Reading and interpreting nutritional labels: correlation

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Reading and interpreting nutritional labels: correlation between schooling
and social class
Guilherme Teixeira de Araújo1
Amanda Krüger2
Silmara Richter2
Júlio Sérgio Marchini3
1
Master’s Student, Division of Internal Medicine, University Hospital, Faculty of
Medicine of Ribeirão Preto, University of São Paulo
2
Undergraduate students of the Lutheran Educational Association Bom Jesus /
IELUSC
3
Full Professor, Division of Internal Medicine, University Hospital, Faculty of
Medicine of Ribeirão Preto, University of São Paulo
Correspondence to:
Guilherme Teixeira de Araújo
R. Thomaz Nogueira Gaia, n° 1645, Apto 13, Jd. São Luiz
Ribeirão Preto – SP
CEP: 14020-290
Telefphone: (16)8151-9384
e-mail: [email protected]
2
Abstract
Introduction: Healthy nutrition is one of the pillars for the promotion of health
and the prevention of chronic-degenerative diseases and therefore it is of
fundamental importance to read and interpret the nutritional labels of the foods
consumed. The objective of the present study was to assess the reading habits
and the ability to interpret the nutritional labels of the population of a large city in
the state of Santa Catarina. Methods: An interview consisting of 13 multiplechoice questions and two open questions was held with shoppers at two large
supermarkets in Joinville – SC. Results: Ninety-three percent of the
interviewees stated that they consider it important to read the nutritional labels,
with 71% of them habitually reading them and 49% having avoided to buy a
product based on the nutritional information. Those who were best able to
interpret the terms were males (p=0.05), individuals with complete higher
education (p=0.3), and upper class individuals (p<0.05). We emphasize that
most of the interviewees had difficulty in defining the terms “light” and “diet”.
Conclusion: The economic and cultural elite has the habit of regularly reading
nutritional labels, in addition to being better able to interpret correctly the
information contained in them.
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Introduction
A healthy diet is one of the pillars of the promotion of health and the
prevention of chronic-degenerative disease. Thus, it is of fundamental
importance to read and interpret the nutritional labels of the foods consumed in
order to make a more appropriate choice1-5.
In 2001, with the advent of MERCOSUL, the Brazilian government,
through the National Agency of Sanitary Surveillance (ANVISA), made
mandatory the presence of nutritional information in the labels of all foods
offered to consumers6,7, a measure that had already been adopted in the US in
19908. The objective of this measure, among others, was to stimulate the
ingestion of healthier foods and to improve the communication between
consumer and manufacturer9,10. In the US, the amount spent to educate the
population about the real importance of reading labels reached about half a
billion dollars in 200711. Other nations have made efforts to implement
measures that would stimulate reading food labels and that would help their
interpretation. In 2005, the Brazilian government launched a primer promoting
the reading and interpretation of nutritional labels12, but the reach of this
measure is not known.
The objective of the present study was to determine whether the adult
population of consumers of industrialized foods has the habit of reading the
nutritional labels and can interpret correctly the information they contain, thus
being able to identify a healthier or less healthy food. We also investigated
whether there is a difference in habits and in the interpretation of this
information according to social class and educational level and evaluated the
reach of access to the primer published by the Brazilian government in 2005.
Methods
The study was conducted in Joinville, a city in the Northeast of the state
of Santa Catarina, in which different population groups regarding social class
and schooling are represented. Located along parallel -48.84° at latitude -26.3°,
the city has an estimated population of 500 thousand inhabitants and a per
capita GDP of R$ 21,538.0013.
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The participants were chosen at random and by drawing lots at two large
food sale centers selected on the basis of size and coverage of the attended
population, over a period of 11 months. Men and women older than 18 years
willing to sign an informed consent form to participate in the study were
interviewed.
The participants answered a questionnaire administered by a previously
trained interviewer. The questionnaire contained 13 multiple-choice questions
and two open questions. The first part of the questionnaire contained questions
concerning schooling and possessions of the respondent according to the
questionnaire of the Brazilian Association of Research Companies (ABEP),
which was used for the classification of social class14, i.e., upper class (classes
A1 and A2 of ABEP), middle class (classes B1 and B2 of ABEP), and lower
class (classes C1, C2 and D of ABEP).
The second part of the questionnaire inquired about the habits of reading
and interpreting nutritional labels. Regarding the question about the
interpretation of the concept of “light”, the reply was considered to be correct
when the respondent stated that it referred to a food of reduced energy or
containing any reduced nutrient (at least 25%) compared to a standard food.
Regarding the question about “diet” products, the reply was considered to be
correct when the responded stated that it referred to products containing trace
or no amounts of some nutrients12.
Finally, the third part of the questionnaire showed three fictitious labels
referring to a cereal bar and asked the interviewee to choose the healthiest or
the least healthy option. The healthiest product was defined as the one
containing smaller amounts of saturated fat, trans fat, sodium and cholesterol
and a larger amount of fibers. The least healthy product was defined as the one
containing the greatest amount of saturated and trans fat, sodium and
cholesterol, and a smaller amount of fibers.
The collected data were tabulated and analyzed statistically using the
EpiInfo™, 2008 software.
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The study was previously approved by the Research Ethics Committee of the
University Center Bom Jesus of the Lutheran Educational Institution of Santa
Catarina, Joinville, SC.
Results
A total of 276 persons were interviewed, 198 (72%) of them women. The
mean age of the population studied was 37±12 years, and most subjects (33%)
were in the 18 to 29 year age range. Regarding schooling, most subjects had
complete higher education (37%). The sample contained no illiterate subjects.
Table 1 presents the study population according to sex and social class.
Regarding the reading of nutritional labels, 93% of the interviewees
stated that they considered it important, with 71% being in the habit of reading
this information and 49% having avoided buying a product based on its
nutritional information.
Sixty-five percent of the male participants and 74% of the females were
in the habit to read the nutritional labels. The age range of the subjects who
most frequently read the labels was from 40 to 49 years (80%), as shown in
Figure 1. The social class who most read the nutritional information was the
upper class, whereas, the lower the social class, the lower the frequency of
reading the labels, although the difference was not statistically significant
(p=0.07) (Figure 2). The schooling of the subjects who most frequently read the
nutritional labels was complete higher education (p<0.01). The main reason
reported for failure to read the labels was that the letters were small.
When asked whether they knew what a light product was, 82% replied
that they knew what the term meant, but only 19% were able to explain the term
correctly. The most frequent replies explaining what a light product was were
“products with fewer calories” and “fat-free products”. When asked about diet
products, 75% stated that they knew what a diet product was, although only 7%
were able to explain the term correctly. The most frequent replies were: “they
are products for diabetics’ and “they are sugar-free products”. The groups most
able to interpret the terms correctly were males (p=0.05), subject with complete
higher education (p=0.3), and subjects belonging to the upper class (p<0.05).
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The information that most called the attention of the interviewees was
that concerning energy and trans fat and the one that least called their attention
concerned unsaturated fats and sodium. The information most frequently read
by both men and women concerned energy, 24% and 34%, respectively. The
upper social classes paid more attention to trans fat, while the middle and lower
classes paid attention to energy. The most frequent intention of the interviewees
when reading nutritional labels was to read all the information, followed by
learning about the calories of the products. When “others” was mentioned, the
most frequent objective was to learn about the validity of the product. The
intention of reading the nutritional labels according to social class is presented
in Table 2,
Only three (1%) interviewees had already had access to or read the
manual of orientation for the reading of nutritional labels issued by the federal
government. Forty-eight percent of the interviewees stated that they did not
understand the information contained in the labels, but 87% were able to
identify the healthier nutritional table and 85% were able to identify the less
healthy table. Among those who were unable to identify the healthier or less
healthy table were males and persons of lower social class and with incomplete
elementary education.
Discussion
The data of the present study demonstrated that the economic and
cultural elite is more regularly in the habit of reading nutritional labels, in
addition to being better able to interpret correctly the information they contain. A
study conducted in Brasília15 obtained results similar to those obtained by us in
Joinville, perhaps due to the similar economic and cultural pattern of the two
cities. A study conducted on the Afro-American population16 demonstrated that
obese persons, women and persons with more years of schooling are in the
habit of reading nutritional labels more frequently.
Although most subjects considered it important to read the nutritional
labels, only one third of the interviewees were in the habit of reading them and
half of them had avoided buying a product because of the nutritional information
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on its label. This demonstrates that that there may be a difficulty in the
interpretation of the data or a lack of consumer interest in buying products
considered to be healthier.
Although most of the sample knew about the terms “light” and “diet”, a
majority was unable to define their meaning, in agreement with results obtained
in studies conducted in Campinas17. Even so, most of the interviewees were
able to select a healthier product among three choices, with the cultural and
economic elite showing the best performance in this respect.
The overwhelming majority of the interviewees never learned about, or
had contact with, the orientation primer about nutritional labels issued by the
Federal Government, a fact demonstrating the need for greater investments and
alternative approaches in order to expand the reach of this campaign. The
mandatory use of nutritional labels in food products was a great conquest of
Brazilian consumers, who now can know what they are consuming and can
choose a healthier food among several others. However, it is of no use to have
the information, to be in the habit of reading it and to be unable to interpret it
satisfactorily, a situation that could be defined as “nutritional illiteracy”. On this
basis, it is necessary to expand public measures in order to stimulate a correct
interpretation of the information contained in nutritional labels, thus enabling
Brazilian consumers to choose healthier foods.
We may conclude that, although reading nutritional labels is a healthier
mechanism for choosing the foods to be consumed, the population is not in the
habit of reading these labels frequently and has difficulty in interpreting them
correctly. There is the need to expand the nutritional education of the population
and to improve the presentation of the labels by increasing, for example, the
size of the letters.
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Table 1 – Distribution of the population according to social class and sex
Class*
Male sex
Female sex
Total
(percentage)
Upper
classes
Middle
classes
Lower
classes
A1
1
2
3 (1%)
A2
7
12
19 (7%)
B1
13
37
50 (18%)
B2
29
69
98 (36%)
C1
20
57
77 (28%)
C2
8
16
24 (32%)
C3
0
5
5 (2%)
* Social classes defined by ABEP14
Table 2 – Motivation to read nutritional labels according to social class
Item
Low classes+
High
Middle
classes*
classes#
To find out about the calories
4 (18%)
30 (20%)
22 (21%)
To find out about the amount
6 (27%)
27 (18%)
20 (19%)
4 (18%)
25 (17%)
20 (19%)
To compare similar products
8 (36%)
21 (14%)
10 (9%)
To read all the information
5 (23%)
34 (23%)
21 (20%)
No special reason
2 (9%)
34 (23%)
29 (27%)
Others
0 (0%)
6 (4%)
1 (1%)
of fat and sodium
To find out about vitamins,
minerals and fibers
* Classes A1 and A2 ofABEP14
#
Classes B1 and B2 of ABEP14
+
Classes C1, C2 and C3 of ABEP14
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Figure 1 – Prevalence of nutritional label reading according to age range
(years)
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Figure 2 – Prevalence of nutritional label reading according to social class