Single human gene codes for individual taste profiles
influential role genetics plays in the taste profile of
individuals, reports Lindsey Partos.
Taste is a key driver in the €3.2 trillion global food industry and a greater understanding of the physiology of consumers, and their genetic make-up, could lead to strong market advantages.
Researchers at Monell Chemical Senses Center in the US assert that each human carries his or her own distinctive set of taste receptors: which gives them a unique perception of how foods taste.
How an individual perceives taste comes down to a single gene, they say.
Co-study author Paul Breslin explains: "Our paper shows that a single gene codes for multiple forms of a taste receptor, with each form having a differing sensitivity to taste compounds."
Scientists at the Monell Center related individual perception of the bitter-tasting compounds PTC and PROP to variation in a bitter taste receptor gene known as hTAS2R38.
The scientists claim their findings have provided "an improved understanding" of why individuals differ in their ability to taste some bitter compounds.
They can now use their procedure to understand why people are sensitive to other tastes, such as sweet or umami (meaty), as well as flavours and other types of bitter compounds.
This latest fundamental research will compound and fuel a notion in the food industry, still at grass roots level, that foods of the future may well be anchored in individual taste profiles.
Last year scientists at the world's number one food manufacturer Nestle detailed findings that different species had 'specific gustatory adaptation' with regards to nutrition and food choice.
Dr. Johannes le Coutre, who headed the Nestlé study, told FoodNavigator.com at the time that taste receptors might not only convey taste into the body. "This is pure speculation, but taste receptors might also sense the food and chemicals that pass into the body, an individualised tool that responds to flavours and food.
We believe that maybe there is a measurement of food passing by, that regulates the individual by means of a metabolic evaluation and physiological adjustment," he said.
Implicit is the suggestion that different people have different tastes, and supports ongoing research in the rapidly emerging field of nutrigenomics, or nutritional genomics.
Nutrigenomics, the study of how nutrients and genes interact and how genetic variations can cause people to respond differently to food nutrients, is still in its infancy but scientists predict that their work could bring about radical changes in how food is grown, processed and consumed, and lead to personalised diets tailored to the genetic make-up.
In the future, nutrigenomics could become a major slice of the buoyant functional foods sector - forecast to double within five years in the UK alone from €1.2 billion to €2.47 billion - as consumers turn to products targeted at their profile. In 2003, sales of functional foods and drinks were estimated to be over six times the value of those in 1998.
For the latest US study researchers cloned two forms (haplotypes) of the hTAS2R38 gene and expressed the corresponding receptors in a cell culture. The two haplotypes, known as PAV and AVI, vary with respect to amino acid substitutions encoded at certain positions on the taste receptor protein.
In the cell culture experiments, small amounts of the bitter compounds activated cells expressing the PAV form of the receptor, whereas cells expressing the AVI form were unresponsive to the same compounds.
Cells expressing other haplotypes (eg PVI, AAI or AAV) had intermediate sensitivity to the bitter compounds.
"The studies demonstrate that while each human may have 25 or so bitter receptor taste genes, because each gene can code for multiple receptors with differing sensitivities, there may be hundreds of different bitter taste receptors in the human population as a whole, leading to wide individual variation in perception of bitterness," conclude the Monell researchers.
The existence of both bitter "tasters" and "non-tasters" has the scientists curious for more answers. Breslin comments:"From a human evolutionary perspective, we want to understand how and why both tasters and non-tasters evolved and were maintained in the gene pool.
"Usually when we see a trait like this, there is a biological advantage to maintaining the variation. We're wondering what that could be."
Full findings of the study are published in the February 22 issue of Current Biology.
