student profile: Ms Alison Luk


Thesis work

Thesis title: The carbohydrate matrix, nitrogen source and fat as a lever to manipulate the gut microbial community state

Supervisors: Laurence MACIA , Andrew HOLMES

Thesis abstract:

Understanding how diet affects human health is fundamental to improving public health and individual dietary choices. Many studies have shown clear links between dietary intake, alterations in the gut microbial community, and host physiological changes. However, accurate predictions of microbial and host responses to diets remains a challenge, since many different dimensions of diet can affect these interactions. By using in vivo mouse models, we are able to systematically manipulate the dietary composition to investigate diet-microbiota-host interactions, and the emergent outcomes of microbiota and host health.

In my project, I will focus on the carbohydrate dimension of diet, which has been strongly impacted by food processing. Diets high in processed foods typically have low proportions of complex carbohydrates, such as fibre, and high proportions of simple carbohydrates, such as sugars. Such foods are highly digestible by the host, which greatly reduces the nutrient availability in the large intestines, and thus places selective pressures on the microbial community. The aim of my project is to understand how the dietary carbohydrate profile affects the gut microbial composition and diversity, as well as host physiology, metabolism and immunity. Furthermore, I will investigate how these effects change in the context of different dietary macronutrient compositions.

Through this research, we will gain a perspective on the importance of dietary fibre quality and quantity on health, and hence the impact of incorporation of processed foods into diets. This knowledge of the microbial and host responses to diet will ultimately enable targeted diet manipulations to modify the gut microbiota and influence host health in personal dietary choices and treatment therapies.

Note: This profile is for a student at the University of Sydney. Views presented here are not necessarily those of the University.