Low protein intake during pregnancy is related to lower insulin resistance among GDM exposed children
A new study published in the American Journal of Clinical Nutrition by Danish Diabetes Academy Post Doc Ekaterina Maslova, in collaboration with colleagues at Rigshospitalet, University of Iceland, and Aarhus University, aimed to examine the association of maternal protein intake during pregnancy with child metabolic health at age 9-16 years, focusing specifically on a high-risk group of children whose mothers were diagnosed with gestational diabetes (GDM).
The study showed that substituting carbohydrates for protein during pregnancy was related to slightly higher adiposity among GDM-exposed children. Furthermore, low maternal protein intake (<=12.5% of daily energy intake) was associated with lower insulin resistance in this group.
LONG-TERM CONSEQUENCES OF GDM
Gestational diabetes is defined as high blood sugar that develops during pregnancy and usually disappears after birth. It is now fairly well-established that there are both short- and long-term consequences of GDM to women and their children. These include worse metabolic health (e.g. increased adiposity, insulin resistance) and higher risk of type 2 diabetes. Close observation and lifestyle interventions after birth has the potential to reduce the risk of some of the long-term consequences in these children. However, it may be possible to modify the risk already during pregnancy and change the children’s health trajectory before birth.
WHAT IS CURRENTLY KNOWN ABOUT MATERNAL PROTEIN INTAKE IN PREGNANCY AND CHILD METABOLIC HEALTH?
Previous evidence on protein intake in pregnancy has primarily come from animal studies focused on low-protein diets (6-12% of daily energy) and observational data in humans based on general populations. Results from human studies have found a variety of conflicting results. However, these studies were carried out across a wide range of offspring age groups spanning from before birth to age 40, representing different stages of development and health progression. None of these studies included metabolically susceptible populations.
Ekaterina Maslova and her colleagues recently showed that maternal protein intake, especially from animal sources, was related to a higher risk of overweight in 19-21-year-old offspring in a population-based Danish cohort. Accordingly they wanted to examine whether similar association would extend to a group of children who were already at higher risk of poor metabolic outcomes.
MATERNAL PROTEIN INTAKE AT THE EXPENSE OF CARBOHYDRATES ASSOCIATED WITH MODEST INCREASES IN CHILD ABDOMINAL FATTY TISSUE
This study examined 1234 Danish children born 1996-2002 whose mothers had enrolled in the Danish National Birth Cohort. 608 of these children came from a pregnancy affected by GDM and 626 children were random controls. Mother provided information on a variety of sociodemographic and lifestyle factors during the pregnancy, including dietary intake. The children underwent a clinical examination, that included fasting blood samples (to quantify insulin resistance) and dual energy X-ray absorptiometry scan (to measure fatty and lean mass tissue).
After adjusting for potential confounders, higher maternal protein intake at the expense of carbohydrates was associated with a tendency for higher abdominal fat mass %, but not insulin resistance measured through HOMA-IR. Importantly, this was seen only in GDM-exposed children.
LOW MATERNAL PROTEIN INTAKE ASSOCIATED WITH LOWER CHILD INSULIN RESISTANCE
Studies of low protein intake in pregnancy have been done in either experimental conditions in animal labs or extreme situations of human famines. Ekaterina Maslova and her colleagues wanted to determine the association of low protein in a free-living, well-nourished population of pregnant women with metabolic health in their children. They set a cut-off at 12.5% energy from protein, which was the upper limit of intake for the lowest 10% of women. They then compared these women to the remaining 90%.
"Low protein at this level was associated with lower fasting insulin and insulin resistance, but again only among the children exposed to GDM. We noted that this intake level was higher than those studied in animal experiments (6-12% of energy), so we could not exclude that poor metabolic outcomes existed among children whose mothers had much lower protein intake", Ekaterina Maslova states.
WHAT'S NEXT?
According to Ekaterina, this was the first study to examine maternal protein intake as a potential mitigator of child metabolic health in a high-risk group of GDM-exposed children - it would be important to see other studies replicating these findings in a more homogenous population. In this cohort, the age of children varied from 9 to 16 years, and the children were in different stages of puberty. This would have affected both their levels of adiposity and insulin resistance.
"Even though age and puberty were adjusted for in the statistical models, high metabolic variability may have obscured some of the results. Nevertheless, the results raise some important questions around pregnancy dietary interventions in women diagnosed with GDM to improve long-term child health", Ekaterina concludes.
AUTHORS AND AFFILIATIONS
Ekaterina Maslova1-3, Susanne Hansen1, Louise Groth Grunnet4, Marin Strøm1, Anne Ahrendt Bjerregaard1, Line Hjort3-5, Freja Bach Kampmann3,4,6, Camilla Møller Madsen4, AC Baun Thuesen4, Bodil Hammer Bech7, Thorhallur I Halldorsson1,8-9, Allan A. Vaag4-5, Sjurdur F Olsen1,10
1Centre for Fetal Programming, Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark2Department of Epidemiology and Biostatistics, Imperial College, London, UK
3Danish Diabetes Academy, Odense, Denmark
4Department of Endocrinology - Diabetes and Metabolism, Rigshospitalet, Copenhagen Denmark
5Faculty of Health and Medical Sciences, Copenhagen University, Copenhagen, Denmark 6Division for Diet, Disease Prevention and Toxicology, National Food Institute, Technical University of Denmark, Søborg, Denmark
7Section for Epidemiology, Department of Public Health, Aarhus University, Aarhus, Denmark
8Faculty of Food Science and Nutrition, School of Health Sciences, University of Iceland, Reykjavik, Iceland
9Unit for Nutrition Research, Landspitali University Hospital, Reykjavik, Iceland
10Department of Nutrition, Harvard Chan School of Public Health, Boston, MA, USA