Background: Fruit and vegetable consumption is linked to many positive health outcomes, nevertheless many adolescents do not consume fruit and vegetables on a daily basis. Methods: Data of 488,951 adolescents, aged 11-, 13- and 15- years, from 33 mainly European and North American countries/regions participating in the cross-sectional Health Behaviour in School-aged Children surveys in 2002, 2006 and 2010, were used to investigate trends in daily fruit and vegetable consumption between 2002 and 2010. Results: Multilevel logistic regression analyses showed an increase in daily fruit and vegetable consumption between 2002 and 2010 in the majority of countries for both genders and all three age groups. A decrease in consumption was noticed in five countries for fruit and five countries for vegetables. Conclusion: Overall, a positive trend was noticed, however increases in daily fruit and vegetable consumption are still indicated.
Adolescence is an important developmental life stage characterized by high nutrient requirements to meet rapid growth. Dietary habits established during adolescence may also persist into adulthood,1 and thus much emphasis has been placed on improving dietary habits at a young age.
Fruit and vegetable consumption in particular has received much attention. Diets high in fruit and vegetables are associated with a lower risk of cancer,2 coronary heart disease,3 stroke4 and other chronic diseases. Therefore, as well as promoting health during adolescence, meeting the recommendations for fruit and vegetable intake can have positive implications for long term health.
The World Health Organization (WHO) recommends at least 400 g of fruit and vegetables daily; and national recommendations are either close to or above this target.5 To date, studies from Europe and North America indicate that the majority of children and adolescents fail to reach these recommendations.5,6
Many countries have implemented programmes, policies and strategies to increase fruit and vegetable intake, often with a focus on home-based (e.g., 5 a day campaigns), school (e.g., school fruit schemes, free school meals) or community settings.7–9 It is thus appropriate to review whether changes over time have occurred and explore whether national efforts to increase fruit and vegetable consumption have been effective. So far, it appears that dietary trend analyses among children and adolescents have been focused on the country or regional levels, for example, the UK,10,11 USA,12–15 Norway,1 Denmark16 and Lithuania,17 To our knowledge, no study has examined trends in fruit and vegetable intake cross-nationally in nationally representative samples of 11-, 13- and 15-year old boys and girls, using standardized questionnaires, and this is the aim of this study.
Data were obtained from the Health Behaviour in School-aged Children (HBSC) study collected in 2002, 2006 and 2010. Only data from countries who participated in all three surveys were included for the present paper: in total, 488 951 adolescents (11-, 13- and 15-year olds) from 33 countries or regions.
Children were asked to assess their frequency of consumption of fruit and vegetables by ticking one of seven responses: ‘never’, ‘rarely/less than once a week’, ‘once a week’, ‘two to four times a week’, ‘five to six times a week’, ’once a day, every day’ and ‘more than once a day, every day’ for both items. Response options were recoded into dichotomous outcome variables (1 = daily, 0 = less than daily).
As gender and age differences in fruit and vegetable consumption have previously been found, frequencies of daily fruit and vegetable consumption were standardized for age and gender by country (i.e., equal number of respondents per age*gender category). Multilevel logistic regression analyses were conducted for each country separately and pooled for the total sample. Additional analyses were run by gender and age. MLwin version 2.25 was used to perform the three-level analyses (adolescents nested within schools nested within countries). Age, gender and survey year were included in the models as dummy indicator variables, as compared with a reference category. P-values < 0.01 were considered significant.
In figures 1 and 2, daily fruit and vegetable consumption is represented using spider charts. On each axis, the corresponding country’s fruit and vegetable prevalence is displayed for each of the three time points, with countries organized by 2010 prevalence. In 2010, daily fruit consumption ranged from 15% in Greenland to 49% in Denmark and French Belgium, and daily vegetable consumption from 20% in Estonia to 55% in Flemish Belgium. Pooled analyses over all countries indicated a significant time trend of increase in daily fruit [OR = 1.22 (99% CI: 1.18–1.25)] and vegetable consumption [OR = 1.20 (1.17–1.22)], from 2002 to 2010. The increase was mainly observed between 2002 and 2006; OR for fruit and vegetable for 2002 to 2006 were 1.16 (1.13–1.18); and 1.16 (1.14–1.19), respectively. For 2006 to 2010 the OR were 1.06 (1.03–1.08); and 1.03 (1.01–1.05).
Separate analyses by country indicate significant increases from 2002 to 2010 in two-thirds of the countries and significant increases in vegetable consumption in 18 countries. The most pronounced increases in fruit consumption (OR > 1.6) were found in Denmark, England, Norway, Ukraine, USA and Wales. A significant decrease in fruit consumption was noted in five countries (Germany, Greenland, Greece, Poland and Portugal), while no significant differences were found in six countries (Czech Republic, Spain, Croatia, Macedonia, Sweden and Slovenia). The most pronounced increases in vegetable consumption were found in Spain, Denmark, Hungary, England, Wales, Greece and Austria (OR > 1.6). A significant decrease in vegetable consumption was found in five countries (Germany, Lithuania, Latvia, Poland and Russia). No significant differences were detected in 10 countries (Belgium-Flanders, Canada, France, Croatia, Ireland, Italy, the Netherlands, Portugal, Slovenia and Ukraine).
In general and across all countries, girls were more likely to consume fruit and vegetables than boys [ORfr = 1.39 (99% CI: 1.37–1.41); ORveg = 1.38 (1.36–1.41)]. In terms of trends according to age, 15-year olds were less likely to consume daily fruit and vegetables than 13-year olds [ORfr = 0.79 (0.78–0.81); ORveg = 0.92 (0.90–0.94)] who in turn were less likely to consume daily fruit and vegetables than 11-year olds [ORfr = 0.78 (0.77–0.80); ORveg = 0.86 (0.85–0.88)]. The increase
s in daily fruit and vegetable consumption from 2002 to 2010 were significant for boys [ORfr = 1.18 (1.14–1.21); ORveg = 1.15 (1.12–1.19)] as well as for girls [ORfr = 1.25 (1.22–1.29); ORveg = 1.23 (1.19–1.27)] and for each of the three age groups [ORfr11y1.25 (1.20–1.29); ORfr13y; 1.22 (1.17–1.27); ORfr15y1.19 (1.14–1.24); ORveg11y1.20 (1.16–1.25); ORveg13y; 1.17 (1.13–1.22); ORveg15y1.21 (1.15–1.26)].
To our knowledge, this is the first report of trends in fruit and vegetable intake in youth across several countries examined using standardized methodology. This study found that overall a positive trend in fruit and vegetable consumption was observed between 2002 and 2010 mainly due to a significant increase between 2002 and 2006 and plateauing thereafter. The increase may reflect the success of national policies and initiatives implemented in the early 2000s including educational messages, subsidized fruit and vegetables and increased fruit and vegetables at schools. For example, in Denmark a nation-wide 6-a-day initiative has been conducted since 2001 to increase the intake of fruit and vegetables in the population.16 In Norway, a subscription programme to increase fruit and vegetable intake was initiated in 1996 and made nationwide in 2003, and a free programme (without parental payment) was implemented nationwide in 2007.18 However, analysis of national and local policies and programmes are needed to confirm any influence on trends in fruit and vegetable intake among adolescents.
Despite this general positive trend in fruit and vegetable consumption, a decrease was noticed in a few countries. Possible explanations include: a reduction in fruit and vegetable production due to unfavourable climate conditions resulting in a rise in prices, economic crises forcing families to reduce the intake of unnecessary items (such as fruit and vegetables), adolescents being more independent and busier leading to more reliance on convenience food.
A second major finding is that large proportions of adolescents do not eat fruit and vegetables on a daily basis. This highlights the importance of a continued focus on promotion of fruit and vegetable consumption as indicated by other studies. For example, in the Pro Children Project, the fruit and vegetable intake of 11-year-old children was far below the food-based dietary guidelines in the nine participating countries.5 Similarly, a quarter of the Healthy Lifestyle in Europe by Nutrition in Adolescence adolescents, from 11- to 17-years old in eight European countries, did not consume any fruit during 2 recalled days6. In their study, boys reached the recommendations for fruit and vegetables by only about 40 and 30%, respectively, whereas for girls this was ∼50 and 35%, respectively. In addition, in our study, girls’ daily fruit and vegetable consumption was higher than boys’.
Finally, some strengths and limitations should be noted. Strengths of this study are the use of a large cross-national data set of adolescents across three different age groups, the use of standardized methods; and on-going validation of the included instruments.19 Nonetheless, the validity of self-reported dietary methods among adolescents has been questioned.19,20 In addition the food frequency questionnaire only includes frequency of intake, and no information is collected on amounts of fruit and vegetables consumed. Moreover, no definitions of fruit and/or vegetables are provided, so there may be differences in interpretation across countries. Seasonal bias may also influence cross-country comparisons, as time of data collection varied by country and access to fruit and vegetables may also vary by season.16 Finally, we cannot exclude the possibility that the heightened focus on fruit and vegetables in many countries may have increased awareness16 and/or social approval bias, although the questionnaires were completed anonymously and hence students had no reason to feel pressurised by peers and/or society.
In summary, between 2002 and 2010 a positive trend in daily fruit and vegetable consumption among adolescents across most countries was observed, but there is still room for improvement. A review of fruit and vegetable policies and initiatives across countries could help to explain the changes documented and help guide future strategies to increase fruit and vegetable intake among adolescents.
HBSC is an international study carried out in collaboration with WHO/EURO. The international coordinator was Professor Candace Currie, University of St. Andrews, and the databank manager was Professor Oddrun Samdal, University of Bergen. A complete list of participating countries and researchers is available on the HBSC website (http://www.hbsc.org). The data collection for each HBSC survey is funded at the national level.
A paper entitled ‘Cross-national trends in Fruit and Vegetable consumption’ was presented as part of a symposium at the International Society for Behavioural Nutrition and Physical Activity conference in San Diego in May 2014.
Conflicts of interest: None declared.
First study to examine trends in fruit and vegetable intake cross-nationally in nationally representative samples of 11-, 13- and 15-year-old boys and girls.
A positive trend in daily fruit and vegetable consumption among adolescents across most countries was observed between 2002 and 2010.
A few countries experienced a decline in fruit and vegetable consumption between 2002 and 2010.
Further insight into fruit and vegetable policies and initiatives across countries could help to explain changes in intake and guide future strategies to increase fruit and vegetable intake among adolescents.