Macronutrient intake

The case study results show that there was an apparent decrease of 12.6 percent in total energy adequacy between 1988 and 1999. This reduction was observed across all regions and socio-economic status quintiles, and in both urban and rural locations (Table 2). Rural locations had higher adequacies than urban ones, and the South had higher adequacies than the other three regions. However, differences across regions and locations were higher in 1988 than in 1999. It should be noted that the dietary intake data of the 1988 and 1999 surveys are not directly comparable. Different food composition databases were used in the analysis of each survey. Also, the availability of food outside the home increased dramatically between 1988 and 1999, and the data indicate that in 1999 people ate away from home more often. As food consumption outside the home is often underreported, underreporting in 1999 can be expected. In addition, the case study team had clear indications of large rates of underreporting among overweight and obese women, probably resulting from a slim ideal body shape in Mexican society. According to case study estimates, obese women were 1.51 times more likely to underreport than women within the normal range of reference body weight (95 percent confidence interval = 1.35, 1.69) (Campirano et al., 2001). The prevalence of high BMI (> 25) in women increased from 35 percent in 1988 to 59 percent in 1999; therefore, greater underreporting is expected in 1999. Thus it is clear that these surveys are not directly comparable and that the 1999 survey has greater underreporting.

Despite the evidence for underreporting of energy intakes, both fat intake and fat adequacy showed increases between 1988 and 1999 in all but rural locations and populations in the lowest socio-economic status quintile (Tables 2 and 3). A similar trend was seen for the percentage of energy derived from fat, where the increase between surveys was far smaller in rural and poor populations. This increase apparently occurred at the expense of both protein and carbohydrate intakes (Table 4). Protein adequacy at the national level was above the adequacy rate, and decreased from 1988 to 1999 across all groups.

TABLE 4
Nutrient intake by age group, 1988 and 1999

Sources: MNS-1, 1988; MNS-2, 1999.

Micronutrient intake

At the national level, the adequacy of intakes of vitamins A and B12 and folate increased between the 1988 and 1999 surveys (Tables 2, 3 and 5). The magnitude of the increase was substantial for both vitamin A (from 23.8 to 68.7 percent) and folate (from 18.0 to 67.0 percent). While the intake adequacy of these vitamins increased similarly across all stratification levels, the absolute adequacy of intake of vitamin A (but not folate) remained much lower in the lowest socio-economic quintile (45.5 percent) than in the highest (95.5 percent); regional differences for vitamin A adequacy were minor. The adequacy of iron intake, on the other hand, decreased by about 30 percent at the national level, and reductions were observed in all the stratification levels. Intake data for neither vitamin D nor zinc were available in MNS-1 (1988) (Tables 5 and 6). Vitamin D adequacy at the national level in MNS-2 was 71.2 percent, but there was a large discrepancy between the lowest and the highest socio-economic status tertiles. The median adequacy for zinc intake in MNS-2 was 82.8 percent, and varied little among regions and socio-economic status quintiles.

TABLE 5
Women’s mineral intakes and percentage adequacy, by region and location, 1988 and 1999

^a,b,c,d Different superindices represent statistically significant differences among regions.
º Statistically different from rural locations.
Sources: MNS-1, 1988; MNS-2, 1999.

TABLE 6
Women’s mineral intakes and percentage adequacy, by socio-economic status and education, 1988 and 1999

^a,b,c Different superindices represent statistically significant differences among socio-economic index tertiles.
^* Statistically different from middle and higher education.
Sources: MNS-1, 1988; MNS-2, 1999.

TABLE 7
Mean food intake in Mexico

Mean g or ml of purchased food
* Statistically different from rural.
^a,b,c, Different superindices represent statistically significant differences among socio-economic index tertiles.
^d,e,f,g. Different superindices represent statistically significant differences among regions.
Sources: MNS-1, 1988; MNS-2, 1999.

Food intake

Food intake information was not available from MNS-1. However, some trends in food intake among stratification groups were observed with data from MNS-2 (Table 7). Consumption rates of both maize products and legumes were substantially greater in the lowest socio-economic quintile (290.1 and 52.5 g, respectively) than in the highest (121.3 and 20.6 g, respectively). Similar differences in maize and legume consumption were also apparent among regions, with the highest intakes occurring in the South and the lowest in Mexico City. In contrast, women of higher socio-economic status consumed more meat than those of lower socio-economic status (100.3 versus 63.3 g). Of the regions, Mexico City had the highest meat consumption (89.1 g) and the Central region the lowest (70.1 g). Milk intake showed a similar pattern to meat, although with more dramatic differences: the highest socio-economic quintile consumed about four times more milk products than the lowest (201.8 versus 54.5 g). Fresh vegetable and fruit intakes, as well as soft drink consumption were also greater among the highest socio-economic quintile than the lowest. At the national level, a total of 204.7 g of sweet drinks and sugar were consumed daily, with a higher intake in the North (253.1 g) than the South region (172.1 g). Urban locations consumed almost twice the amount consumed in rural locations. The average daily fats and oils consumption was 10.0 g, and did not differ substantially among stratification groups.