast cancer risk factors allowed the NHS to document an association between menstrual irregularities, a proxy for polycystic ovary syndrome (PCOS), and increased risk of diabetes and cardiovascular disease. The NHS II found that infertility associated with ovulation problems and gestational diabetes are largely preventable through diet and lifestyle modification. It also identified developmental and nutritional risk factors for pregnancy loss, endometriosis, and uterine leiomyomata. As women in NHS II age, it has become possible to address questions regarding long-term health consequences of pregnancy complications and benign gynecologic conditions on chronic disease risk. Furthermore, the NHS3 and GUTS are allowing new lines of research into human fertility, PCOS, and transgenerational effects of environmental exposures.

CONCLUSIONS

The multigenerational resources of the NHSs and GUTS, including linkages of related individuals across cohorts, can improve women's health from preconception through late adulthood and onto the next generation.