Our Year 10 Science students were given a National Science Week treat when Professor Eugeni Roura, a nutritionist from the University of Queensland, came to speak to them about obesity, chemosensory mechanisms in the body and gut health. Professor Roura currently leads a research team with the main interest related to understanding the mechanisms involved in sensing dietary nutrients and their involvement in appetite modulation and food intake in humans.

The context for Professor Roura’s talk was the rise in obesity over the last few decades. He posed the question: Why, when we know about which foods are healthy, do we eat food that is bad for us and makes us fat?

Professor Roura then explained the processes of tasting food and how the olfactory (smell) also plays a significant part. He demonstrated how integral the sense of smell was to taste by asking the students to pinch their noses while trying to taste a lolly. While one can differentiate sweet and sour with the taste buds on the tongue, the ability to smell the vapours coming off the lolly allow us to see if it is lemon, strawberry or aniseed flavour. Our bodies hone in on certain combinations of sweet/flavours and these are not necessarily good for us.

The second demonstration was around how some people are “super tasters” or have a certain DNA combination that allows them to make nuanced differentiation of taste. Each student was given a strip of paper imbued with a bitter chemical (quinine). Only about half the population can sense this and so it proved as half the audience grimaced as the taste came through after chewing the paper. Super tasters have an enhanced ability to differentiate nutrients and so, presumably, can make wiser choices about their diet.

A 7.5M garden hose also provided context to how long the human small intestine is. 90% of the nutrients from the food we eat are absorbed through the small intestine as food makes its way from stomach to rectum.

One of the last points made by Professor Roura told the boys much about how we need to re-think our interaction with food. Our bodies are amazingly complex organisms that are programmed from thousands of years of survival to eat food to store energy. If we follow our gut-reaction (pun intended) and do this in 21st century Brisbane we quickly become obese. We need to be food aware and balance our energy needs with our energy outputs.

Mr David Fisher
HEAD OF SCIENCE