Your Hatred Of Broccoli May Be Hardwired In Your Microbiome


Dr. Katie Spalding

Katie has a PhD in maths, specializing in the intersection of dynamical systems and number theory.

Freelance Writer


"I don't like it mommy, it tastes like S-methyl-?-cysteine sulfoxide." Image credit: Jeka/

We have, believe it or not, reached Fall, which can only mean one thing. No, not Thanksgiving – well, yes OK, Thanksgiving, but specifically: brassica season.

Broccoli, cauliflower, Brussels sprouts – you name it, our moms have probably boiled it for far too long and told us to “eat up, it’s delicious.” But for many of us, those words were nothing but a dirty lie: of course Brussels sprouts aren’t tasty, you know they aren’t, and so do the other millions of people across the planet who force themselves to smile through plates of the bitter little fart-balls each dinner time.


Well, we have good news and bad news. The good news is that, according to a study published this week in the Journal of Agricultural and Food Chemistry, you can’t help it: it’s literally written into your oral microbiome to hate brassicas. The bad news is that this is technically only true if you’re a baby who doesn’t want to eat their vegetables because they’re icky.

“Significant negative relationships were found between children’s liking scores for raw cauliflower [and their oral microbiome],” the study explains. “Although negative relationships were found for the same ions for the adult group, they were not significant.”

In other words: people do seem to grow out of it. But what exactly is it that’s causing the squick in the first place? According to the study, it’s something called S-methyl-ʟ-cysteine sulfoxide: a “unique substrate present in Brassicas that produces odor-active sulfur volatiles” when certain people eat it. If you have the right levels of certain bacteria in your oral microbiome, the authors explain, it can affect the “in-mouth odor development” from the vegetables, making them taste about as delicious as you would expect from something described by the phrase “in-mouth odor development.”

Interesting – and a handy excuse come Christmas dinner – though that may be, it’s not news: scientists have known for over a decade that the oral microbiome plays some role in how we perceive taste. But what they didn’t know, and what this new study has shown, is the significance of the biome in children.


The team made the discovery using a technique called gas chromatography-olfactometry-mass spectrometry (ironically, quite the mouthful). This allowed them to identify the main odor compounds in raw and steamed cauliflower and broccoli, which they then presented to study participants (98 parent-child pairs, with children aged between 6-8) and told them to sniff. The odors were rated by the adults and children involved; dimethyl trisulfide, which the researchers describe as smelling “rotten, sulfurous and putrid”, was perhaps unsurprisingly rated the worst.

The team then mixed saliva samples from the study participants with raw cauliflower powder and analyzed the volatile compounds produced over time. The levels varied widely from person to person, but were similar between children and their parents, the researchers found. But while children with higher levels of the sulfur volatiles disliked their veggies the most, the same wasn’t seen in adults – in other words, kids may not have more sulfur volatile production than adults, but they experience their yukky effect much more intensely.

“To the best of our knowledge, this is the first study that attempts to measure differences in the rate of development of sulfur volatiles in saliva between adults and children and potential impacts on vegetable liking,” conclude the authors. “A significant negative relationship between the degree of sulfur volatile production and liking in children provides an intriguing new potential explanation for differences in liking for Brassica vegetables, especially in children.”


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