Our taste receptors are subject to genetic variations that mean what smells great to some tastes foul to others, writes Jennifer Bowden.
Q: Your article about reducing salt intake by using herbs and spices for flavouring (“Shaking the habit”, December 3) started me thinking about coriander. I’m not fond of the taste of coriander, but others love it. Why the difference?
A: It’s estimated 3-21 per cent of the general population dislike coriander, varying with ethnicity. I routinely avoid dishes containing coriander because it has an overpowering unpleasant taste for me. Coriander-haters generally describe it as tasting soapy, and they sometimes detect a rancid or dirty flavour. In contrast, coriander-lovers taste a fresh, green, almost citrus-like flavour. How can taste perceptions be so diverse?
Environmental, cultural and biological factors, including genetics, all shape our food preferences. Researchers identified the first evidence for genetic differences influencing food preferences through studies of twins and families.
A 2012 US twin study, for instance, investigated genetic influences on perceptions of taste and smell associated with items ranging from sucrose and sodium chloride to ethanol, coriander and basil. They found variations in three genes linked to coriander “liking”. These three genes code for a bitter taste receptor, a signalling component for taste common to both bitter and sweet perception, and a receptor for “pungent chemicals found in foods”, according to the findings published in Chemical Senses. These differences may explain why some people love coriander and others find it dreadful: it literally tastes and smells different to them.
Considerable research has investigated the genetic differences that encode taste receptors for sweet, umami and bitter perceptions, but less is known about sour and salty perceptions.
A well-known example of a genetic difference for bitter taste is the TAS2R38 bitter taste receptor. Variants of this gene result in vast differences in tasting of a bitter compound known as PROP (6-n-propylthiouracil). About 30-40 per cent of the European population cannot taste the PROP compound, while the remaining 60-70 per cent perceive it as moderately to intensely bitter.
I discovered this first-hand in my university days when a food technology lecturer got my entire class to take a PROP test. While I gagged at the taste of it on an ice cream stick, the student next to me couldn’t taste anything. It was an eye-opening experience watching the varying reactions to the same compound among the students.
Variations in individual ability to taste PROP have also been linked to a preference for vegetables such as brassicas and other bitter foods, sweets, spicy foods and alcoholic drinks. Genetic variants in taste receptors can also influence our preference for wine (white versus red) and tea (yes, some people are genetically loaded to not like tea).
From a public health perspective, things got interesting with the discovery of genes that appear to encode people with a preference for fatty-food groups, such as bacon, pork chops and goat’s cheese, along with groups of genes that seemingly influence people’s preference for vegetables. Researchers have even investigated whether these genetic preferences for vegetables affect body composition. They found people with groups of genes coded to prefer certain vegetables tended to have slightly leaner bodies than others.
Still, genetics don’t entirely predetermine our lives. We’re all born with an innate tendency to dislike bitter tastes, and we learn to adapt and accept bitter flavours through repeated food tastings. If your coriander aversion affects your lifestyle (it turns up often in meals nowadays), you can re-educate your taste buds. For example, crushing coriander leaves may reduce the concentrations of compounds that coriander-haters find unpleasant. So a good starting point to gently re-educate taste buds may be a coriander-based pesto.
A similar approach can be used with other foods we dislike but want to enjoy – for example, cucumber could initially be eaten grated into a tzatziki dip before moving onto slices in a salad. Again, start with minimal quantities and work your way up to a stronger flavour; you may even become a coriander-lover!
