Marco Polo’s Fires

Interview to Paolo Gasparini

Some things never change even after a thousand years. When Marco Polo crossed the boundless lands of Persia at the end of the 13th century, he saw the “Devil’s Wells” with his own eyes as they burned away relentlessly.

Even today anybody travelling across the Steppes of modern day Azerbaijan can admire the perpetual flames fed by oil emerging at the surface. The scientists on the Marco Polo exhibition can confirm this after travelling 14,000 km along the Silk Route in 2010, collecting genetic data to explain how sensorial  perception varies in different populations. A route embracing different tastes, colours, flavours and smells right across seven states from Georgia to China, across inhospitable lands and inaccessible mountains, among beekeepers and camel drivers, nomadic shepherds and spice traders.

A thousand years are also a drop in the ocean for genetic codes. Sometimes variations in them can tell us about events that historians have not yet spoken about. So, in order to take a snapshot of the genetic features of populations living along the Silk Route, the scientists on the expedition followed the tracks taken by the famous Venetian merchant when he travelled to the East.

The expedition was organised by Burlo Garofolo Hospital, Sissa Medialab and the Terra Madre Association.

The modern-day Marco Polos included the geneticist Paolo Gasparini, who helped collect the endless array of data now about to be published.

To what extent do our genes affect the evolution in eating habits?

Each of us is born with our own genetic imprint that defines our sense of taste or, in other words, the way in which we sense what is bitter, sweet, tangy and salty. In the case of bitterness, for example, we have three well-defined groups: non-tasters or those people who can hardly taste it; those who can taste it in a very intense way, so-called supertasters; and, lastly, an in-between group. The distribution of these different variations differs from population to population. In the Mediterranean 30-35% are non-tasters, while in India the figure exceeds 50%.

Which is the more important, genetics or the environment?

This is rather like the question of the chicken and the egg. Of course we cannot overlook the availability of foodstuffs in our surrounding environment or the influence of high temperatures that have forced various

populations to preserve food by means of spices, drying or smoking. But genetics takes precedence.

Did you experience this on your travels?

Of course. We began in Caucasus where about 15% of the population are super-tasters before travelling to the Highlands of Pamir in Tajikistan where the percentage is over 30%. Because things have a bitter taste to the people of Pamir, their food is mainly very sweet: the national dish is called atolla, a soup made out of  mulberry flour, dried apricots and black peas. It is so sweet that we would consider it a dessert.

What are the effects of these differences?

Super-tasters tend to have a more limited, monotonous and unvarying diet. They refuse to eat anything bitter like radish, rocket salad, beer, chicory, cabbage, un-sugared coffee or grapefruit. The non-tasters are more willing to sample and experiment with very different kinds of foods, like ethnic dishes. In India, where over half the population are non-tasters, the food is, indeed, extremely spicy.

The Silk Route was one of the first examples of globalisation, even though people travelled by camel back in Marco Polo’s times. Nowadays, in contrast, everything moves so fast…

That does not mean, however, we are willing to embrace everything. Ethnic types of cuisine, for example, have had to adapt to the genetic predispositions of Westerners.

Take oriental food: anybody who has been to China will have tasted an extremely varied, spicy and vegetable-rich cuisine, very different from the kind imported to Europe. That also applies to wasabi, an extremely spicy Japanese radish, which, according to tradition, should be spread between raw fish and rice: in the West though, except for a few exceptions, it is served separately from the sushi.

What kind of tests did you carry out?

We carried out a series of extremely thorough sensorial tests, such as the tests for taste, favourite foods ,  sense of smell, hearing, sight and, above all, colours. But we also measured a set of parameters such as weight and height. An extensive study of the data was completed just a few weeks ago and we are already

seeing some interesting correlations between food types and health. For example, the absence of diabetes in Pamir, despite an imbalance in diet towards very sweet foods.

What are the main differences between the various populations you encountered?

The presence of certain genes varies among different populations and you can see that just by looking at the face of a Georgian or Chinaman. We have discovered that this variation in distribution causes sensible differences in the perception of smells: even though this was a spice route, for example, there are certain recurring mistakes such as the confusion between cloves and cinnamon. Or, for example, in Georgia we discovered that lots of people have difficulties in perceiving colours. These studies will also turn out to be useful for people studying the history of migrations.

How did people react to you?

We were welcomed enthusiastically by all the different populations we met along the way. For them it was a bit of a celebration: they were amused at the idea of a team of scientist in uniform, who had come up with the idea of retracing Marco Polo’s journey.

Despite the tastes of supertasters, coffee is drunk to socialise.  Is it the same along the Silk Route?

As you progress further towards the east, coffee is gradually replaced by tea, which is a good way of flavouring boiled (and hence sterilised) water. Some countries really drink lots of it, some people claimed they drank as much as 5litres-a-day!

Where will your next expeditions be to?

This summer we will complete the Marco Polo expedition by spending a week in Armenia, a country we missed out last year because of unrest between the Azerbaijani and Armenians that would have prevented us from continuing our journey towards Azerbaijan. We are now trying to raise money for another major  expedition in 2013: we want to travel right across the Cordillera delle Ande from Columbia to Patagonia.