18 Nov 2017

Hunger pangs: solving the secrets of appetite

From This Way Up, 12:45 pm on 18 November 2017

Fighting obesity, cutting food waste, and even making our food production systems more efficient ... could all this be achieved by unlocking the chemical signals that regulate appetite and satiety in our brains?

For the first time a team of scientists at The University of Warwick have identified the key brain cells that control our appetite, a discovery that could revolutionise the weight loss industry. Called tanycytes, these cells detect amino acids from food and in turn signal to our brains that we feel full.


Photo: (Cel Lisboa on unsplash.com)

The tanycytes, which literally means “long cells”, are found right in the centre of the brain, according to Professor Nicholas Dale, who led the team’s research. Dr Dale says he believes the tanycytes sense a range of amino acids through multiple receptors similar to those in the tastebuds of the tongue.

“The similarities with the tastebuds are remarkable, because different amino acid receptors in the tongue sense different types of amino acids, and we see this in the tanycytes as well,” he says. “So we know they’ve got at least two amino acid sensing receptors - one of them senses essential amino acids, and the other senses non-essential amino acids.”

Professor Nicholas Dale (Supplied)

Professor Nicholas Dale (Supplied) Photo: University of Warwick

Foods such as pork shoulder, beef sirloin steak, chicken, mackerel, plums, apricots, avocados, lentils and almonds are high in two key amino acids -  arginine and lysine -  that activate the tanycytes and therefore make us feel fuller quicker.

The researchers made their discovery by adding concentrated amounts of arginine and lysine into brain cells. They found that within 30 seconds, the tanycytes detected and responded to the amino acids, releasing information to the part of the brain that controls appetite.

Although the research is still ongoing, Dr Dale says the discovery opens up exciting possibilities for creating more effective diets.“I think one could imagine either a functional food with some sort of additive, or even just reformulating certain foods in different ways,” he says.

“I suppose the food manufacturers would have mixed opinions about this because they’d be reformulating food to make people eat less which would be a slight hit on their bottom line, but you could imagine that people could slightly modify their diets and potential hack into their system to alter how hungry they feel, or how full they feel.”

New Zealand has one of the worst rates of obesity in the world for OECD countries. According to results from the annual Ministry of Health survey released last week, 32.2 percent of the country’s adult population are now considered obese, a figure that has increased 5.7 percent in the last 10 years.

Tanycytes on the right side of the brain, stained red to highlight their processes

Tanycytes on the right side of the brain, stained red to highlight their processes Photo: Matei Bolborea

t- tanycte, tp -tanycyte process A -astrocyte (another type of glial cell) 3V -third ventricle.

t- tanycte, tp -tanycyte process A -astrocyte (another type of glial cell) 3V -third ventricle. Photo: Michael Halassa and Nicholas Dale.