People purchase foods based on their income level,
their belief in a food's health benefit and cost. However,
ethnicity and gender also impact people's food choices,
according to researchers at the Johns Hopkins Bloomberg School of Public
Health. The study, published in the March 7 advance
online publication of European Journal of Clinical
Nutrition, reports that food choice also is influenced
by environmental factors, such as reliance on fast food,
food advertising and food pricing, and on individual
factors, such as taste, palatability, convenience and
health benefits.
The study sample included 4,356 U.S. adults ages 20 to
65 from two nationally representative cross-sectional
surveys conducted by the U.S. Department of Agriculture,
the Continuing Survey of Food Intakes by Individuals and
the Diet and Health Knowledge Survey. The researchers, with
the Johns Hopkins
Center for Human Nutrition, examined diet quality
indicators, such as the amount of energy, energy density,
total fat and saturated fat in foods consumed by study
participants. They also considered the quantity of fruits
and vegetables, fiber, calcium and dairy products consumed
and the overall quality of people's diet, which was
assessed using two indices, including one recommended by
the USDA. The key findings are as follows:
Considerable ethnic and gender
differences exist in the association between socioeconomic
status, perceived barrier of food price, perceived benefit
of diet quality and dietary intake.
Income constraints on individuals
and families can lead to a poorer quality diet. When buying
food, African-Americans with lower incomes saw food price
as more important than did whites with the same income
level.
Caucasians of lower socioeconomic
status ate more fat and saturated fat. African-Americans
showed no association between income level and fat
intake.
Among all study participants and
independent of income, the perceived barrier of food price
appears to increase sodium intake while reducing fiber
intake.
Perceived benefit of diet quality
was directly related to better nutritional behavior,
including consuming foods lower in saturated fat and eating
more fiber, fruits and vegetables. Compared to men, women
were more concerned about meeting food guidelines in order
to improve their health.
Women had lower energy, energy
density, total fat, saturated fat, cholesterol and sodium
intake than men. Yet, men had higher intake of fruits and
vegetables, fiber, calcium and dairy products, particularly
because they consumed more food.
"Low socioeconomic status may cause a significant
food-cost barrier, which, in turn, reduces the quality of
an individual's diet. Considering the growing obesity
crisis, it is important to make healthy foods accessible to
poor segments of the population and to empower them to eat
a healthy diet by lowering the price of healthy foods and
enhancing tailored nutrition education," said Youfa Wang,
co-author of the study and an assistant professor in the
Bloomberg School's
Department of International Health. "Programs that
promote positive attitudes towards the benefits of healthy
diets can improve diet quality for both genders and all
ethnicities."
May A. Beydoun, co-author of the study and a
postdoctoral fellow in International Health, said,
"People's diets are affected by many factors. We examined
some of those factors. Therefore, a large proportion of the
association between income level and dietary intake could
not be explained by the perceived barrier of food price or
the perceived benefit of diet quality."
The authors recommend additional studies aimed at
uncovering the complex relationships between socioeconomic
status, nutritional knowledge, attitudes and perceptions,
and dietary behavior and food choices.
The study was supported by grants from the Johns
Hopkins Bloomberg School of Public Health, the U.S.
Department of Agriculture, the National Institute of
Diabetes and Digestive and Kidney Diseases and the Johns
Hopkins Center for a Livable Future.