Less-energy-dense diets of low-income women in California are associated with higher energy-adjusted diet costs

The quality and monetary value of diets consumed by adults in the United States

BACKGROUND

Food prices are an established determinant of food choice and may affect diet quality. Research on diet cost and diet quality in representative populations has been hindered by lack of data.

OBJECTIVE

We sought to explore the distribution of diet cost and diet quality among strata of the US population and to examine the association between the 2 variables.

DESIGN

In this cross-sectional study, monetary costs of diets consumed by participants in the 2001-2002 NHANES were estimated with the use of a national food price database. Healthy Eating Index (HEI)-2005 values were estimated with the use of the population ratio method for the calculation of average scores. Mean daily diet costs, energy-adjusted diet costs, and HEI-2005 scores were estimated for subpopulations of interest. Associations between energy-adjusted diet cost, HEI-2005 scores, and HEI-2005 component scores were evaluated.

RESULTS

Higher energy-adjusted diet costs were significantly associated with being older and non-Hispanic white, having a higher income and education, and living in a food-secure household. Higher diet costs were also associated with higher HEI-2005 scores for both men and women. Women in the highest quintile of diet costs had a mean HEI-2005 score of 69.6 compared with 52.5 for women in the lowest-cost quintile. Higher diet cost was strongly associated with consuming more servings of fruit and vegetables and fewer calories from solid fat, alcoholic beverages, and added sugars.

CONCLUSION

Given the observed association between diet cost and diet quality, helping consumers select affordable yet nutritious diets ought to be a priority for researchers and health professionals.

Following federal guidelines to increase nutrient consumption may lead to higher food costs for consumers

The federal Dietary Guidelines for Americans, 2010, emphasized the need for Americans to consume more potassium, dietary fiber, vitamin D, and calcium, and to get fewer calories from saturated fat and added sugar. We examined the economic impact of meeting these guidelines for adults in King County, Washington. We found that increasing consumption of potassium--the most expensive of the four recommended nutrients--would add $380 per year to the average consumer's food costs. Meanwhile, each time consumers obtained 1 percent more of their daily calories from saturated fat and added sugar, their food costs significantly declined. These findings suggest that improving the American diet will require additional guidance for consumers, especially those with little budget flexibility, and new policies to increase the availability and reduce the cost of healthful foods.

Regional price differences and food consumption frequency among elementary school children

OBJECTIVE

Food prices may affect diet and weight gain among youth and lead to geographic disparities in obesity. This paper examines the association between regional prices and consumption frequency of fruit/vegetables and snack items among elementary school children in the USA.

STUDY DESIGN

Observational study using individual-level survey data of fifth-grade children (average age 11 years) and regional food prices based on store visits in 2004.

METHODS

Dependent variables are self-reported consumption frequency in fifth grade; primary explanatory variables are metropolitan area food prices relative to cost of living. Multivariate regression analysis.

RESULTS

Price variation across metropolitan areas exists, and lower real prices for vegetables and fruits predict significantly higher intake frequency. Higher dairy prices predict lower frequency of milk consumption, while higher meat prices predict increased milk consumption. Similar price effects were not found for fast food or soft drink consumption.

DISCUSSION

The geographic variation in food prices across the USA is sufficiently large to affect dietary patterns among youth for fruit, vegetables and milk. The price variation is either too small to affect children's consumption frequency of fast food or soft drinks, or the consumption of these foods is less price sensitive.

Dietary energy density and successful weight loss maintenance

Research shows a positive relationship between dietary energy density (ED) and body mass index (BMI), but dietary ED of weight loss maintainers is unknown. This preliminary investigation was a secondary data analysis that compared self-reported dietary ED and food group servings consumed in overweight adults (OW: BMI=27-45kg/m(2)), normal weight adults (NW: BMI=19-24.9 kg/m(2)), and weight loss maintainers (WLM: current BMI=19-24.9kg/m(2) [lost≥10% of maximum body weight and maintained loss for ≥5years]) participating in 2 studies, with data collected from July 2006 to March 2007. Three 24-h phone dietary recalls from 287 participants (OW=97, NW=85, WLM=105) assessed self-reported dietary intake. ED (kcal/g) was calculated by three methods (food+all beverages except water [F+AB], food+caloric beverages [F+CB], and food only [FO]). Differences in self-reported consumption of dietary ED, food group servings, energy, grams of food/beverages, fat, and fiber were assessed using one-way MANCOVA, adjusting for age, sex, and weekly energy expenditure from self-reported physical activity. ED, calculated by all three methods, was significantly lower in WLM than in NW or OW (FO: WLM=1.39±0.45kcal/g; NW=1.60±0.43 kcal/g; OW=1.83±0.42 kcal/g). Self-reported daily servings of vegetables and whole grains consumed were significantly higher in WLM compared to NW and OW (vegetables: WLM=4.9±3.1 servings/day; NW=3.9±2.0 servings/day; OW=3.4±1.7 servings/day; whole grains: WLM=2.2±1.8 servings/day; NW=1.4±1.2 servings/day; OW=1.3±1.3 servings/day). WLM self-reported consuming significantly less energy from fat and more fiber than the other two groups. Self-reported energy intake per day was significantly lower in WLM than OW, and WLM self-reported consuming significantly more grams of food/beverages per day than OW. These preliminary findings suggest that consuming a diet lower in ED, characterized by greater intake of vegetables and whole grains, may aid with weight loss maintenance and should be further tested in prospective randomized controlled trials.

A cost comparison of more and less nutritious food choices in US supermarkets

OBJECTIVE

The present study directly compared prices of more and less nutritious foods within given categories in US supermarkets.

DESIGN

Foods selected from six supermarkets in Jackson County were categorized using the five criteria of the Nutrition Detectives™ (ND) programme and an item-to-item cost comparison was made using posted prices. The nutritional quality of foods was distinguished using the clues of the ND nutrition education programme for elementary-school children and validated using the Overall Nutritional Quality Index.

SETTING

Supermarkets in Jackson County, MO, USA.

SUBJECTS

Not applicable.

RESULTS

The average price of the item for more nutritious foods did not differ significantly from that of less nutritious foods overall ($US 2·89 (sd $US 0·74) v. $US 2·85 (sd $0·68), P = 0·76). More nutritious breads cost more than less nutritious breads ($US 3·36 (sd $ US 0·28) v. $US 2·56 (sd $US 0·80, P = 0·03), whereas more nutritious cereals ($US 2·46 (sd $US 0·69) v. $US 3·50 (sd $US 0·30), P < 0·01) and cookies ($US 2·76 (sd $US 0·50) v. $US 3·40 (sd $US0·28), P < 0·01) cost less.

CONCLUSIONS

Our findings indicate that it is possible to choose more nutritious foods within many common categories without spending more money and suggest that making small improvements in dietary choices does not invariably cost more.

Diet cost, diet quality and socio-economic position: how are they related and what contributes to differences in diet costs?

OBJECTIVE

To examine diet costs in relation to dietary quality and socio-economic position, and to investigate underlying reasons for differences in diet costs.

DESIGN

Dietary intake was assessed by a 4 d food diary and evaluated using the 2005 Healthy Eating Index (HEI). National consumer food prices collected by Statistics Sweden and from two online stores/supermarkets were used to estimate diet costs.

SETTING

Sweden.

SUBJECTS

A nationally representative sample of 2160 children aged 4, 8 or 11 years.

RESULTS

Higher scores on the HEI resulted in higher diet costs and, conversely, higher diet costs were linked to increased total HEI scores. Children who consumed the most healthy and/or expensive diets ate a more energy-dilute and varied diet compared with those who ate the least healthy and/or least expensive diets. They also consumed more fish, ready meals and fruit. Regression analysis also linked increased food costs to these food groups. There was a positive, but weak, relationship between HEI score and diet cost, parental education and parental occupation respectively.

CONCLUSIONS

Healthy eating is associated with higher diet cost in Swedish children, in part because of price differences between healthy and less-healthy foods. The cheapest and most unhealthy diets were found among those children whose parents were the least educated and had manual, low-skill occupations. Our results pose several challenges for public health policy makers, as well as for nutrition professionals, when forming dietary strategies and providing advice for macro- and microlevels in society.

Are socio-economic disparities in diet quality explained by diet cost?

BACKGROUND

Socio-economic disparities in nutrition are well documented. This study tested the hypothesis that socio-economic differences in nutrient intakes can be accounted for, in part, by diet cost.

METHODS

A representative sample of 1295 adults in King County (WA) was surveyed in 2008-2009, and usual dietary intakes were assessed based on a food-frequency questionnaire. The monetary value of individual diets was estimated using local retail supermarket prices for 384 foods. Nutrients of concern as identified by the 2005 Dietary Guidelines Advisory Committee were fibre, vitamins A, C and E, calcium, magnesium and potassium. A nutrient density score based on all seven nutrients was another dependent measure. General linear models and linear regressions were used to examine associations among education and income, nutrient density measure and diet cost. Analyses were conducted in 2009-2010.

RESULTS

Controlling for energy and other covariates, higher-cost diets were significantly higher in all seven nutrients and in overall nutrient density. Higher education and income were positively and significantly associated with the nutrient density measure, but these effects were greatly attenuated with the inclusion of the cost variable in the model.

CONCLUSIONS

Socio-economic differences in nutrient intake can be substantially explained by the monetary cost of the diet. The higher cost of more nutritious diets may contribute to socio-economic disparities in health and should be taken into account in the formulation of nutrition and public health policy.

Relation of food cost to healthfulness of diet among US women

BACKGROUND

Few studies have evaluated the cost of a diet that may prevent cardiovascular disease. High scores on the Alternative Healthy Eating Index (AHEI) have been associated with lower rates of cardiovascular disease.

OBJECTIVE

We sought to evaluate the cost of a dietary pattern that may prevent cardiovascular disease among women residing in the United States.

DESIGN

By using food-cost data from the US Department of Agriculture, we explored relations between spending on food and AHEI scores among 78,191 participants in the Nurses' Health Study. By using linear regression, we estimated the change in AHEI score (range: 2.5-87.5) for a $1 increase in spending on various food groups.

RESULTS

Study participants in the highest energy-adjusted spending quintile spent 124% as much money each day as those in the lowest quintile. The difference in AHEI scores (10th-90th percentile) between all study participants was 30 index points (Spearman's correlation coefficient between total spending and AHEI = 0.44). The difference in AHEI scores (10th-90th percentile) within each quintile of spending ranged from 25 to 29 index points. Greater spending on nuts, soy and beans, and whole grains was associated with a higher AHEI score. Greater spending on red and processed meats and high-fat dairy was associated with a lower AHEI score.

CONCLUSIONS

Although spending more money was associated with a healthier diet, large improvements in diet may be achieved without increased spending. The purchase of plant-based foods may offer the best investment for dietary health.

Maternal dietary counseling in the first year of life is associated with a higher healthy eating index in childhood

Food preferences are established in early childhood and track later in life. Therefore, it is important to promote healthy feeding practices as early as possible. A randomized field trial was conducted with 500 mother-child pairs from a low-income area of São Leopoldo, State of Rio Grande do Sul, Brazil, to evaluate the impact of a nutritional intervention in the first year of life on the dietary quality of 3- to 4-y-old children. Mother-child pairs were randomized either to intervention and control groups and dietary counseling was provided for mothers in the intervention group during 10 home visits in the course of the first year of life. These visits were carried out by fieldworkers who counseled the mothers about the Ten Steps for Healthy Feeding from Birth to Two Years of Age, based on the WHO guidelines. Dietary intake was assessed at 3-4 y of age for 345 children using two 24-h food recalls. Overall diet quality was determined by the Healthy Eating Index. The prevalence of poor diet in the intervention group was lower compared with the control group [relative risk (RR) = 0.30; 95% CI = 0.13-0.71). The number of children who achieved the 75th percentile for the vegetable and fruit component score was higher in the intervention than in control group (RR = 1.95; 95% CI = 1.31-2.89 and RR = 1.49; 95% CI = 1.07-2.07, respectively). Such data provide evidence that dietary counseling for mothers during the first year of life improves the overall dietary quality of children in a low-income population.

The cost of US foods as related to their nutritive value

BACKGROUND

Comparisons of the cost of different foods relative to their energy and nutritive value were conducted in the 1800s by the US Department of Agriculture (USDA).

OBJECTIVE

The objective was to reestablish the relations between food cost, energy, and nutrients by using contemporary nutrient composition and food prices data from the USDA.

DESIGN

The USDA Food and Nutrient Database for Dietary Studies 1.0 (FNDDS 1.0) and the Center for Nutrition Policy and Promotion food prices database were used for analysis. For 1387 foods, key variables were as follows: energy density (kcal/g), serving size (g), unit price ($/100 g), serving price ($/serving), and energy cost ($/kcal). A regression model tested associations between nutrients and unit price ($/100 g). Comparisons between food groups were tested by using one-factor analyses of variance. Relations between energy density and price within food groups were tested by using Spearman's correlations.

RESULTS

Grains and fats food groups supplied the lowest-cost dietary energy. The energy cost for vegetables was higher than that for any other food group except for fruit. Serving sizes increased with water content and varied inversely with energy density of foods. The highest prices per serving were for meats, poultry, and fish, and the lowest prices per serving were for the fats category. Although carbohydrates, sugar, and fat were associated with lower price per 100 g, protein, fiber, vitamins, and minerals were associated with higher price per 100 g, after adjustment for energy.

CONCLUSIONS

Grains and sugars food groups were cheaper than vegetables and fruit per calorie and were cheaper than fruit per serving. These price differentials may help to explain why low-cost, energy-dense foods that are nutrient poor are associated with lower education and incomes.

Dietary patterns of obese high school girls: snack consumption and energy intake

In order to develop an obesity management program for teenagers, we compared obese and non-obese girls attending high schools in terms of their dietary practices related to snack consumption. Dietary records were collected for 7 days. No significant differences were found for the average daily energy intake between obese and non-obese girls. However, the highest energy intake was greater for obese girls while not much difference was found for the lowest amount of energy intake. Obese girls had significantly lower intakes in calcium (P < 0.01), vitamin A (P < 0.001) and folate (P < 0.01). Mean energy intake from snack (594.1 ± 312.1kcal) was significantly higher for obese girls than for non-obese girls (360.1 ± 173.1kcal) (P < 0.001). A significant, positive correlation was observed between energy intake from snack and total daily energy intake (r = 0.34 P < 0.01) only for obese girls. In case of dietary behaviors, obese adolescent girls consumed significantly greater number of items for snacks and fewer foods for regular meals compared to non-obese girls (P < 0.05). This study suggested that obesity management programs for adolescents should focus on providing strategies to reduce snack through enhancing balanced regular meals.

Study of Use of Products and Exposure-Related Behaviors (SUPERB): study design, methods, and demographic characteristics of cohorts

BACKGROUND

Exposure to toxic chemicals in the home is a growing concern. This report presents an overview of the recruitment, methods for data collection, instruments used to collect data, and participant demographics for a study examining behaviors that influence exposure to environmental toxins in the home environment, also known as SUPERB (Study of Use of Products and Exposure Related Behaviors).

METHODS

The methods involved three different platforms: telephone interviews, internet-based surveys, and home-based monitoring. The purposes of SUPERB were: first, to compare data collection platforms with regard to feasibility, acceptability and reliability; and second, to provide longitudinal population-based data characterizing seasonal and long-term changes in exposure-related behaviors including food consumption, temporal-spatial activity, and household product use.

RESULTS

Two cohorts of households were enrolled: families (one parent and one child) from northern California and older individuals (age 55+) from central California. Parents (n = 499) in Northern California families were on average 36 years of age, 47.1% were Latino or nonwhite, and 10.2% took the survey in Spanish. Most of the children enrolled (n = 566) were under 6 years (82.7%). The older adults enrolled (n = 156) were, on average, 66 years of age and 23.7% were Latino or nonwhite, but only 2.6% completed the survey in Spanish.

CONCLUSIONS

We found that oversampling was successful in improving recruitment of under-represented subgroups, such as those with low education, thereby increasing diversity of our study sample. Protocols that minimize participant time, e.g., use of bar scanners and scales rather than questionnaires regarding use of household products, and the implementation of these protocols by staff who built relationships of trust, resulted in high retention over a longitudinal data collection scheme. A relatively small fraction of those who volunteer for longitudinal internet surveys are consistent in filling them out. Future reports will provide critical information on cross-sectional, seasonal and longitudinal patterns of exposure related behaviors in young children, parents of young children, and older adults.

Are the lowest-cost healthful food plans culturally and socially acceptable?

OBJECTIVE

Nutritious yet inexpensive foods do exist. However, many such foods are rejected by the low-income consumer. Is it because their use violates unspoken social norms? The present study was designed to assess the variety and cost of the lowest-cost market basket of foods that simultaneously met required dietary standards and progressively stricter consumption constraints.

DESIGN

A mathematical optimisation model was used to develop the lowest-cost food plans to meet three levels of nutritional requirements and seven levels of consumption constraints.

SUBJECTS

The nationally representative INCA (National Individual Survey of Food Consumption) dietary survey study of 1332 adults provided population estimates of food consumption patterns in France. Food plan costs were based on retail food prices.

RESULTS

The lowest-cost food plans that provided 9204 kJ/d (2200 kcal/d) for men and 7531 kJ/d (1800 kcal/d) for women and met specified dietary standards could be obtained for <1.50 euro/d. The progressive imposition of consumption constraints designed to create more mainstream French diets sharply increased food plan costs, without improving nutritional value.

CONCLUSIONS

Minimising diet costs, while meeting nutrition standards only, led to food plans that provided little variety and deviated substantially from social norms. Aligning the food plan with mainstream consumption led to higher costs. Food plans designed for low-income groups need to be socially acceptable as well as affordable and nutritious.