Although a link between lack of nutrient uptake and disease has often been highlighted, the finding that education and cost have a role to play in choosing nutritious foods could have important implications for the demographic range of future studies.
“Nutritional epidemiology has historically been based on the premise that nutrient exposures are directly linked to health outcomes,” the authors wrote. “However, nutritional status is also intimately linked to socioeconomic status, and the findings reported here raise the possibility that the higher monetary cost of nutritious diets may provide one explanation for these observations.”
Additionally, they said that even when socioeconomic status of survey respondents is taken into account, fewer studies have included the variables of diet cost and education.
The study, carried out by researchers at the University of Washington, focused on the dietary choices of 164 adults, who recorded how frequently they consumed 152 different foods and 22 beverages and kept a four-day food diary. They also completed demographic and behavioral questionnaires.
The results showed that the nutritional content of the respondents’ diets is closely linked to socioeconomic status: Energy-dense diets of fast food, candy and desserts tended to be nutrient-poor and consumed by those on lower incomes. Lean meats, fish, fruit and vegetables, on the other hand, are nutrient-rich, but provide less energy by weight.
“Higher quality diets were not only more costly per 2000 kcal but were associated with higher household incomes and education of study participants. Education, rather than incomes was the dominant factor. More highly educated respondents reported higher quality and therefore more costly diets, independent of household income level.”
The study also found that women chose less energy dense diets, spending on average $8.12 for every 2000 calories, while men spent $7.43 for the same amount of energy. Reflecting the fact that the men ate more than the women, men spent more per day on food - $6.72 compared to $6.21.
For both genders, higher energy density was connected to lower intakes of potassium, fiber and vitamins C and E, and higher levels of saturated fat.
“Future studies, based on more representative samples, will be needed to elucidate the connections between diet quality and diet cost across socioeconomic strata,” the authors concluded.
Meanwhile, food manufacturers are facing growing pressure to cut saturated fats from their formulations, due to their link with raised cholesterol levels, a risk factor for cardiovascular disease.
Source: Journal of the American Dietetic Association
Volume 109, Issue 5 (May 2009), pp. 814-822
“Lower-energy-density diets are associated with higher monetary costs per kilocalorie and are consumed by women of higher socioeconomic status”
Authors: Pablo Monsivais, Adam Drewnowski.