The Effects of Isolation and Confinement on Food Perceptions

A recent study indicated that confinement and isolation could affect how individuals perceive food aromas.

Researchers from RMIT University conducted a study comparing the perception and emotional responses of 44 individuals in two different environmental conditions: microgravity (zero gravity) and isolated confinement.

The study, published in Food Research International, sought to clarify why astronauts find food tastes different in space, leading them to struggle with regular meals during extended missions.

Participants were placed in reclined chairs to simulate microgravity and underwent a simulation of the International Space Station (ISS), which is a confined and isolated environment, using virtual reality (VR) goggles.

Eight different aromas were tested, including vanilla, almond, lemon, lemon myrtle, eucalyptus, peppermint, vinegar, and lemongrass.

Among the aromas, lemongrass was the only one perceived more intensely in the confined environment compared to microgravity.

Smell plays a crucial role in the perception of flavor, so a loss of smell can significantly impact the ability to taste food.

“This foundational work is essential for developing improved space foods and enhancing the eating experience for individuals in isolated or confined environments,” said Co-lead researcher Julia Low in a statement to The Epoch Times via email.

“These findings are also relevant for other populations, such as older adults in nursing homes, who live in similar environments on Earth.”

Why These Aromas?

The study’s first author, Grace Loke, explained that the research team selected different aroma categories and chose commercially available aromas to represent them.

“For instance, trigeminal aromas that provide cooling, spicy, warming, or pungent sensations were represented by eucalyptus, peppermint, and vinegar,” Loke mentioned.

Trigeminal aromas activate the trigeminal nerve, eliciting various sensations like freshness, stinging, burning, and tingling, commonly known as pungent sensations.

Co-lead researcher Low mentioned that while the team plans to test complex foods in the future, the current focus is on understanding how food aromas are perceived fundamentally and the impact of space-like environments on this perception.

Aroma Perception in Space

Past research on the altered taste experienced by astronauts has centered on microgravity, whereas this study concentrated on confinement and isolation.

Low highlighted the fact that most people typically eat in a social setting.

“The results suggest that a remote, confined environment like the ISS and individual variations in sensitivities can influence aroma perception, making certain foods smell unfamiliar,” she remarked.

“This research opens up opportunities for personalized meal plans for astronauts and individuals living in solitary conditions on Earth, demonstrating the potential of VR to explore eating variations under stress.”

Loke noted that their preliminary studies indicate no noticeable difference in how a limited range of food aromas are perceived in a normal environment compared to a microgravity environment.

However, conclusive findings will require testing in actual microgravity conditions.

This is because gravity on Earth pulls bodily fluids into the legs, whereas in space, these fluids are evenly distributed, causing blocked nasal passages initially. The body eventually adapts, and the fluid shift balances out, resolving the blockage and improving the ability to smell, thus affecting taste.

Newman mentioned that future studies would combine VR and microgravity to better emulate the astronaut experience and develop food plans for longer missions.

The study indicates that a simulation incorporating both environments could aid in preparing astronauts for the psychological challenges of eating in confined and remote spaces.

Emotions and Aromas

Aromas were perceived differently during the VR simulation based on the individual’s emotions at the time.

For instance, individuals experiencing happiness or positive emotions perceived vanilla and almond aromas as more potent.

Conversely, mildly stressed participants found vinegar aroma less intense.

Co-lead researcher Lisa Newman suggested that the connection between stress and vinegar perception might explain why astronauts prefer certain foods during missions that they might not enjoy on Earth.

For example, astronauts often request condiments like hot sauce to enhance flavors in space due to the loss of taste intensity.

The reason why specific smells are enhanced with more positive emotions remains unknown.

“It may be related to the chemical compositions of the aromas—particularly with almond and vinegar, which are polarizing aromas (either strongly liked or disliked),” Loke speculated.

“Therefore, polarizing scents might be more pronounced with positive emotions, which warrants further investigation.”

The Exceptional Scent

Among the scents tested, lemongrass was the only aroma perceived more strongly in microgravity.

“Lemongrass has a floral and earthy aroma, while the other aromas are more pungent, spicy, or sweet,” Loke explained.

“This difference in aroma profile may elucidate why lemongrass seemed less intense in the VR simulation compared to the microgravity setting.”

However, the reason why floral and earthy aromas are more potent in simulated microgravity than in the confined VR experience remains unclear.