Evrim Yazgin
Cosmos science journalist
A world-first study on common food aromas might explain why food tastes bad in space.
The researchers from RMIT University believe the new study, published in the International Journal of Food Science and Technology, might help not only astronauts but people on Earth living in isolated environments get enough nutrition.
“Previous astronauts or space travellers have reported that food doesn’t taste the same in space as it does on Earth,” first author Grace Loke, a PhD candidate at RMIT, tells Cosmos. “Imagine having your meals pre-planned months ahead because they tasted good on Earth, only to dislike them in space. Usually flavour is lost.”
Loke says condiments like Tabasco sauce are popular for space flights to compensate for flavour.
“The difference in flavours experienced on Earth versus in space could also explain why astronauts typically only meet about 80% of their energy needs in space,” Loke adds.
Previous research shows that aroma plays a big role in food flavour.
In the new study, the team tested the perception of vanilla and almond extracts and lemon essential oil. They measured how this perception changed among 54 adults from normal environments on Earth to the confined setting of the International Space Station (ISS), simulated using VR goggles.
They found that vanilla and almond aromas were more intense in the ISS-simulation, while the lemon scent was unchanged.
A particular sweet chemical found in almond and vanilla aromas called benzaldehyde, and a person’s sensitivity to the smell, could explain the changed perception.
“A greater sense of loneliness and isolation may also play a role, and there are implications from this study around how isolated people smell and taste food,” says lead researcher Dr Julia Low, also from RMIT. “One of the long-term aims of the research is to make better tailored foods for astronauts, as well as other people who are in isolated environments, to increase their nutritional intake closer to 100%.”
“The environment of the ISS can be very isolating and confining,” adds Loke. “The best way to think about it is remembering what it was like during the pandemic lockdown – stuck in your room or house with no access to the outside world.
“Some people on Earth also live in similar environments, like the elderly in nursing homes, military personnel on deployment, submariners, oil rig workers, etc. The outcomes of this research could benefit their food systems and encourage better nutrition.”
One might imagine that physiological changes from being in space would be the determining factor in astronauts enjoying their food less.
Low-gravity causes fluid to shift from the lower to the upper parts of the body. This creates facial swelling and nasal congestion which affects smell and taste. But these symptoms begin to disappear within a few weeks. Despite this, astronauts still say they are not enjoying their food.
The new research suggests spatial perception plays a significant role in smell and taste.
Co-researcher Associate Professor Gail Iles, a former astronaut instructor from RMIT, says lack of nutrition is dangerous, especially in long-term missions.
“What we’re going to see in the future with the Artemis missions are much longer missions, years in length, particularly when we go to Mars, so we really need to understand the problems with diet and food and how crew interact with their food,” Iles explains.
“The incredible thing with this VR study is that it really does go a very long way to simulating the experience of being on the space station. And it really does change how you smell things and how you taste things.”
“The results of this study could help personalise people’s diets in socially isolated situations, including in nursing homes, and improve their nutritional intake,” Low adds.
“We speculate that using food flavourings with a sweet nature to them could be used to enhance our flavour perception of other foods.
“But up to a certain point, adding too much might be unpleasant to the overall food – this needs to be studied. For example, if you have a hazelnut latte with an overpowering hazelnut flavour, it could disturb the general flavour or taste of your coffee.”
Loke tells Cosmos that more aromas could be studied.
“We have only looked at 3 food aromas, but food is generally a lot more complex, so this is something we may look into in the future.”
