Julia Low

Maintaining adequate nutritional intake and body mass is critical in spaceflight and its terrestrial analogs; however, comprehensive evidence on dietary intake patterns and nutritional adaptations during long-term isolation and confinement remains limited. Following PRISMA guidelines, this systematic review synthesizes evidence on dietary intake and nutrition-related adaptations in isolated and confined environments. Across 184 studies, dietary structure ranged from highly standardized to highly variable. Energy intake differed substantially across habitats, whereas macronutrient distributions remained within recommended ranges, characterized by stable protein intake across habitats and more variable carbohydrate and fat contributions. Body mass generally decreased, with the greatest heterogeneity observed in terrestrial isolated, confined, and extreme environments. Vitamin D insufficiency was consistently reported but could be effectively prevented through supplementation. Overall, isolated and confined environments challenge nutritionally adequate food systems, and current evidence is insufficient to draw firm conclusions on optimal strategies, particularly for longer-duration space missions.

This study investigated whether adding an immersive virtual reality simulation of the International Space Station (VR-ISS) to short-term -6° head-down tilt (HDT) position altered food perception and the broader eating experience. HDT was implemented using the NOVA360 motion simulator, which enabled the postural analogue to be combined concurrently with the VR-ISS. Eighty participants were assigned to HDT or HDT + VR-ISS (n = 40 per context) and evaluated two chocolate snacks (brownie and cookie) and two liquid products (chocolate-flavoured milk and tomato soup). Product-related outcomes included sensory intensity and liking, while context-related responses included affective state, perceived stress, loneliness, engagement and qualitative experience. For the chocolate snacks, adding VR-ISS did not significantly alter sensory intensity or liking. In contrast, liquid intensity was higher in HDT + VR-ISS than in HDT (3.69 ± 0.88 vs 3.00 ± 1.03; p<0.001), while liking remained comparable between contexts. The combined context was also associated with lower valence and dominance during eating (p=0.021 and p=0.004, respectively), higher overall perceived stress (3.68 ± 2.68 vs 2.75 ± 2.20; p=0.006), and lower total engagement (51.53 ± 12.69 vs 56.63 ± 5.36; p=0.023) than HDT alone. Perceived loneliness increased during exposure to both contexts but did not differ between them. Qualitative responses reflected bodily discomfort in both contexts, with additional spatial disorientation and bodily adjustment under HDT + VR-ISS. Overall, adding immersive spacecraft context to HDT produced selective, product-dependent sensory responses but clearer changes in affective and task-related experience. Combined postural and immersive analogues may therefore enhance the ecological relevance of ground-based space-food testing while highlighting the importance of product-specific evaluation.

Space food systems are central to sustaining astronaut health and performance, yet inadequate dietary intake, weight loss, and nutrient shortfalls remain recurring concerns during human spaceflight. These risks are expected to intensify as missions extend beyond low-Earth orbit, where crews will experience prolonged isolation, confinement, monotony, and limited resupply. Altered flavour perception has been proposed as an important contributor to reduced food acceptability and intake, but the interacting mechanisms remain poorly understood. This narrative review synthesises evidence from spaceflight reports, astronaut accounts, ground-based analogues, and food sensory science to examine how sensory, physiological, environmental, and psychological factors shape food perception and eating behaviour in space. Particular attention is given to olfaction, which contributes substantially to flavour perception and may be affected by microgravity-related fluid shifts, enclosed cabin odours, sensory monotony, and changes in mood, stress, and social connection. The review highlights that changes in space food experiences are unlikely to arise from a single factor; rather, they reflect the combined influence of altered chemosensory function, environmental context, affective state, individual variability, and food-system constraints. Emerging digital technologies, including virtual and extended reality, offer promising ground-based tools for simulating space-like contexts and improving the ecological validity of sensory evaluation. Insights from space research also have broader relevance for Earth-based populations exposed to isolation, confinement, sensory loss, or reduced appetite. A more integrated, personalised, and context-sensitive approach to space food research is needed to support nutrition, wellbeing, and performance during future long-duration missions, and guide innovation in terrestrial food systems more broadly.

Using an online survey, we investigated how the importance of olfaction influences eating behaviour among adults aged 55 and over across six countries/regions (n=627): Australasia (Australia and New Zealand), China, Germany, Sri Lanka, Thailand, and the United Kingdom (UK). Participants (self-reported as healthy) were assessed on four olfactory importance subdomains: application, consequence, association, and aggravation. Additional self-reported measures included body mass index (BMI). Both univariate and multivariate analyses revealed significant country/region-level differences with participants from Western countries reporting lower overall olfactory importance than those from Asian countries (F(5,618) = 20.79, p<0.001). Country/region-level analyses further confirmed this pattern, with the higher scores on overall olfactory importance observed in China, Sri Lanka, and Thailand, and lower scores in Australasia, Germany, and the UK. Notably, these cultural and country/region differences remained consistent irrespective of age, gender, or BMI. However, age and BMI showed independent effects: individuals over 70 years reported greater olfactory importance than younger groups (F(5,618)=4.77, p=0.020), while higher BMI was associated with lower importance ratings (F(5,618)=3.92, p=0.037). Principal component and cluster analyses identified two distinct clusters: one with higher olfactory importance, primarily consisting of participants from Asian countries/regions, and another with lower importance, predominantly from Western countries/regions. These clusters were unrelated to age, gender, or BMI. The findings indicate that cultural context plays a stronger role than individual demographic factors in shaping the perceived importance of olfaction during eating. This suggests the need for culturally sensitive approaches when designing olfactory interventions and highlights the significance of assessing perceived relevance alongside psychophysical measures when evaluating the importance of olfaction in eating behaviour in older people.

Space food systems rely on enclosed delivery formats (e.g., straw-fitted pouches) to enable safe consumption in microgravity, yet their influence on sensory perception remains poorly understood. This study investigated how delivery method and environmental context interact to shape flavour perception, ease of consumption, affective responses, and engagement during liquid food consumption in simulated space environments. A total of 200 participants were randomly assigned to one of five contexts: neutral sitting, microgravity posture, virtual reality (VR) neutral, VR International Space Station (VR-ISS), and −6° head-down tilt (HDT). Participants evaluated five shelf-stable liquid products that differed in viscosity and flavour profile, delivered either via a straw in a pouch or directly from a pouch. Results showed that viscosity moderated contextual effects, with thicker liquids exhibiting greater sensitivity to contextual changes. The VR-ISS context increased perceived flavour intensity, while straw-based consumption consistently enhanced intensity and ease of consumption across contexts. In contrast, overall liking was primarily driven by product characteristics rather than context or delivery method. Immersive and posture-altered contexts elicited stronger affective responses, with VR-ISS associated with higher engagement and HDT linked to reduced valence and greater negative affect. These findings demonstrate that delivery format is not a neutral factor, but a key determinant of sensory and affective responses in simulated environments. Incorporating space-relevant delivery systems is therefore critical for improving the ecological validity of sensory studies in space analogues and other constrained eating contexts.

Long-duration space missions present challenges for maintaining food acceptability under altered environments and contextual conditions. This study examined how simulated space environments affect sensory and affective responses to food. In a between-subjects study, 250 adults (50 per context) evaluated two shelf-stable chocolate-based snacks with contrasting textures (cookie: crunchy; brownie: soft) under five contexts: neutral sitting, microgravity posture, Virtual Reality with neutral cues (VR-neutral), VR simulating the International Space Station (VR-ISS), and combined microgravity posture + VR-ISS. No statistically significant differences were observed between neutral sitting and microgravity posture, nor between neutral sitting and VR-neutral contexts, under the present design. However, immersive VR contexts (VR-ISS and combined posture + VR-ISS) were associated with perceptual shifts, including higher perceived vanilla intensity, lower chocolate intensity, and increased crunchiness (p < 0.05). Compared with the VR-neutral context, these findings suggest that immersive environmental content, rather than headset hardware alone, was associated with the changes in sensory perception. Immersive contexts also increased valence and arousal and broadened emotional profiles. Effects were generally product-dependent, with brownies (softer texture) demonstrating greater perceptual stability across contexts than cookies (crunchy). These findings demonstrate that immersive VR space analogue environments can affect sensory and affective responses in controlled laboratory settings. Identifying context-sensitive perceptual dimensions provides a structured basis for future research examining how immersive environmental cues interact with product structure under space-relevant conditions.

The Head-Down Tilt (HDT) is a widely used space analogue for studying food-related chemosensory perception, as it simulates key physiological effects of weightlessness on the human body. However, the integration of this method with Virtual Reality (VR) tools remains underexplored, presenting an opportunity to improve the efficacy of space analogues. A dual study design was used to investigate the combined effect of a -6° HDT and a VR-simulated spacecraft environment on orthonasal (sniffing) and retronasal (in-mouth) odour perception, along with affective responses, and overall experience. In total, 200 participants (orthonasal n=105; retronasal n=95) evaluated three food odours for intensity and liking in one of three randomly assigned contexts: Central Location Test (CLT; non-VR), VR-simulated spacecraft (VR-Space), or a combined VR-simulated spacecraft and -6° HDT condition (VR-HDT). Findings suggest greater almond odour intensity in the VR-Space context compared to the CLT and VR-HDT contexts, but only during retronasal evaluation. In contrast, greater almond liking was found in the VR-HDT context than in the CLT, specifically during orthonasal evaluation. Participant engagement measures captured significantly lower interest (affective value) and focus (active involvement) in the VR-HDT context relative to the CLT and VR-Space. Generally, the VR-HDT experience elicited more negative valence and higher perceived stress compared to both contexts, with moderate levels of loneliness comparable to the VR-Space context. These findings highlight the potential value of integrating digital immersion with altered posture to enhance the ecological validity of space analogues for assessing sensory and affective responses.

This study explores the influence of Virtual Reality (VR) tools and digitally simulated environmental contexts on food odour perception and affective response. Participants experienced three contexts: a Central Location Test (CLT), Virtual Reality-Home (VR-Home), and Virtual Reality-Space (VR-Space). In a two-phase study design, 211 healthy individuals assessed the intensity and liking of five food odours through either the orthonasal (n=112) or retronasal (n=99) olfactory pathways, with each person randomly assigned to one context. Validated and adapted scales measuring affective state, emotional dimensions, perceived stress response, and engagement were administered to identify differences across contexts. Results indicated that odour perception differed by odour delivery pathway and specific odour type, possibly due to contextual familiarity and the inherent attributes of the odour stimuli. High engagement levels were observed across all contexts, indicating that the VR environments effectively provided a sense of immersion suitable for sensory evaluation. Interestingly, the VR-Space context appeared to promote more negative emotional valence, greater emotional arousal and a reduced sense of emotional control (dominance), along with higher perceived stress levels. However, these negative affective outcomes may be considered desirable, particularly in contexts like VR-Space, where the goal was to simulate an environment that induces stress or negative affect akin to that experienced during spaceflight. These findings offer limited evidence that VR tools or digital immersion alone significantly alters sensory perception or affective responses, but instead, supports its potential as a tool for simulating and studying sensory experiences in stressful, confining, and isolating environments like space.

The global prevalence of iron (Fe) deficiency anemia (IDA) continues to pose major public health challenges, necessitating the development of effective fortification strategies. Dairy‐based systems are promising vehicles for Fe fortification and delivery due to their widespread consumption and nutritional value, although their complex matrix presents significant challenges for maintaining Fe bioavailability and product quality. This review critically evaluates current knowledge on Fe fortification in dairy systems, integrating evidence on Fe forms, physicochemical interactions between Fe and the matrix, and their consequent effects on Fe bioavailability and physical functionality. Emerging fortification strategies are highlighted. Conventional Fe salts, including ferrous sulfate, ferrous fumarate, and ferric pyrophosphate, have varying degrees of solubility and absorption but are often associated with adverse sensory changes, lipid oxidation, and reduced product stability. Fe–ligand complexes, including protein‐, carbohydrate‐, and Maillard reaction product (MRP)‐based systems, can impart improved stability to the fortified product and bioavailability by minimizing interactions with inhibitors of Fe absorption. The incorporation of Fe into dairy matrices influences product pH and structural and functional properties while also accelerating lipid oxidation and sensory deterioration when inorganic salts are used. Strategies such as Fe chelation, microencapsulation, and co‐fortification with enhancers have shown potential to mitigate these limitations. In addition, the role of prebiotics, probiotics, and MRPs in modulating Fe absorption remains complex and context dependent. Despite promising advancements, gaps remain in understanding interactions between Fe, proteins, carbohydrates and MRP and their implications for Fe fortification of dairy systems. Future research should focus on developing integrated fortification approaches enabling the design of next‐generation functional dairy foods to effectively combat global Fe deficiency.