Investigating the consumption status of Functional drinks (fortified) based on the theory of planned behavior and the stages of change model in female employees

doi:10.21203/rs.3.rs-2504982/v1

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Investigating the consumption status of Functional drinks (fortified) based on the theory of planned behavior and the stages of change model in female employees

https://doi.org/10.21203/rs.3.rs-2504982/v1

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Introduction:Functional foods are foods that by adding certain components to them reduce the risk of disease or improve the health of the body. Therefore, this study was aimed to determine the consumption status of functional (enriched) drinks based on the theory of planned behavior and the stages of change model.

Materials and Methods: This study was a cross-sectional descriptive-analytical study that was conducted on534 female employees of Birjand offices in 2022 who were selected by stratified sampling method. The data was collected by using the functional food questionnaire, which includes three parts, demographic information, measuring the stages of change, and planned behavior theory constructs regarding the consumption of functional drinks. The data was analyzed using SPSS software through descriptive and analytical statistical tests. The significance level was considered as p <0.05.

Results: Most of the participants were married (87.9%) and 7.6% were on a special diet. The majority of the participants (45.5%) made their purchases from chain stores. More than half of the people (74.1%) read food labels. Half of the participants (51%) were familiar with functional food. Based on the structure of the stages of change, the largest number of people consume probiotic drinks (buttermilk, kefir, etc.) were in the maintenance stages (31.2%) and who consume milk fortified with vitamin D were in the contemplation stage (37.3%) and who consume vitamin-enriched juices and fortified milk with iron and fat-free milk and vegetable milk were in the pre-contemplation stage, which consisted 38.4%, 42.5%, 30.8%, and 37.7% of participants, respectively. The mean score of the participants in the subscales of attitude, behavioral control, and subjective norm was 17.69±3.05, 16.83±2.88, 21.73±4.33, respectively.

Conclusion: The results of this study showed that the most drinks that female employees consumed regularly were probiotic drinks, while they did not intend to use functional juices (pre-contemplation stage) and subjective norms had the greatest effect on the intention to use drinks. Therefore, it seems that these theories can be used as a framework in designing educational programs in order to increase the consumption of functional foods and improve women's health.

Enriched Food

Beverages

Drinks

Theory of Planned Behavior

Model of Change Stages

Consumers' awareness of the relationship between food and health has increased their interest in healthy food(1). Healthy eating prevents most diseases like chronic diseases such as diabetes, cancer and cardiovascular problems (1-3) Chronic diseases are often caused by an inappropriate food pattern (4). The World Health Organization (WHO) estimates that more than two billion people worldwide suffer from micronutrient deficiencies. Recently, foods and drinks have been known as functional foods that are used in the prevention and management of diseases (5).

Functional foods are foods or food components that are useful for health beyond basic nutrition. Bioactive compounds present in these functional foods prevent several diseases and thus improve the quality of life (1, 6). Functional foods contain specific minerals, vitamins, essential fatty acids, dietary fibers, antioxidants, probiotics, prebiotics, synbiotics and other bioactive compounds,, which can provide a specific function to any type of food that contained them (7-9)Regular consumption of such foods facilitates the effective management of diseases such as cardiovascular disease (CVD), tumor, diabetes and blood pressure, as well as improving memory, mental health, the health of the fetus, losing weight, and reducing the risk of chronic and degenerative diseases, and osteoporosis (6, 8, 10-13).

Functional drinks are included in the category of functional foods, which are important sources of vitamins, polyphenols, minerals and dietary antioxidants(14). Beverages are the most widely used category of functional foods due to the ease of dissolution of functional components and ease of consumption (5, 15). Functional beverage products include dairy beverages (enriched beverages), prebiotic-based beverages, probiotic-containing beverages, non-dairy plant-based beverages made from soy, rice, barley, almonds, or coconut, Grain-based foods, micronutrient-enriched drinks, fortified milk (enriched with calcium, omega-3 and vitamins), fermented drinks such as kefir, fruit juices (enriched with vitamins and omega-3), fortified waters (enriched drinks) with vitamins and minerals, sports and energy drinks, herbal drinks) (5, 16-18). Probiotics can be obtained from various sources of cow's milk, i.e. dairy products, as well as from various non-dairy sources such as fruits, vegetables, grains and legumes (19).

Studies show that the behavior of consumers of functional foods is not only dependent on knowledge, but also influenced by demographic factors (2, 16, 20). Consumers' perception of the effectiveness of functional foods affects their attitude towards functional foods, and therefore increases their intention to buy functional foods (2, 7, 16, 20). Increasing consumer awareness and descriptive and supportive norms have a positive effect on the perception of the effectiveness of superfoods (13). The theory of planned behavior (TPB) with the constructs of subjective norm, attitude and perceived behavioral control has been used in studies that investigate health promotion and disease prevention behaviors and can be used in investigating the behavior of consuming functional foods (21) (Figure 1).

The methods in which food choice behavior is measured based on psychological models can help researchers to better understand consumer behavior; one of the ways to achieve this goal is to use the Model of Change Stages. The stages of change model include 6 stages: pre-contemplation, contemplation, preparation, action, maintenance, and relapse (Figure 2) (22, 23). Up to our best of knowledge there is no study to employ these models to investigate the behavior of women employee in consuming functional drinks in Iran. The present study was conducted with the aim of investigating the consumption of functional drinks (enriched) based on the theory of planning behavior and the model of the stages of change in female employees of Birjand, Iran.

2.1. Study design and participants

The current research was a cross-sectional descriptive-analytical study that was conducted in the spring of 2022 on the female employees in the offices of Birjand, Iran. The number of samples was calculated using the following formula according to the study by Salmani (2).The sample size was calculated as 441 people with considering 20% downfall, at least 534 people were considered.

In this study, offices were classified into groups of 10 according to the population of female employees. Offices with less than 10 female personnel were placed in the first category and offices with 10 and 20 people in the second category and so on up to a population of 100 people. Offices include 100 to 200 people were classified in the last category. In each floor, according to the population of the floor, the required number of samples was randomly selected. Inclusion criteria were filled informed consent and desire to participate in the study, being employed in one of the offices of Birjand, and the exclusion criteria was incomplete completion of the questionnaire.

2.2. Study instrument

The research tool was a standard questionnaire (2). The questionnaire consisted of four parts of demographic information, awareness measurement, and the structures of the stages of change and the structures of planned behavior model. The demographic information section included 20 questions related to characteristics such as age, marital status, level of education, number of family members and children, family income, shopping place, reading food labels, etc. The second part of the questionnaire was in the form of 2 awareness questions, a multiple-choice question in which the correct option was assigned a score of one and the incorrect options were assigned a score of zero, and there was also a question in the form of yes or no. The third part was a question related to the stages of change model regarding the consumption status of functional drinks (include: iron-enriched milk, vitamin D-enriched milk, fat-free milk, plant-based milks such as soy milk, almond milk, dough and probiotic drinks, kefir and vitamin-enriched juices). The questions of the change stages model were in 6 stages: pre-contemplation, contemplation, preparation, action and maintenance and relapse, and according to the situation explained about the stages of change, people chose only one option (one stage) for each drink. In the section of the planned behavior model, the questionnaire had 5 questions in the subscale of attitude (included positive or negative feelings towards the consumption of drinks in the person), 6 questions in subjective norms (opinions of reference and important people for the person who approve or reject consumption of functional drinks) and 5 questions were the construct of perceived behavioral control (shows the ease or difficulty of consuming the functional drink by people). The scale of the questions of the planned behavior model was 5-point Likert (from completely agree, somewhat agree, no opinion, somewhat disagree to completely disagree) with a score of 1 to 5. The minimum score obtained was 16 and the maximum score was 80. Cronbach's alpha of the standardized questionnaire was 0.78 (2).

2.3. Statistical analysis

After collecting the data, it was recorded in SPSS (version 19) and described using descriptive statistics for quantitative variables (mean and standard deviation, median and interquartile range) and for qualitative variables (number and percentage). To check the assumption of normality, Kolmogrov-smirnov test was used. Independent t-test (non-parametric equivalent was Mann-Whitney) and one way analysis of variance (ANOVA) (Kruskal-Wallis was non-parametric equivalent) with Tukey's post hoc test were used to compare two and more quantitative groups at significance level (P <0.05).

In this study, 534 female employees in the offices of Birjand were investigated. The average age of the participants was 40.32 ± 7.6 years. Most of the participants were married (87.9%) and had an income between 125 and250 dollar (49.3%), the bachelor's degree (45.7%) consisted the highest proportion of participants education. A small percentage of participants (7.6%) had a special diet and most of the participants (45.5%) purchase from chain stores. About 74.1% of people read food labels and half of the participants (51%) were familiar with functional food (Table 1).

Based on the structure of stages of change, regarding the consumption of iron-enriched milk (Chart 1-a), the highest percentage of people (42.5%) were in the pre-contemplation stage, and the lowest percentage of participants (2.6%) were in the relapse stage. Regarding the use of milk enriched with vitamin D (Chart 1-b), the largest number of participants (37.3%) was in the contemplation stage and the least number of people (4.7%) were in the relapse stage regarding the consumption of this drink. About the consumption status of vegetable milk (Chart 1-d), most of the participants (37.7%) were in the pre-contemplation stage and the fewest (5.2%) were in the relapse stage (Chart 1). The average score of the structure of attitude and subjective norm regarding the consumption of these milks had a significant difference with the model of stages of change (P<0.001) (Table 2). The highest (30.8%) rate of the participants was about the state of consumption of skim milk (Chart 1-c) in the pre-contemplation phase and the lowest (5.6%) rate was related to the preparation phase (Chart 1). The average score of the attitude and subjective norm regarding the consumption of skim milk had a significant relation with the stages of change model (P<0.006 and P<0.001) (Table 2).

Most of the participants (31.2%) were in the maintenance phase and the least number of ones (5.4%) were in the preparation phase regarding the consumption of probiotic drinks (dough, kefir, etc.) (Chart 1-e). The average score of the attitude and subjective norm regarding the consumption of probiotic drink with the stages of change model had a significant contribution (P<0.002 and P<0.001) (Table 3). Most of the participants (38.4%) were in the pre-contemplation stage and a small percentage (3.9%) were in the relapse stage regarding the consumption of Vitamin enriched juice (Chart 1-f).

The average score of the attitude and subjective norm regarding the consumption vitamin enriched juice had a significant difference with the stages of change model (P<0.001) (Table 3)

Based on the findings of the current study, the average score of attitude with shopping from hypermarket had a significant difference (P=0.01). There was also a significant difference in the average score of the subjective norm construct in shopping from hypermarkets (P<0.001) and shopping from chain stores (P=0.05). There was a significant difference in the mean score of the subjective norm construct in reading food labels (P<0.002). The average score of participation in shopping (P<0.002) and the amount of family income (P=0.039) also showed a significant difference with the construct of subjective norm (Table 4).

Considering the prevalence of non-communicable diseases such as obesity and diabetes in human societies, the consumption of functional beverages can play an important role in preventing diseases and also reduction the risk of disease or improving the body health. Therefore, regular consumption of these foods can create a suitable nutritional style in the individuals and society(1, 2, 6). Eating habits are influenced by many factors including food taste and preferences, place and environment, food availability, product safety, difficulty or convenience in buying and consuming food, culture, attitudes and beliefs of people about food, economy, media and marketing methods (24). The theory of planned behavior (TPB) and the stages of change model have been used in various health domains, including eating and drinking behaviors (25-27)

4.1. The status of consumption of functional drinks based on the model of stages of change

According to the results of the current study, in the case of drinks such as iron-enriched milk, vegetable milk and skim milk, most people had not consumed this product and had no desire (intention) to use this product (28) that is in agreement with studies of Rouhani-Tonekaboni et al (29) and Etehadnezhad et al (30). Regarding milk enriched with vitamin D, most of the participants had not (6)used the product, but they had the intention to consume the product (contemplation stage). In the case of vitamin D-enriched juices, most of the participants were in the pre-contemplation stage and they had no intention for consuming this drink. Most of the participants had regular consumption of probiotic drinks (maintenance stage), which was consistent with the study of Kim Juyoung et al (31)in relation to a probiotic and functional drink.

The reason for the constant consumption of probiotic drinks may be due to extensive advertising, which has been done by the media or nutritionists. Consumption of plant-based milk and iron-fortified milk was very low among the participants, which may be because of these types of milk that are not well known, less available to the public, or less advertised. It can be also due to people's belief in this matter, the belief that iron enrichment of milk is ineffective due to the interference of iron absorption by calcium. In the study of Etehadnezhad et al (30), another reason for reducing the consumption of dairy was mentioned due to lactose intolerance in people. In the study of Nolan-Clark et al (32), a high level of mistrust regarding the effectiveness of functional foods for health was mentioned as a barrier to consumption.

4.2. The status of consumption of functional drinks based on the model of planned behavior

Regarding the consumption of functional drinks, all drinks in the attitude construct showed a significant relationship with the stages of change model, which is consistent with the studies of O’Connor et al (33), Salmani et al (2), Moodi et al (3), Schnettler et al (34), E Carrillo et al (35), N Urala and L Lähteenmäki (36), Chen MF (7), Ali, Akhter and D.B.Rahut (20) and Kraus et al (16). All of these studies are on the same side and conclude that along with the increase of attitude towards the consumption of functional foods, the probability of consumption was increased, and they call the attitude as one of the strong predictors of the consumption of functional foods. It is also in line with the study of Wang and Chu (13), which showed that the intention of Danish and Norwegian consumers to buy functional foods is influenced by their attitudes towards these foods.

Attitudes are characterized by a person's beliefs about the specific consequences of performing a behavior, such as consuming functional foods, which is measured by evaluating its consequences (Ajzen, 1991). Unfortunately, people do not believe in consuming functional foods for various reasons, including distrust of food manufacturers, exposure to conflicting information, fear of unpredictable and dangerous side effects, and distrust of the health claims of these products. Considering that in the case of most of the functional drinks, women employees were in the pre-action stage (pre-contemplation, contemplation, preparation) and considering the effect of attitude on the consumption of functional foods, the dissemination of more information from a reliable source such as health professionals through Different communication channels are necessary to increase people's willingness to consume functional foods. In fact, advertising and communication campaigns can influence consumer awareness of functional foods and their health benefits (3). Drinks also showed a significant relationship with the stages of change model in the construct of subjective norms, which are in line with the studies of Salmani et al (2) and Lalor et al (37). The results of Wang and Chu 's (13) showed that descriptive and prescriptive norms had an indirect effect on consumers' willingness to buy functional foods through their effect on attitude. In Nystrand and Olsen's study (38), it is stated that people's attitudes directly affect subjective norms. Subjective norm is determined by one's beliefs about whether important people in one's life approve or disapprove of performing a certain behavior (Ajzen1991). This normative influence is created by injunctive norms (beliefs about the approval or disapproval of behavior by others) and descriptive norms (beliefs about whether others in one's social networks do this behavior) (Glanz, 2008). Therefore, subjective norms affect the consumer's intention to buy functional foods (13). The study of Shen et al (39) also showed that if the influential and important people of consumers have positive opinions and attitudes towards a type of food, consumers will most likely have a high intention to buy that type of food.

In order to influence people's perception, producers of functional foods can use important public figures (celebrities) and encourage people to consume this type of food. The chosen celebrity should be someone who represents a healthy lifestyle. Bakti et al's study (40) also stated that family members can influence each other in the consumption of functional foods. Results of present study showed that functional drinks in the behavioral control construct did not show a significant relationship with the stages of change model, which is consistent with the studies of Bakti et al (40), Salmani et al (2), Patch et al (41) and O'Connor,EL and White,KM (33), however, the results of the studies by Moodi et al (3) and Xin, Li and Seo, Sunhee Sunny (42) showed that perceived behavioral control is significantly related to the consumption of functional foods. Perceived behavioral control is a person's perception of the ease or difficulty of a given behavior. This perception is determined by people's beliefs regarding the existence of factors that may make it easy or difficult to perform a certain behavior (Ajzen1991). The high price of a profitable product compared to a similar non-profitable product and people's low confidence in the effectiveness of these products can be an obstacle to buy this product. A large percentage of the studied women were also married, which may influence the decision and desire of their husbands to buy food.

4.3. Demographic information

Based on the results of the current study, place of shopping, reading the food label, participation in the food shopping, and the amount of family income showed a significant difference with the constructs of the planned behavior model. Most people's purchases were from chain stores and hypermarkets. Buying from hypermarket had a significant difference in the constructs of attitude and subjective norm. Buying from chain stores had also a significant difference in attitude, which was in line with the studies of Hong et al (43) and Salmani et al (2).

This study showed that people who the highest consumption of functional foods had bought from hypermarkets, which may be due to the abundance of this type of food in these shopping centers. Also, the abundance of other consumer products that lead to saving time for buyers to go to other shopping places may be effective. Sometimes, in this type of stores, there are representatives from food companies who explain the type of food, which in some way affect the awareness and attitude of the buyers. Hypermarkets also create the impression that they are suitable for providing various products (43). The high variety of products that may be due to the large space of the hypermarket is also effective in attracting the attention of people to buy from this place. It is also possible that the satisfaction of buying different food items and other non-food products at the same time and place leads to recommendations to friends and neighbors, which has an impact on subjective norms.

In this study, label reading showed a significant relationship in the construct of subjective norms, which was in line with the study of Tian,Yan et al (44). In Tian.Yan et al's study, attitudes, descriptive norms, and nutrition literacy were significant predictors of food label usage intentions. Coulson,Neil's study (23) showed that a higher percentage of people who always read the food label read were in the maintenance stage. The results of our study showed that friends and important people in a person's life can play a significant role in reading food labels and drawing attention to functional foods and drinks and increasing the consumption of functional foods. Lack of shopping time and the ability to understand food labels (nutrition literacy) are also important in label reading. In Nolan-Clark et al's study on normative beliefs, it was shown that these beliefs are more stable and less inclined to change behavior than control and behavioral beliefs through nutrition education (32), therefore, improving nutrition literacy increases label reading and the effect of subjective norms causes permanence behavior. In other demographic variables such as education, income, number of children, etc, there was no significant difference with the model constructs, which is in line with Babicz-Zielinska and Jezewska-Zychowicz's study (45) and Moodi et al's study, it was stated in this study, Ozen, Pons, and Tour (2012) systematically reviewed twenty-three studies around the world on the consumption of functional products belonging to different food categories. They concluded that it was not possible to distinguish how education level and socio-economic characteristics clearly affect the consumption of functional foods (3).

However, in the results of other studies, these demographic variables were significantly different, such as the study of Kim,Juyoung et al (31)in which the effect of gender, education, geographic region and culture were significant.

According to the findings of this study, the attitude and subjective norms of people are the main determinants of the consumption of functional drinks. The results of present study showed that due to the fact that half of the people are familiar with functional foods, most of them are in the pre-performance stages and have very little consumption of these foods, which should be further investigated and other main factors influencing the choice behavior. People's attitudes towards functional products including positive experience such as the feeling of pleasure, taste and convenience of shopping and the type of culture in other employed and non- employed people should also be investigated.

Due to the high importance of these drinks, it is possible to identify people in different stages of behavior change and by educating people (people who are in the stages before action and relapse) about the benefits of consuming functional foods and increasing awareness caused a change in the attitude of family members and influenced the subjective norms of people. Also, the findings of this study have helped to design health interventions by health education specialists, which can be an effective step towards improving the health of individuals and society. The findings of this study will be valuable for marketers in the functional food industry to create marketing communication strategies and facilitate the development of this industry.

Ethical Approval and Consent to participate

This study was confirmed by the ethical committee and institutional review board of BUMS (IR.BUMS.REC.1401.086). Filling of the questionnaire was voluntary and anonymous by the respondents. Informed consent was obtained orally from all participants.

Consent for publication

Not Applicable.

Availability of data and materials

Data is available upon reasonable request from corresponding author.

Funding

Not Applicable.

Authors' contributions

AT performed the study; MM, TZ, EN and FS designed and supervised the study. FS performed the statistical analysis. All Authors read and approved the final version of the manuscript.

Acknowledgments:

This article is the result of a research project with project code 5925 and code of ethics IR.BUMS.REC.1401.086. The authors would like to express their appreciation and gratitude to the esteemed Vice President of Research and Technology of Birjand University of Medical Sciences for their financial support and also to the participants in this study.

Conflict of interest:

The authors of the article declare that there is no conflict of interest in the present study.

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Table 1: Frequency distribution of demographic variables in the studied women

variable		Std. Deviation	Mean
age (years)		7.6	40.32
Number of family member		1،17	3.90
Number of children		1.11	1.74
variable		Percentage	Number
Marital status	Single	87.9	471
Marital status	Married	2.1	65
Level of Education	Diploma	3.0	16
	Associate degree	5.2	28
	Masters	45.7	245
	Senior	39.2	210
	Ph.D	6.9	37
Read food labels		74.1	397
Familiarization with functional foods (FF)	Familiar with FF	50.9	273
Familiarization with functional foods (FF)	Knows the definition of FF	60.4	324
Placement in a particular period	Pregnancy	2.2	12
	Breastfeeding	6.3	34
	Menopause	11.9	64
	None	79.5	426
Having a special diet		7.6	41
family income	Less than 125 dollar	6.7	36
	125 and to 250 dollar	49.3	264
	More than 250 dollar	44.0	236
Place of shopping	Supermarket	35.4	190
	Chain stores	45.5	244
	Special shops	35.8	192
	Local market	41.6	223
	Hypermarket	44.4	238
Participation in the purchase of food		89.0	477
Responsible in the purchase of food		37.9	203

Table 2: Comparison of the average scores of the constructs of the TPB according to the SOC

Iron-enriched milk	Model structures	attitude		Perceived behavioral control		subjective norm
	Stages of change	x̄±SD	m(IQR)	x̄±SD	m(IQR)	x̄±SD	m(IQR)
	Stages I	16.84±3.34^b,c,e,d	17.00(4.00)	16.84±2.87	17.00(4.00)	20.49±4.61^b,c,e,d	21.00(6.00)
	Stages II	18.12±2.59^a	18.00(3.00)	16.68±2.87	17.00(4.00)	22.33±3.83^a,e,d	22.00(4.00)
	Stages III	18.56±2.66^a,b	18.00(3.75)	17.15±2.50	16.50(4.75)	22.25±3.57^a,d	22.50(4.75)
	Stages IV	19.46±2.24^a,b,c	19.50(3.00)	17.04±2.96	17.00(5.25)	24.50±3.85^a,b,c	24.00(5.00)
	Stages V	18.82±2.93^a,f	18.50(4.00)	16.82±3.20	17.00(4.25)	23.85±3.67^a,b	24.00(3.25)
	Stages VI	17.14±2.85^e,d	16.50(5.25)	17.85±2.95	18.50(3.25)	21.57±4.62^d	22.00(4.50)
	P-value	<0.001		0.567		<0.001
vitamin D-enriched milk	Stages I	16.56±3.50^b,c,e,d	16.00(3.00)	16.56±3.02	17.00(3.00)	20.01±4.61^b,c,e,d	19.00(5.00)
	Stages II	18.00±2.82^a,f	18.00(4.00)	16.97±2.95	17.00(4.00)	21.99±4.02^a,e,d,f	22.00(4.00)
	Stages III	18.18±2.54^a,f	18.00(3.00)	17.26±2.23	18.00(3.00)	23.05±3.85^a,f	23.00(4.00)
	Stages IV	18.82±2.46^a,f	19.00(3.00)	16.90±2.54	17.00(4.00)	23.52±3.38^a,b,f	24.00(3.00)
	Stages V	18.69±2.47^a,f	18.00(3.00)	16.86±2.98	17.00(4.00)	23.41±3.96^a,b,f	23.00(6.00)
	Stages VI	16.40±2.69^b,c,e,d	16.00(3.50)	16.52±2.48	16.00(2.50)	19.88±4.03^b,c,e,d	21.00(4.50)
	P-value	<0.001		0.498		<0,001
skimmed milk	Stages I	17.17±3.47^e	17.00(5.00)	17.74±3.11	17.00(4.00)	20.71±4.85^c,e,d,f	21.00(6.00)
	Stages II	17.64±3.02	18.00(4.75)	16.81±3.06	17.00(4.00)	21.45±4.03^c,e,d	22.00(5.75)
	Stages III	18.80±2.70^f	19.00(4.00)	17.46±3.32	18.00(4.25)	23.40±4.17^a,b,f	23.50(5.50)
	Stages IV	18.47±2.07^f	18.00(3.00)	17.00±2.34	17.00(2.75)	23.20±3.59^a,b,f	24.00(4.00)
	Stages V	18.08±2.37^a	18.00(3.00)	16.82±2.57	17.00(3.50)	22.62±3.65^a,b,f	23.00(4.00)
	Stages VI	17.09±3.72^c,d	17.00(5.00)	16.70±2.45	17.00(3.00)	21.09±4.69^a,c,d	21.00(6.00)
	P-value	<0.006		0.712		<0,001
vegetable milk	Stages I	16.92±3.37^c,b,e	17.00(4.00)	16.68±2.95	17.00(4.00)	20.65±4.75^b,c,e,d	20.00(6.00)
	Stages II	17.94±2.92^a	18.00(4.00)	17.01±2.88	17.00(4.00)	22.18±3.92^a	22.00(4.00)
	Stages III	18.77±2.32^a	18.00(3.00)	17.37±2.76	17.00(4.00)	22.39±4.15^a	23.00(4.00)
	Stages IV	17.95±2.20	18.00(4.00)	16.72±2.40	17.00(2.00)	22.75±3.21^a	23.00(3.00)
	Stages V	18.53±2.76^a	18.00(3.00)	16.70±3.07	17.00(3.00)	23.04±3.94^a	23.00(6.00)
	Stages VI	18.00±2.81	18.00(4.00)	16.36±2.80	16.00(3.00)	21.71±4.56	21.50(7.50)
	P-value	<0.001		0.271		<0,001
a: significant difference by stage I , b: significant difference by stage II, c: significant difference by stage III, d: significant difference by stage IV, e: significant difference by stage V, f: significant difference by stage VI. Stage I: Pre-contemplation Stage II: Contemplation, Stage III: Preparation, Stage IV: Action, Stage V: Maintenance, Stage VI : Relapse m(IQR): Median)Interquartile Range( x̄±SD:Mean ±Std. Deviation TPB: Theory of planned behavior SOC: stages of change model

Table 3: Comparison of the average scores of the constructs of the TPB according to the SOC

Vitamin enriched juice	Model structures	attitude		Perceived behavioral control		subjective norm
	Stages of change	x̄±SD	m(IQR)	x̄±SD	m(IQR)	x̄±SD	m(IQR)
	Stages I	16.82±3.26^c,d,e	17.00(4.00)	16.55±2.58	17.00(3.00)	20.21±4.55^b,c,d,e	20.00(5.00)
	Stages II	17.97±2.71	18.00(4.00)	17.30±2.92	17.00(5.00)	22.21±3.96^a,d	22.50(4.25)
	Stages III	18.75±2.55^a,f	19.00(3.00)	17.24±3.12	17.00(4.50)	23.08±3.73^a	24.00(4.50)
	Stages IV	18.50±3.08^a	19.00(4.75)	16.87±2.73	17.00(4.00)	24.12±4.08^a,b,e,f	22.50(4.75)
	Stages V	18.45±2.80^a	18.00(3.00)	16.60±3.30	17.00(4.00)	22.34±4.42^a,d,e,f	24.00(5.50)
	Stages VI	17.38±2.85^c	17.00(4.00)	16.57±2.69	17.00(4.00)	22.89±3.61^d	23.00(4.25)
	P-value	<0.001		0.351		<0.001
dough and probiotic drinks	Stages I	17.12±3.50^c,d,e	17.00(4.00)	16.98±2.86	17.00(4.00)	20.44±4.68^b,c,d,e	21.00(6.00)
	Stages II	17.54±3.08	18.00(4.00)	17.00±3.04	17.00(4.00)	21.82±4.13^a	22.00(5.00)
	Stages III	18.69±2.07^a,f	18.00(4.00)	17.20±2.88	18.00(3.00)	22.62±3.68^a,f	23.00(6.00)
	Stages IV	18.51±2.37^a,f	19.00(3.00)	16.66±2.41	17.00(3.00)	22.76±4.08^a,f	22.50(4.75)
	Stages V	17.96±2.84^a,f	18.00(4.00)	16.73±2.78	17.00(3.00)	22.34±4.18^a,f	23.00(4.00)
	Stages VI	16.92±3.23^c,d,e	16.50(4.00)	16.42±3.32	17.00(4.00)	20.78±4.33^c,d,e	22.00(6.25)
	P-value	<0,002		0.844		<0.001
a: significant difference by stage I , b: significant difference by stage II, c: significant difference by stage III, d: significant difference by stage IV, e: significant difference by stage V, f: significant difference by stage VI. Stage I: Pre-contemplation Stage II: Contemplation, Stage III: Preparation, Stage IV: Action, Stage V: Maintenance, Stage VI : Relapse m(IQR): Median)Interquartile Range( x̄±SD:Mean ±Std. Deviation TPB: Theory of planned behavior SOC: stages of change model

Table 4: Comparison of the average scores of the TPB constructs according to the studied variables

variable		attitude		Perceived behavioral control		subjective norm
variable		x̄±SD	m(IQR)	x̄±SD	m(IQR)	x̄±SD	m(IQR)
Buy from the supermarket	Yes	17.23±3.04	17.00(4.00)	16.87±2.74	17.00(3.25)	20.85±4.31	21.00(6.00)
	No	17.93±3.03	18.00(4.00)	16.81±2.95	17.00(4.00)	22.20±4.27	22.00(6.00)
	P-value	0.01		0.60		0.001
Buy from a chain store	Yes	17.91±3.06	18.00(4.00)	17.09±2.83	17.00(3.00)	21.95±4.36	22.00(5.00)
	No	17.50±3.02	17.00(4.75)	16.62±2.90	17.00(3.00)	21.53±4.30	22.00(6.00)
	P-value	0.05		0.058		0.27
Read the label	Yes	17.84±2.86	18.00(4.00)	16.97±2.79	17.00(4.00)	22.00±4.24	23.00(5.00)
	No	17.25±3.48	17.00(5.00)	16.43±3.08	17.00(3.00)	20.92±4.49	21.00(6.00)
	P-value	0.06		0.15		0.002
Participation in the purchase	Yes	21.89±4.33	22.00(5.00)	16.83±2.91	17.00(4.00)	17.69±3.08	18.00(4.00)
	No	20.35±4.11	20.00(4.00)	16.88±2.58	17.00(2.00)	17.66±2.80	17.00(5.00)
	P-value	0.68		0.93		0.002

Chart 1 is available in the Supplementary Files section.

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Chart1.jpg
Chart 1: The frequency of stages of change model

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Investigating the consumption status of Functional drinks (fortified) based on the theory of planned behavior and the stages of change model in female employees

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