Research published by the Center for Public Health Nutrition at the University of Washington and the Center for Human Nutrition at Johns Hopkins School of Public Health has found that, contrary to a recently released USDA study, nutrient dense diets are more expensive. The study was funded by a grant from the National Institute of Health.
The study was conducted on a random sample of 2,000 adults in the Seattle Obesity Study. The researchers assessed dietary intakes and converted them into quintiles. The diet cost for each quintile was then calculated using supermarket prices in the Seattle area, choosing the least expensive foods that were rich in the chosen nutrients.
Higher food costs were associated with higher intakes of these nutrients
- Vitamins C, A, E, and B12
- Beta carotene
- Potassium
- Magnesium
- Dietary fiber
These important nutrients were less expensive:
- Calcium
- Vitamin D
- Iron
- Folate
The researchers found that the cost difference was most pronounced for vitamin C, beta carotene, potassium, and magnesium because those nutrients are found in fruits and vegetabels. It’s easier to get calcium and vitamin D on a lower cost diet, because dairy products are less expensive, and iron and folate are relatively inexpensive because grains are enhanced with those nutrients.
Unfortunately, lower cost diets were associated with higher intakes of saturated fats, trans fats, and sugars. Those are the compounds that are associated with a higher risk of disease.
The USDA study looked at “aspirational” diets and measured the c0st of food in nutrient density, as opposed to this study, which looked at real life diets.
The study’s authors say that, “the present findings have implications for future research. First, diet cost variables ought to be taken into account in future studies on diets and disease risk. Second, further research is needed to identify cheaper ways of promoting beneficial nutrients to the consumer, particularly among lower income and lower education groups.”
