A gene for headlines?
Under the headline “Studies show food preferences are written in genes,” the Herald has an interesting story by CSIRO scientist Nicholas Archer about genetic variation in taste and smell receptors (and largely not about food preferences). The same story was at The Conversation, under the headline “Blame it on mum and dad: how genes influence what we eat.”
The text makes much more reasonable claims about food preference. It says
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.
and later
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.
It’s only the headlines that are over the top, but that’s a consistent problem with genetics stories.
When you see a genetics headline, the first thing to think about is whether the trait it talks about has changed over the past century or so. Human genetics hasn’t had time to.
We can look at changes over recent time to show the enormous non-genetic influences on food choice. The biggest ones are due to wealth, but there are actual changes in preferences as well.
For example, raw fish would have been an unusual food preference for Aucklanders of European descent forty years ago. It’s not that raw fish was unavailable back then; that was how it came from the shop. It’s just that people didn’t eat it raw, because ick. Now, raw fish is an absolutely routine form of fast food. That’s not because of a change in genetics, it’s because of cultural change spreading from the US. As another example, many European-ancestry people like spicier food than their parents or grandparents did, not because of a change in genetics, but because of a change in exposure to spices early in life. You can easily think of more.
“Mum and dad” do have a big influence on what we eat, but most of it happens well after conception.
Thomas Lumley (@tslumley) is Professor of Biostatistics at the University of Auckland. His research interests include semiparametric models, survey sampling, statistical computing, foundations of statistics, and whatever methodological problems his medical collaborators come up with. He also blogs at Biased and Inefficient See all posts by Thomas Lumley »