A new research project will look back a generation to investigate whether the epigenetic expression of future parents with obesity can be altered before pregnancy – and thereby reduce the risk of their future children developing metabolic diseases. More knowledge in this field will improve the understanding of early intervention initiatives to counteract overweight among children and adolescents.
Children and adolescents develop overweight through complex interaction of physical, mental and social factors according to Forebyggelse af overvægt blandt børn og unge, (Preventing obesity among children and young people) published in Danish in 2021 by Vidensråd for Forebyggelse (Danish Knowledge Council for Prevention).
The report compiles the current best knowledge on the development of overweight among children and adolescents and concludes that no strong evidence indicates that the existing interventions used to prevent overweight are effective. One reason may be that the preventive efforts begin after the child has been conceived – which is simply too late.
A new research project, Pre-pregnancy Weight Loss and Reducing Childhood Overweight (PREPARE CHILD), will therefore look back a generation to investigate whether lifestyle interventions can alter the epigenetic expression of future parents to reduce the risk of their children developing obesity and other metabolic conditions such as diabetes and heart disease.
“Epigenetics is how our genes are expressed. A person with a specific type of epigenetic expression has an increased risk of some diseases. Interventions can change the epigenetics, and we can reduce or increase the risk of developing diseases later in life,” explains Nina Geiker, Associate Professor, Department of Exercise, Nutrition and Sports, University of Copenhagen, who is carrying out the PREPARE CHILD project in collaboration with Aarhus University Hospital and Hvidovre Hospital.
Investigating future mothers and fathers
PREPARE CHILD is an intervention study in which half the participants will be selected to follow a weight-loss programme before pregnancy, and the other half will comprise a control group.
A total of 240 men and women are involved in the project. Of these, 120 will participate in the intervention group, in which both men and women are supposed to lose 10% of their body weight before a planned pregnancy. The actual weight loss happens through a low-calorie diet – better known as a powder regimen. After weight loss, both men and women receive expert guidance from dietitians on how to best maintain their weight loss, even during a future pregnancy.
The remaining 120 people will be divided into two control groups*. One group will receive guidance according to the recommendations, and the other will be monitored without either intervention or guidance. The trial participants will also undergo measurement for sperm quality (for men), microbiology in the vagina (for women), body composition and blood markers.
Unlike most other studies that focus on preventing overweight in connection with pregnancy, PREPARE CHILD involves both women and men, since the epigenetic expression of both parents is relevant to the future child.
“Even though the woman is pregnant, the future father is very much involved in creating the new child. After all, he provides 50% of the child’s genome. So far, there has not been much focus on fathers in the studies we have done. This may be one reason why the studies have not shown effectiveness, because we have only had half the data. In addition, fathers also have a strong motivating effect on the mothers. If you have a joint project to create a child as a family, then you will also be more motivated to adhere to the intervention,” says Nina Geiker.
Dietary changes among pregnant women lead to considerable improvements
Overweight and especially obesity among pregnant women are associated with a greater risk of the child developing overweight and having comorbidities later in life. There is also a greater chance of complications during pregnancy and in connection with the birth itself.
Nina Geiker previously studied how changing dietary habits among pregnant women with overweight can affect both mother and child. This happened most recently in the APPROACH study, which was also an intervention study. Nina Geiker led an investigation into whether changing dietary habits among pregnant women with overweight could reduce the pregnant women’s body weight, the baby’s birth weight and the risk of complications during pregnancy.
A total of 279 women participated in the study. Half changed their diet, eating a larger proportion of protein and of carbohydrate with a low glycaemic index, taking longer to be absorbed into the blood than other types. The other half acted as a control group.
The results of the study have been published in The American Journal of Clinical Nutrition.
The study showed a significant improvement for the women who followed the dietary change. During pregnancy, they gained 1.7 kilos less than the control group, and they had fewer complications in pregnancy. A startling result of the study was that only about half as many women in the intervention group gave birth by caesarean section as in the control group: 15.4% of the women who followed the dietary change gave birth by caesarean section versus 28.8% of the women in the control group.
The significantly lower number of caesarean sections is a relevant discovery because this type of birth can increase the mother’s risk of infection and the baby’s risk of allergies, asthma and obesity later in life.
The results among pregnant women provided the idea for even earlier interventions
The APPROACH study thus shows that changing the diet of already pregnant women can have several positive outcomes for the mother, but the study showed no significant difference between the intervention group and the control group in the children’s birth weight and other quantitative measurements of newborns.
In an interview with Sundhedspolitisk Tidsskrift, Nina Geiker explains that the results of the study therefore justify considering whether intervening even earlier could prevent overweight among children even more effectively. The results of the APPROACH study therefore form the basis for the new PREPARE CHILD study, in which the researchers expect to be able to influence the epigenetic expression of the mother, the father and the child.
“We hope that we can optimise the epigenetic expression of the parents by making dietary changes and getting them to lose weight. We also hope that we can see changes in the child’s epigenetics – and see how this is physically expressed through the child’s lower fat mass and healthier blood markers in relation to the risk of developing disease,” explains Nina Geiker.
In the latest episode of the Forskningsfortællinger podcast (in Danish) at the top of this article, you can listen to Nina Geiker explain more on the perspectives of the PREPARE CHILD project and how the project is carried out.
The connection between overweight and stigma
The podcast also examines the psychosocial problems many children and young people with overweight often experience, especially those with obesity. According to the report by the Danish Knowledge Council for Prevention, many children and young people with obesity are affected by stigma, bullying and teasing, low self-esteem and reduced quality of life.
Forskningsfortællinger has therefore interviewed Laila Walther, CEO of the Danish Association against Eating Disorders and Self-harm, who is closely involved in combatting the stigmatisation of people with overweight.
*After publication of this article, there has been an adjustment in the design of the project. This means that there will be just one control group instead of two. The control group will not receive dietary guidance but will be examined in the same way as the intervention group.