For the uninitiated the mere idea of smearing a sticky blackish sludge of brewer’s yeast on a piece of toast and then eating it for breakfast might trigger a wee bit of nausea, and yet there are people in this world who love Marmite.
Why?
Taste Preference
Like many of the other Big Questions we face in this life, the answer is complicated. And then there’s the fact that Marmite is one of those polarizing foods you either love or hate.
We’re into science, and we like to ask probing and even provocative questions here at 23andMe. So we wanted to know if we could learn a little about whether genetics might play a role in your choice of breakfast spreads. 
Genetics, after all, factors into our taste preferences. Whether it’s liking Salty v. Sweet snacks, or have an aversion to Bitter Taste, or a dislike of Cilantro, your genes pay at least a small role. And don’t get us started on “supertasters.” These kinds of culinary inclinations are determined by a complex interaction between your environment, your lifestyle, and, yes, your DNA.
So what about Marmite? (We’re going to leave Vegemite, Marmite’s even more robust Aussie cousin, in the pantry for now.)
What About the Genetics?
Genetics explains some of the appeal of Marmite, according to a new genome-wide association study by researchers at 23andMe.
Looking at data from more than 100,000 23andMe customers of European descent who consented to participate in research — and who know what the heck Marmite is — Peter Chisnell, PhD., a 23andMe Health R&D scientist found three genetic variants associated with “loving” Marmite.
In follow-up analysis, Peter looked at the area in the genome where we saw the strongest genetic association. It is near a gene related to olfaction, a key to our sense of taste. The SNP is near the SIX3 gene, a “homeobox protein,” and acts like a master controller for the expression and regulation of a bunch of genes.
“It’s a giant sledgehammer kind of gene that affects a lot of things,” said Peter.
Smell and Taste
Large changes in its function have been shown to disrupt neurodevelopment in mice, including a part of their brain responsible for olfaction. We don’t really know exactly how these small genetic changes in people could explain differences in taste, but it’s plausible that changes in the sense of smell may make one more prone to like the salty savory flavor of Marmite.
Along with the association found near the SIX3 homeobox gene, the study found an association near the gene OR12D1, an olfactory receptor. Finally, Peter’s analysis noted a significant single nucleotide polymorphism (SNP) associated with loving Marmite near the NRXN3 gene, which is involved in the nervous system, including behavioral traits like fear and empathy, but also tendencies toward addiction and obesity.
What these all may or may not mean regarding a preference toward the salty-savory taste of Marmite is about as opaque as the dark syrupy spread itself. After all, our sense of taste is a complex process.
Taste receptors on our tongue bind to a set of chemical compounds in food to recognize specific odorants or tastants and then sends that information to our brains. There are receptors for five types of tastes — sweet, sour, salty, bitter, and savory, also known as umami. Several different genes are essential for taste and smell. So, for example, the TAS1R and TAS2R gene group is involved in the perception of sweet, umami, and bitter perception. The hundreds of genes that are part of the olfactory receptor gene group also play a role.
The Cultural Story
Beyond the biology involved in taste is a whole slew of cultural and environmental factors that go into what each of us likes and doesn’t like to eat.
We see a little of that in 23andMe’s study because we also looked beyond genetics. The 23andMe researchers broke down individuals by sex and also by country, not just where they currently reside but where they were born. Men were more likely to love Marmite than women, for instance. The difference between men and women isn’t likely explained by the genetic associations we analyzed, Peter said. The data also gets interesting when you break it down geographically.
This offers a great example of how culture also plays a role in taste preference. Genetics can’t really explain the differences in why some countries have more Marmite lovers than others. This is because countries have about the same proportion of people who are genetically predisposed to liking Marmite.
As you would expect, the researchers found that most people who knew about Marmite lived in Commonwealth countries with strong ties to the UK. And unsurprisingly, some of those same countries were where you found the most Marmite lovers — New Zealand, South Africa, Australia, and the UK. But also among the countries that ranked highest for loving it were Russia and Turkey.
Among those places that ranked highest for hating Marmite were the US, Canada, and Ireland.
“We don’t have a great biological mechanism to explain those differences,” said Peter. “The cultural story seems more plausible to me than a biological explanation.”
An Acquired Taste
Food preferences and acquired tastes are greatly influenced by the culture we live in.
And why do you have more Marmite haters in Canada, Ireland, and the US? There are no discernable genetic differences to explain that.
Interestingly, none of the genetic associations we found for loving Marmite were in the genes associated with bitter taste receptors. Nor did we replicate any of the associations in the only other genome-wide association study on Marmite.
And yes, our GWAS is actually not the first one on Marmite. A few years back, the company that has made the spread since the first World War launched the Marmite Gene Project. In collaboration with another company, they ran a GWAS using just 261 people. That tiny study found 15 SNPs associated with Marmite preference. But the researchers acknowledged that the study lacked statistical power. None of the SNPs or genes identified in that study were replicated in our own.
