Biomedical Sciences, Biomed Biopharm Res., 2022; 19(2):265-277
doi: 10.19277/bbr.19.2.290; PDF version here [+]; Portuguese html version [PT]
Adherence to the Mediterranean food pattern and sociodemographic factors in students of the 3rd cycle of basic education on Terceira Island, Azores, Portugal
Leandro Oliveira 1, Francisco Sousa 2,3 & Maria Graça Silveira 4,5
1CBIOS – Universidade Lusófona’s Research Center for Biosciences & Health Technologies, Campo Grande 376, 1749-024 Lisboa, Portugal; 2School of Social and Human Sciences of the University of the Azores, Rua da Mãe de Deus, 9500-321 Ponta Delgada, Açores, Portugal; 3Interdisciplinary Centre of Social Sciences - Campus of the University of Azores CICS.NOVA.UAc, Rua da Mãe de Deus, 9500-321 Ponta Delgada, Açores, Portugal; 4School of Agrarian and Environmental Sciences of University of the Azores, Rua Capitão João d’Ávila – Pico da Urze 9700-042 Angra do Heroísmo, Açores, Portugal; 5Biotechnology Centre of Azores, Rua Capitão João d’Ávila – Pico da Urze 9700-042 Angra do Heroísmo, Açores, Portugal*
The Mediterranean food pattern (MFP) has been identified as promoting health and preventing certain chronic diseases. The objective of this study was to determine the adherence to MFP in a sample of students in the 3rd cycle of basic education of the Terceira Island and its relationship with sociodemographic factors and weight status. Data was collected between May and June 2015. A direct application questionnaire that included KIDMED was used to assess adherence to the MFP. A total of 303 students aged between 11 and 19 years old participated in this study, mostly female (57.8%). Most students (64.4%) showed an intermediate level of adherence to the MFP and the prevalence of overweight was 33%. Boys had a higher percentage of regular consumption of breakfast cereals and fatty fruits and daily consumption of two yogurts and/or 40 g of cheese. Students who had a vegetable garden and helped to tend it or who belonged to families with additional members under the age of 18 had greater adherence to MFP. No associations were found between other sociodemographic factors and adherence to MFP. Based on these results, it is suggested to reinforce existing food education programs in schools, as well as develop other programs with a multidisciplinary approach that promotes adherence to the MFP.
Keywords: Mediterranean Food Pattern, students, KIDMED, weight status, Azores
Received: 01/07/2022; Accepted: 06/09/2022
The expression "Mediterranean Diet" was first used in the 1960s and is associated with a reduction of the incidence of chronic diseases and a longer life expectancy. This cultural, historical, and health model has been recognized in Portugal, Spain, Morocco, Italy, Greece, Cyprus, and Croatia by UNESCO as an Intangible Cultural Heritage of Humanity since December 4, 2013 (1).
The Mediterranean Food Pattern (MFP) is characterized by a high intake of fresh, seasonal, and low processed foods (fruits and vegetables, whole grains, pulses/legumes, and oilseed fruits), moderate intake of dairy products (preferably cheese and yogurt), preferential intake of fish or white meats (to the detriment of red meats), regular but moderate consumption of wine (tending to accompany meals), use of herbs and spices for seasoning, and olive oil as the main source of fats (2). Thus, we can see that from a nutritional perspective, MFP is low in saturated fats, simple carbohydrates, and animal protein, and is rich in antioxidants, fiber, and monounsaturated fats; MFP has also been reported to have an adequate ratio of omega-6/omega-3 fatty acids (3).
Several studies have demonstrated the health benefits of MFP, namely in the prevention and treatment of chronic diseases such as obesity (4), cardiovascular diseases (5), type 2 diabetes mellitus (6), metabolic syndrome, and protection against various types of cancer (7), neurodegenerative diseases, depression, and respiratory diseases (8).
Despite these benefits, only 26% of the Portuguese population has a high level of adherence to the Mediterranean diet, with the majority of the population having consumption of pulses/legumes, vegetables, and oilseeds below the desirable level (9). Furthermore, recent data report that 57.5% of Portuguese adults (63.1% of men and 52% of women) are pre-obese or obese, and that about one in three children is overweight, with more than 10% of them being obese (10).
Thus, it appears necessary to promote MFP among the Portuguese population, especially among children, as eating habits are shaped in childhood (11). Thus, it is necessary to develop more effective interventions adjusted to the characteristics of this population group. Therefore, the objective of this study is to evaluate the level of adherence to the MFP in students in the 3rd cycle of basic education of the Terceira Island and its relationship with sociodemographic factors and their weight status.
Materials and Methods
This is a cross-sectional study whose population consisted of students who attended the 3rd cycle of basic education in basic schools on Terceira Island, Azores, Portugal. Data collection took place between May and June 2015.
Sample and procedures
On Terceira Island, there are seven organic units (schools or groups of schools) of the regional education system (four in Angra do Heroísmo and three in Praia da Vitória). Five units (three in Angra do Heroísmo and two in Praia da Vitória) agreed to participate in the study. The aim was to reach at least 50% of the classes each year of the 3rd cycle of basic education in each participating school. These classes were selected for convenience according to the recommendation of the school board. The questionnaires were distributed to the students and completed in the classroom, with a researcher present to clarify doubts.
A questionnaire consisting of four sections was used. Section I was related to sociodemographic characterization and anthropometric data (gender, age, nationality, city of residence, number of household members, weight, height, etc.). Section II referred to food consumption, using a qualitative food frequency questionnaire and the Portuguese version of the Mediterranean Diet Quality Index for children and teenagers (KIDMED) (12). Section III was directed to questions related to knowledge about food. Finally, Section IV addressed the perception, beliefs, and attitudes towards health-promoting foods. Only data referring to Section I and KIDMED was examined for this paper. The KIDMED index consists of a set of sixteen questions related to daily consumption and frequency of consumption of specific foods. These questions were rated with a score (+1 or -1) according to their accordance with the MFP. The sum of the values obtained (between 0 and 12) enables the categorization of MFP adherence into three levels: level 1 - high adherence (≥ 8); level 2 - intermediate adherence (4 to 7) and level 3 - low adherence (≤ 3). Body mass index was classified according to the World Health Organization criteria for children (13).
The present study was conducted following the ethical standards established in the 1964 Declaration of Helsinki and its subsequent amendments (14)or comparable ethical standards. The Board of the evaluated schools approved the present study. The completion of the questionnaires by the students took place after authorization from their guardians through an informed consent authorization form. The students were also asked if they wanted to participate in the study, and after an affirmative answer from both, the questionnaire was distributed.
Following data collection, statistical processing was performed using IBM SPSS Statistics, version 26.0 for Windows. Descriptive statistics consisted of calculating the mean and standard deviation (SD) in the case of cardinal variables and calculating the relative and absolute frequencies in the case of ordinal and nominal variables. To compare the mean orders of the independent samples, the Mann-Whitney test was used, and the chi-square test was used to compare proportions between qualitative variables. A significance level (p) of 0.05 was considered in all analyses.
A total of 366 students agreed to participate in the study, with parental consent. However, 63 questionnaires were rejected because they were not filled in correctly or because some data was missing. Most participants were female (58%), aged between 14 and 16 years (66%), attending the 9th grade (68%), and residing in rural areas (85%) in Angra do Heroísmo (73%). Regarding weight status, most were classified as having normal weight (66%), however, 33% were overweight (pre-obese or obese). A more detailed description is shown in Table 1.
In Table 2 we present the distribution of student responses to the KIDMED index by sex. In general, most students consumed: at least one piece of fruit or fruit juice per day, fresh or cooked vegetables at least once a day, pulses (legumes) more than once a week, fish regularly, and used olive oil at home. Most students indicated they had the habit of having breakfast, in addition to consuming both dairy products and cereals or similar (bread, etc.). However, low consumption of oleaginous fruits was reported, and on the other hand a high consumption of fast food, more than once a week, and of pastries (cookies, croissants, cakes, etc.) and sweets several times a day. Compared with females, males had a higher prevalence of consumption of fruits, cereals, or derivatives (bread, etc.) for breakfast, oleaginous fruits, yogurts, and/or cheese. The total mean KIDMED score was 5.59 (standard deviation: 2.06) points. In terms of the prevalence of adherence to the MFP, 14.9% had low adherence, 64.4% had intermediate adherence, and 20.8% had high adherence.
Table 3 presents the relationships between sociodemographic characteristics and levels of adherence to the MFP. In general, it appears that most students have an intermediate level of adherence to the MFP. The number of household members and the number of children positively influence the level of adherence to MFP. In addition, students who usually help their parents to maintain a vegetable garden had a higher level of adherence to MFP compared to those who do not. There was no relationship between adherence to MFP and sex, age, city and zone of residence, having a vegetable garden, or weight status.
This cross-sectional study aimed, firstly, to evaluate the level of adherence to MFP in students of the 3rd cycle of basic education on Terceira Island, and secondly, to study the relationship between adherence to MFP and sociodemographic factors and their weight status.
Regarding weight status, a prevalence of 33.0% of excess weight was found. This value is close to that found in a study with young students from the Algarve (29.4%), but higher than the value found in a study conducted in 17 Portuguese cities (Aveiro, Braga, Coimbra, Évora, Faro, Figueira da Foz, Funchal, Guimarães, Leiria, Lisboa, Mirandela, Porto, Viana do Castelo, Vila Real, Viseu) (15) and is above the national average (10).
Most students do not consume oleaginous fruits at least 2 to 3 times a week, so their consumption should be encouraged. Nuts are excellent sources of mono unsaturated and polyunsaturated fats (such as omega-3 fatty acids), vitamins (vitamin E and folic acid), minerals, fiber, and substances with antioxidant properties (16). These foods can be a good option for an intermediate meal, and their consumption is associated with benefits in the prevention of cardiovascular diseases (17). It is also worth noting that consuming fast food more than once a week, eating confectionery or pastry products for breakfast, and eating sweets or treats several times a day should be discouraged. These foods are high in simple sugars, salt, and saturated fats (18), and their excessive consumption is associated with several chronic diseases and overweight (19-21).
In our study, there was a higher prevalence of an intermediate level of adherence to the MFP, which is in agreement with other studies on Portugal's mainland. In the study by Barbosa (22) published in 2012, an average adherence to MFP of 7.19 (SD = 2.04) was found in 212 7th grade students who attended a school in Braga, while the average was found on Terceira Island was 5.59 (SD = 2.06) points. In another study in northern Portugal involving 166 children from two primary schools in Póvoa de Lanhoso (23), 61.4% of "high adherence" to MFP was reported at 61.4%, while we found only 20.8% on Terceira Island. Alves (24), in their study carried out in Vila Real, which involved 281 secondary schools, students reported a median of 4 points of adhesion to the MFP, that is, lower than the average we found on Terceira Island. In Guimarães, in a study (25) with 464 students in the 1st cycle of basic education, a prevalence of intermediate adherence to the MFP was found (69.1%), slightly higher than that found on Terceira Island.
Concerning the central region of Portugal, in a study by Vaquinhas et al. (26) including 98 children from the 2nd cycle of basic education in a school in Coimbra, there was a high level of adherence to the MFP (85.7%), much higher than that found on Terceira Island. Another study (27) with 3995 children and adolescents aged 2 to 21 years old from Santarém and Alpiarça reported a high level of adherence to MFP (62.0%), higher than that found on Terceira Island.
The intermediate level of adherence to MFP found on Terceira Island is similar to that found in another study, which was carried out in Tavira with 1952 young people, aged between 3 and 19 years old (28). In our study, however, the percentage of high adherence to MFP in our study is lower than their reported 24.4%. Further, if we compare our results with the study of Mateus & Graça, also conducted in the Algarve region, the high adherence reported in our study is much lower than their reported 52.5% (12). Finally, in a study including 223 children and young people aged between 6 and 16 years old from a basic school in Funchal (Madeira), high adherence to the MFP was reported by more than 50% of the participants (29).
The adherence to MFP among students from Terceira Island is lower than that found in other regions of the country. Thus, it is recommended that measures be taken to increase this adherence, taking into account the benefits in health promotion and disease prevention associated with MFP (as described above).
No projects/initiatives were found with the specific purpose of increasing adherence to the MFP in the Azores, however, indirectly we can highlight the participation of some educational establishments in the EcoEscolas project (with national scope), which aims to encourage the development of activities, to improve the environmental performance of schools, and find solutions to improve the quality of life at school and in the community (30). Some of these activities are related to healthy and sustainable food, with an emphasis on the Mediterranean diet. However, on Portugal's mainland, there are other projects/initiatives involving schools that deserve to be highlighted, namely the "Eat Mediterranean: A program to reduce nutritional inequalities in school meals" (2015-2017) (31), and the MEDITA project “Mediterranean Diet promotes health” (2017-2020) (32) which aims to promote healthier lifestyle habits in young people in the Algarve region in children and adolescents in the Andalusian region, based on the concept of the Mediterranean Diet.
In this way, food education projects could be developed aimed at students in the 3rd cycle of basic education to promote adherence to the MFP, for example, cooking workshops, associated with pedagogical vegetable gardens, video viewing, or participation in debates, and these could also be extended to the rest of the school community. Improving the (school) food supply, namely the nutritional quality of canteen/buffet meals and vending machines following MFP principles (excluding wine) could also be a strategy to be adopted.
It is also important to note that our study has some limitations, including the fact it is limited to Terceira Island and thus it is not representative of MFP adherence within the Azorean archipelago. In addition, its transversal design does not allow the extrapolation of its results. Moreover, the questionnaires were completed by the students and, although they had the opportunity to clarify any doubts they may have, they may present some bias. On the other hand, the participants cover the entire Terceira Island, with five of the seven schools with the 3rd cycle of basic education participating in the study. Therefore, we have a representative sample of the island, distributed among its two municipalities. To our knowledge, this is the first study conducted in the Azores archipelago that evaluated adherence to MFP in such a young age group, only one study (33) conducted in 2008 evaluated adherence to MFP among adolescents (15 to 18 years), and the prevalence of high adherence to MFP found was similar to that in our study. It is important to emphasize that the results presented here can also serve as a point of comparison and support for future interventions to promote MFP. In addition, they can be used to develop food education interventions on this topic that are better adapted to the characteristics of students in the 3rd cycle of basic education on the island of Terceira.
The high prevalence of overweight (pre-obesity and obesity) and the low "high" adherence to MFP reveals the need to promote adherence to this food pattern in this population. Therefore, we emphasize that collaboration between the health and education sectors is extremely important for the promotion of healthy eating. The school thus appears as an ideal environment to educate for this purpose, as well as for the creation of healthy eating habits at an early age. The results presented may be useful for future community interventions designed to promote healthier eating habits.
Authors Contributions Statement
LO, FS, and MGS, conceptualization and study design; LO, experimental implementation; LO, data analysis; LO, drafting, editing and reviewing; LO, tables; LO, FS and MGS, supervision and final writing.
This study was supported by the Calouste Gulbenkian Foundation, under the contest "Literacy in Health 2014 — Citizens and Health: improving information, improving decision-making" within the scope of the project "Health-promoting foods in a school context - more knowledge, better growth”.
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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