It turns out that whether you like dark chocolate or milk chocolate may have a little bit to do with your genetics.
We know that our bitter and sweet taste perceptions are highly associated with different genetic variants.
A lot of work has focused specifically on bitter taste perception associated with a variant in the TAS2R38 gene. Some people have it and some don’t.
About a quarter of 23andMe customers don’t have the bitter taste variant – making them more likely to have a taste for hoppy beer, broccoli or dark chocolate. A variant in theTAS2R38 gene enables some to perceive the bitterness of the chemical propylthiouracil, or PROP. Some so-called supertasters not only perceive bitterness but also can discern more saltiness, sweetness and spice, suggesting that there are other genes involved in our food preference.
So of course the TAS2R38 variant doesn’t explain everything. While surveys of in the United States show that more than half of Americans prefer milk chocolate to dark, among 23andMe customers dark chocolate wins out. Almost half of 23andMe customers prefer dark chocolate, while about 39 percent say they like milk chocolate. That may have to do with genetics, but it is more likely related to a mix of other non-genetic factors.
And there are plenty of genetic factors that researchers are still exploring. For instance, a genome wide association study done last year found 17 genes related to liking certain foods – including among other things dark chocolate, blue cheese and liver – that belong to the groups of genes that apparently have nothing to do with taste or smell perception.
All this just goes to show that, like love, our food preferences are complicated.