March 8, 2010

Researchers: Fat Could Be ‘Sixth Taste’

There are five known tastes detected by the human tongue, -- sweet, salty, sour, bitter and umami (a protein-rich taste found in foods like soy sauce) -- but according to Australian researchers a sixth taste may soon be added to that list.

"Through our study we can conclude that humans have a sixth taste -- fat," said Russell Keast, from Deakin University, on Monday.

Researchers tested 30 people's ability to taste fatty acids placed in plain solutions and found that all of them were able to determine the taste. Although some needed higher concentrations to do so.

Researchers also screened 50 people to determine how sensitive they were to the taste and found that the ability to taste fat was linked to their weight. Researchers feel that the discovery could lead to better ways to counter obesity.

"We found that the people who were sensitive to fat, who could taste very low concentrations, actually consumed less fat than the people who were insensitive," Keast told AFP. "We also found that they had lower BMIs (Body Mass Indexes)."

Keast said that research suggested that the taste of fat could trigger a mechanism in the body. "We all like eating fatty foods. What we speculate is (that) the mechanism is to do with stopping eating. Your body is able to tell you you've had enough and stop," he explained. Otherwise, in those who are insensitive to the taste, they do not get the feedback and continue to eat.

It is possible that people may become desensitized to the taste of fat, where it is readily available and consumed frequently, and people can become prone to overeating calorie-rich foods, he added.

The research was conducted in collaboration with the University of Adelaide, New Zealand's Massey University and CSIRO. The results were published in the British Journal of Nutrition.

The fat taste has not been classified as a taste yet, but Keast says the evidence is strong and it should be considered. For something to be classified as a taste there needs to be proven receptor mechanisms on taste cells in the mouth. "We have what... we will call possible candidate receptors for fat on taste receptor cells," he said.


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