Toxins drove evolution of human taste sense
17 August 2005
Plant toxins in the diets of early humans drove the evolution of a bitter taste receptor better able to detect them, suggests new genetic research by scientists at UCL, Duke University Medical Center and the German Institute of Human Nutrition.
The ability to discern bitter flavours likely offered a survival advantage by protecting ancient people from poisonous fare, the researchers concluded. Today, however, the same sensory sensitivity may have adverse consequences for human health, they added, by causing an aversion to bitter-tasting nutrients, some of which might lower the risk of cancer and heart disease. …
The team reported its findings in 'Current Biology'. The researchers included senior author Professor David Goldstein, of the Duke Institute for Genome Sciences & Policy (IGSP) and lead author Dr Nicole Soranzo [UCL Department of Biology]. Formerly of UCL, Goldstein is Director of the Duke Center for Population Genomics & Pharmacogenetics. …
"Humans have devised a number of behavioural habits to inactivate toxins in foods, such as soaking of seeds, baking or cooking," Soranzo said.
"Because of these other means of protection, it is generally thought that the ability to recognize compounds through the sense of taste is less important for people than it is for other animals.
"However, detecting signatures of selection for a bitter taste receptor suggests that sensory detection of dangerous foods played an important role at certain times during the course of our evolution," she added. …
"Bitter compounds are a heterogeneous class, some of which are toxic and some of which lower the risk of cancer and heart disease," Soranzo said. "Owing to their bitter taste, these compounds are routinely removed by the food industry and represent a key limitation in increasing the nutrient content of plant foods.
"While this gene variant may have been advantageous in our past through avoidance of natural toxins, one might speculate that it may now contribute to increasing disease risk through lowered intake of such beneficial compounds."
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