Promoting fruit and vegetable consumption: Methodological protocol of a randomized controlled community trial.

This study aimed to develop community educational activities in Brazilian primary health care settings. A randomized controlled community trial was conducted to encourage fruit and vegetable consumption (FV-RCT) in a representative sample of consumers aged 20 years or older in a Brazilian city. The fruit and vegetable consumption was classified according to the transtheoretical model's stages of change, reflecting different degrees of readiness for change. The educational activities were based on the transtheoretical model and a problematizing-dialogic pedagogy, planned by an interdisciplinary team, using information collected in a qualitative pilot study. The actions were conducted over seven months, and baseline data were collected from 1483 participants. The educational strategies included workshops interspersed with motivational messages conveyed via postcard, interactive environment-based activities, and informative material. In the workshops, different techniques were used - conversation circles, image theatre, self-portraits, cooking and art as experience. The applied intervention based on the chosen theories implied in a refinement of the intervention, but, nevertheless, proved to be feasible for large population groups and to the scenario of health services. Thus, this interdisciplinary FV-RCT study represents an effort to advance methodological issues and provide theoretical subsidies for actions.

RCT Entities:   Population Interventions Outcomes

Introduction

Documents of the World Health Organization have highlight the need for countries to commit themselves to the proposition and implementation of effective, integrated, sustainable evidence-based public policy for the prevention and control of chronic non-communicable diseases (NCDs) and associated risk factors, mainly by strengthening primary health care [1,2].

The scientific community has presented alternatives; however, the interventions proposed constitute a heterogeneous set of methods, with different combinations of intensity, time and behaviours evaluated (compromising reproducibility), generally resulting in minimal changes to lifestyles and participants health [3]. Few studies have been conducted in the context of health services, despite their importance in providing a practical solution [4]. In addition, behaviour-based interventions do not explain the theories used and how each construct was applied [5,6]. We have few methodological articles, which would favour reproduction of methods and consequently verify the consistency of findings. With respect to participants, researches have shown a low participation rate; most studies do not observe participants' attitudes and perceptions concerning diet and health and disregard the fact that some people are not ready to introduce changes [7].

To overcome these issues, the use of educational theories is fundamental. The theories promote reflection, guiding action, and facilitating the understanding of interactions that constitute human behaviour [8]. The methods and theories used should facilitate the planning of distinguished interventions, respecting participant characteristics such as environment, culture, perception, attitude, difficulties, and motivation to accomplish behaviour change [7].

Despite the importance of these issues, most published epidemiological studies focus on the effects of interventions on a certain behaviour or disease, without providing sufficient explanation concerning the methods used or their application in real-life contexts [9]. Hence, we have a gap regarding the understanding of educational theories and practices, and the knowledge and reapplication of methods.

In this way, this study will present the methodology of an innovative intervention proposal in the promotion of fruit and vegetable (FV) consumption in adult consumers, based on individuals' perceptions of their consumption habits, using different theories. To our knowledge, this study is one of the first Randomized Controlled Community Trial for FV promotion (FV - RCT) held in the health service system of a low-income country; proposing to jointly evaluate the process and the effectiveness of the intervention, with a considerable sample.

In consideration of the key role of methodological choices in planning and developing educational activities, this study aimed to present the protocol of the FV - RCT, a community educational nutrition intervention, provided in Brazilian primary health care. The main objective of the FV - RCT study was to evaluate, among a vulnerable population, the effectiveness of a nutrition intervention on FV consumption. In this article, we describe the methods and present baseline data and preliminary results.

Material and methods

Study setting and participants

The study was conducted in Belo Horizonte, Brazil, the eighth-largest city on the South American continent, with an estimated population of 2,375,151 inhabitants and a high Human Development Index value (0.810) [10].

One of the characteristics of the public health system in Brazil is heavy investment in primary care. The system is divided into different health services, such as basic health units and the Health Academy Program (HAP). The HAP, which was the scenario examined in this study, focuses on the promotion of health care by encouraging physical activity, leisure, and healthy eating, and other activities at no cost to participants [11]. The practice of physical exercise is guided by a physical education instructor and is offered for 60 min, three times a week per class.

The FV - RCT study was conducted in the HAP scenario: a randomized controlled community trial to encourage FV consumption in a representative sample of service users.

The HAP centres were selected via stratified cluster sampling in each of nine strata representing the nine administrative districts of the municipality. In each geographic stratum, formed according to the nine administrative regions of the municipality, two units were selected from low-income areas in the municipality and randomly assigned to the intervention (IG) or control group (CG).

Therefore, 18 centres were included in the study, nine with participants in the IG, and nine with participants in the CG; these centres were representative of the municipality, with reliability of 95% and error of less than 1.4%.

In each selected centre, participants in the study included all aged 20 years or older and habituated to the activities within the centres (e.g., regular participation in physical exercise in the preceding month). Pregnant women and individuals with cognitive difficulties preventing research participation were excluded from the study.

Participants in the IG and CG participated in the routine activities of HAP, which included physical activities, for three times a week during one hour. The CG did not participate in any activity related to nutritional intervention. During intervention development, we investigated and recorded educational activities related to nutrition and FV consumption among participants in the CG and IG, regardless whether these were conducted by the research team. We found that no further specific action of FV consumption was released for the CG until the follow-up evaluation at seven months.

FV - RCT intervention group

An important step in planning the FV - RCT intervention was the pilot study that had been previously conducted in order to examine the practices, barriers, facilitators, and social representations related to FV consumption. It allowed the activities adaptation according to participants' subjective needs [12] and identification of the shortcomings that should compose the activities. These shortcomings were related to food portions; nutritional information about FV (vitamins and minerals); and means of overcoming obstacles to changing FV consumption, which were associated with cost, flavour, family support, time required to buy and prepare food; and difficulties in access to quality FV.

The educational activities for intervention were developed by a trained interdisciplinary team consisting of dietitians, educators, and psychologists with expertise in health education. In order to standardize methodology, intervention development was performed by a team of three dietitians, who alternated between application and observation of the process, aided by at least three graduate students in Nutrition at all times.

Invitations to attend the workshops were made in writing and by telephone, one week in advance, with up to three contact attempts made on different days; thereafter, the invitation was left with a family member. Furthermore, physical educators in the centres propagated intervention during exercise classes.

The interdisciplinary team defined educational strategies and listed those that would be appropriate for the theoretical framework used.

Theoretical intervention approach

Educational activities were established based on problematizing-dialogic pedagogy of Paulo Freire [13], the pillars of the transtheoretical model (TM) [7], information gained via a qualitative pilot study [12] and literature review involving the factors associated with FV consumption.

The TM includes four pillars: stages of change, processes of change, self-efficacy, and decisional balance. The model facilitates the planning and implementation of various actions according to individuals' specific characteristics including perception, availability, attitude, and motivation to make behavioural changes [7,14].

Regarding stages of change, motivation for change defines phases that guide action planning and development. In the precontemplation stage, individuals do not intend to change their behaviour in the foreseeable future. In the contemplation stage, individuals recognize the need to change but require action to shape their motivation. In the preparation stage, individuals are ready to change their behaviour within 30 days. In the action stage, individuals are capable of short, immediate changes for a period of up to six months. In the maintenance stage, individuals' behaviour was changed more than six months previously, requiring the prevention of relapse and consolidation of gains [7].

To establish feasibility of intervention development in primary care service, the participants were regrouped as follows according to the stages of change with respect to FV consumption: preaction (precontemplation and contemplation stages), preparation stage, and action (action and maintenance stages).

The interventions were constructed according to each grouping, using the other components of TM. There are five cognitive and five behavioural processes of change. These processes underlie the understanding of how change occurs in stages. Cognitive processes are more effective in the preaction and preparation stages; and educational activities should focus on increasing awareness of behaviour and its consequences. The behavioural processes are directed to the action stages; providing more specific and detailed information [7]. Interventions also aimed to (1) increase individuals' confidence in their ability to achieve the desired behaviour when faced with obstacles (self-efficacy) [15] and, (2) increase awareness of the benefits of a healthy diet while minimizing the factors against change (decisional balance) [15].

Problematizing-dialogic pedagogy, proposed by Paulo Freire, was chosen for intervention development, to advance the TM and advocate autonomy and empowerment, as proposed in the HAP [8,13]. In this proposal, education creates the possibility of liberation, which promotes conscientious attitudes and presumes a horizontal and dialogical relationship between participants, which is aimed at knowledge exchange instead of a relationship in which one is superior to the other [13].

Observers' team and analysis plan

The observation of the intervention was made through an observation questionnaire. The questions were previously tested in a HAP centre not participating in the research in order to make the necessary adjustments to its application. The observation questionnaire recorded theme, objective (and if it was reached), number of participants, duration, description of how the action occurred, problems, participants doubts, satisfaction of participants and how was the participation of the subjects involved in the activities. It was performed by four trained dietician.

Also, considering evaluation of intervention effectiveness, initial and final face-to-face interview was performed by trained staff (dieticians or students of nutrition). The primary endpoint is change in FV consumption (grams) during follow-up. Secondary endpoints include mediating variables related to the main outcome: knowledge of FV season/crop; FV availability at home; and behaviour (stages of change, self-efficacy, and decisional balance).

In this study we present the descriptive statistics for participant's characteristics at baseline. The future analysis plan includes between-group differences for participants and non-participants at follow-up; and within-group changes. In order to analyze the impact on the primary outcome, generalized estimating equation will be used to examine the change in FV consumption. This analytic method examines time-varying dependent variables in relation to time-varying (variables that change over time) and time-constant (variables that do not change over time).

The study was approved by the University Ethics Research Committee (No. 0537.0.0203.000–11) and City Hall (No. 0537.0.0203.410–11A) and registered in the Brazilian Registry of Clinical Trials (RBR-9h7ckx; website: www.ensaiosclinicos.gov.br/rg/RBR-9h7ckx/). This study was conducted according to the guidelines laid down in the Declaration of Helsinki and all participants were informed about the objectives and methods of the study via letter and signed the written consent prior to participation.

Results

FV - RCT intervention group: participants' characteristics

From 3414 participants of 18 HAP centres, educational activities were developed for 1483 participants (43.4%) (9 HAP centres were IG) and implemented for seven months, in blocks of three centres.

Table 1 presents baseline characteristics of participants. FV - RCT intervention group participants were mostly women (87.0%), adults with low education and income, and with a high prevalence of NCDs. However, most reported being in group action, with a high average of FV consumption (360.0 g) (Table 1).

Table 1

Baseline characteristics of participants of group intervention (n = 1483).

Characteristics	n	Value
Sex (%)
Female	1291	87.0
Age (years)	1483	56.6 ± 12.2
Family income per capita ($)	1349	301.3 (96.5; 888.9)
Education (years)	1482	6.9 ± 4.1
Marital status (%)
Married	906	61.1
Divorced	132	8.9
Single	211	14.2
Widow	234	15.8
Profession (%)
Housewife	426	28.7
Retired	543	36.6
Unemployed	39	2.6
Employed	475	32.0
Body mass index (Kg/m2)	1415	27.9 ± 4.7
Waist circumference (cm)	1414	86.8 ± 10.9
Diseases (%)
Hypertension	796	53.7
Diabetes	245	16.6
Dyslipidemia	644	43.8
Stages of change Fruit and Vegetable (%)
Preaction	279	18.8
Preparation	515	34.7
Action	689	46.2
Fruit and Vegetable consumption (g/day)	1462	360.0 (97.1; 720.0)

After performing Shapiro–Wilk test to assess normality of the quantitative variables, variables with normal distribution were presented in mean and standard deviations; and variables with non-normal distribution in median and interquartile ranges. Income - Brazilian Real to Dollar ($): 2.25 was the average exchange rate during the data collection period.

Educational strategies

The following strategies were defined: workshop, motivational message via postcard, environment-based activity associated with the panel setting (particularly those concerning the interactive activity in the setting, e.g., movies and culinary), and delivery of informative material. All strategies were tailored according to the transtheoretical model (TM)’s stages of change, with the exception of the informative material and environment-based activities.

The educational activities addressed the following topics: health and food consumption; purchase, seasonality, and cost of FV; preserving the nutritional and sensory quality (from acquisition to consumption) of FV; guidelines for diversifying methods of preparation and consumption; sensory characteristics; portions; nutritional information, and family support.

Fig. 1 shows the timeline for educational strategies development. The educational strategies used in the activities (workshops, postcard with motivational messages, interactive environment-based activities and informative material) are presented in Fig. 2, showing their theoretical and developmental characteristics.

Fig. 1

Timeline for educational strategies development.

Fig. 2

Description of educational strategies.

In the workshops different techniques were used, as described below:

Conversation circles: Are characterized by space for dialogue, communication, and the exchange of experiences and information. The main objective is the development of the participant's autonomy via problematization, socialization of knowledge, and reflection on actions to promote empowerment [16].

Image theatre: Uses mainly concrete images to express emotions. One's own or another person's gestures constitute language and express feelings, problems, and ideas. The images constructed by the body are participants' creations, which facilitate the expression of thoughts, since images are easier to create than words [17].

Self-portrait: Assists the construction of one's identity in relation to the community, the neighbourhood, the city, the world, and one's emotions. When someone draws yourself, he/she is doing his/her self-portrait, which may arouse many questions [18].

Cooking: Facilitates the appreciation of cultural, social, and symbolic dimensions of feeding, embracing a moment of experience and the exchange of that experience. The cooking workshop allows one to be closer to individuals' daily lives, establishes contact with food, preparation of recipes, and tasting different preparations, which can provide new alimentary possibilities [19].

Art as experience: Helped to construct the educational strategies, permeating the encounter with the unexpected in the context of the participants' lives, trying to evoke and/or renew the meaning of food in their lives, involving different emotions (pleasure, frustration, sadness and joy) and cover the subject in its totality [20,21].

Educational strategies according to the transtheoretical model

The activities were developed with the completion of 10 different workshops, which were held on 540 different occasions, and four interactive environment-based activities, which were repeated 171 times. In addition, 4449 postcards and 1483 educational materials were distributed. To monitor the frequency with which users participated in FV - RCT intervention, the names of all participants were recorded.

Fig. 3 describes the educational strategies performed according to the TM, their objectives, techniques and materials.

Fig. 3

Educational strategies according to the groupings based on the Transtheoretical Model stages of change.

In the preaction group, the activities aimed to promote knowledge about healthy eating and to show its benefits; to provide to individuals tools to analyze their own diet; to increase awareness of the behaviour and its consequences; increase self-confidence in adopting healthy eating; and assist in identifying barriers to change and map out joint strategies to overcome them. In this group, strategies such as conversation circles, image theatre and self-portrait, were used to enhance the expression of feelings, sensations and thoughts, as well as reflection on the possibility of behaviour change (Fig. 3).

The preparation group focused on the signification of feelings, sensations and thoughts related to health. Participants elaborated a “plan of action” to be achieved within 30 days and were assisted to achieve feasible objectives related to FV intake, without being overburdened with excessive targets. Other strategies included self-portrait and sensory exploration of FV (Fig. 3).

In the action group, the activities provided individualized detailed materials; and favoured individual's skills in changing long-term behaviour and facing new difficulties, encouraging the maintenance of gains and prevention of relapse. The strategies involved cooking; social support; to develop ability to face new difficulties; thus, stimulating to promote and maintain changes achieved (Fig. 3).

Discussion

In order to conduct an intervention to promote FV consumption in health service, it was necessary to use different educational strategies aligned according to the chosen theories. This effort, although exhaustive because it involved a large contingent of people, proved feasible and apparently important to promote sustainable changes in participants' diet.

Theoretical and methodological choices regarding lifestyle interventions should encourage dialogical and emancipatory educational activities that promote independent and voluntary healthy lifestyles. There is a need to overcome proposals for actions that merely intervene without promoting health. Educational activities planned and developed through listening, dialogue, and joint production of knowledge, favour citizenship and autonomy, complying with health promotion principles [22].

The planning and development of intervention passes through several stages that should be discussed within an interdisciplinary team. This process includes local reality, the individuals involved, social representations, and the definition of educational theory and methodology, which guides the selection and construction of educational strategies.

The FV-RCT intervention revealed participants in a vulnerable situation, with low socioeconomic condition and high prevalence of NCDs, showing the importance of lifestyle intervention. Socioeconomically disadvantaged individuals typically demonstrate low quality dietary intake, live in neighbourhoods with lower access to healthy food and are more likely to develop NCDs [23]. The innovative HAP service represents an important initiative to promote health, prevent, and control prevalence of NCDs in populations with high social vulnerability. The FV-RCT intervention took into consideration important factors that affect food behaviours, such as social determinants, culture, food and social environment, possible cognitive difficulties, appropriate language in its development, between others.

In addition, the FV-RCT intervention was implemented mainly for women participants. The gender imbalance affects external validity of the study, which should be generalized mainly for the primary health care setting. It is well documented in literature that most participants of healthcare services in Brazil are women, which is an issue out of the control of researchers. This is likely due to service access (which can hinder the permanence of the economically active public) and also cultural (while women are more attentive to health issues, men are more resistant to seeking primary care and prevention actions) [[24], [25], [26]].

The use of educational theories may impose challenges. It is worth to highlight the ones related to the application of the TM, which was used in this study. There was a need for all individuals classified according to the five stages of change to participate in the educational activities, including those in the action and maintenance stages, which increased the complexity of intervention logistics, mainly because of the numbers of activities and participants involved. Some studies have examined only those individuals considered at risk of the target behaviour (i.e., those in the preaction stage) [22,27]. However, individuals in the action and maintenance stages should also be included, considering that some of their eating behaviours might require improvement [28], and they may be subject of relapse, particularly in view of today's obesogenic environment.

In this study, FV - RCT intervention were performed by the preaction, preparation, and action subgroups; this could have limited the educational activities developed, leading to the exclusion of approaches addressing these stages from each group. However, it is worth to note that 711 meetings in nine centres of health services were required to conduct considering the three groups, which raises the question as to whether it is viable and applicable to perform specific activities for the five stages in the context of primary care. It should also be noted that individuals in the early and late stages are sufficiently similar to allow the use of similar processes of change and strategies related to decisional balance and self-efficacy.

Intervention to promote the health of individuals, families, and communities should be prioritized in the context of health services, enabling the application of scientific evidence to practice situations that echo improvements in the health of the population under real-life conditions, to the detriment of studies performed under ideal, unviable conditions in the human context [9]. In this way, careful and systematic planning associated with institutional commitment, community mobilization, and focus on critical behaviours have been shown to be essential.

For the appropriate use of educational theories in the development of health actions, certain methodological steps must be employed. Special attention should be paid to interdisciplinary planning and the theoretical alignment of the professionals responsible for their implementation. The theoretical development of educational strategies is extremely important considering the challenge of training qualified facilitators aligned with the educational strategies proposed [29]. The interdisciplinary approach facilitates the articulation of knowledge and enrichment of skills, strengthening professionals and enhancing educational activities [22,30].

To ensure advancement of health-promotion interventions, it is fundamental the expansion of vehicles that allows the dissemination of methodology and detailed description of actions. This disclosure could be accomplished by publishing methodological studies and sharing the strategies and techniques developed, including their particularities and specificities, provided that they ensure the researchers authorship. Access to the methodology of health actions facilitates the reapplication of studies, resulting in verification of the results consistency and identification of valid and reproducible methods in different contexts.

We also highlight the potential for these studies to support new research that contributes to improve effectiveness of actions and public policies, which is a pressing global need.

Conclusion

The applied intervention based on the chosen theories implied in a refinement of the intervention with the inclusion of different educational strategies, which consider the context involved in the objective investigated. But, nevertheless, the intervention proved to be feasible for large population groups and to the scenario of health services.

Thus, this interdisciplinary FV-RCT study represents an effort to advance methodological issues and provide theoretical subsidies for actions. It can provide detailed information for lifestyle intervention and has the potential to make a substantial contribution to the development of nutrition interventions that are applicable to and attractive for populations, especially those at public health system.

Funding

This work was supported by Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG) [grant numbers APQ-033376-12, 21618/2013, PPM-00254-15]; and Conselho Nacional de Pesquisa (CNPQ) [grant number 476686/2013-0]. Funding sources had no involvement in the conduct of the research; in study design; in the collection, analysis and interpretation of data; in the writing of the report; in preparation of the article, or in the decision to submit the article for publication.

Number registration

RBR-9h7ckx in Brazilian Registry of Clinical Trials.