Taste has nothing to do with the bumpiness of your tongue, say scientists


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The Independent Online

Thousands of concerned citizens have stuck their tongues out in the name of science and proved that being a “supertaster” has nothing to do with the number of bumps on your taste buds.

Supertasters are the minority the population who have a heightened sense of taste – particularly for bitter compounds – and for many years scientists have linked the trait with the number of “fungiform papillae” or sensory bumps on the tongue.

However, with the help of 3,000 “citizen scientists”, researchers have now proved that there is in fact no link between the number papillae on someone’s tongue and whether or not they can taste certain kinds of bitter compounds.

“There is a long-held belief that if you stick out your tongue and look at the bumps on it, then you can predict how sensitive you are to strong tastes like bitterness in vegetables and strong sensations like spiciness,” said Nicole Garneau of the Denver Museum of Nature and Science in Colorado.

“The commonly accepted theory has been that the more bumps you have, the more taste buds you have and therefore the more sensitive you are…[but] no matter how we looked at the data, we couldn't replicate this long held assumption that a high number of papillae equals supertasting,” Dr Garneau said.

Supertasters are defined by whether they can detect the presence of two bitter-tasting compounds, phenylthiocarbamide (PTC) and propylthiouracil (PROP), and geneticists have shown that this ability depends to a large extent on certain variations of a gene known as TAS2R38.

However, scientists believed that the density of taste buds on the tongue also played a part – a belief that goes back more than 20 years – and that taste bud density and supertasting could also explain food pickiness in some children who were more sensitive to bitter-tasting substances in spicy foods and in vegetables such as Brussels sprouts.

Dr Garneau and her colleagues tested the theory with the help of 3,000 visitors to the Denver museum’s Genetics of Taste Lab. The number of sensory papillae were counted on each tongue and each volunteer was assessed for their sensitivity to PROP.

Nearly 400 of the volunteers also had their genetic makeup analysed to see which kind of TAS2R38 gene they had inherited.

The results of the study, published in the journal Frontiers of Integrative Neuroscience, showed that the density of sensory papillae on a person’s tongue could not “in any way” be used to predict whether or not they could taste PROP. The researchers found that this was true irrespective of gender, age or a person’s genetic makeup with respect to the gene TASR38.

However, the study confirmed that TAS2R38 on its own did play a significant role in determining someone’s tasting ability, although it could not completely explain all the differences seen between different people.

Dr Garneau said that the findings question the scientific definition of supertasting and suggested the term itself should be replaced by one that indicates a spectrum of tasting abilities between people rather than whether someone falls into one camp or another.

“What we know and understand about how our bodies work improves greatly when we challenge central dogmas of our knowledge. This is the nature of science itself,” Dr Garneau said.

“As techniques improve, so too does our ability to do science, and we find that what we accepted as truth 20, 30, or 100 years ago gets replaced with better theories as we gather new data, which advances science,” she said.

“In this case, we've proven that with the 'Denver Papillae Protocol', our new method for objective analysis for papillae density, we were unable to replicate well-known studies about supertasting,” she added.

What is a supertaster?

People vary greatly in their sense of taste which can be explained by both cultural upbringing and experience, as well as genetics. Scientists have defined “supertasters” as those people who are revolted by the taste of the bitter compounds propylthiouracil (PROP) and phenylthiocarbamide (PTC).

About 25 per cent of people are considered to be supertasters, although the proportion can vary between the sexes and between ethnic groups. It also seems that children are more sensitive to the sense of bitterness than adults, which may explain why many of them find Brussels sprouts revolting.

Although scientists showed in the 1960s that supertasting had a genetic component, it was not until the early 1990s that researchers suggested that tongue anatomy may also play a role in the form of the number of sensory papillae on the taste buds.

This has led to the widely-held view that the number of bumps on the tongue can indicate how good you are at discerning different tastes, such as the quality of a particular wine or the culinary ability of a certain chef. However, the latest research appears to have disproved this theory and has even called into question the entire notion of “supertasters”.