Genes and Smell

Do you balk at the smell of blue cheese? Can you pick out the scent of fresh apple slices in a fruit salad? It turns out our individual sniff perception is rooted in our genes, say researchers at the New Zealand Institute for Plant & Food Research in Current Biology.

Take the highly controversial herb cilantro, which disgusts many who can taste its “soapy” undertones. But cilantro and its coriander seeds have been used for generations in traditional recipes from Asia to Latin America. Some of this smell and taste perception is based on cultural differences, but these reactions are most closely linked to genetic variations.

“We were surprised how many odors had genes associated with them,” said study author Dr. Jeremy McRae in a press release. “If this extends to other odors, then we might expect everyone to have their own unique set of smells that they are sensitive to. These smells are found in foods and drinks that people encounter every day, such as tomatoes and apples. This might mean that when people sit down to eat a meal, they each experience it in their own personalized way.”

Researchers used a genome-wide association study to determine which parts of the DNA sequence differ among people who can smell certain compounds and those who can’t. Study participants were asked to smell malt, apples, blue cheese, and β-ionone, found in violets.

Surprisingly, there were few differences in the proportion of people who could smell individual test compounds, and little diversity among different ethnic groups in the frequency of genes that allow people to detect these smells. The variations may not have been drastic, but the study did affirm scientific theories about smell perception.

In general, the researchers add, women are better than men at detecting odor compounds, and our sense of smell deteriorates with age.

Do You Like It?

Personal tastes are the result of environmental influences, but smell perception is what helps us create these likes and dislikes in the first place. Our sensitivities depend on olfactory receptors, molecules on the nose’s sensory nerve cells that send the brain an impulse telling us how to interpret the smells we come in contact with.

“Emotions and experience are always important, as we all have them and they are likely all different,” said study co-author Dr. Richard Newcomb. “However, knowing the genetics allows us to factor for the genes and gives us more power to explore questions such as the role of emotions and experience.”

What you’re picking up through your nostrils might not even be a matter of taste, but may just depend on what you are better able to discern than others. For example, Newcomb told Healthline, “when you are drinking a glass of Pinot Noir wine you are highly likely to be experiencing the ‘violet’ note that the winemaker has put on the bottle, while others may not be.”

He adds, “[certain] genes did associate with different categories of liking, but we think this is due to the fact that those with less sensitive versions of genes were less able to detect the compounds.”

Foods Crafted Just for You

The researchers foresee a number of advancements in the food industry as a result of their studies. Imagine food products and marketing tailored to people with specific genetic expressions.

“We envisage first helping [food industry experts] appreciate that their food developers may be different in how they perceive key food flavors,” Newcomb said. “We still use a nose a lot in food development. It's still faster and cheaper than a machine. Second, we can give them a feel for the percentages of their target market that will be able to smell a given flavor by extrapolating out to all humans on the planet using public domain databases of human genetic variation.”

This kind of marketing may be far in the future, but in the meantime, you'll know why certain scents tickle your particular fancy.

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