They say the eyes are the window to the soul. But perhaps it is the tongue. Research into taste sensitivity - our ability or inability to taste certain substances - has in recent years drawn increasing attention to the tongue. This research has revealed that anatomical differences in our tongues tell us much about the foods we are likely to love and loath. The differences are also predictive of obesity levels and certain physical and psychological illnesses.
So what is it about the tongue that makes it so telling?
The answer lies in the genetic heritability of tastebud formations. Like eye colour, we also have distinct formations of taste buds: many, few, dense, sparse, large and small. Also like eye colour, our taste bud formations are genetically inherited. These differing formations influence our ability to taste certain bitter substances. Geneticists have categorised people into three distinct groups: super-tasters (lots of taste buds), tasters (fewer taste buds) and non-tasters (very few taste buds). For example, per square centimetre, non-tasters have 96 taste buds, tasters have 184, while super tasters boast around 425.
There are simple tests that can be used to differentiate these groups.
The most commonly used involve participants rating the taste of a bitter compound such as the chemical phenylthiocarbamide (PTC). To super-tasters, PTC tastes extremely bitter, whereas non-tasters generally report no taste at all, and the tasters report that it's not that bad.
Interestingly, cross-national studies of taste status have revealed a fairly high degree of variability in taste sensitivity across different nations and ethnic groups. For example, amongst Caucasian North Americans, around 26.5 per cent of the study population were either non-tasters or tasters. Among Australian Aborigines, however, tasters and non-tasters comprised 49.7 per cent of the study population.
To date, no published studies have looked at taste sensitivity amongst Gulf Arabs. Such studies are important because of the growing body of research linking taste sensitivity with food aversions, obesity and serious illnesses.
We decided to rectify the lack of Arabian Gulf data and explore taste sensitivity in a fairly large sample of Emiratis. In our study, we administered a simple PTC taste test to 200 Emirati students, males and females, at Zayed University in Abu Dhabi. We found that 52 per cent of the Emirati students could be categorised as non-tasters or tasters. These rates are closer to those reported for Australian Aborigines (49.7 per cent), than North Americans (26.5 per cent).
This is perhaps explicable in terms of regional traditions of first cousin marriage. Similar consanguineous marital practices are also common amongst Aborigines.
The other 48 per cent of our students were super-tasters. Like super-tasters elsewhere in the world, they were also more likely to dislike bitter-tasting vegetables like cabbage, broccoli and Brussels sprouts. This aversion is potentially problematic as these dark-green cruciferous vegetables are linked with greater cardiovascular health, less obesity and lower incidence of certain types of cancer.
The biggest health-related problems facing the UAE today are all hugely influenced by diet and other related lifestyle factors. In the context of cardiovascular disease, the Health Authority-Abu Dhabi note several areas for particular concern amongst the Emirati population: hypertension (17 per cent), blood lipid abnormalities (36 per cent), obesity (36 per cent) and diabetes (21 per cent). The more we know about the various lifestyle, environmental and genetic factors associated with these problems, the better we will be able to target appropriate health promotion and illness prevention strategies. The tongue, even when silent, tells us much about our vulnerabilities. Perhaps it's time to start listening.
A final note: our research might also have resolved why many women complain about their husbands not appreciating the food they cook. Men are more likely to be non-tasters than women. So it's not that they don't care, it's just in their genes.
Justin Thomas is an assistant psychology professor at Zayed University in Abu Dhabi. Wahda Ali is a senior at Zayed University, majoring in health science