Open Access
Original Article, Biomed Biopharm Res., 2023; 20(1):25-36
doi: 10.19277/bbr.20.1.306; PDF version [+]; Portuguese html [PT] 


Food Labeling - Knowledge among university students in the Lisbon region: an exploratory study

Leandro Oliveira 1 ✉️, Catarina Manoel 2, Márcia Ribeiro 2, Diogo Pedro 2, Catarina Simões Rodrigues 2 & Carina Rossoni 2,3 This email address is being protected from spambots. You need JavaScript enabled to view it.

1 - CBIOS - Center for Biosciences & Health Technologies, Universidade Lusófona de Humanidades e Tecnologias, Campo Grande 376, 1749-024 Lisboa, Portugal
2 - Escola de Ciências e Tecnologias da Saúde da Universidade Lusófona, Av Campo Grande, 376, 1749-024, Lisboa, Portugal
3 - Universidade de Lisboa – Instituto de Saúde Ambiental da Faculdade de Medicina, Avenida Professor Egas Moniz, 1649-028 Lisboa - Portugal



Food labeling is important for consumers to have access to accurate nutritional information and to guide them in choosing healthier foods, but its correct understanding and use by consumers is equally important. This study aims to assess higher education students' knowledge of labeling and relate it to demographic factors. This is an exploratory observational study whose data collection was carried out through an online questionnaire, in the period between November and December 2022. In this study, 124 higher education students participated, mostly female (74.2%), living in the Lisbon metropolitan area (97.9%), who did not practice physical exercise/sport (98.4%), and who had no type of food allergy or disease (84.7%). The mean age of the participants was 20.1 ± 1.9 years old. The mean score for knowledge about food labeling was 5 ± 1.8, with a maximum of 8 points. No relationship was found between knowledge about labeling with demographic characteristics. However, the results point to the need to increase knowledge about food labeling, as well as about the interpretation of nutritional information.

Keywords: food labeling, students, nutrition claims, nutritional information, nutrition


To Cite: Oliveira, L., Manoel, C., Riberio, M., Pedro, D., Simões Rodrigues, C., Rossoni, C. (2023) Food Labeling - Knowledge among university students in the Lisbon region: an exploratory study. Biomedical and Biopharmaceutical Research, 20(1), 25-36.

Correspondence to: This email address is being protected from spambots. You need JavaScript enabled to view it. (L. O.); This email address is being protected from spambots. You need JavaScript enabled to view it. (C. R.)
Received 28/02/2023; Accepted 15/05/2023



Food labeling can serve as an economical tool for providing nutritional information and communication to consumers at the point of purchase, helping them make more informed and healthier food choices (1). However, some consumers are influenced by labeling to consume certain trendy foods (e.g., functional foods) that they may not necessarily need, believing that these foods are healthier (2). In general, food labeling includes the nutrition facts table, serving size, and ingredient list, which are used to communicate basic nutritional information. Currently, information about the nutritional composition and health benefits has been increasingly highlighted on packaging, resulting in more sophisticated food labeling. Examples include the inclusion of nutrition fact panels, nutritional traffic light systems, logos, and nutritional and health claims on the front of the packaging (3).

The literature has shown that there are various determinants of food label use, such as sex, age, level of education, health and nutrition knowledge, among others (4-6). According to the study conducted by Shangguan et al. (2019) (6), which consisted of a meta-analysis compiling intervention studies assessing various exposures to food labels, food labels had a positive impact on subsequent food consumption. The results showed a reduction in energy intake by 6.6%, total fat intake by 10.6%, and consumption of other unhealthy foods by 13.0% (including sugary beverages, alcoholic beverages, potato chips, and white bread). Additionally, the consumption of vegetables increased by 13.5%.

In this sense, specific consumer groups like young adults can be a target for the implementation of strategies that utilize food labeling to promote healthier food choices. By tailoring food labeling initiatives to address the unique needs and preferences of young adults, it is possible to effectively encourage them to make more informed and healthier choices regarding their dietary habits (1,7). The transition of young adults to higher education represents a phase of transition into adulthood, during which time some healthy behaviors may be lost due to adaptation to a new environment, academic pressure, and economic factors (7). This can lead to the development of unhealthy habits and behaviors, such as increased consumption of foods high in sugar, fat, and salt, and decreased consumption of fruits and vegetables (7). In fact, according to a meta-analysis, nearly two-thirds of higher education students experience weight gain during their time in university, and the rate of weight gain is higher compared to the general population (8). Some studies in young adults have shown that the use of food labeling has been associated with healthier eating choices, mainly due to their choosing fewer foods rich in energy, fat, and sodium, such as salty snacks and desserts, and increased choice for foods with greater fiber content, such as fruits and vegetables and whole grains (7). However, it is important to note that the percentage of young adults/university students who consult the nutritional information on food labels is low (4,7). Furthermore, the literature regarding the use, knowledge, and interpretation of food and nutritional labeling in Portugal is scarce, especially concerning young adults and university students.

Thus, it becomes important to assess the knowledge and interpretation of food labeling among young adults and university students in order to develop strategies that can improve their food choices. Therefore, the aim of this study is to evaluate the knowledge of university students regarding food labeling and relate them to demographic factors.


Materials and Methods

Procedure and sample

This is a cross-sectional, exploratory study with a quantitative approach whose sample consisted of higher education students at Universidade Lusófona in Lisbon, Portugal. The inclusion criteria for participation in the study were: to be ≥18 years old, and to be attending Universidade Lusófona for two semesters. For data collection, an online questionnaire (available between November and December 2022) was used through the GoogleForms® platform, and all data were self-reported. An invitation was made by social networks to participate in the study, including a direct link to the questionnaire. Thus, a non-probabilistic snowball sampling was used.

The questionnaire, in Portuguese, was comprised of two sections: demographic and health characterization (sex, age, place of residence, practice of physical exercise, existence of any food allergy or disease, etc.) and knowledge about food labeling, based on a study developed by Morais et al. (2020) (9), which originally included 24 questions related to the following dimensions: meaning of nutrition claims, interpretation of nutrition information, and label interpretation of ingredient list and serving size/nutrient content. Correct answers were counted with one point each, to a maximum of 24 points. In our questionnaire, eight questions were selected to assess knowledge regarding the dimensions of “nutrition claims” and “meaning and interpretation” of food labels. Correct answers were awarded 1 point and wrong answers 0 points (maximum score: 8 points). In addition, we added two more questions: 1. "If the packaging of a food claims to be “fat free”, will you check its nutritional information on the label?”; 2. “Considering that the packaging of a food is attractive, what is the tendency to verify its nutritional information?”.

Ethical considerations

This study was carried out following the ethical norms established in the Declaration of Helsinki of 1964 and its subsequent amendments or comparable ethical norms. The protocol, considering all the principles of good practice in human research, was previously submitted to the institutional Ethics Committee. Information about the study was provided to all volunteers and an informed consent was provided in which the objective and protocol of the study were explained in detail, confidentiality and exclusive use of the data collected for the present study were guaranteed, with the data being treated in a way that guaranteed anonymity.

Statistical analysis

The statistical analysis of the present study was performed using the IBM SPSS Statistics software, version 26 for Windows. Descriptive statistics consisted of calculating the absolute (n) and relative (%) frequencies and calculating the mean ± standard deviation for the quantitative variables. Fisher's exact test was used to assess independence between pairs of variables, the Mann-Whitney test to compare mean orders between independent samples. Spearman's correlation coefficient (r) was used to assess the degree of association between pairs of continuous variables. The null hypothesis was rejected when p < 0.05.



In this study, 124 individuals participated, the majority of whom were female (74.2%). They lived in the metropolitan area of Lisbon (97.9%), did not engage in physical exercise/sports (98.4%), and reported having no food allergies (84.7%). The mean age of participants was 20.1 ± 1.9 years old. The analysis, performed using Fisher's exact test, did not reveal any significant differences in sex and place of residence (p=0.758), practicing physical exercise/sport (p=0.451), or having food allergies (p=0.573), so the data were not presented separately. However, there was a difference in mean age between sexes (p=0.038), with the mean age of females (19.9 ± 1.8 years) being lower than that of males (20.7 ± 2.0 years).

The results of the questions related to the interpretation of food labeling and the use of nutritional information are presented in Table 1. The majority of participants responded that they know how to interpret a food label if they are presented with one (66.9%). Additionally, 57.3% of participants indicated that they would check the nutritional information on the label if the packaging mentions that the food is "fat-free", and 52.4% stated that they are more likely to check the nutritional information if they find the packaging of the food attractive.

Table 1 - Interpretation of food labeling and use of nutritional information (n=124).

Table 2 displays the results of the assessment of student's knowledge of food labeling. The majority of participants responded that "functional food" on a label indicates that the product can produce beneficial physiological effects on health (66.9%), "contains gluten" on the front label of a product indicates that the product contains a protein present in cereals that can cause allergic reactions when consumed (72.6%), and "zero (0%) trans-fat" on the front label of a food indicates that the product is totally free of trans fat (53.2%). In terms of the meaning and interpretation of food labeling, the majority of participants responded that ingredients are listed in descending order based on their quantity in the product (69.4%), "diet" foods are intended for nutrient-restricted diets, which can be carbohydrates, fats, proteins or sodium (54.0%), and the statement "light" foods only have a reduction in calories is false (63.7%). Additionally, most participants responded that a food without added sugar only contains sugar naturally present in its ingredients (91.9%) and that a product labeled as both an "enriched food" and a "nutrient replacement food" indicates that iron, vitamins A, C, and D were added to the product that were already naturally present (41.9%). The mean score for knowledge about food labeling was 5 ± 1.8, with a maximum of 8 points.


 Table 2 - Assessment of knowledge about food labeling (n=124). Answers considered correct according to Morais et al. (9) are indicated with an asterisk (*).

A relationship was found between knowledge about food labeling and the question “if you are faced with a food label, do you know how to interpret it?” (p=0.035), and participants who claimed to know how to interpret labels obtained a higher score (5.2 ± 1.4 points) than the counterpart (4.6 ± 1.5 points.)

No relationship was found between knowledge about food labeling and sex (p=0.364), age (r: 0.049; p=0.592), place of residence (p=0.640), having any type of food allergy or disease (p=0.405).



This study aimed to assess knowledge about food labeling using students attending Lusófona University (Lisbon, Portugal) as a sample. In general, the participants stated that when faced with a food label, they knew how to interpret it. However, evaluating their knowledge, the average score obtained was slightly higher than the midpoint of the scale used.

The results presented are more satisfactory than those outlined in a previous study on food labeling conducted in Portugal, which reported that only 20% of consumers (n=467) were able to comprehend all the information provided on the label. These findings highlight the persistent challenges faced regarding consumer understanding and proper utilization of food labeling information (5). A study conducted with university students in Chongqing, China (4) revealed low levels of knowledge regarding food labeling and its use. Only 21.3% of university students knew how to interpret a food label, and 48.4% utilized or consistently used nutrition labels. Notably, medical students exhibited higher levels of knowledge than students enrolled in other courses.

According to the study by Silva et al. (2022) (5), female individuals show greater concern when buying food, taking longer to make their choices, and reporting that labels influence their food choices. Another study (4) reports that females are more likely to understand the nutrition labels of prepackaged foods, and compared to junior college participants, senior college and graduate school participants had a higher probability of understanding food nutrition labels for prepackaged items. In our study, no relationship was found between demographic characteristics and knowledge of food labeling. However, finding a higher level of knowledge among female participants would be expected, as described in other studies. This result may be because now males are also increasingly concerned about their health, and are more careful with their nutrition, as well as other health and wellness issues.

Regarding nutritional claims, it was found that most students were familiar with the meaning of "contains gluten" and "functional food", similar to another study (9) with Brazilian consumers (n=418), recruited at a university. On the other hand, most university students in our study mistakenly considered that when there is a claim “zero (0%) trans-fat” it can be said that the product is completely free of trans fat, as in the Brazilian study (9). Indeed, according to Portuguese legislation, a claim that a food "does not contain saturated fat" can only be made when the sum of saturated fat and trans fatty acids does not exceed 0.1 g of saturated fat per 100 g or per 100 ml of the food (10). Therefore, this claim does not mean that the food is completely free of trans fat, but rather that the amount present in that food is not considered significant enough to use other terminology, as stated Morais et al. (9).

Regarding "diet" and "light" foods, the understanding of the university students assessed in this study was lower than that found in a study with university students in Brazil (9). However, in relation to enriched foods, the knowledge of our sample was slightly lower compared to the same Brazilian study. Regarding comparative claims, it is necessary that the products being compared are clearly indicated to the end consumer (10). Although regulated, these terms may still be unfamiliar to consumers, as generally, the Portuguese consumer does not have a high level of knowledge about food labeling (5).

Finally, it is important to emphasize that although the knowledge about food labeling found in this study was slightly above the midpoint of the scale, further clarification is needed for this population group, as there are difficulties in understanding and interpreting nutritional labeling, even basic concepts. In this sense, other studies have already reported the need for nutritional information on food packaging to be simpler and clearer, allowing consumers to choose their foods more consciously and with a view to promoting their health and well-being (1,5,9). Thus, these results point to the need for interventions to improve knowledge about labeling, whether through awareness campaigns using social media or printed materials such as posters or brochures distributed on campus. Another interesting form of intervention would be the development of workshops on reading and interpreting food labels.

Limitations and future directions

This study has some limitations, such as its cross-sectional nature, which does not allow for the extrapolation of results, the small number of participants, and the sampling method used. However, it is important to note that this is an exploratory study that allowed for a first approach to the issue of food labeling among university students in Portugal. As for future studies, it would be important to evaluate other dimensions related to knowledge about food labeling, such as the obligation or not of certain nutritional information, and the interpretation of information on the label related to nutritional information. It would also be important to study students' perceptions of the usefulness and importance of nutritional information, as well as its use. Another aspect to be considered in future research is the distinction between students by type of course (health vs. non-health) and to verify if there are differences between these two groups.



Approximately 70% of the participants stated that they are able to interpret food labeling, however, the average score for knowledge about food labeling was 5 ± 1.5 out of 8 points. Participants who claimed to be able to interpret labels obtained a higher score than those who admitted not being able to interpret them. No relationship was found between knowledge about labeling and sociodemographic characteristics. Further studies are needed to obtain more solid conclusions on this subject. However, the results point to the need to increase knowledge about food labeling, as well as about the interpretation of nutritional information. It is suggested that food education campaigns be developed to increase students' knowledge about food labeling, so that they can make more conscious and informed choices.


Authors Contributions Statement

LO, CM, MR, DP, and CSR, conceptualization and study design; CM, MR, DP, CSR, data collection; LO, data analysis; LO, drafting and editing; LO and CR reviewing; LO, tables; LO and CR, supervision and final writing.



Not applicable.



The authors would like to express their thanks to all participants.


Conflict of Interests

The authors declare there are no financial and/or personal relationships that could present a potential conflict of interests.



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