Hate the taste of Brussels sprouts? Do you find coriander disgusting or perceive honey as too sweet? Your genes may be to blame.
Everybody’s food preferences vary and are shaped by their unique combination of three interacting factors: the environment (your health, diet and cultural influences); prior experience; and genes, which alter your sensory perception of foods.
The food we eat is sensed by specialised receptors located in the tongue and nose. The receptors work like a lock and are highly specific in the nutrients or aromas (the keys) they detect. Sweet receptors, for instance, detect only sweet molecules and will not detect bitterness.
When you eat, your brain combines the signals from these specialised taste (in the mouth) and olfactory (aroma in the nose) receptors to form a flavour. Flavour is further influenced by other perceived qualities, such as the burn of chilli, the cooling of mint, or the thickness of yogurt.
Our unique sensory worlds
Humans have about 35 receptors to detect sweet, salty, bitter, sour, umami and fat tastes. They have around 400 receptors to detect aroma. The receptor proteins are produced from instructions encoded in our DNA and there is significant variation in the DNA code between individuals.
In 2004, American researchers identified that olfactory receptors were located in mutational hotspots. These regions have higher than normal genetic variation. Any of these genetic variants may change the shape of the receptor (the lock) and result in a difference in perception of taste or aroma between people. (Post continues after gallery.)
Another American study shows that any two individuals will have genetic differences that translate to differences in 3 per cent to 40 per cent of their aroma receptors. This suggests we all vary in our flavour perception for foods and that we all live in our own unique sensory world.
How much sugar do you add to your tea?
Our ability to perceive sweetness varies a lot and is partly controlled by our genes. A recent twin study found genetics accounts for about a third of the variation in sweet taste perception of sugar and low-calorie sweeteners. Researchers have identified specific gene variants in the receptors that detect sweetness: TAS1R2 and TAS1R3.
There is also high variation in the detection of bitterness. However, the story is more complicated than sweet taste, as we have 25 receptors that detect different bitter molecules. Bitter receptors evolved to detect and stop us from eating harmful toxins. That’s why bitterness is not widely liked.