Qualitative exploration of the factors influencing the use of dietary supplements in Iranian women: introduction to areas of focus for developing interventions.

BACKGROUND: Literature shows that the consumption of Dietary Supplements (DS) is more common in Iran. This study aimed to explore the experiences of a sample of Iranian women regarding the factors influencing the use of DS.
METHODS: This qualitative content analysis study was conducted in Qods city, Tehran province, Iran from January to March 2020. Forty-two semi-structured in-depth interviews were performed with women. The participants were asked about their experiences about the determinants of the consumption of DS. After the first round of the interviews was done, we performed content analysis of the data and continued up to data saturation.
RESULTS: Two main themes including personal factors (with 5 subthemes including sociodemographic characteristics, perceived benefits of DS, history of illness, physiological conditions, and lifestyle factors) and socio-economic factors (with 3 subthemes including subjective norms, the price of food and commercial considerations of the sectors involved in the production and sale of DS) emerged as the experiences of the participants as to the intake of DS.
CONCLUSIONS: These variables may suggest areas which need to be focused on for performing more effective interventions to affect appropriate consumption of DS in Iran.

Introduction

All over the world, the use of dietary supplements (DS), especially multivitamin-mineral products, is on increase and a large number of people use them routinely (1–4). In this regard, the result of a study in Iran showed that the prevalence of the use of DS among Iranian women and men was 43.2% and 20.4%, respectively [1]. Also, Gahche et al. indicated that 70% of older adults in the United States had used 1 DS in the past 30 days; 54% of them used 1 or 2 products, and 29% used ≥4 products [2]. Sekhri and Kaur reported that 68.3% of the general public in India used multivitamin supplements [3]. In some countries, the use of DS has doubled in the past several years [5].

Despite the benefits of using some DS in people who need to receive it [6], these products are mostly self-prescribed with no input from informed medical sources such as doctors, or pharmacists [7]. DS may directly cause toxic reactions or may interact with other supplements or prescription medications. Some of DS have been contaminated with heavy metals [8]. The result of a study showed that about 23,000 emergency department visits in the United States annually were associated with the side effects of DS, such as cardiovascular manifestations [9]. In a study, mortality has been attributed to the use of some vitamins and minerals, such as iron [10]. The result of a study showed that high calcium use was associated with increased risk of coronary artery calcification [11]. Moreover, the high beta-carotene, vitamin A, and vitamin E use may increase mortality [12]. Unfortunately, most of the consumers of DS are unaware about its possible adverse effects or medication-supplement interactions [13].

Taking DS is influenced by such factors as gender, educational level, age, income, physical activity, body mass index, history of chronic diseases and belief about the benefits of DS [3, 14, 15]. However, additional information regarding the reasons behind the use of DS in each country is required to develop appropriate and effective interventions for its correct usage [5].

Despite the excessive use of DS in Iran [16, 17], to the best of our knowledge, no study has been conducted to determine the reasons for the use of DS from perspective of Iranian consumers. Therefore, the objective of the present study was to explore the experiences of a sample of Iranian women as to the factors influencing the use of DS.

Materials and methods

Design and participants

A qualitative content analysis design (conventional method) was used to identify the experiences of a sample of women regarding the factors influencing the use of DS in Qods city, Tehran province, Iran, from January to March 2020. Those participants who used DS were selected.

The sampling method used was Judgement sampling (or Purposive). To obtain the maximum information, a wide variety of women who used DS were selected from different places such as health centers, pharmacies, shops selling DS, etc. In this study, the inclusion criteria were: a) female sex, b) Iranian nationality, c) residence in Qods city, and d) willingness to participate in the present study and share their related experiences. All the participants were informed about the objectives of the study and signed the informed consent form. The ethics committee of Iran University of Medical Sciences approved the protocol of the present study (# IR.IUMS.REC.1397.935).

Data collection

Semi-structured interviews were conducted using guide questions and applying the individual interview technique. Authors 1 and 2 conducted the interviews. Author 1 is a Ph.D student and has experience in conducting qualitative research and interviews. Author 2 is also an assistant professor of education and health promotion and a researcher in the field of nutrition and health and has published several qualitative studies in this field. With the permission of the study participants, the interviews were recorded via audiotape and transcribed verbatim by two of the researchers of the study. Interviews were conducted in one of the primary health care facilities, but if the participants were not satisfied, in coordination with them, another place where the participants were more comfortable such as workplaces, parks, sports clubs and so on were selected. The time of conducting interviews was arranged with the participants’ consent. Each interview lasted between 20 and 25 min. After the interview, the interviewees were honored with a gift.

The topic of interviews included the history of using DS by the study participants and the factors affecting the use of DS by them. The interviews were started with the general questions about age, educational status, employment status, and marital status. Then, they were followed by some questions such as “What DS do you take and how do you take them? What are the reasons for taking these supplements by you? Explain please. How do you feel when you take these supplements? Has your doctor prescribed these supplements for you? Or not? Who around you (family and friends) use DS? What supplements? What are the reasons for taking these supplements by them? In your opinion, what is the consumption of DS in the society? High, medium or low? What personal, social, political, economic, health, etc. factors affect the consumption of DS? Explain please. Also, all the interviews were carried out face to face and all body language and the faces movements of the interviewees were recorded. Sampling was continued until we reached data saturation.

Ethics approval and consent to participate

The study was approved by the ethics committee of Iran University of Medical Sciences, Tehran, Iran (Ethical Approval Code: IR.IUMS.REC.1397.935). All participants were informed about the study objectives and completed a consent form. They were assured that their voices were kept secured and coded according to each participant's identification number.

Data analysis

Data analysis was carried out simultaneously with data collection. The interviews were first recorded and then rewritten word for word. After each interview, the coding was done by authors 1 and 2. Through reviewing of the interviews repeatedly, a general impression was obtained and then based on the statements of the individuals, the meaning of the units was obtained. The researchers identified the initial code in the data and then evaluated the degree of similarity among these codes. Through further review of the versions, the initial codes were merged to determine the main content of the data, the emerged categories were compared and scrutinized during the interviews to show the categories that revealed subtle differences in data. Therefore, were identified the main themes and sub- themes. For better analysis, the codes, sub-themes and themes were discussed with all authors and competent methodology experts. Data were collected until the saturation phase was achieved [18].

Rigor

To obtain in-depth data, maximum sampling was employed according to age, and level of education. The study participants' agreement for long-term interaction with the researchers of the present study was achieved. Member check was carried out with 15 participants to ensure that the analysis reflected their actual experiences [19].

Results

Forty-two participants were interviewed. The demographic features of the participants are presented in Table 1. After data analysis, two main themes including a) personal factors and b) socio-economic factors emerged as the experience of the study participants regarding the reasons for using DS, which is examined separately in the following section (The categories and sub-categories are summarized in Table 2).

Table 1

Demographic characteristics of the study participants (n = 42).

Variables	n	%	Mean	SD
Age			38.90	17/6
Sex(Female)	42	100
Marital status
Single	17	40.47
Married	25	59.52
Educational level
Illiterate	1	2.38
≤12 th grade	8	19.04
>12 th grade	33	78.57
Employment status
Self-employed	2	4.76
Employee	8	19.04
Casual laborer	2	4.76
Household duties	25	59.52
Student	5	11.90
Consumption DS
Sometimes	3	7.14
Often	8	19.04
Always	31	73.80

Table 2

Categorization of the themes and subthemes.

Themes	Subthemes	Codes
Personal factors	Perceived benefits of dietary supplements	1. Increasing fitness and weight loss 2. Reducing hair loss 3. Increasing skin health and beauty 4. Improving mood (e.g anxiety and anger) 5. Reducing the body's needs to unhealthy or unsafe foods 6. Filling the nutritional gaps in the diet
	History of illness	1. Diabetes 2. Intolerance of lactose 3. Hyperlipidemia 4. Autoimmune diseases 5. Persistent weakness 6. Muscle ache 7. Anemia
	Physiological condition	1. Pregnancy or planning to get pregnant 2. Lactation 3. Oral contraceptive use
	Sociodemographic characteristics	1. Age 2. Household income 3. Educational level 4. Urbanization
	Lifestyle factors	1. Tobacco smoking 2. Having physical activity 3. Trying to weight
Socio-economic factors	Subjective norms	1. The use of dietary supplements by people around (including family members, co-workers, neighbors, friends, and others) 2. Encouragement to use dietary supplements by doctors, health care providers, pharmacy staff, family members and mass media
	The price of food	1. High price of fruits and vegetable 2. High price of meat and protein 3. High price of dairy products 4. High price of organic or healthy products
	Commercial considerations of the sectors involved in the production and sale of dietary supplements	1. Economic benefits of the sale of dietary supplement by dietary supplement industry 2. Economic benefits of the sale of dietary supplement by pharmacies and drug stores

Personal factors

Personal factors with 5 subthemes including perceived benefits of DS, history of illness, physiological condition, sociodemographic characteristics, and lifestyle factors were identified as one of the influencing factors for the use of DS among the participants.

Perceived benefits of DS

One of the most common reasons for using DS is its perceived benefits. This type of perception occurs in people for various reasons. Part of this perception is due to the growing desire of people for fitness and physical beauty such as beauty and skin health, and another part is due to the tendency to fill nutritional gaps and reduce the side effects of micronutrient deficiencies such as anger and anxiety. The subjects told that DS may increase fitness, reduce the hair loss, increase the skin health and its beauty, improve the mood, reduce the body's needs to unhealthy or unsafe foods, and fill nutrient gaps in the diet. They stated:

‘I have been taking DS such as multivitamin, selenium, zinc and vitamin C for a long time… Due to the use of these supplements, my skin is very clear and nice’ (F37), ‘When I take DS, I feel that my body becomes stronger and fresher…’ (F23), ‘DS may prevent any illness or pain’ (F32), ‘… the consumption of DS has positive effects on the mood, mind, concentration, nervous and mental health, and brain function’ (F50), ‘… I was stressed and anxious… one of my colleagues said that you probably have anemia or lack of vitamin in your body and I started to take DS’ (F29), ‘To prevent carcinogenic and pathogenic effects of environmental pollution, parasites and free radicals on my body, I take multivitamins, zinc, selenium and calcium’ (F39), ‘The quality of foods is decreasing nowadays. I feel that foods cannot meet my body's nutritional needs…; therefore, I, my children, and other relatives need to take DS’ (F27), ‘Since fruits and vegetables are contaminated with toxins, they cannot provide the necessary vitamins, fiber and minerals to human body. Therefore, it would be better to use DS (F48).

History of some illnesses

From the participants’ perspectives, another factor affecting the use of DS was the history of some illnesses. Many participants stated that the history of illnesses such as diabetes, lactose intolerance, hyperlipidemia, muscle aches, persistent weakness, anemia, and autoimmune diseases may affect the use of DS, ‘My immune system is weak… I am often sick. Therefore, I consume multivitamins’ (F19), ‘I have constant fatigue and weakness and my muscles ache. I feel better when I take DS’ (F40), ‘I went to the doctor and he said that, due to my weak body anemia, I should take iron supplement. I decided to take iron and folic acid and other multivitamins’ (F56), ‘My parents have diabetes. I am susceptible to this disease. I avoid a lot of foods, so, I have to take DS’ (F37).

Physiological conditions

A number of participants told that some physiological conditions such as being pregnant or planning for pregnancy, breastfeeding, and using oral contraceptive might influence the use of DS: ‘I will not get pregnant. I take supplements like Pharmaton, zinc, selenium, vitamin E, and powders like Ginseng every day to get pregnant …’ (F26), ‘I use DS to have a normal and comfortable delivery… and give birth to healthier babies’ (F33), ‘I used DS during lactation…’ (F48), ‘Everyone should take vitamin supplements, especially women that use oral contraceptives’ (F48), ‘When I take oral contraceptive pills, I use DS to prevent nausea and other side effects of these pills’ (F37).

Sociodemographic characteristics

Sociodemographic characteristics including age, employment status, educational level, household income, and urbanization have significant effects on the use of DS. Participants stated:

‘DS should be taken by people aged above 32 years. The intake rates for DS increase with age’ (F64), ‘Since my and my wife's income and education level are high, we consume DS regularly…’ (F48), ‘Occupation is a factor influencing the use of DS. I am an employee and do not have enough time to prepare and eat some foods (e.g. salad and vegetable). I prefer to take DS’ (F39). ‘Those who have a good job and income are more likely to consume one or more DS…’ (F47), ‘Urbanization may generate more physical and mental concerns. The use of DS is more prevalent among people who reside in urban areas’ (F48).

Lifestyle factors

Some participants stated that the use of DS was associated with lifestyle characteristics such as physical activity, tobacco smoking and attempts to control the weight: ‘DS increases energy and physical strength. I think they are essential for the body, especially for people who exercise regularly’ (F32), ‘Given that I'm very obese, I cannot eat all kinds of food. I have decided to lose weight, so I take DS’ (F45), ‘Because I am a professional swimmer, I take DS regularly’ (F19), ‘People will have better weight control and fitness if they take DS in addition to exercise and proper nutrition’ (F23), ‘The use of DS may reduce appetite and lead to better weight control’ (F30(, ‘Smoking reduces the absorption of vitamins consumed through food. I take DS because I smoke’ (F26).

Socio-economic factors

Socio-economic factors also affect the use of DS. The majority of the participants believed that socio-economic factors with 3 subthemes including subjective norms, the price of food, and large-scale advertisement of DS industry were the influencing factors in the use of DS by them.

Subjective norms

Encouraging others can lead to the use of DS. Part of this effect is due to the use of DS by those around the person and their encouragement to use them, and the other part is by effects visual and audio attractions contained in these products or related information. Many participants mentioned and emphasized that they were under pressure and persuasion of their spouse, mother, sister, friends, colleagues and other people around them, pharmacy staff and technicians, health providers and social media about the use of DS, ‘My wife takes DS every night. She believes that a woman should always take care of her body and it would be better for you to consume DS…’ (F30(, ‘My sister and friends introduced the types of DS to me. According to their advice, I use DS to increase my energy and reduce fatigue’ (F22), ‘Employees of pharmacies highlighted the benefits of DS to persuade people to buy and consume it’ (F21), The images and labels of the products of DS are so appealing and attractive for me. When I see these packages in the drugstore, instead of buying one supplement, I buy all kinds of them’ (F28), ‘A large amount of information provided by virtual sites may increase the use of DS’ (F30(, ‘Some healthcare providers emphasize that taking DS may prevent aging and disease’ (F21).

The price of foods

Increasing prices of food products such as organic products, fruits, vegetables, meat and dairy products, etc. and the inability of people to buy have significant effects on food choices and consumption of different food groups by them that leads to increased consumption of DS by people.

Some of the participants talked about the importance of the price of foods in increasing the intake of DS. They mentioned that the price of foods was on increase and they had to use DS, ‘Everything is expensive. We can't buy some fruits, vegetables or nuts... We have to use all kinds of multivitamins and supplements’ (F29), ‘I didn't use any DS in the past years. After increasing the price of dairy products and meat, I take supplements every day’ (F30), ‘Nutrient-rich foods are more expensive than lower-quality foods. I have to eat multivitamins, zinc, selenium, calcium and so on to meet my body's needs’ (F54).

Commercial considerations of the sectors involved in the production and sale of dietary supplements

Commercial considerations was another factor that increases the use of DS. This impact is due to the increasing growth of the DS industry in recent decades and the profits and interests of companies producing these products, which leads to more production and variety of these products and multifaceted marketing for more sales.

A number of participants told that commercial considerations of the sectors involved in the production and sale of dietary supplements are the factor affecting the use of these supplements, ‘The DS industry is so lucrative that various companies are regularly producing new multivitamins and persuade people to consume them’ (F33), ‘The huge profit of pharmacies and drug stores from the sale of DS increases marketing them. This marketing may enhance the use of DS by people’ (F39), ‘Drug stores try to sell new DS to people for more profits’ (F48).

Discussion

The results of the present study provided information on the participants’ experiences of the factor influencing the use of DS. It is recommended that tailored and effective interventions should be designed to make people aware of the risks of uncontrolled and uncorrected intake of DS in Iran.

Perceived benefits of DS were known as one of the personal factors influencing the use of DS. In the same line, Mohdzaki et al. and Alfawaz et al. showed that looking beautiful and maintaining healthy hair were two of the main reasons for consumption of DS among females [20, 21]. Margit Pajor et al. showed that users believed that DS might improve mental and physical health and reduce health complaints. They also noted that one of the reasons of using DS by adults was that they believed that the quality and safety of food products might have declined recently; they are of the opinion that food contains considerably lower amounts of vitamins and minerals [22]. In a study by Dickinson et al., it was reported that 42% of the participants took DS to fill nutrient gaps in their diet [23]. Despite the positive effects of some DSs on the skin and hair health, psychological state, and the reduction of weight [24, 25, 26], taking them more than the needs of the body has some adverse effects [27]. Nowadays, given the motivation of most people for fitness and weight loss, a great opportunity has been created for the supplement industry to produce and market a wide range of DSs claiming weight loss, while there is evidence of some direct side effects or combination and interactions with other drugs [28]. Women should be advised to consume a balanced, healthy diet, which includes vitamins A, B, C, and E -rich foods and be encouraged to adopt safe weight reduction methods.

In our study, some participants reported that the history of some illnesses might affect the intake of DS. Literature showed that adults who had a history of a chronic disease or those who thought they themselves had got these diseases subjectively had more preference for using DS than those who did not [29, 30]. In line with these results, Islam et al. showed that “to recover from disease” was the mostly reported reason for using DS among adult population in southern Bangladesh [26]. Bailey et al. found that 18% of US adults used DS to lower their cholesterol level and have a healthy heart [31]. Salgado et al. found that 10.3% of Brazilian road runners used DS for their fatigue [32]. Pillay and Pillay also reported that 62.5% of dietetic students used DS for strengthening their immune system [33]. Considering the history of disease in people may help to identify those in need of education regarding the supplements and the adverse effects of using them through self-description.

Several participants reported that some physiological conditions such as being pregnancy or planning for pregnancy, breastfeeding and oral contraceptive use may influence the use of DS. In the same line, Aronsson et al. and Morin et al. showed that being pregnant with the first child and pregnancy planning were two predictors for the intake of DS in mothers [34, 35]. Picciano and McGuire also reported that in North America, half of pregnant or lactating women use some form of DS [36]. Despite the fact the using some DS during pregnancy might be important for maternal and fetal health [6], literature showed that mean intakes of thiamin, riboflavin, niacin, folic acid, vitamins B6, B12, and C, iron, and zinc from DS alone were at or above their respective recommended dietary allowances (RDAs) among pregnant and lactating DS users. About 50% of pregnant and 40% of lactating women consume DS based on the recommendation of a health care provider [37]. It is suggested that during pre-pregnancy counseling, the women's diet should be taken into account, and DS should be prescribed to ensure they meet the RDAs for essential nutrients.

Some study participants indicated that sociodemographic characteristics including the age, employment status, educational level, household income, and urbanization may affect the use of DS. Previous studies confirmed that age and educational level variables impacted the use of DS [2, 34, 38]. In this regard, Cowan et al. demonstrated that the highest income group among US adults were the highest consumers of DS [4]. Austin et al. showed that increased use of DS in US coast guard personnel was associated with high intensity operational occupations [39]. Since the sociodemographic characteristics may determine different behaviors regarding the intake of DS, further research is recommended among other groups with different demographics features.

Some participants indicated that the use of DS was associated with lifestyle characteristics such as the physical activity level, tobacco smoking and desire to control weight. This finding is consistent with those of Bailey et al. and Mullie et al., indicating that DS users were more likely to report exercise or physical activity more frequently than non-users [31, 40]. It is worth mentioning that athletes or individuals with high physical activity consume DS for enhancing energy, improving performance, and increasing the level of endurance [32]. Previous studies revealed that BMI≥25.0 and BMI≥30.0 kg/m2 were recognized as one of the factors influencing the use of DS [34, 41]. Our participants mentioned that smokers were more likely to take DS than non-smokers. This finding is consistent with those of similar studies that showed using DS was more observed among smokers than non-smokers [15, 42]. Thus, nutritionists or other health care professionals should consider lifestyle as confounders of using DS and are recommended to convince their clients that a balanced diet can meet the needs of physically active people, smokers and those who tend to control their weight. In addition, clients should be made aware that DS must always be used under the supervision of a specialist.

Socio-economic factors with 3 sub-themes emerged as one of the factors that impacted the use DS among the participants. One of the sub-themes was subjective norms. Subjective norms and social pressure to take DS may motivate the females to decide to use it [43]. Both users and even non-users of DS reported that they had been exposed to different social influences for the intake of DS [22]. Conner et al. noted that the media had powerful influence on a person's decision to consume DS [44]. Given that the social pressure is a facilitator in starting and continuing the use of DS, health care professionals should be aware of the culture and attitude of the community towards DS intake and are recommended to educate the individuals through mass media about benefits as well as complications of DS.

The second socio-economic factor that influenced DS consumption among the study participants was high price of food. Rao et al. in a systematic review stated that healthier choices of food groups, especially for meats/proteins, were more expensive per serving than the less healthy ones [45]. Studies have shown that the increase of price affects the quantity and quality of food consumed. For example, the results of a study by Green et al. showed that increasing the price of different food groups such as meat and serials was one of the reasons for reduction of their consumption [46]. Ball et al demonstrated that reduction in the price of healthier food products such as fruits and vegetables lead to increase in their consumption [47]. Given the fact that for a large number of low-income women the cost of food is an obstacle to buying and eating healthier foods, opportunities for reducing financial barriers to healthy diet may decrease the intake of DS. Thus, increasing food security should be more considered by policy- makers.

The third socio-economic factor that was reported to influence DS consumption among the study participants was commercial considerations of the sectors involved in the production and sale of DS. They stated that the profits from the sale of DS caused these industries to do a lot of marketing. Literature showed that the reasons for DS intake were closely aligned with marketed claims [48]. DS industries heavily rely on marketing tools to sway consumer opinion [49]. Given that the DS market in Iran is experiencing a significant growth [50], the authorities are suggested to take measures to ensure that advertising claims about the health benefits of DS is correct.

One of the strengths of this study was to examine the determinants and beliefs of women about DSs which were done by qualitative method and comprehensively. Also, the diversity of participants from different groups with different demographical characteristics led to better conclusion. However, the small number of participants and the nature of qualitative studies can reduce the generalizability of the findings.

Conclusion

The results of the present study showed that the use of DS might be affected by certain personal and socio-economic factors. This research provided the basis for consumer education about the benefits and adverse effects of DS according to sociodemographic considerations, physiological conditions, lifestyle factors, history of illnesses, and socio-economics factors.

Declarations

Author contribution statement

Akramsadat Hoseini and Tahereh Dehdari: Conceived and designed the experiments; Performed the experiments; Analyzed and interpreted the data; Contributed reagents, materials, analysis tools or data; Wrote the paper.

Mahnaz Solhi, Seyedeh Tayebeh Rahideh and Leila Janani: Conceived and designed the experiments; Analyzed and interpreted the data; Contributed reagents, materials, analysis tools or data; Wrote the paper.

Funding statement

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Data availability statement

No data was used for the research described in the article.

Declaration of interests statement

The authors declare no conflict of interest.

Additional information

No additional information is available for this paper.