It's in the Genes: the Biology of Food Preference

There might be a reason you love a good curry and can’t stomach spinach. A group of European scientists have begun work on a project that could eventually explain everything from your insatiable sweet tooth to your superhuman tolerance for spicy foods. New research on the “genetics of food preferences” suggests our tastes and distastes for certain foods may have their origins in our evolutionary histories, and that our genetic makeup may actually dictate which foods we find attractive, and which ones we abhor. The project – officially called Marco Polo (after the explorer who famously travelled the trade route centuries ago) – examines DNA from a number of cultures and communities along Eurasia’s historic Silk Road in an effort to determine how genetic variation translates to palatal differences within and across cultures. And while Marco Polo’s orchestrators still have significant work to do before the project sees its conclusion, early research has already turned up some interesting results which could, given time, lead to advancements in food science and changes in the direction of food industry research.

The Silk Road is home to ongoing research on the genetics of food preference.

Paolo Gasparini, a medical geneticist at the University of Trieste (Italy), and Enrico Balli, Medialab Director at the International School of Advanced Studies in the same city, conceived the Marco Polo project as a means of investigating and mapping the “genetic roots of food preference and of the senses that contribute to it.” The two (who would later enlist the help of Terra Madre co-founder Lilia Smelkova) wanted to know for certain whether individual and/or group dietary preferences could be boiled down to specific coding within our DNA. It now appears it can. More importantly, they wanted a better understanding of how those genetic properties are, in turn, manifest as behavior. In other words, Gasparini and Balli were not only concerned with why we appreciate or detest the foods we do – observing the presence of relevant DNA markers satisfied that curiosity – but they also wondered very specifically how those markers come to influence our opinions and manipulate our dietary behaviors.

What they discovered, makes sense and even seems obvious in retrospect. It turns out that our tastes for certain foods depend on more than just our sense of taste. In fact, our opinions about food are shaped by each and every one of our senses. How many times have you heard someone declare they might like eggs, for example, if only it weren’t for the off-putting, gelatinous texture? Similarly, have you ever been driven mad by the crunch of a crisp apple bitten or a handful of nuts munched?  These are reactions that, while having nothing to do with our sense of taste, play an important role in determining our dietary preferences. Thus, while we may do our best to avoid wrinkling our noses at the smell of asafoetida or to overlook the awkward appearance of eggplant, we are, in doing so, struggling against our own biology.  We are hardwired to have these reactions.  They are the vestiges of a different era in human history, long gone by, when an adverse reaction (or lack thereof) to, say, the color or bitterness of poisonous berries could have been the difference between life and death.

Visual cues such as bright colors are one of many influences on our dietary interests. (Photo by Sean Gallup/Getty Images)

So why the Silk Road? Gasparini and Balli had a solid theory – that genetics, not lifestyle, account for the differences in food preferences across cultures – but needed some corroborating evidence. In other words, they needed to locate and isolate specific genes that could be shown to code for characteristics associated with dietary preference. What the Silk Road had to offer, in terms of contributing to a solution to the problem, was a series of cultures and communities that, while separate and autonomous in their own right, still belonged in many ways to a larger community in the Silk Road itself.  The history of the trade route was such that the communities along it had long and extensively exchanged “goods, ideas, and genes.”  This is important because it meant that much of the Silk Road community was genetically and culturally homogenous – or, they shared very similar genetic material in addition to practicing similar lifestyles, eating similar foods, etc.  The fact that the communities on the Silk Road were similar in so many regards was exactly what made it attractive as a locale for the Marco Polo Project.  That made it easier for Gasparini and Balli to trace any differences – in this case, those in food preference – to genetic variation, which they did:

The scientists have already identified eight variants in known genes, including one for an ion channel involved in sensing spicy-hotness, which are associated with a taste for particular foods. And they have found that variants of the gene for the TAS1R2 protein, part of a sweetness receptor, are associated with a strong liking for vodka and white wine (N. Pirastu et alJ. Food Sci.; in the press).

These early results, although by no means exhaustive, are significant in more ways than one.  Most basically, they allow us to interpret our own dietary preferences and limitations on a personal level.  Everything from your incredibly low tolerance for spicy foods to the fact that tomatoes give you killer heartburn may be traced back to your own genetics.  And while it may not mean you can necessarily change these dietary phenomena – sorry, but you won’t be chomping on Jolokias any time soon – you can, for the time being, at least understand them.

Indeed, we can potentially learn a lot about ourselves from what has already come of the Marco Polo project (and what presumably will as more data is gathered), but Gasparini’s and Balli’s research has significance beyond explaining our personal quirks. Their findings speak to both the previously unclear details of our evolutionary history, and the potential future of food science.  Yes, just as we may be able to exploit these findings to better understand our dietary past, we also will most certainly put it to use to influence our dietary futures. Food companies are already seizing on such data as they search for ways to adapt their product to regional markets.  Furthermore, and more importantly, the Marco Polo research may lead to ways to create healthier foods that still satisfy the dietary urges that we are, we’ve learned, genetically compelled to have. And if the fruits of this research turn out to be a product that tastes as good as a fatty steak without clogging my arteries, I am all for it.

Our Old Town storefront pays tribute to the flavors of the Silk Road.

As a non-scientist, it can be hard for me to fully appreciate the significance and implications of research like that of the Marco Polo project.  But it does, at least, make sense of behaviors I see in our store on a regular basis.  Scarcely does a customer walk into the store without commenting aloud that they are either enamored with or overwhelmed by the scent of the place. In the same vein, customers will commonly declare the beauty of our paprika, laud the depth of flavor in our Back of the Yards Garlic Pepper Butchers Rub, or admire the aroma of our saffron as they open the cabinet in which it is housed. And every once in a while, a taste of our Vulcan’s Fire Salt will send a curious customer running for the water cooler, while his buddy plays it cool, sampling a second shake.  I hadn’t ever spent a lot of time thinking about these various reactions, but I can now appreciate the fact that they happen as they do, for a reason.  It’s all in the genes.

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