Bitter ‘supertaster gene’ linked to increased health risks microbiologystudy

People who carry a bitter “supertaster gene” have been linked to various health conditions including bipolar disorder and poor kidney function, University of Queensland researchers have found.

Using large-scale genome studies and the UK Biobank database, UQ researchers examined the impact of the TAS2R38 gene on food preference and health risks. The study is published in the European Journal of Nutrition.

Dr. Daniel Hwang from UQ’s Institute for Molecular Bioscience said 70% of the population carried at least one copy of the gene.

“TAS2R38 controls how strongly we taste bitterness in foods such as broccoli and brussels sprouts—making them taste extremely bitter to some people,”‘ Dr. Hwang said.

“If you carry two copies of the gene, you’re highly sensitive to bitter-tasting chemical compounds phenylthiocarbamide and propylthiouracil.”‘

Dr. Hwang said the gene has long sparked interest in how taste perception influences health outcomes.

Researchers split the study into two components—the first using data from about 500,000 participants aged between 37 and 73 from the UK Biobank, one of the world’s largest human genetic databases, to investigate food preferences.

The second component examined the impact of the gene on a range of health conditions using data from some of the biggest studies conducted globally.

The study found people with copies of the TAS2R38 gene tend to consume less horseradish, grapefruit and alcohol, are less likely to add extra salt to their meals, and tend to prefer cucumber, melon and tea.

There was also an association with chronic kidney disease, and increased odds of having bipolar disorder.

“People with the gene are more sensitive to salty tastes—they are less likely to add extra salt because foods are already salty enough,” Dr. Hwang said.

“But interestingly, they enjoy foods that are moderately salty and end up eating more salt overall, which could impact kidney function over time.”

Researchers also found people with the TAS2R38 gene are less likely to experience gut inflammation.

Dr. Hwang said an individual’s gut microbiome is possibly related to what they eat because sensory perception is linked to food choices.

“We found that people with this gene have more Parabacteroides—a type of bacteria that’s actually linked to better gut health and lower inflammation,” Dr. Hwang said.

But he said while the gene’s link with the gut microbiome and diet can be explained, the higher risk of bipolar disorder is unclear.

“This information will be useful in designing more personalized nutrition plans,” Dr. Hwang said.

The TAS2R38 gene evolved to help early humans detect the bitterness of potentially poisonous foods, increasing their chances of survival in the wild.

Although the gene was discovered in the early 2000s, scientists in the 1930s found some people could taste the bitterness of a chemical called phenylthiocarbamide while others couldn’t, suggesting a genetic basis for the trait.

“While more work is needed, the study provides new research directions for understanding this bitter taster receptor gene in human health,” Dr. Hwang said.