Dietary habits of High School Population in Mostar, Bosnia and Herzegovina

Adolescence is a period of life when prevalence of overweight, obesity and chronic non-communicable diseases rise the fastest. This period of life is very important for adoption of healthy lifestyle habits. Those include regular physical activity and diet, which could prevent nutrient deciencies and may limit harmful behaviors contributing to the epidemic of non-communicable diseases in adulthood. There are a small number of surveys on a large number of high school and student population about this topic in low-to middle income countries. The aim of this study was to examine dietary habits and frequency of physical activity and presence of non-communicable diseases in immediate family. Survey was conducted in 6 secondary schools of city of Mostar through an anonymous questionnaire. The study involved 482 adolescents (279 boys and 203 girls) aged 17 and 18. For data entry and analysis SPSS (version 25) was used. Association between variables was determined using chi-square.

the use of catering services is associated with healthier food habits, which are closer to nutritional recommendations compared to those not using them [8]. In absence of school canteen, young people from Mostar are forced to take a breakfast or lunch in fast food objects and bakeries around the school.
That breakfast and lunch are usually nutrient-poor, energy-dense food, which leads to poor dietary habits later in life. In addition, dietary pattern, characterized by high consumption of energy-dense food, fast foods, sugar-sweetened beverages and soft drinks, as well as low ber intake, appears to contribute to an increase in body fat in early adulthood [10].
Aim of this research is to reveal dietary habits and frequency of physical activity of scholars of different schools in city of Mostar in accordance to gender and to examine their knowledge about proper nutrition and food pyramid.

Methods
Survey was conducted in November 2019, in 6 secondary schools of the city of Mostar through an anonymous questionnaire entitled "Estimation of the Eating Habits of High School Students in the City of Mostar". The respondents were young people aged 17 and 18. The survey included 482 high school students (279 boys and 203 girls). Distribution by age and gender is shown in Table 1. First part of the survey contained questions on general characteristics of study population, i.e. gender and age, whilst second part contained 18 questions about dietary habits and food preferences, question about physical activity, about frequency of non-communicable diseases in their close family, and question about presence of allergy or food intolerance.

Results
The obtained results showed adequate knowledge of understanding terms "nutrition" and "Food pyramid", 88.6% and 95.6% respectively ( Table 2, Table 3). Girls showed better knowledge than boys for both terms, and difference between genders is statistically high signi cant.  However, there is no statistical signi cance between gender and daily number of meals (X 2 = 3.31; df = 2; p = 0.191).
Breakfast is consumed regularly by 35.7% of participants (Table 4). There is statistical signi cance between gender (X 2 = 6.090; df = 2; p = 0.048) in breakfast consumption. Females are less likely to consume breakfast regularly, half to one hour after waking up, than boys (29.6% vs 40.1% respectively). Both genders (163 of males and 90 of females which is 52.5%) drink adequate amount of water (1.5 to 2 liters per day) (Fig. 2), and 25.5% of both genders drink less than 1 liter (27 of males and 96 of females), while 22% drink 3 liters or more. Difference between genders is highly signi cant (X 2 = 99.158; df = 2; p = 0.000).
Besides water, for beverages 46.3% of all respondents consume regularly soft drinks (47.7% of boys and 44.3% of girls), carbonated and non-carbonated, while 13.3% of boys and 13.8% of girls do not consume it at all. Boys consume soft drinks more often than girls, but it is not statistically signi cant difference.
The percentage of students who consume cereals and whole cereal products every day is quite low and it is 12.9%. Students who consume this food 1 to 2 times per week is 17.8%, 51% of students take it rarely (less than 1 times per week) and even 18.3% of them have never consumed whole cereals products. Girls were less likely to consume whole cereals and their products than boys ( Fig. 3 For vegetables (X 2 = 1.243; df = 2; p = 0.537) and fruits (X 2 = 0.253; df = 2; p = 0.881) consumption there is no signi cant difference between males and females. Dairy products are consumed daily by 66.6% of adolescents, 68.5% boys and 64% girls (X 2 = 1.333; df = 2; p = 0.513). There is a link of consumption between gender within this food category.  Figure 4 shows consumption of different types of oils and fats between adolescents. It is visible that they prefer butter (29%), olive oil (21.4%) is on the second place and followed by re ned vegetable oil (19.3%), other type of oil/fat (coconut oil, animal fat) (18%), and margarine (12.2%). (X 2 = 15.083; df = 4; p = 0.005). Difference between genders is highly signi cant. Boys prefer butter and other types of oil/fat, and girls prefer more re ned vegetable oil and margarine.
Out of all of all adolescent, 33.2% have in their immediate family someone with NCD (23.7% of males and 46.3% of females). As visible, difference between genders is highly signi cant (X 2 = 27.182; df = 1; p = 0.000). In addition, we investigate allergy or food intolerance of study population. 10% of all participants have some allergy or food intolerance. Analysis of collected data shows statistical signi cance in the presence of allergy or food intolerance between genders (X 2 = 4.368; df = 1; p = 0.037). 13.3% of girls and 7.5% of boys answered a rmative.
Out of all participants (N = 482) only 1 boy was vegan, and 1 girl followed vegetarian diet. 12.9% participants answered that follow some other "special diet", mostly boys (43 of them) and 19 girls, so there is highly signi cant difference between genders (X 2 = 5.923; df = 3; p = 0.115). Speci c reduction diets are also very often among adolescence, and could lead to eating disorders (WHO, 2018). Answer to question "Have you been on some reduction diet for the past year?" 18.2% of girls and 11.8% of boys answered a rmative (X 2 = 3.876; df = 1; p = 0.049). Difference between genders is signi cant.
Together with dietary habits, the practice of physical activity is another important factor to reduce risk of NCD. In this survey, boys do physical activity more often than girls do, which is visible in Table 6.
Difference between genders is highly signi cant (X 2 = 49.077; df = 2; p = 0.000). Discussion Results from this research are similar to those from studies done in neighborhood countries [3,11,6,12,13] probably due to the similar geographical, social and cultural characteristics. In addition, comparison with some larger health and nutrition surveys [14,15] is possible even though Bosnia and Herzegovina belongs to low-to middle income countries.
Since the study population was mature enough (17 and 18 years old), they showed good knowledge about nutrition and related terms as expected. Results are in accordance with similar research [3] where girls also showed better knowledge.
According to guidelines for adolescence, adolescents should have 5 to 6 meals per day (3 main meals and 2 to 3 snacks) to ensure adequate amount of energy for all daily activities. When an adolescent's overall energy and nutrient needs are not met, linear growth may be slowed, stunting may occur, and sexual development and menarche may be delayed [2]. Out of all participants, 77.4% have 3 to 5 meals per day. This nding is consistent with those of other studies on similar population. In research [11] on student population in the city of Mostar, most common response was 3 to 5 meals per day between participants (48.63%, of which 49.32% of males and 38.36% of females). We observed similar difference in genders results (Fig. 1). But overall results are better in this research. Reason could be in age difference between studied population, where respondents from research of Banožić et al. [11] are university population in Mostar, with different obligations during the day. Results from this research are more similar to the results of the cross-sectional AVENA study, which included 1978 adolescents from ve Spanish cities. Results from AVENA study show that 80.4% of boys and 75.9% of girls have four or more meals during the day. This study also showed that adolescents eating more than four meals per day had lower skin folds and waist circumference [14]. A several observational studies showed a consistent association of skipping meals with increased obesity risk in children [16]. Therefore, increasing meal frequencies to 5 per day with adequate nutrition quality could be a possible target for early prevention of overweight and obesity, and consequently chronic non-communicable diseases [16].
Relatively low percent of students (35.7%) does not consume breakfast half to one hour after waking up regularly (Table 4). That is in accordance with results of [13] research on 229 high school students between 15 and 18 years old at Travnik also in Bosnia and Herzegovina. In that research 37.78% of males and 32.37% of girls does not consume breakfast regularly. In another research in Banja Luka, Bosnia and Herzegovina [12] only 25% of 119 high school students breakfasting on regular basis. Research [3] on 117 adolescents shows that 36.8% of high school students from continental part of Croatia skip the breakfast. According to some researches, breakfast consumption has been associated with improved cognitive performance, tend to lower body mass index (BMI), bone and cardiovascular health of eaters, and exhibit a healthy weight control than at breakfast skippers. Conversely, breakfast skippers tend to have higher BMI, poorer food choices and greater energy intake from snacks [17,18,19]). In the large Iranian study of 78,905 university students aged 18 years and older, male students who consumed breakfast frequently had higher intake of fruits, dairy, and lower intake of fast foods and carbonated beverages than those who consumed it infrequently [20].
Conclusion from the Third National Health and Nutrition Examination Survey [18] was that not only breakfast consumption itself is associated with BMI, but also the type of food eaten for breakfast, affects BMI. Eating cereals or quick breads for breakfast is associated with signi cantly lower body mass index compared to skipping breakfast or eating meats or eggs.
An adequate intake of water for 17 and 18 years old boys and girls is 2 liters per day, including drinking mineral water and water contained in food [21]. That is the same as for adults older than eighteen. Water is a nutrient essential for life and health. Even minor losses can have adverse effects on body thermoregulation and physical activity capacity, feelings of fatigue, concentration and alertness and cognitive function [22], what is especially important for school children and students. The results for water intake between genders are very similar to the results [11] and for high school population in Serbia, Belgrade [6] where 45% of boys and 47% of girls drink 1 to 1.5 L of water per day. According to [11], girl teenagers consume in average smaller amount of water than boys. The most common response, in this survey, between girls (47.3%) was 0.5-1 liter per day, what is equivalent to 6 glasses of water, and the most common response between boys (58.4%) was 1.5-2 liters per day what is equivalent to 8 glasses. This may be due to different physical needs for water between genders. According to this survey, girls are less physically active than boys so explanation could be nd in their lower needs for water.
Consumption of soft drinks is in accordance with other surveys on similar population [11,13]. According to [3] on high school population in Vinkovci, Croatia boys consumed soft drinks more often than girls (47.7% vs. 36.1%), as in this research (47.7% of boys vs. 44.3% of girls). Regular intake of soft drinks increase energy intake, what can contribute to obesity and risk of NCD. Findings from well-powered prospective cohorts have consistently shown a signi cant association and a direct dose-response relationship between sugary beverages consumption and long-term weight gain and risk of type 2 diabetes [23]. Calorically sweetened beverages contribute to obesity through their caloric load, because intake of sugary beverages or beverages with high-fructose corn syrup does not produce a corresponding reduction in the intake of other food, so beverage calories are "add-on" calories. Soft drinks have also been implicated in the risk of the development non-alcoholic fatty liver disease and insulin resistance [24]. This is a reason why mineral water needs to be the rst choice for children and adolescents to quench thirst.
Cereals and cereal products were rarely eaten (51% of participants eat less than one time per week) (Fig. 3) and that nding is consistent with similar study [13]. Among 229 participants aged 15 to 18 years, there was 30.1% of students who never consumed cereals, 31.9% of them consume it 1 time per week, 18.3% 2 to 4 times per week, and 19.7% for 1 and few times every day [13]. Question about whole grain consumption, was not included in other similar surveys done in Bosnia and Herzegovina. Most data come from US but it was also including in some survey in Europe. For example, in large Italian INHES study on sample of 561 children and adolescents (5-19 years old), 62.6% of all girls and boys were nonconsumers of whole grain food, 15.5% were occasional consumers (< 1 time/ week) while 21.9% were regular consumers (≥ 1time/week) [15]. In the UK 15% of children and teenagers do not consume whole grain at all, and in Germany for the same population that is 19% [25]. In numerous epidemiological studies consumption of whole grain products is associated with lower risk of chronic diseases such as coronary heart disease, stroke, diabetes type 2 and colorectal cancer. It also has positive health bene ts through regulating blood pressure, insulin sensitivity and plasma cholesterol [15]. The Mediterranean diet pyramid recommends the consumption of one or two serving of cereals at each meal, in the form of bread, pasta, rice, couscous but preferably whole grain. Taking into consideration that whole grain products have higher levels of dietary bers, vitamins (B vitamins), minerals (zinc, phosphorus, magnesium, iron) and bioactive compounds such as antioxidants and other phytochemicals, they must be included in adolescent`s daily diet. Foods high in dietary bers, such as whole grain cereals and vegetables, can promote satiety and therefore may have in uence in weight regulation by improving appetite regulation and tending to constrain excess energy consumption during the day [25].
Having in mind recommendations for vegetables and fruits consumption (5 portions of 400 g a day) results are not satisfactory (Table 5). In similar research [12] on 119 students in another city in Bosnia and Herzegovina, 39.5% of participants consumed vegetables once a day, 23.5% twice a day and 10.9% 3 times a day. Considering fruits consumption, 22.7% of participants consumed fruit once a day, 31.3% twice and 16.8% three times daily in the same study. In study [11] the most common response for consumption vegetables and fruits was 2 to 4 times per week, for both males and females. Vegetables and fruits supply vitamins and minerals to the diet as also dietary ber, phytochemicals that function as antioxidants, phytoestrogens, and anti-in ammatory agents and through other protective mechanisms. Therefore consumption of vegetables and fruits is linked to lower incidence of chronic diseases [26].
Analysis of the collected data, shows that 66% of adolescents consume dairy products every day. The similar results are obtained in the study [12] where 59.7% of adolescent population consumes milk and dairy products on a daily basis. Products as milk, yogurt and cheese should be on a daily menu of young boys and girls. Recommendations are approximately three to ve servings per day for adolescents, encouraging low-fat dairy products. Decreased milk consumption negatively in uences calcium and vitamin D intake, which are important for bone development, dental integrity and maintenance of healthy body composition [27].
Regarding adolescent's consumption of red meat results are not wanted (Table 5). Similar to the study [12], adolescents have dietary preferences to consume red meat mostly up to 3 times per week. For children, meat is important source of valuable proteins, vitamins A, B 1 , B 12 and niacin, iron, zinc and other micronutrients [28]. For adolescents aged 17 and 18, recommendations as for adult healthy population could be applied. Evidence from last decade point out connection between increased consumption of red meat, especially in its processed forms and health effects, especially for cardiovascular and cerebrovascular health [28]. In most cases, the muscle meat from beef, veal, pork, lamb, venison is de ned as "red" meat. Recommendation is also to moderate consumption of processed meats because these are high in fat and salt, classi ed as Group 1 carcinogens for humans, based on epidemiological studies. The strongest, but sill limited, evidence suggest that eating processed meat causes colorectal cancer, and some evidence links it with pancreatic and prostate cancer [29,30].
Considering that 33.2% of young participants have someone in immediate family with some chronic noncommunicable disease (DMT2, hypertension, or some other cardiovascular disease) more attention should be paid on consumption of this food group, but also for group of oils and fats. Very large percent of adolescents prefer butter, which is saturated fat, and can in uence a total cholesterol level in blood and consequently have association with NCD. According to Mediterranean diet, mono and polyunsaturated fatty acids (olive oil) reduce blood cholesterol level and risk of heart diseases when they substitute one portion of saturated fatty acids in the diet. Consumption of olive oil reduces LDL cholesterol simultaneously affecting HDL cholesterol [31].
Since 12.9% participants answered that follow some other "special diet", mostly boys, we supposed that maybe they followed some ketogenic diet (because of popularity and more physical activity), but more detailed survey should be carried out to con rm this.
Girls are more susceptible to reduction diets in this survey as also in similar survey [3]. Also interesting facts are that girls had more allergy or food intolerance than boys. There are no such results from similar researches from neighbor countries but there is also a small number of other studies about allergy or food intolerance prevalence in adolescent population. Conclusion, from the Isle of Wight Birth Cohort (n = 1456) on prevalence and longitudinal trends of a food allergy, is that food allergy is highly prevalent in infancy with partial resolution during late childhood. A number of children acquire new food allergy during adolescence, resulting in a relatively higher prevalence at 18 years [32]. That newly acquired allergy is often result of primary sensitization to inhalant allergens with subsequent sensitization to cross-reactive allergens in food [33]. Since this was in the form of single question in this survey, further investigation about type of allergy and intolerance is needed.
Boys are physically more active than girls (Table 6), which was also showed in other studies [14,6]. In above-mentioned AVENA study connection between physical activity and obesity development was shown [14].

Limitations of The Study
There was any question about consumption of sh and student's preferences about it. That is extremely important in adolescent's diet and for assessment of their dietary habits.

Conclusion:
Knowledge about nutrition has a direct impact on dietary preferences and choices. The overall results suggest the need to develop programs for promotion of healthy lifestyle among adolescents. A special attention should be paid to promote intake of vegetables and fruits and discourage intake of energydense micronutrient-poor foods and sugar sweetened beverages. A healthy and maintained diet and regular physical activity could be an effective strategy for the prevention of NCD and obesity. Therefore, survey results were presented on 12.  Availability of data and materials The datasets used and analyzed during the current study are available from the corresponding author on reasonable request.

Figure 1
Daily numbers of meals between genders in the studied population Figure 2 Daily intake of water between male and female students   Preferable oil/fat in adolescent's daily diet