Obesity and Metabolic Health
The Obesity and Metabolic Health unit is working to:
- determine the genetic, biochemical and physiological impact of altered nutritional exposures in early life on body fat mass and insulin sensitivity in offspring
- elucidate the mechanisms underlying the early life origins of obesity and metabolic disease
- identify effective nutritional strategies for improving the metabolic health of future generations
- verify the efficacy of these nutritional interventions in humans.
Our research is focused on the role of maternal and infant nutrition, particularly an increased supply of omega-3 fatty acids, in determining body composition and insulin sensitivity of future generations.
The Early Origins of Food Preferences
Whilst there are many factors contributing to the current obesity epidemic, there is no doubt that excessive consumption of high-fat, high-sugar ‘junk foods' plays a major role. It is also clear that some individuals are able to resist the temptation to over-indulge in junk foods, while others find this much more difficult. Recent work from our laboratory has shown that individuals who are exposed to an excessive supply of junk foods before birth or in early infancy are more likely to overconsume junk foods later in life, leading to the idea that an increased preference for junk foods can be set up very early in life. This study will use an animal model to look at how a mother's diet during pregnancy can change the feeding behaviour of her offspring, and the biological mechanisms that lead to these behavioural changes.
Low Glycemic Index Diets for improving maternal and infant outcomes
Modern diets are becoming increasingly enriched in quickly digested carbohydrates which have a high-glycemic index (GI). Compared to low GI diet, high GI diets result in increased glucose concentrations after eating and reductions in insulin sensitivity (a major risk factor for type 2 diabetes). Consequently, switching from a high to low-GI diet positively affects metabolic health, especially glucose control, and is associated with a reduced risk of type 2 diabetes in adults. Exposure to an increased glucose supply before birth or in early infancy results in an increased risk of obesity and type 2 diabetes in child and adult life. However, no studies have determined whether consuming a low-GI diet during pregnancy can improve metabolic outcomes of the offspring. This research will use an animal model to test whether consuming a low-GI diet during pregnancy and lactation can reduce the risk of obesity and insulin resistance in the offspring. This will provide an evidence base for recommending low-GI diets during pregnancy as a means of reducing the risk of type 2 diabetes in future generations of Australians.
The role of omega-6 fatty acids in the early origins of obesity
The omega-6 polyunsaturated fatty acids (n-6 PUFA) are abundant in vegetable oils and spreads and are consumed in high amounts as part of the typical Western diet. These fatty acids have pro-inflammatory and pro-adipogenic properties in adults, leading to concerns that excess consumption of these fats by pregnant and lactating women may have negative effects on the metabolic health of the offspring. This research aims to determine the impact of maternal high n-6 PUFA diets on offspring health outcomes, and determine whether these outcomes are improved by reducing dietary n-6 PUFA intake.
The Epigemone and the Early Origins of Obesity
Evidence is emerging that nutritional insults in pregnancy and early life can affect specific genes, and thus predispose progeny to greater health risks later in life. Importantly, these changes can be transmitted to subsequent generations - meaning that the nutritional environment that an individual is exposed to early in life has the potential to affect the health of their grandchildren. Furthermore, it is now clear that nutrients can also influence the Epigenome, the set of reversible markers on the DNA of an individual which influence how genetic material is "read" and utilised and that changes in the epigenome that occur early in life can lead to permanent changes in gene expression. We are investigating in clinical studies the potential for specific nutrients in the maternal diet to affect the epigenome of the offspring. We are also exploring whether there are any epigenetic marks present at birth that are related to body fat mass in the offspring later in life.
Establishing Tools for Accurately Assessing Body Composition in Young Children
Growing concerns about the increasing incidence of obesity in young children has led to a need of developing quick, safe and accurate methods for assessing body composition in this population group. Compared with adults, accurately measuring body composition in young children has a number of additional challenges in particular the fact that bone density, hydration status and proportion of fat and lean muscle change with age, and the validity and accuracy of many of the standard approaches has been questioned. Our group recently acquired a BOD-POD system for measuring body composition. Although this system is widely used in adults, and has been shown to be highly accurate in adults, it has had limited use in children. This project aims to validate the use of the BOD POD in children and apply this technology to determine the effect of different nutritional interventions during pregnancy/infancy on body fat mass in childhood.
Over the next 3-5 years, the Obesity and Metabolic Health unit will increasingly explore strategies for limiting the predisposition to obesity through nutritional interventions applied in the perinatal period. We will use emerging technologies to characterise infant and child body composition to gain new insights into the impact of different nutritional practices in early life on growth quality in the first few years of life.