It’s a struggle that many parents regularly face at dinner time, and now a new study may finally shed light on why so many children dislike broccoli.
Researchers from Australia found chemicals in the mouths of children could be behind their dislike of brassica vegetables, including broccoli, cauliflower and sprouts.
Enzymes produced by the vegetables react with bacteria in the mouth and produce unpleasant, sulphurous odours, according to the experts.
While parents had the same levels of enzymes in their mouths, their reaction to broccoli doesn’t tend to be as bad, which the team says could be from learning to accept the food.
Chemicals in the mouths of children could be behind their dislike of broccoli, cauliflower and sprouts, according to a new study into the brassica vegetables
The new study found that the same enzyme is produced by bacteria inside the mouth of some people, and taste for broccoli depends on levels of the enzyme.
Previous research found that adults have different levels of the enzyme in their saliva, but it wasn’t clear whether children also had varying levels, or what the impact was on their food preferences, according to the team.
Damian Frank and colleagues at the Commonwealth Scientific and Industrial Research Organisation (CSIRO) in Canberra, who conducted this research, wanted to investigate differences in sulphur volatile production in saliva from children and adults.
Dr Frank said it is well known that differences in taste preferences exist between adults and children following innate likes and dislikes.
‘Children are reported to have a stronger preference for sweetness than adults and much-reduced acceptance of bitterness,’ he explained.
‘Bacteria naturally present in some human individual’s saliva can further increase the production of sulphur volatiles in the oral cavity, thereby potentially affecting the in-mouth flavour and perception of Brassica vegetables.’
Broccoli are all members of the family of vegetables that also includes cabbage, collard greens, kale, and turnips, and often left to the side of a child’s dinner plate
Using a technique known as gas chromatography-olfactometry-mass spectrometry, they identified the main odour-active compounds in raw and steamed Brassica vegetables, including cauliflower and broccoli.
They then had 98 groups of a parent and child aged between six and eight, to rate the odours produced from the individual compounds coming from the veg.
Dimethyl trisulfide, which smells rotten, sulphurous and putrid, was the least liked odour by children and adults.
The team then mixed saliva samples with raw cauliflower powder and analysed the volatile compounds produced over time.
There was a large range of levels of sulphur volatile production from one individual to the next, according to the researchers – some having a lot, some very few.
They found that children had similar levels to their parents, which can be explained by similar microbiomes in the mouth passed from parent to child.
Children whose saliva produced high amounts of sulphur volatiles disliked raw Brassica vegetables the most, but this relationship was not seen in adults, who might learn to tolerate the flavour over time.
These results provide a new potential explanation for why some people like Brassica vegetables and others (especially children) don’t, the researchers say.
The results have been published in the American Chemical Society’s Journal of Agricultural and Food Chemistry.