Print version ISSN 0036-3634
Salud pública Méx vol.51 suppl.4 Cuernavaca Jan. 2009
Fruit and vegetable intake in the Mexican population: results from the Mexican National Health and Nutrition Survey 2006
Consumo de frutas y verduras en la población mexicana: resultados de la Encuesta Nacional de Salud y Nutrición 2006
Ivonne Ramírez-Silva, MScI; Juan A Rivera, PhDI; Xochitl Ponce, MScI; Mauricio Hernández-Ávila, MD, PhDII
ICentro de Investigación en Nutrición y Salud. Instituto Nacional de Salud Pública, Cuernavaca Morelos. México
IISecretaría de Salud. Mexico
OBJECTIVE: To quantify fruit and vegetable (FV) dietary intake in the Mexican population and compliance with international recommendations.
MATERIAL AND METHODS: FV dietary intake (FV-DI) and compliance with international recommendations were obtained in a representative sample of a Mexican population ages 1-59 years old using dietary data from the Mexican National Health and Nutrition Survey 2006 (ENSANUT 2006).
RESULTS: Average FV-DI for different age groups range from 61 to 72 g for fruits and 26 to 56 g for vegetables. Average total FV intakes were 88.7 g in preschool-age, 103.1 g in school-aged children, 116.3 g in adolescents and 122.6 g in adults. The lowest intakes were observed in the northern region and among the population with the lowest wellbeing levels.
CONCLUSIONS: Less than 30% of the Mexican population had adequate intakes of FV. Developing and implementing strategies aimed at increasing intake of these food groups is a national priority.
Key words: fruits; vegetables; children; adolescents; adults; Mexico
OBJETIVO: Cuantificar la ingestión dietética de frutas y verduras y el apego a recomendaciones internacionales en la población mexicana.
MATERIAL Y MÉTODOS: La ingestión dietética de frutas y verduras y el apego a recomendaciones fueron obtenidas en una muestra representativa de la población mexicana de entre 1 a 59 años de edad, usando datos sobre dieta de la Encuesta Nacional de Salud y Nutrición 2006 (ENSANUT 2006).
RESULTADOS: Los promedios de ingestión dietética para los diversos grupos de edad fluctuaron entre 61 y 72 g en frutas y 26 y 56 g en verduras. Los promedios de ingestión dietética total de frutas y verduras fueron: 87.5 g en preescolares, 103.1 g en escolares, 116.3 g en adolescentes y 122.6 g en adultos. Los menores consumos se observaron en la región norte y en la población con los menores niveles de bienestar.
CONCLUSIONES: Menos de 30% de la población tuvo consumos adecuados. El desarrollo e implementación de estrategias y programas que contribuyan a aumentar el consumo de estos alimentos es de alta prioridad.
Palabras clave: frutas; verduras; niños; adolescentes; adultos; México
The World Health Organization (WHO) estimates that 2.7 million lives lost due to cardiovascular disease could be prevented if fruit and vegetable (FV) intake were adequate.1 FV have beneficial effects on health and on body mass index (BMI) since they provide vitamins, minerals, fiber, and other dietary factors, such as photochemicals with different protective effects, stimulating the immune system and other physiological systems.2,3 It has been largely documented that a high FV consumption is associated primarily or secondarily with less incidence of obesity,4-6 cardiovascular disease,7-10 diabetes mellitus type II,10,11 and several types of cancer.12 Several of these chronic diseases are currently of high prevalence among the Mexican population.13,14 Obesity is a risk factor for the development of chronic diseases.15 FV intake play an important role in preventing overweight and obesity due to their ability to produce satiety, their high fiber and water content, and their low energy density.6 In addition, a low intake of FV has a detrimental effect on mineral and vitamin status, with negative consequences on health.16,17 Based on food balance sheet data, availability of FV has increased worldwide; however, their consumption has decreased in some countries, particularly in low and middle income countries.8,18 It has been documented that FV intake is far less than the recommended amounts.19 A 30% decrease in FV purchases at the household level in Mexico has been documented.20 However, there is no nationally representative information regarding FV dietary intake (DI) in Mexico.
Therefore, the objective of this study is to describe FV intake as well as compliance with international recommendations in the Mexican population aged 1 to 59 years old and in key relevant subpopulations. The information from this study can help identify research questions and develop actions, strategies and policies aimed at improving FV intake among the Mexican population.
Material and Methods
Population and study design
Data analyzed came from the Mexican National Health and Nutrition Survey 2006 (ENSANUT 2006) conducted between October 2005 to May 2006, which collected information from 48 304 households. A detailed description of sample procedures and methodology has been published elsewhere.21 The probabilistic sample is representative at the national level and of rural and urban areas, the 31 states and Mexico City.
The aim of the ENSANUT 2006 was to collect information on the health and nutrition of the Mexican population. Analyses in this article include information from a random subsample of about 30% of the population for which dietary data were obtained. This subsample is representative of the Mexican population and provides adequate numbers for estimations for most of the categories studied.
Age groups considered for this study were: preschool-age children (1 to 4 years old), school-age children (5 to 11 years old), adolescents (12 to 18 years old) and adults (19 to 59 years old).
Dietary data: Dietary data were obtained through a 7-day semi-quantitative Food Frequency Questionnaire (FFQ). The FFQ listed 101 foods including 13 fruits and 19 vegetables. A detailed description of the dietary data collection and processing can be found elsewhere.22
Anthropometric data: Weight and length (for children <2 years) or height (for subjects 2 years of age or older) of each subject were obtained according to techniques described by Lohman (1981)23 by trained and standardized personnel.24 Weight (in kg) was obtained and recorded with a precision of 100 g using digital scales (Model 1583, Tanita, Tokyo, Japan) which were calibrated daily. Height was measured using a wall stadimeter with a 2 m capacity and a 1 mm precision (Model E-1, Dyna Top, Mexico City, Mexico) and length was measured using a locally made wooden board with 1 mm precision. Height, length and weight data were used to compute anthropometric indicators to classify individuals into overweight and obesity categories. Body mass index (weight/[height]2) (kg/[m]2) was computed for individuals from 5 to 59 years of age. For children from 1 to 4 years old, weight for height z-scores (WHZ) were obtained based on the new WHO growth standards published in 2006,25 using the processing program provided by WHO.26
Sociodemographic data: Demographic data and housing characteristics were obtained using a household questionnaire. The information for the purpose of this analysis included: head of household schooling, age of the subjects studied, ethnic background (indigenous or non-indigenous), characteristics of the household and possession of goods.
Consent for participation was obtained. The project was approved by the Human Subjects Committee of the National Institute of Public Health (Instituto Nacional de Salud Pública, INSP).
Variables included in analyses
The variables for this study included FV dietary intake (g), adequacy of FV (% population consuming total or one-half of amounts recommended by the World Health Organization and the American Heart Association AHA), region of the country, area of residence (urban or rural), household wellbeing condition index (HWCI), ethnic background, age, sex and BMI categories.
Definitions: Vegetables were defined as plants having edible parts such as: leaves (cabbage, lettuce, spinach, etc.), stems (celery, etc.), sprouts (asparagus, etc.), flowers (cauliflower, artichoke, etc.), pods (green beans, etc.), roots (carrots, beets, etc.), bulbs (onion, garlic, etc.), fruits culturally considered vegetables in Mexico (tomato, cucumber, avocado, etc.), and green seeds (peas, broad beans), except for mature seeds from spike or gramineae (corn, wheat, rice, oats, etc.) as well as pulses (beans, lentils, chickpeas, and soybeans). Fruits were botanically defined as fleshy edible parts from trees or fresh plants containing seeds.1
From this perspective, FV are considered foods characterized as low energy density and rich in vitamins, minerals, fiber and other bioactive components. Therefore, tubers were not considered in the vegetable group in this study, given their high starch content and low contribution of fiber and other micronutrients.1 Fruit juices were excluded due to their high content of fructose and energy and low fiber content1 and because of evidence suggesting negative effects on health.27-29
Fruit and vegetable of Dietary Intake (FV- DI). The estimation of intake was performed through calculation of grams of food intake per day based on the FFQ.23
Consumption was expressed in grams rather than in calories, since most recommendations use this unit. Adequacy intake of FV (AI-FV), was evaluated considering compliance with recommendations to prevent cardiovascular disease as defined by who and the AHA.30,31
Recommended intakes were 200g for 1 to 4 years-old children, 300 g for 5 to 8 years-old30 and 400 g for subjects between 9 to 59 years.31 Subjects were classified into three categories according to their intakes relative to age-specific recommendations: a) adequate intake: at or above recommended intake or adequacy of 100% or more; b) moderately inadequate intake (from 50% to 99% of recommended intake) and c) highly inadequate intake (less than 50% of recommended intake or adequacy less than 50%).
Regions: The country was divided into four regions: 1) north (including the status of Baja California, Baja California Sur, Coahuila, Chihuahua, Durango, Nuevo Leon, Sonora and Tamaulipas); 2) center (Aguascalientes, Colima, Guanajuato, Jalisco, State of Mexico, Michoacan, Morelos, Nayarit, Queretaro, San Luis Potosi, Sinaloa, Zacatecas); 3) Mexico City and 4) south (Campeche, Chiapas, Guerrero, Hidalgo, Oaxaca, Puebla, Quintana Roo, Tabasco, Tlaxcala, Veracruz and Yucatan).
Urban and rural areas: Were characterized according to the National Institute of Statistics, Geography and Informatics criteria, with urban areas as localities with >2500 inhabitants and rural areas as localities with <2500 inhabitants.
A Household Wellbeing Condition Index (HWCI): Was computed using household characteristics and possession of goods through principal components analysis (PCA). We used the first component of the PCA, which explained 46% of the variance. The variables in the model were floor material, ceiling material, total number of rooms in the household, possession of refrigerator, washing machine and stove as well as the number of electric appliances in the household (radio, TV, video player, telephone, and computer). The HWCI was divided into quintiles to categorize the wellbeing condition; thus, subjects in the low wellbeing quintile had the lowest wellbeing condition and those in the highest quintile (5) had the highest conditions.
Ethnic background: A household was classified as indigenous when at least one member of the household older than five years old spoke an indigenous language.
Body Mass Index categories: For the adult population, BMI cutoff points were those recommended by who: underweight <18.5 kg/m2, overweight 25 to 29.9 kg/m2 and obesity >30 kg/m2.15 For subjects between 5 to 18 years old, cutoff points used were those specific for underweight, overweight and obesity per age and sex, proposed by Cole et al.32 For children younger than five years old, overweight and obese children were defined as weight-for-age z-scores (WAZ) higher than two standard deviations (SD) and underweight children were defined as below -2.0 SD, using the new WHO growth standards.25,26
Diet information was examined for validity. Data of individuals with dietary information considered invalid were excluded according to the following criteria: a) individuals with dietary intake adequacies above five standard deviations (SD) for energy and nutrients, according to estimated average requirements by age and sex, considering physical activity, b) individuals having dietary adequacies lower than 25% of the total daily energy intake; and c) individuals with FV intake (in grams) higher than five standard deviations (intakes considered implausible). Pregnant and breastfeeding women were excluded from the analyses. Average FV-DI and proportion of the population who attained the recommendation were estimated for each age group according to sociodemographic and BMI categories characteristics.
FV-DI intakes were log-transformed to obtain a normal distribution.
Adjusted FV mean intakes and proportion of subjects who complied with recommended intakes AI-FV were estimated using multiple linear regressions and ordinal models, respectively. In both cases, models adjusted for potentially confounding variables (age, sex and HWCI). Statistical tests for the differences among categories of the variables studied were performed using these models. To adjust for the study design, the SVY module in STATA was employed. Statistical significance was stated at a p< 0.05.
We analyzed a total of 3224 children 1-4 years old, 8294 children 5-11 years old, 7722 adolescents 12 to 18 years old and 16349 adults 19 to 59 years old, representing: 7072563, 14802442, 16422791, and 48908755 people for each age group, respectively (Table I and II). Table I also shows the sample sizes for all the categories of the variables for which information on intake is presented. For most categories large sample sizes are observed. The smaller samples are found, as expected, in children < 5 years of age. For most categories in this age group sample sizes are above 380. However, relatively small sample sizes (n < 150) are found in Mexico City (n= 149), and in the overweight (n= 128), obesity (n= 62) and underweight (n= 50) categories. For school-age children, the only category with sample size < 150 is the underweight category (n= 117). For adolescents, the only category with less than 150 cases is the underweight category (n= 87) and for adults, none of the categories had < 150 cases.
Fruit and vegetable intake and adequacy
Tables I and II describe daily FV dietary intake by age group, according to sociodemographic and BMI categories. In all age groups fruit intake was substantially higher compared to vegetable intake, with 61.3 g vs. 26.2 g for preschool children, 68.9 g vs. 34.2 g for school children, 72.9 g vs. 43.4 g for adolescents, and 65.8 g vs. 56.8 g for adults, respectively. The total amount of FV-DI for each age group is far below recommended intakes. The percentage of subjects with AI-FV was: 30.8% of preschool-age children, 17.0% of school-age children, 19.2% of adolescents and 24.2% of adults.
Results on FV-DI (g) as well as proportions of the AI-FV are presented below by age category.
Preschool-age children: Children from the northern region reported a significantly lower fruit intake compared to children from the south (50.5 vs. 65.2 g, respectively; p< 0.05). Urban children reported a significantly higher fruit intake compared to children living in rural settings (65.6 vs. 53.1 g; p< 0.05). Fruit intake had a progressive and significant increase from HWCI quintile 1 to 4 (49.2 g to 85.1 g; p< 0.05). Children aged 3 (70.5 g) and 4 (66.3g) years old reported a significantly higher fruit intake compared to children aged 1 year old (47.5 g; p< 0.05).
Preschool children living in Mexico City reported the highest vegetable intake (31.9 g) compared to the other regions of the country, while children from the north reported a significantly lower vegetable intake (21.3 g) compared to their counterparts from the other regions (p< 0.05). A progressive increase in vegetable intake was observed as HWCI improved (p< 0.05). A significantly higher vegetable intake was observed among children with adequate BMI (26.8 g)compared to obese children (17.3 g; p< 0.05). Older children reported a significantly higher vegetable intake compared to younger children (29.0 vs. 22.3 g, respectively; p< 0.05) (Table I).
Total AI-FV followed the same pattern as FV-DI. Children from the north reported lower AI-FV (28.7%) than children from Mexico City (32.2%; p< 0.05), although differences between center and south were not statistically significant. AI-FV was lower in the first two quintiles of HWCI relative to the upper quintiles (p< 0.05) and a trend of higher intake with higher HWCI was evident (Figure 1).
School-age children: Children aged 5 to 11 years living in the north present the lowest fruit intake (53.1 g) compared to children from the other regions (p< 0.05) and in particular to children from Mexico City, who presented the highest fruit intake (84. 7 g; p< 0.05). Fruit intake among children from the lowest HWCI was the lowest (57.2 g) compared to the better-off group (81.6g) (p< 0.001) and to the intermediate quintiles (p< 0.05). Fruit intake in children aged 5 years old was the highest (75.9 g) compared to children aged 9 and 11 years old which reported the lowest fruit intake (62.9g and 62.5 g, respectively, p< 0.08) (Table I).
Vegetable intake was significantly lower in children living in the north (28.6 g) relative to the other three regions (p< 0.05). Children living in Mexico City had higher intakes (49.3 g) than those living in the north (28.6 g) and the center (32.8 g; p< 0.05). Urban school-age children reported a significantly higher vegetable intake than rural children (35.6 g vs. 31.9 g; p< 0.05). A significant and progressive increase in vegetable intake was observed as HWCI improved (27.0 g for quintile 1 vs 46.5 g for quintile 5; p< 0.05) (Table I).
The lowest adequacy of FV intake was reported among children living in the north (14.2%) relative to the center, Mexico City and the south (p< 0.05). Indigenous children had a significantly slightly higher AI-FV compared to non-indigenous children, and the difference was statistically significant (17.4% vs. 17.0%, respectively; p< 0.05). Better-off children (quintile 5) reported higher adequacy intake than worst-off children (quintiles 1 and 3; p< 0.05) and a trend of higher intake with higher HWCI was evident (Figure 1).
Adolescents: Fruit intake was substantially lower in the north (48.7 g) compared to the other regions of the country (center, 77.2 g; Mexico City, 75.2 g; and south, 81.9g; p< 0.05). Surprisingly, indigenous adolescents, a group that lives in poverty, reported a significantly higher fruit intake (87.3 g) than non-indigenous adolescents (70.6 g; p< 0.05). Eighteen year-old adolescents had significantly lower intakes than adolescents from other age groups (p< 0.05).
Vegetable intake in the north (35.7 g) was significantly lower than intake in the center (44.7 g), Mexico City (50.2 g) and the south (43.1 g; p< 0.05). A significant and progressive increase in vegetable intake was documented from quintile 1 (36.1 g) to quintile 4 (52.5g; p< 0.05) (Table II).
Adolescents from the north of the country reported lower adequacy of FV intake (15.9%; p< 0.05) compared to adolescents from the other regions (center, 19.0%; Mexico City, 22.2%; and the south, 20.2%). Adolescents from quintile 1 (16.6%) reported lower AI-FV relative to adolescents from quintile 4 (22.6%) and 5 (21.1%; p< 0.05) (Figure 2).
Adults: Fruit intake was significantly lower in subjects living in the north (45.7 g) compared to the other regions of the country (p <center, 67.3 g; Mexico City, 68.2 g; and south, 75.9 g; p< 0.05). Fruit intake significantly and progressively increased from quintile 1 (55.4 g) to 5 (101.9 g). All differences with the highest quintile were statistically significant (p< 0.05). Overweight subjects consumed a significantly higher fruit intake than obese adults (74.1 g vs. 61.9 g, respectively; p< 0.05). A significantly higher intake of fruit was observed among women (75.5 g) compared to men (52.3 g; p< 0.05). Fruit intake significantly and progressively increased with age (19 to 29 years old, 53.4 g; 30 to 39 years old, 69 g; 40 to 59 years old, 74.1 g). Differences between the youngest and all other groups were statistically significant (p< 0.05) (Table II).
Adults living in the north (49.9 g) reported a significantly lower vegetable intake compared to those living in the center (59.8 g), Mexico City (61.5 g) and the south (56.2 g; p< 0.05). There was a significant and progressive increase in vegetable intake form quintile 1 (43.2 g) to quintile 5 (87.2 g; p< 0.05). Overweight adults reported a significantly higher vegetable intake (60.5 g) than underweight adults (37.8 g; p< 0.05). Women's vegetable intake (61.2g) was significantly higher than men's 50.2 g; p< 0.05). Adults aged 19 to 29 years old reported a significantly lower vegetable intake (47.1 g) compared to older adults (p< 0.05) and adults between 40 to 49 years old reported a significantly higher vegetable intake compared to their counterparts (63.2 g; p< 0.05) (Table II).
Subjects with the lowest percentages of AI-FV were found in the north (20.4%) and in the low HWCI (19.6%); compared to their counterparts (p< 0.05). A clear trend of higher intake with higher HWCI was observed (Figure 2).
In summary, the overall results show consistent FV intake patterns across age categories for regions and wellbeing conditions. Residents from the northern region of the country had the lowest average intake of both fruits and vegetables compared with all other regions, for all age groups. In general, amounts of both fruits and vegetables consumed among those in the poor (lower HWCI) quintiles were inferior to those in the high HWCI quintiles. An exception was fruit intake in adolescents, where no differences among HWCI quintiles were observed.
Differences in intakes among categories of other variables were not consistent across age groups. Intakes in rural areas were lower than in urban areas in children less than five years old (of both fruits and vegetables) and in school-age children (only of vegetables). In contrast, fruit intake in adolescents was lower in urban relative to rural areas. Intakes of both fruits and vegetables were lower at younger ages in children less than 5 years old (< 2 years vs. > 3 years) and adults (< 29 years vs. > 30 years) and vegetable intake was also lower in younger adolescents (12 years vs. 13 and 14 years). In contrast, for adolescents, older subjects had lower fruit intakes than younger subjects (18 years vs. 12, 16 and 17 years). Female adults had higher FV-DI but not female children. Intakes were similar in indigenous and non-indigenous populations, with the only exception being fruit intake, which was lower in non-indigenous adolescents. Patterns were not consistent for BMI categories.
Large percentages of subjects with highly inadequate intakes of FV (less than 50% of the recommended intake) were observed in all age groups. The proportions with highly inadequate intakes were about 40% in preschool-age children, between 50 and 60% in school-age children and adolescents, and between 40 and 50% in adults.
This study documents a low dietary intake of FV among the Mexican population relative to international recommendations. Low intakes were observed both in fruits and vegetables and in all age groups, regions, ethnic groups, wellbeing categories, urban and rural populations and both sexes. Only 30.8% of preschool children, 17.0% of school children, 19.2% of adolescents, and 24.2% of the adult population fulfilled the recommended intakes.
The consistent lower intake in low wellbeing quintiles for all subgroups studied suggests barriers to the FV-DI among the poor. Although data does not allow identification of the specific reasons for the lower intakes among the poor, the possible reasons include lower demand due to, for example, higher prices of fruits and vegetables per calorie relative to energy-dense low-price foods, and/or to social and cultural factors linked to poverty. Another set of potential reasons may be due to lower FV supply in areas where poor populations live or problems of access to markets due to limitations in transportation systems.
Another consistent finding across all subgroups studied was lower intake of FV in the north, adjusting for wellbeing conditions, age and sex. This finding indicates that there are barriers to the consumption of FV in the north, which are more likely to be in the demand rather than the supply side, given the relative higher development and wellbeing in the north and the fact that the differences persist after adjusting for wellbeing conditions; they may have to do with cultural factors or with changes in food patterns as a result of the food and nutrition transition due to modernization. An alternative cause of lower DI-FV in the north may be that the north faces climate conditions that are less favorable for FV production relative to other regions. Studies should be conducted to identify the reasons for the lower FV-DI in the north.
The fact that the indigenous population's intake is generally similar to the non-indigenous population, after adjusting for wellbeing conditions, suggest that FV supply in Indigenous communities, which are usually more isolated than non-indigenous communities, is not the main problem. It is possible that the more restricted markets in isolated indigenous villages are compensated with local production. This finding reinforces the hypothesis that lower intakes in certain groups are probably more related to demand than supply.
A peculiar finding was the fact that rural and indigenous adolescents intake more fruits than urban and non-indigenous adolescents. Again, it is unlikely that this lower intake could be explained by limitations in supply. It is more likely that it has to do with demand issues, such as changes in eating patterns related to modern and urban life; for example, eating more fast food and outside the home.
Adult women and older adults (> 30 years old) consumed more FV than men and than younger adults (19 to 29 years old). This higher intake may reflect a greater interest of women and older adults in health and healthy lifestyles or eating more frequently at home as opposed to eating fast food or away from home.
There was not a consistent pattern of differences in intake among BMI categories. Although there is evidence in the literature that low energy density diets are associated with lower risk of obesity,3,4 the cross-sectional nature of the data in this study is not adequate to study causal associations. In addition, several other dietary factors and physical activity may explain energy balance. However, despite the lack of a consistent pattern, there were two age groups children less than five years old (for vegetables) and adults (for fruits) in which lower BMIs were associated with higher intakes.
The discussion so far has focused on the differences among categories of the variables studied; however, the most important finding is the strikingly low intake of fruits and the even lower intake of vegetables in the population as a whole. The remarkably low intakes are more evident when the percentages of highly inadequate intakes (less than 50% of recommended intakes) are examined. These percentages range from approximately 40 to 60% for the different age groups.
FV-DI in the preschool Mexican population (87.5g) is comparable to low income Southeast Asian countries such as Bangladesh, India and Nepal (94 g/person/day).33 In the adolescent and adult population, average consumption (116.3 g and 122.6g, respectively) would be similar to those of countries such as Estonia, Kazakhstan, Letonia, Lithuania, and the Russian Federation (approximately 195g/person/day). The low consumption in school-age children (103.1g) is a special case, in which no country was found to be comparable.
Ruel et al. and Rojas et al. report higher average FV intake in urban than rural areas in developing countries (Burundi, Kenya and Costa Rica).34,35 Our findings were similar only for children. Although rural areas could have greater access to FV in theory, given that most of the production occurs in these areas, however consumption is usually low probably because most of the production goes to the market and that availability of a variety of FV is more sustainable throughout the year in urban areas.36,37
Another identified factor associated with DI-FV in the Mexican population was wellbeing conditions. Studies by Fouéré et al.38 and Arimond and Ruel39 found that decreasing economic income was associated with lower DI-FV in Africa, Cambodia, Nepal, Colombia, Peru and Haiti. Hatloy40 reported that when economic income increases in Mali, food diversity also increases, and as a consequence, intake of FV is higher.
It was also found that adult women presented higher DI-FV relative to adult men, consistent with what has been observed in African populations.34 A possible explanation that has been given is that women give FV intake a higher priority than men in order to improve diet quality.41
One of the possible limitations of the present analysis is the considerable number of subjects who were lost as a result of data cleaning and missing data (18.6% pre-school children and 11.6% school children), which could have biased the sample. Analyses were made to determine differences between excluded and non-excluded subjects in the following variables: region, rural/urban area, ethnic background, wellbeing condition quintiles, BMI category, sex, and age. In general, no statistically significant differences were observed in the variables compared (p > 0.05), except for certain particular ages in pre-school children, ethnic background, urban/rural residence and BMI categories in school-age children. A higher proportion of excluded subjects were found at 1 and 2 years of age. Also, a greater proportion of excluded subjects were found in the urban area, non-indigenous and school-age children with adequate BMI. For adults and adolescents, the proportions not included in the analysis (3.4% and 4.2%, respectively) were lower than for children.
There were no estimations of FV intake at the national level before this study. The data analyzed comes from the ENSANUT 2006, which was designed to be representative at national, regional and state levels and by urban and rural areas. Since we excluded foods with high starch content like tubers or pulses, which are high in energy density and protein, our results do not overestimate FV intake as could be the case of other studies43,44 where pulses, potatoes and potato chips were considered as vegetables.
In order to evaluate AI-FV in the pre-school and school population, recommendations from the AHA were adopted. One limitation of this recommendation is that they were made for children from the United States and not for Mexican children. The adult recommendations may be more appropriate since they were made by WHO considering a more international scope.
One limitation of the data is that it does not provide information as to the form in which FV were prepared for consumption. Identifying if FV were fried, boiled or dressed or raw would be important in different studies, as healthy FV could be fried or consumed along with high energy density foods like butter, mayonnaise, and other dressings.
In conclusion, FV intake in the Mexican population was much lower than recommended intakes in all age groups and, particularly, in the school-age and adolescent population. Vegetable intake was much lower than fruit intake. Fruit intake was 2 to 5 times higher than vegetable intake in the different groups, with the highest differences in school-age children and adolescents. In general, the population living in the northern region and lowest HWCI were the subgroups having the lowest intakes and the lowest compliances with recommended intakes of FV. Some subgroups had higher FV-DI, such as the population living in Mexico City and those classified in the highest HWCI; unfortunately this consumption did not reach average recommended intakes and even in these subgroups the percentages of individuals who complied with recommendations were in all cases less than 35%.
Research is needed to better understand the reasons for the general low intakes and in certain subgroups. Using the results of this research, the development and implementation of programs, strategies and policies aimed at improving FV intake in the different population groups is recommended. This could be done through: a) information and communication strategies aimed at improving food preferences towards a higher intake of FV in all age groups, and b) improving the availability and lowering the prices of these foods for lower income households as needed. Particular programs should be developed in schools to increase the availability and intake of fruits and to create a new culture of FV consumption in the new generations.
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Received on: April 11, 2008
Accepted on: April 28, 2009
Address reprint requests to: Dr. Juan A. Rivera Dommarco. Instituto Nacional de Salud Pública. Av. Universidad 655, col. Santa María Ahuacatitlán. 62100 Cuernavaca, Morelos, México. E-mail: firstname.lastname@example.org