Dietary intake and processes of behaviour change in a nutrition education intervention for pregnant women in rural Malawi: A cluster-randomised controlled trial

AbstractObjective: To examine if increased intake of locally available nutrient-dense foods among pregnant women improved the quality of their dietary intake and if use of the Theory of Planned Behaviour could explain changes in their dietary behaviour.Design: We used data from a randomised controlled trial where the intervention group received nutrition education and dietary counselling. We promoted the use of recipes that utilised powders to enhance dietary diversity. We examined how the intervention achieved changes in dietary intakes and used mixed effects logistic regression models with random effects at village level to explore changes over time of the outcomes, adjusted for selected explanatory variables.Setting: The study was conducted in twenty villages in rural Malawi.Participants: Data from 257 pregnant women who were enrolled during late first trimester and followed until birth.Results: The intervention achieved improvements in the Dietary Diversity Score (DDS) and the Six Food Group Pyramid (SFG) score, especially in intakes of micronutrient-rich foods. A third of the women in the intervention group attained optimal DDS, whereas about 50 % attained optimal SFG. The theorised behaviour mediators (i.e. nutrition attitudes, nutrition behaviour control and subjective norm) that had improved were also significantly associated with high DDS.Conclusions: Improved dietary intakes were achieved through promoting the use of locally available nutrient-dense foods. Attainment of high DDS was a consequence of the women’s belief in the effectiveness of the proposed nutrition recommendations. We identified critical personal and environmental constraints related to dietary intakes during pregnancy in a low-resource setting.

We conducted the randomised trial at Namkumba area in Mangochi, Southern Malawi, from January to December 2016. The population of the area is about 150 000, and the inhabitants’ occupations are mainly subsistence fishing and/or farming according to their geographical location in relation to Lake Malawi. We report the data according to the CONSORT guidelines. A village was defined as a cluster that did not share a common border with another village eligible to be a cluster. Twenty clusters were mapped out in the study area and were assigned STATA-generated random numbers to allocate them into either the intervention or control group, generating ten clusters per group. We recruited all consenting primi- and multiparous pregnant women between their 9th and 16th gestational week who were available during the study period and planned to give birth at the health facilities within the study area. We excluded women carrying multiple fetuses and those with severe illnesses. TPB is useful for understanding food choice, health and dietary behaviour(25,26). TPB was applied to this study to identify the psychosocial processes (behaviour mediators) leading to intervention outcomes both for evaluation purposes and to explain the changes in dietary behaviour. Our intervention aimed at enhancing personal and normative nutrition actions(26) towards sustenance of diverse diets, as a consequence of positive nutrition attitudes and behaviour control. We expected that the use of lay counsellors would enhance the social pressure in the community as well as directly influencing the individual participants’ subjective norm. Nutrition education, counselling and cooking demonstrations were the actions designed to influence changes in these behaviour mediators to: (i) enhance individual understanding of the importance of eating diverse food groups; (ii) strengthen the women’s motivation to initiate and sustain diversified diets and (iii) facilitate improvement in nutrition-related skills. This theoretical framework has been validated in similar settings(26,27). The control group was exposed to the standard antenatal health education given in Malawi. Maternal nutrition is one of the popular topics provided. The nutrition education constitutes summarised information of the recommended food groups to be consumed with no provision of cooking demonstrations. The intervention group was exposed to a more expanded and detailed dietary counselling and education in addition to the one provided through standard antenatal care. The specific intervention counselling and education was informed by the findings from a cross-sectional pre-study performed among pregnant women in the same study area(12). These findings implied to recommend inclusion of more fats, vitamin C-rich foods and milk in the diet. Through linear programming, we identified possible food combinations which could increase the intakes of most micronutrients(28). The intervention delivery included a monthly nutrition education sessions, followed by cooking demonstrations and weekly individualised counselling sessions. The intervention promoted consumption of locally produced nutrient-dense food. These foods were not always readily accessible, and many families had to buy them. The most available foods were maize, vegetables, fish and seasonal fruits. Staple taken with only vegetables was the most accessible food combination in the uplands, while in the lakeshore areas, it was staple taken with fish. The most limiting foods were animal foods, some vegetables and legumes(12). The intervention promoted practical ways of addressing challenges relating to food accessibility, that is, the use of food powders of inaccessible foods to optimise dietary diversity of the meals. The recipes utilising these food powders and using multi-mix (one-pot dishes) methods of cooking were developed and promoted. The main ingredients were powders of fish, vegetables and legumes. Use of powders is an effective method of cooking and better suited for the subsistence communities to mitigate inadequate access to food resources, since the ingredients (powders) required less money compared with whole unprocessed foods. Most families could not afford to have Nsima with three different relishes in one meal; however, when powders of fish and ground nuts were used to season vegetables, the diversity of the meal was optimised from two to five food groups (fish as animal food, while ground nuts provided legumes and fats food groups). Furthermore, 100 g of anchovy was considered enough as relish for one person when taken whole, whereas when used as powder to season vegetables, it was possible to share it among a family. If the powder was used only by the pregnant woman, the 100 g of anchovy powder could be used for multiple servings. A set of snacks and main meals recipes utilising these food powders were developed and pretested prior to their use in the intervention. We promoted multi-mix (one-pot dishes) methods of cooking where the powders were thoroughly cooked to address hygiene and food safety issues during the processing of the powders. The intervention also promoted consumption of adequate amounts of food through the following comprehensive dietary recommendations: (i) diverse food groups in the main meals as well as in supplementary meals; (ii) frequent meals and snacks (at least five eating times per day); (iii) double the usual portions of relish (i.e. vegetables, legumes, meats, fish and nuts); (iv) Fe supplements; (v) fruits; (vi) vitamin-C-rich fruit following a meal with beans and (vii) 50 ml of milk (fresh goat milk or from cow milk powder) at least twice a week. It was not possible to use measurements for portioning out foods since this would be perceived as cumbersome to the participants. However, if complying with this comprehensive dietary plan, it could serve as a proxy for adequate consumption. The intervention also promoted absorption of these micronutrients through use of partially fermented whole grains and soaking beans overnight before cooking to reduce the concentration of phytate and polyphenols that inhibit absorption of Fe, Zn and Ca and the use of oils with green leafy vegetables and fruits to promote absorption of vitamins(20,29). Socio-demographics data included area of residence, age, education level, maternal income (has income/no income), number of previous births, number of people in the household, gender of the household head, food security status the previous year (number of months with experienced food shortage) and socio-economic status using a household asset index based on eleven household items according to their monetary value and given scores (very poor = score ≤ 1·25; poor = score 1·25–3·75; well-off =score > 3·75)(30). We used the dietary diversity score (DDS) and the Malawian six food groups (SFG) score to evaluate meal diversity. DDS is the international recommendation for assessing dietary quality in micronutrients(31), while SFG is an example of a food group diversity index that is used to assess dietary quality, including energy(32). The DDS was based on ten food groups as proposed by FAO(30): grains, nuts/seeds, dairy, meat/poultry/fish, eggs, dark green leafy vegetables, other vegetables, vitamin A-rich fruits, other fruits and legumes/pulses. The Malawian SFG pyramid guide includes six food groups: staple, vegetables, animal/fish food, legumes, fruits and fats. We estimated the DDS from 24 h dietary recall data collected at baseline and at study end point. This decision was informed by results from our pre-study which showed that there was a significant correlation between DDS and mean nutrition adequacy ratio for eleven micronutrients, whether using either three or only one 24 h recalls(12). Each food group was weighted equally with the score of 1; hence, the maximum possible score was 10. The DDS was rated as either poor (score 0–4), moderate (score 5–7) or high (score ≥ 8). The SFG-24 h score was obtained from the 24 h recall data. Each food group was weighed equally with the score of 1. The total scores were rated as either poor (score 1–3), moderate (score 4–5) or high (score 6). The affective attitudes were assessed as women’s self-evaluation at baseline and at study end point, that is, before and after the intervention (at delivery) using the same questions: (i) the women were asked if they had changed their diet when they knew they were pregnant, choosing among the answer categories of ‘eating a diverse diet “less”/“same”/“more” frequent or being “anorectic”’. The responses were then collapsed into ‘more’ if they consumed a diverse diet more frequently and ‘less’ if they consumed a diverse diet less frequently; (ii) on food choices, the women were asked if they had any consideration before they chose what to eat, their answer alternatives were eating ‘anything available’/‘having nutritional value’/‘to satisfy my hunger’/‘whatever I desired’/‘no consideration’/‘other answers’. The responses were collapsed to ‘nutritious foods’ if they preferred eating nutritious foods and ‘no’ if they had other answers; and (iii) on use of nutrition advice concerning cooking and eating, the women were asked if they practiced the advice given. Those who said yes were further asked if they practiced the advice ‘consistently’ or ‘occasionally’ or ‘did not apply them’. The perceived difficulty was measured through assessment of nutrition skills. To this end, we assessed the women’s nutrition skills in the preparation of a hypothetical meal, assuming they had access to a variety of foods. We assessed the recipe of the meal using the SFG score of six food groups to evaluate their skills, rating the meal as poor (score 1–3), moderate (score 4–5) or high (score 6). To assess behaviour controllability, the women were asked if they experienced challenges with sustaining a diverse diet, those who said yes were further asked how they handled the situation and their responses were categorised as ‘striving’ (if the woman was able to sustain a diverse diet with difficulties) and ‘managed’ (if the woman did not experience challenges with sustaining a diverse diet). Subjective norm was assessed as individual v. family involvement in sustaining a diverse diet by asking the woman to evaluate influence of self-initiative over family support on sustenance of the diverse diet, and she was further asked to quantify her contributions or her family contribution towards diet sustenance. The responses were categorised as ‘self-initiative’ when she was more confident that she was more influential than her family and ‘family support’ when she indicated very confident that it was due to her family support and also when she was less confident that her contribution was influential. The trial sample size was 218 and was estimated to be required to detect a difference in mean birth weight of 150 g between the control and intervention groups, with a power of 80 % and α = 0·05. Descriptive analysis in SPSS were performed to assess the differences in baseline and study end point characteristics between the two study groups, using the Mann–Whitney U test for continuous variables and the Pearson χ 2 test to find associations between categorical variables. We used the mixed effects binary logistic regression models with random effects at village level to explore changes in dietary diversity and the behaviour mediators (constructs of TPB) and differences between the groups from baseline to study end point. Behavioural mediators that were associated with attainment of high DDS were identified in a logistic regression model after adjusting for demographic factors. All models were fitted using Stata se 15, and the significance level was set at α = 0·05. Our choice for mixed effects logistic regression model was based on the fact that our data did not satisfy some of the requirements of a repeated ANOVA, such as equal observations and equal time intervals.

N/A

• Dima Health