Obesity may blunt your taste buds: Scientists discover part of the brain that processes flavours is less active in severely overweight rats
- Scientists analysed the brain responses of severely overweight rats
- Found the nucleus tractus solitarius, involved in taste processing, ‘lit up’ less
- Obesity has been linked to reduced ‘taste receptor cell expression’
Being obese could blunt a person’s taste buds, research suggests.
Scientists from Binghamton University in New York analysed the brain responses of severely overweight rats after they were exposed to different tastes.
They found the nucleus tractus solitarius (NTS), involved with taste processing, ‘lit up’ less in the obese animals than in their leaner counterparts.
Although the study was carried out in rats, the researchers say the likelihood of the same results occurring in obese humans is ‘good’.
Obesity may blunt a person’s taste buds, research suggests (stock)
Previous studies have linked obesity with reduced ‘taste receptor cell expression’ and lowered activation of key receptor cells.
However, research has also suggested people who carry too much weight get more pleasure from food, which may be fueling the obesity crisis.
Around 39.8 per cent (93.3million) of adults in the US were obese between 2015 and 2016, according to the Center for Disease Control and Prevention.
And in the UK, 29 per cent of adults were classified as obese in 2017, NHS Digital data shows.
Previous research has linked abdominal fat to a reduced sense of smell and taste. However, the extent of this, and why it occurs, was poorly understood.
‘It’s surprising we know so little about how taste is affected by obesity, given the taste of food is a big factor in determining what we choose to eat,’ lead author Professor Patricia Di Lorenzo said.
To find out more, the researchers fed rats a diet of 45 per cent fat and 17 per cent sugar for eight weeks.
Once obese, the animals were ‘implanted with a bundle of microelectrodes in the NTS’.
The rodents were allowed to lick ‘tastants’ – taste-provoking chemical molecules, while the researchers analysed their NTS cells.
Results – published in the journal Frontiers in Integrative Neuroscience – revealed the cell responses were smaller, shorter and took longer to develop than in the lean ‘control’ rats.
‘The taste cells in the diet-induced obese rats conveyed less information about taste quality than cells in lean rats,’ the researchers wrote.
However, the obese animals did have ‘more taste-responsive cells’. The researchers believe ‘NTS cells may be recruited to compensate for weakened taste responses’.
They stress their study was only carried out in rodents, however, the same findings could apply to humans.
‘Others have found the number of taste buds on the tongue are diminished in obese mice and humans, so the likelihood that taste response in the human brain is also blunted is good,’ Professor Di Lorenzo said.
The team are looking into whether gastric bypass surgery could help formerly obese patients recover their sense of taste.
This study contradicts research by the University of Iowa that found obese people enjoy the taste of chocolate for longer than their leaner counterparts.
Lead investigator Professor Linnea Polgreen said: ‘Obesity is a major public-health problem.
‘Taste perceptions may lead to overeating. If people with obesity have different taste perceptions than non-obese people, it could lead to better understanding of obesity and possibly designing new approaches to prevent obesity.’
WHAT IS OBESITY? AND WHAT ARE ITS HEALTH RISKS?
Obesity is defined as an adult having a BMI of 30 or over.
A healthy person’s BMI – calculated by dividing weight in kg by height in metres, and the answer by the height again – is between 18.5 and 24.9.
Among children, obesity is defined as being in the 95th percentile.
Percentiles compare youngsters to others their same age.
For example, if a three-month-old is in the 40th percentile for weight, that means that 40 per cent of three-month-olds weigh the same or less than that baby.
Around 58 per cent of women and 68 per cent of men in the UK are overweight or obese.
The condition costs the NHS around £6.1billion, out of its approximate £124.7 billion budget, every year.
This is due to obesity increasing a person’s risk of a number of life-threatening conditions.
Such conditions include type 2 diabetes, which can cause kidney disease, blindness and even limb amputations.
Research suggests that at least one in six hospital beds in the UK are taken up by a diabetes patient.
Obesity also raises the risk of heart disease, which kills 315,000 people every year in the UK – making it the number one cause of death.
Carrying dangerous amounts of weight has also been linked to 12 different cancers.
This includes breast, which affects one in eight women at some point in their lives.
Among children, research suggests that 70 per cent of obese youngsters have high blood pressure or raised cholesterol, which puts them at risk of heart disease.
Obese children are also significantly more likely to become obese adults.
And if children are overweight, their obesity in adulthood is often more severe.
As many as one in five children start school in the UK being overweight or obese, which rises to one in three by the time they turn 10.