How does that taste?


Are you looking for something to blame for your 'sweet tooth', or perhaps wondering why you have an aversion to certain veggies?

Taste perception plays a huge role in food choices throughout our lifetimes. However, genetic variations, environment circumstances, and cultural and social factors all play their parts in this multi-faceted subject of food choices and preferences.

EATING IS ESSENTIAL AND PLEASURABLE, BUT IT CAN BE DANGEROUS!

Our senses of smell and taste were developed as a defence mechanism to stop us from eating harmful, poisonous substances. Our sense of smell has protected us from eating rotten food and being able to sense smoke from a fire has been very useful. The nose cannot always be relied because some people are actually drawn to smelly cheeses, once they know its safe. These associations and perceptions are complex!

We are all different and some of us will be more sensitive to the smell of sweat which comes from isovaleric acid and is associated with the OR11H7 gene. The very same isovaleric acid we turn our noses up at, is also the smell we pick up from strong cheese.


SWEET TASTE PERCEPTION.

Children live in a different sensory world when it comes to sweet taste and generally prefer higher levels of sweetness than adults. These preferences decrease to adult levels around adolescence, which is coincides with the decline in physical growth.

But what happens when that does not occur and that 'sweet tooth' remains very active in many adult lives?

That's when the genetics of taste become interesting.

Sweet is generally associated with pleasure, but some people reach a cloyingly sweet threshold sooner than others. For 'sweet-likers' sugary and artificially sweetened foods can never be too sweet, or too much. This can be problematic for dental health, overall health and obesity!

There is a strong link to heritability in sweet tooth perception. A study conducted by(Keskitalo et al 2007) showed that the genetic contribution to sweet taste threshold in identical twin girls was 49%.

The culprits are TAS1R2 and an additional gene, GLUT2 which is associated with a higher habitual intake of sugars. GLUT2 is involved with glucose-sensing and is very relative to energy balance and carbohydrate intake.

BITTER TASTE

'One person's pleasure is another person's poison', and, possibly a reason why 'picky' eaters are so difficult to feed and keep healthy.

Bitter tasters are divided into tasters, medium tasters and supertasters.(Bartoshuk et al. 1994; El-Sohemy et al. 2007)

Broccoli is a common example of a healthy cruciferous vegetables that can unfortunately, be a total turn-off for supertasters, and some medium tasters.

Broccoli, bok choy, kale, cabbage, cauliflower, and watercress contain 'bitter' tasting phytochemicals which protect against many chronic diseases but will be avoided by bitter tasters.

It may be useful to disguise this taste for picky children and adolescents, rather than trying to force them to get used to the taste of these phytochemicals.

Have you noticed how some people cannot stomach fresh tomatoes? They are sensitive to the savoury glutamate taste, and the smell of ham on a sandwich is awful for those with a variant in their OR7DA gene. This smell associated with ham is called boar taint odour, and the ability to detect asparagus in urine is down to OR2M7!

Alcohol and coffee are also associated with individual taste receptors!

Danielle Renee Reid and Antti Knaapila (2010) so aptly titled their paper: Genetics of Taste and Smell: Poisons and Pleasures.