Impact of Nutritional Knowledge on Eating Whole Meal Bread

Transcription

1 Impact of Nutritional Knowledge on Eating Whole Meal Bread Marzena Jeżewska-Zychowicz 1 Dr. hab.; Maria Królak 2 MSc Warsaw University of Life Sciences, Warsaw, Poland marzena_jezewska_zychowicz@sggw.pl 1 ; maria.krolak@gmail.com 2 Abstract: Regular consumption of dietary fibre helps in maintaining health. It is an important tool in prevention of overweight, obesity, hypertension, gastrointestinal cancer etc. Nowadays average daily intake of fibre in many population groups is too low in relation to nutritional recommendations. One of the reasons of too small dietary fibre intake is the insufficient amount of wholemeal products in the diet. Too low intake of whole grains as a good source of fibre may appear due to the lack of nutritional knowledge. The objective of the study is to determine the relationships between nutritional knowledge and the frequency of eating of whole meal bread. The questionnaire survey was carried out in March 2013 among 1013 Poles representing national wide sample. The frequency of eating wholemeal bread, general nutritional knowledge, and knowledge about fibre were measured. The higher was general nutritional knowledge of respondents the more they knew about fibre. Nutritional knowledge determined significantly the frequency of wholemeal bread eating but the correlation was negative and week (r=-0.104, P=0.01). The higher was nutritional knowledge, the more seldom they ate wholemeal bread. Similar relationship was achieved in the case of knowledge on fibre (r=-0.161, P=0.01). It can be concluded that strategies focused on increasing whole meal bread consumption cannot be limited to the transmission of nutritional knowledge, even specific knowledge on fibre. The other factors should be taken into consideration. Key words: fibre, bread, nutritional knowledge, health. Introduction Average daily intake of dietary fibre in many population groups is too low in relation to nutritional recommendations (King, Mainous, 2012). One of the reasons of small dietary fibre intake is the insufficient amount of wholemeal products in the diet (Lang, Jebb, 2003; Seal, Jones, 2006), resulting from changing eating patterns and increasing number of substitutes (Siega-Riz, Popkin, 2000). Another reason why dietary fibre is not consumed in sufficient amounts may be the fact that products rich in it are considered not tasty (Baixauli, Salvador, 2008). The other factors that are perceived to have adverse effect on this phenomenon are: higher price of wholemeal products in comparison to their refined equivalents, low availability of cereal products that are a good source of fibre and the fact that these products do not meet expectations of consumers (Adams, Engström, 2000). The more consumers know about food, the more likely they are to undertake nutritional behaviours beneficial for their health. Some research indicate this relation (Barzegari, Ebrahimi, 2011), although in some studies it was not confirmed (Lin, Yang, 2007). As knowledge about food and health is seen as an important determinant of food choice (Sun, 2008; Arvola, Lähteenmäki, 2007), it should be seen as an important factor when a choice of bread is made. The results of some studies have shown that consumers have high knowledge about dietary fibre (Cashel, Crawford, 2001; Lyly, Soini, 2004). They suggest that most of consumers is able to link fibre intake to its beneficial effects on health (Mialon, Clark, 2002), and recognize products which are good sources of fibre (Cashel, Crawford, 2001; Lyly, Soini, 2004). It is a little known about the relations between nutritional knowledge of consumers and their bread choices. Moreover, in Polish population the impact of knowledge about fibre on wholemeal bread eating was not investigated up to now. Thus, the aim of the study is to determine the relationships among nutritional knowledge, knowledge about fibre and the frequency of eating of whole meal bread within Polish consumers. Methodology The data reported in this study is a part of a project on Polish consumers behaviours on the bread market and their determinants. Selection criteria of the sample took into account the representativeness 206

2 of the Polish population due to the province, and then the choice had quota character by gender, education and size of residence place. The questionnaire was completed by 1013 consumers. The data was collected in March 2013 by a marketing agency. The participants were over 21 years old and were solely or jointly responsible for the family s grocery shopping. A pre-test of the initial instrument used a pilot study (n=50) within the population of interest. In the questionnaire the frequency of eating wholemeal bread was measured on a 6-point scale, where 1 once a month or seldom, 2 once a fortnight, 3 once a week, times a week, times a week, 6 -once a day or more. Nutritional Knowledge Scale (NKS) developed by the Commission of Behavioural Determinants of Nutrition from Polish Academy of Sciences was used to assess the participants nutritional knowledge (Table 1). The task of the respondent was to give opinion on each of the statements choosing one of the three following options: 1 I do not agree, 2 I agree, 3 I do not know. Next, the data were recorded due to the correctness of respondent s answer (1 - correct answers, 2 - incorrect answers and 3 - I do not know. When the nutritional knowledge of the respondents was assessed, correct answers were assigned to value 1, and others to value 0. The sum of scores of all items of NKS for each participant was calculated. The higher was the score, the higher was the nutritional knowledge of the respondent. Consumers knowledge about fibre was measured with 3 items: Fibre helps to maintain proper level of blood cholesterol, Fibre satisfies the sensation of hunger, and Fibre accelerates the movement of digested through intestines. The agreement with the statements were marked on a 5-point scales anchored (1) strongly disagree to (5) strongly agree. The sum of scores of three items for each participant was calculated. Consumers perception of wholemeal bread as a good source of fibre was measured with one item Wholemeal bread is a good source of fibre. The need to control the amount of fibre in the diet was expressed by the statements One should control the amount of fibre consumed. The agreement with both statements were marked on a 5-point scales anchored (1) strongly disagree to (5) strongly agree. For statistical analysis IBM Statistics SPSS 21.0 software was used. Cronbach s alphas were calculated to determine the internal consistency of scales regarding the measures of nutritional knowledge and knowledge about fibre. Relationships between different parameters were assessed by calculating Pearson correlation coefficients. A P-value of <0.05 was taken as significant. The range of possible score for the NKS is 0-26 points, with higher scores indicating higher knowledge. The sum of scores of all items of NKS for each participants, and next the mean score of sum (X) and standard deviation (SD) for the sample were calculated. The measure of NKS for the sample had a mean value of (SD=4.43; range 0-22). They were used to determine the ranges for four levels of nutritional knowledge. The low level (minimum sum X-SD) was in the range (14.5% of population), the below average one (X-SD X) was in range (39.1%), the average one (X X+SD) was in range (30.1%), and the high level (X+SD maximum sum) was in range (16.3%). The same way was used to determine the level of knowledge about fibre. The range of possible score for knowledge about fibre is 3-15, with higher scores indicating higher knowledge. The measure for the sample had a mean value of (SD = 2.53). The low level was in the range (19.2 of population), the below average one was in range (27.3%), the average one was in range (35.5%), and the high level was in range (18.0% of population). Results and discussions The sample had a higher proportion of women (53.4%). The average age was 47.6, standard deviation There were 35.5% respondents with education lower than secondary, 36.5% with secondary education, and 27.9% with high education. The percentages of those living in rural areas were 38.4%, whereas 61.6% of participants were living in urban areas. 207

3 The correct opinions on each statement from Nutritional Knowledge Scale are presented in Table 1. Alpha coefficient for NKS was 0.79 showing good internal reliability of the scale. Most of correct opinions related to higher fiber content in whole meal bread than refined one, drinking milk only by children and young people, consumption of fruits and/or vegetables in every meal, limiting fatty foods as a protection against cardiovascular disease, and the presence of beneficial intestinal bacteria in bio yogurts. Only slightly more than 10% of the respondents presented correct opinions on protein as main source of energy in the proper diet, and high nutritional density of sweets and animal fats (Table 1). Table 1 Respondents opinions on items from Nutritional Knowledge Scale NKS (%) Items from Nutritional Knowledge Scale Correct answers N % It is enough to consume cereal products once a day Only children and youth should drink milk Fruits and/or vegetables should be consumed in every meal (R) Ingestion of mouldy bread can cause an infection with Salmonella (R) High salt intake protects against hypertension Limiting fatty foods in the diet helps to prevent cardiovascular disease (R) Frequent consumption of oily fish accelerates the development of atherosclerosis Eating grilled meat is conducive to falling ill with cancer (R) The consequence of a vegetarian diet is an increased risk of anaemia (R) Bio yogurts contain beneficial intestinal bacteria (R) Oil and olive oil contain a lot of cholesterol Wholemeal bread contains more fibre than refined bread (R) Fruits and vegetables are a source of "empty calories" Butter and fortified margarine are characterized by a high content of vitamins A and D (R) Cheese is a better source of calcium than cottage cheese (R) The giblets contain significant amounts of "bad" LDL cholesterol (R) Complex carbohydrates in diet should be replaced by monosaccharide Protein should be the main source of energy in the proper diet Inadequate intake of niacin can cause dermatitis and diarrhoea (R) Exposure to the sun promotes the production of vitamin D in the body (R) Phosphorus is a component of the nervous tissue (R) Calcium to phosphorus ratio in the diet should be 1:1 (R) Eating fruit rich in vitamin C enhances iron absorption (R) Start cooking the vegetables in cold water favours maintaining their nutritional value Sweets and animal fats are characterized by high nutritional density GDA figure placed on food packaging indicates the degree of coverage guideline daily nutrient intake by a portion of the product (R) (R) item requiring reverse scoring to the original questionnaire (score 1 was converted into score 2 and score 2 was converted into score 1) Opinions on dietary fibre and its impact on health are presented in Table 2. The alpha coefficient for consumers knowledge about dietary fibre (0,890) has shown good internal reliability of the scale. More than 50% of participants agreed that fibre helps to maintain proper level of blood cholesterol and 208

4 accelerates the movement of digested through intestines, and wholemeal bread is a good source of fibre (Table 2). These results are confirmed in other studies (Cashel, Crawford, 2001; Lyly, Soini, 2004). The frequency of consuming wholemeal bread was differentiated in the study population. Once a month or less this product was consumed by 12.3% of population, once a fortnight by 18.5%, once a week by 20.9%, 2-3 times a week by 21.6%, 4-5 times a week by 18.5%, and once a day or more by 8.2% of participants. Previous research suggested that demographic variables, such as gender, age and education, were statistically associated with nutritional behaviours (Ares, Gambaro, 2007; Hearty, McCarthy, 2007). Also the nutritional knowledge, attitudes towards food products and nutritional behaviours showed differences after taking into account socio-demographic characteristics of the study populations (Jezewska-Zychowicz, Jeznach, 2013). In this study women were characterized by significantly higher nutritional knowledge, and knowledge about dietary fibre compared to men. Women agreed to a greater extent with opinion that whole meal bread is a good source of dietary fibre and they consumed whole meal bread more frequently than men. The differences between men and women regarding their knowledge of nutrition, as well as nutritional behaviours were reported in several studies (Dean, Raats, 2007; Hoefkens, Valli, 2012), which is mainly explained by greater involvement of women in family feeding and attaching greater importance to the appearance by women (Wronka, Suliga, 2013). Participants aged 30 years and younger represented significantly higher knowledge about dietary fibre than those aged over 60 years (Table 3). Table 2 Respondents opinions on fibre (mean value, standard deviation, %) Items Mean SD Respondents opinions (%) 1* Fibre helps to maintain proper level of blood cholesterol Fibre satisfies the sensation of hunger Fibre accelerates the movement of digested through intestines Wholemeal bread is a good source of fibre One should control the amount of fibre consumed *1- strongly disagree, 2 - rather disagree, 3 - neither agree nor disagree, 4 - rather agree, 5 - strongly agree Nutritional knowledge of people aged over 60 years was significantly lower than those aged years, as well as others, but in the case of the latter, the differences were not statistically significant. Participants aged 50 years and less agreed to a greater extent with the opinion that whole meal bread is a good source of fibre than people aged over 60 years. No statistically significant differences were observed in the frequency of consumption of whole meal bread after taking into account the age of the respondents (Table 3). Participants with higher education represented a significantly greater knowledge about dietary fibre than the others. With the increase in education increased mean value of an opinion on whole meal bread as a good source of fibre. Whole meal bread was eaten less frequently by people with secondary education. There were no significant differences in the average frequency of consumption of this bread by people with higher education and those with education lower than secondary one. Participants who lived in large cities characterized by the greatest knowledge of whole meal bread as a source of fibre, while residents of small towns represented the smallest knowledge. Respondents from small towns represented lower nutrition knowledge, lower frequency of eating whole meal bread and lower control over the amount of fibre intake compared with others. There were no significant differences of opinions on these issues between residents of the villages and the large cities (Table 3). 209

5 Table 3 Respondents profile according to opinions on fibre related issues, nutritional knowledge, frequency of wholemeal bread eating and socio-demographic characteristics (mean value; standard deviation) Variables Knowledge about fibre Wholemeal bread as a source of fibre Control of fibre consumed Nutritional knowledge Frequency of wholemeal bread eating Total 10.79; ; ; ; ; 1.50 Gender Female a ; a ; ; a ; a ; 1.45 Male b ; b ; ; b ; b ; 1.55 Age 30 years old and less a ; a ; ; ; ; years old 11.03; a ; ; a ; ; years old 11.01; a ; ; ; ; years old 10.51; ; ; ; ; 1.47 More than 60 years old b ; b ; ; b ; ; 1.58 Education a ; a ; ; ; a ; 1.57 Lower than secondary Secondary a ; b ; ; ; b ; 1.42 High b ; c ; ; ; a ; 1.51 Place of residence Rural area 10.86; a ; ,37 a ; a ; a ; 1.57 Small town 10.66; b ; b ; b ; b ; 1.59 Large city 10.84; c ; a ; a ; a ; 1.27 Knowledge about dietary fibre significantly correlated with other variables with different strength. The strongest association was found with the opinion of whole meal bread as a source of fibre. Only the relationship between knowledge about dietary fibre and frequency of consumption of whole meal bread was negative. Negative correlations with the frequency of whole meal bread consumption were also demonstrated for the opinions of whole meal bread as a source of fibre and nutrition knowledge. All negative relationships were weak. However, there was no significant relationship between the frequency of consumption of whole meal bread and the opinion on control over the consumption of fibre (Table 4). Bilateral correlations of variables Table 4 Variables No Variables (No) Knowledge about fibre ** 0.443** 0.275** ** Wholemeal bread as a source ** ** 0.281* ** of fibre Control of fibre consumed ** 0.461** * Nutritional knowledge ** 0.281** 0.074* ** (NKS) Frequency of wholemeal bread eating ** ** ** 1 *correlation is significant at P=0.05 **correlation is significant at P=

6 Statistically significant negative correlation between nutritional knowledge, as well as knowledge about fibre, and consumption of whole meal bread requires discussion. Most of the previous studies showed that with increasing nutritional awareness increased consumers interest in healthy food and healthy nutritional behaviours (Dean, Raats, 2007), which should include eating wholemeal bread. Lack of confirmation of these results indicates the need to look for other factors determining to a greater extent this behaviour. It appears that some qualities of wholemeal bread, as the lower scores of sensory attributes of wholemeal bread compared with white bread (Baixauli, Salvador, 2008), the higher price of wholemeal bread (Kuznesof, Brownlee, 2012), as well as its low availability (Arvola, Lähteenmäki, 2007) can reduce consumption of whole meal bread. Thus, they can foster the inverse relationship between knowledge and frequency of whole meal eating. The smallest number of people with nutritional knowledge defined as the average and high consumed whole meal bread with a frequency of once a day or more often, as well as 4-5 times a week, which confirms the negative correlation between nutritional knowledge and frequency of consumption of whole meal bread. Similarly, fewer people with average and high knowledge about dietary fibre consumed once a day or more often whole meal bread, also 4-5 times a week (Table 5). Table 5 Frequency of whole meal bread eating according to nutritional knowledge and knowledge about fibre level (%) Items Frequency of whole meal bread eating Less than once a week 2-3 times a week 4-5 times per week Once a day or more Total (N = 1013) Nutritional knowledge level (P<0.001) Low (N = 147) Below average (N =396) Average(N = 305) High (N = 165) Knowledge about fibre (P<0.001) Low (N = 194) Below average (N = 277) Average (N = 360) High (N = 182) Conclusions The higher was nutritional knowledge and knowledge on fibre, the more seldom the participants ate wholemeal bread. The nutrition education needs to include beside general nutritional information, specific knowledge referring to food products. In future studies there are a need to search for other factors strongly determined consumption of whole meal bread and products rich in dietary fibre. Nevertheless, the complex factors limiting the consumption of whole meal bread should be taken into account. It will then be able to know their individual significance when selecting a product, and the interaction between them. Funding This work was performed within the Project No POIG /12 "Bioproducts", innovative technologies of pro-health bakery products and pasta with reduced caloric value co-financed by the European Regional Development Fund under the Innovative Economy Operational Programme

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