Studies show food preferences are written in genes

The food we eat is sensed by specialised receptors in the tongue and nose. weet receptors, for instance, detect only sweet molecules. Photo / Getty

Hate the taste of Brussels sprouts? Do you find coriander disgusting or perceive honey as too sweet?

Your genes may be to blame.

Food preferences vary and are shaped by 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 in the tongue and nose.

They 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.

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 perceptions, such as the burn of chilli, the cooling of mint, or the thickness of yoghurt.

Humans have about 35 receptors to detect sweet, salty, bitter, sour, umami and fat tastes and around 400 receptors to detect aroma.

The receptor proteins are produced from instructions encoded in our DNA.

In 2004, United States 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.

Another American study shows that any two individuals will have genetic differences that translate to differences in 30 per cent to 40 per cent of their aroma receptors.

This suggests we vary in our flavour perception for foods and live in our own unique sensory world.

A recent twin study found genetics account 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.

There is also high variation in the detection of bitterness.

However, 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.

One of these bitter taste receptors (TAS2R38) controls the ability to detect a bitter compound called Prop (propylthiouracil).

Genetics has also been linked to whole foods, such as coriander preference, coffee liking and many others. Photo / Carolyn Robertson

Based on the ability to detect Prop, people can be split into two groups: "tasters" or "non-tasters".

Tasters often dislike bitter green vegetables, such as broccoli and Brussels sprouts.

Prop status has also been used as a marker of food preferences, with non-tasters shown to eat more fat and better tolerate chilli.

Genetics has also been linked to whole foods, such as coriander preference, coffee liking and many others.

But genes have only a small influence on preference for these foods due to their sensory complexity and also the contribution of your environment and prior experiences.

Understanding the influence of genes on taste perception offers a way to personalise products tailored specifically to your needs.

This could mean tailoring a diet to a person's genetics to help them lose weight. Indeed, genetic testing companies already offer dietary advice based on your individual genes.

Food products based on personal tastes are already in supermarkets. Salsa can be bought in mild, medium and hot.

We are just beginning to understand how genes alter our sense of taste and smell.

Another important research area will be to understand if our taste genes can be modified. Imagine if you could alter your food preferences to consume healthier foods.