Potential nutritional and economic effects of replacing juice with fruit in the diets of children in the United States

Abstract

Context

Dietary guidance for children emphasizes fruit over fruit juices but little is known about the potential nutritional and economic impact of substituting fruit for juice.

Objective

To estimate the nutritional and economic effects of substituting whole fruit for juice in the diets of children in the US.

Design

Secondary analyses using the 2001-2004 National Health and Nutrition Examination Survey (NHANES) and a national food price database. Energy, nutrient intakes and diet cost were estimated before and after fruit juices were completely replaced with fruit in three models that emphasized fruits that were fresh, low-cost, and widely-consumed and a fourth model that partially replaced juice with fruit, capping juice at recommended levels.

Setting

A nationwide, representative sample of children in the US.

Participants

7,023 children ages 3-18.

Main Outcome Measures

Difference in energy, nutrient intakes and diet cost between observed and modeled diets.

Results

For children who consumed juice, replacement of all juice servings with fresh, whole fruit led to a projected reduction in dietary energy of 233 kJ/day (−2.6% [95% CI −5.1, −0.1%]), an increase in fiber of 4.3 grams/day (+31.1% [95% CI 26.4, 35.9%]) and an increase in diet cost of $0.54/day (+13.3% [95% CI 8.8, 17.8%]).

Conclusions

Substitution of juice with fresh fruit has the potential to reduce energy intake and improve the adequacy of fiber intake in children’s diets. This would likely increase costs for schools, childcare providers and families. Cost impacts could be minimized by selecting processed fruits but fewer nutritional gains would be achieved.

Introduction

One hundred percent fruit juice (FJ) makes up a substantial part of the total fruit intakes of children and is a major contributor to their total nutrient intake¹. However, FJs have energy densities similar to sugar-sweetened beverages and might contribute to excess energy intake², overweight³ and weight gain⁴. The evidence linking FJ with overweight is mixed, a point that was acknowledged by the Dietary Guidelines Advisory Committee (DGAC)⁵. Nevertheless, the 2010 Dietary Guidelines recommended that no more than half of total fruit servings be in the form of FJ, based on the suggestion that whole fruits confer greater health benefits.

This recommendation placed the Dietary Guidelines in line with previous recommendations from the American Academy of Pediatrics to limit FJs and encourage fruit⁶. Those recommendation drove the suggested changes to the Special Supplemental Nutrition Program for Women Infants and Children, which reduced FJ and introduced a fruit and vegetable benefit⁷. More recently, the Institute of Medicine’s recommendations for improving school meals⁸ and the Child and Adult Care Food Program⁹ both prioritized whole fruit over FJ.

Little quantitative information exists about the potential nutritional effects of substituting fruit for FJ in the diets of children under current eating patterns. Substituting whole fruit for FJ might reduce energy content of the diet while increasing intake of fiber^10-12. Substitution might also drive up food costs, given that FJs are often more affordable than fresh fruits¹³. Thus the complete substitution of whole fruit for juice has the potential to substantially change and improve the nutrient intakes of children while at the same time increasing costs for schools, childcare providers and families. Accordingly, nutrition recommendations and policies need to take into account potential costs as well as benefits. This study used data from the National Health and Nutrition Examination Survey (NHANES) to examine the potential nutritional benefit and economic costs of substituting fruit for FJ in the diets of US children.

Methods

Subjects

Our analyses were based on children and adolescents (3-18y) who completed a valid 24-hour recall during either of two cycles of the NHANES: 2001-02 and 2003-04. We analyzed these two cycles of NHANES since they allowed us to link quantities of foods and beverages consumed to MyPyramid equivalent servings (see below). These releases also allowed us to link each food and beverage consumed with nationally representative food prices, through a database described below. Adolescent girls who were pregnant, based on self-report or positive pregnancy test, were excluded (n=70). The use of this existing, publicly available dataset did not qualify as “human subjects research” and was exempt from human subjects review by the University of Washington IRB.

Dietary Assessment in NHANES

All examined survey participants are eligible to participate in the dietary interview, the protocol and methods of which are fully documented elsewhere¹⁴. Dietary intakes were based on a single 24-hour dietary recall. NHANES staff monitored interviewers and developed criteria to determine the acceptability of each recall¹⁰.

For children 12 and older the child was the primary source of dietary recall information, but could be assisted by an adult who had knowledge of their diet. For children 6-11 the child was the primary respondent, but the proxy was present and able to assist. For children under 6, dietary recall interviews were conducted by proxy¹⁰.

Fruit Juice Classification

We identified FJs from the individual foods file, defining them as beverages with a 1-digit USDA prefix code of 6 (USDA fruit category), that contained the word “juice” in their short description and that contained no added sugars from the MyPyramid Equivalents database. Fruit nectars and vinegars, sugar-sweetened fruit drinks and fruit juice drinks are included in the USDA fruit food grouping but were not defined as FJs in the present analysis. FJ servings less than 60 grams (approximately 2 fluid ounces) were excluded from the analysis, since such small servings may be used in recipes and are not likely to represent opportunities for substitution. This exclusion eliminated 32 instances of juice consumption by children and adolescents age 3-18 years.

Diet Cost

The methods for deriving the monetary cost of diets in the NHANES rely on merging the dietary recalls with nationally representative food prices released by the Center for Nutrition Policy and Promotion¹⁵. The analytic procedures have been described previously¹⁶. We computed diet cost from each individual’s dietary recall by multiplying the price per gram with the portion of each food consumed by the respondent and then summing these values for each participant. Diet cost estimations were based on all foods and beverages reported, excluding tap water, bottled water and alcoholic beverages.

Substitution Models

The key feature of this study was the systematic replacement of FJ with fruit under four different scenarios, described below. Fresh and prepared fruits including canned, frozen and dried options were eligible for substitution in place of FJ. Prepared fruits containing added sugars were not eligible for inclusion. In some cases this exclusion removed frequently consumed canned and frozen fruits (e.g., canned peaches in syrup). The quantity of fruit used in the substitution models was dependent on the quantity of FJ reported in the recall. All four substitution models replaced FJs with equal portion sizes of fruit using MyPyramid equivalents of fruit servings¹⁷. It should be noted that weight of MyPyramid servings vary depending on the food or beverage. For example, a single MyPyramid fruit serving of fresh, raw apple is 106g while the same serving of raw orange is 184g.

The first three models replaced all servings of FJ with fruit, differing only on the type of fruit that was substituted. The first model replaced each FJ with the fresh, intact form of the same or similar fruit (e.g., apple for apple juice). For mixed FJs with specified ingredients the first ingredient was used. For mixed FJs with non-specified ingredients or juices without a relevant fresh equivalent, such as cranberry juice, apples were used since apples are both an important ingredient in blended FJ and the most frequently consumed whole fruit. The second model recognized economic constraints and identified the lowest cost equivalent of the FJ consumed. The lowest cost option was identified in the food prices database as the lowest cost per gram. Examples include applesauce (no sugar added) for apple juice or canned oranges for orange juice. In some cases (e.g., grapes) the replacements for the first two models were the same. A third model recognized social norms, by substituting each FJ serving with the most frequently consumed raw fruits: apple, orange or banana. Each FJ serving was randomly assigned one of these replacements at a 1/3 probability.

A fourth model only replaced servings of FJ that were in excess of amounts recommended by the American Academy of Pediatrics⁶. This value was 4 fl oz for young children (age 3-6) and 8 fl oz for older children (age ≥7). Energy and nutrients were included from the FJ up to the amount allowed. Random allocation of apple, orange and banana were applied to the excess amount of FJ consumed. The random allocation was used since many children consumed different types of juice. The features of the four models are summarized in Table 1.

Table 1. Whole fruit for juice substitution models.

Model	Approach	Example: 248 g Apple Juice (MyPyramid serving) consumed by a 5 year old child
1	Full substitution Fresh equivalent	106g Apple, raw
2	Full substitution Lowest cost	244g Applesauce, unsweetened
3	Full substitution Most common	136g Banana, raw (weight = 0.33) 106g Apple, raw (weight = 0.33) 184g Orange, raw (weight = 0.33)
4	Partial substitution Most common1	124g Apple juice + 53g Apple, raw

Portions for juices servings replaced at a 1:1 ratio with fruit based on MyPyramid equivalents.

¹Fruit replaces only fruit juice amounts greater than 4 fl oz for children 3-6 years and 8 fl oz for children and adolescents age ≥ 7 years, following recommendations from the American Academy of Pediatrics ⁶.

Outcome measures and statistical analysis

The population effects of substitution were examined for all children and separately for juice consumers (children consuming ≥ 60 grams on their recall day). Survey-weighted means were estimated for diet composition and cost for the observed data and the four substitution models. Age-specific models were also evaluated using three age groups (3-5, 6-11, and 12-18). Diet composition effects of substitution were quantified for energy (kilojoules), dietary weight (grams) and four nutrients. Three of the nutrients, dietary fiber, potassium and calcium, are shortfall nutrients in the diets of children⁵. Vitamin D is also a shortfall nutrient but was not available in the nutrient database linked to these releases of NHANES. Although not a shortfall nutrient among children, vitamin C effects were also examined as FJs are an important source for this nutrient¹⁸.

Statistical analyses focused on determining whether the substitution models resulted in a substantive change in nutrient intake. This approach was used since the nature of our models imposed a change in nutrient intake and diet cost. For nutrients, a 10% daily value threshold was used to represent a change of public health significance (2.5 g for fiber, 350 mg for potassium, 100 mg for calcium and 6 mg for vitamin C). A 10% change in cost was the threshold value for diet cost. For energy, there is little consensus on what warrants a substantive change, so model effects were reported and no hypothesis testing was done. A survey-weighted Wald test was used for all statistical testing following the estimation of survey-weighted means. This approach fully accounted for the complex nature of NHANES data. All analyses used Stata 11.0 (College Station, TX).

RESULTS

Sample characteristics

Valid dietary recalls were available for 7023 of the 7756 respondents aged 3-18y over both survey cycles. The characteristics of the weighted sample for all 7023 respondents are shown in Table 2.

Table 2. Demographic characteristics of children aged 3-18 years in NHANES 2001-04.

	Total Sample		Juice Consumers1		Non-Consumers
	N	Weighted %	N	Weighted %	N	Weighted %
Total	7,023	100.0	2,385	33.4	4638	66.6
Age Group (years)
3 – 5	1,050	17.6	512	26.6	538	13.1
6 – 11	2,036	37.4	776	39.3	1,260	36.4
12 – 18	3,937	45.0	1,097	34.1	240	50.5
Race/ethnicity
Non-Hispanic white	2,078	62.9	605	57.7	1,473	65.4
Non-Hispanic black	2,371	15.3	885	18.2	1,486	13.9
Mexican American/Other Hispanic	2,366	17.2	829	20.3	1,537	15.6
Other/mixed race	208	4.7	66	3.9	142	5.1
Income to poverty ratio
< 2	3,931	46.8	1,362	46.7	2,569	45.3
2 – 3.99	1,663	29.9	501	26.2	1,162	31.8
≥ 4	1,068	23.3	379	24.1	689	22.9
Missing	361		143		218

¹Juice consumers defined by intake of at least one portion (> 60g) of 100 percent fruit juice.

Consumption of 100% fruit juice

For the single 24h recall, at least one serving (>60g) was reported by 33.4% of the total child sample across both survey years. 17.8% of children consumed more than the recommended amounts of fruit juice (4 oz for age 3-6 and 8 oz for age ≥ 7). For all children 3-18y, FJs accounted for 46% of MyPyramid servings of total fruit in the diet. The share varied by age, with FJ contributing 49, 44 and 46% of the total fruit servings for children 3-5, 6-11 and 12-18 years, respectively. The mix of 100% fruit juices consumed was dominated by a few varieties, with orange, apple, unspecified fruit juice blends and grape, accounting for 52.6, 27.5, 10.0, and 5.7 percent of all juices consumed, respectively (95.8% total). Mixed vegetable juice, carrot and tomato made up only 1.1% of all juices combined.

Substitution effects on energy and nutrient intakes

For the overall sample of children, all substitution models lowered dietary energy and dietary mass. Fiber was increased in all four models but vitamin C, potassium and calcium were reduced to varying extents. The results of the four models and the observed dietary characteristics for the overall sample are shown in Table 3.

Table 3. Observed and projected differences (95% confidence intervals) for energy, nutrients and diet costs among children in the United States. All children (n=7,023) and juice consumers only (n=2,385).

	Observed	Model 1 Fresh equivalent	Model 2 Lowest cost	Model 3 Most common	Model 4 Capped	Benchmark for effects1
Energy Intake (kJ) 1
All children	8830 (8689, 8970)	−77 (−85, −70)	−26 (−29, −23)	−52 (−57, −46)	−22 (−27, −17)	N/A
Juice consumers only	8986 (8761, 9211)	−233 (−252, −214)	−80 (−87, −72)	−155 (−169, −141)	−67 (−81, −53)
Dietary Fiber (g)
All children	12.8 (12.5, 13.2)	1.4 (1.3, 1.6)	1.2 (1.1, 1.3)	1.5 (1.3, 1.6)	0.6 (0.5, 0.7)	>2.5 g or
Juice consumers only	13.7 13.2, 14.2)	4.3 (4.0, 4.6)‡	3.5 (3.3, 3.7)‡	4.4 (4.1, 4.7)‡	1.8 (1.6, 2.1)	<−2.5 g
Potassium (mg)
All children	2305 (2230. 2380)	−65 (−71, −59)	−49 (−54, −44)	−30 (−37, −24)	−14 (−19, −9)	>350 mg or
Juice consumers only	2724 (2633, 2814)	−195 (−209, −180)	−147 (−158, −136)	−91 (−108, −73)	−41 (−55, −27)	<−350 mg
Calcium (mg)
All children	1005 (966, 1044)	−4 (−7, −1)	−14 (−17, −11)	−10 (−13, −7)	−3 (−5, −2)	>100 mg or
Juice consumers only	1071 (1017, 1125)	−13 (−22, −3)	−43 (−53, −33)	−31 (−40, −21)	−10 (−15, −5)	<−100 mg
Vitamin C (mg)
All children	86 (81, 91)	−3 (−5, −2)	−7 (−8, −6)*	−11 (−13, −9)‡	−4 (−5, −3)	>6 mg or
Juice consumers only	144 (136, 152)	−10 (−13, −7)*	−22 (−25, −19)‡	−34 (−38, −28)‡	−12 (−16, −9)†	<−6mg
Diet Cost ($)
All children	3.87 (3.78, 3.97)	0.18 (0.15, 0.22)	0.02 (0.01, 0.03)	0.09 (0.08, 0.11)	0.05 (0.04, 0.07)	>$0.3872
Juice consumers only	4.08 (3.95, 4.22)	0.54 (0.46, 0.63)†	0.06 (0.04, 0.09)	0.28 (0.24, 0.32)	0.15 (0.11, 0.20)

¹Benchmarks for nutrients are based on 10% daily values.

²10% of average diet cost for children

^*indicates p<0.05,

^†indicates p<0.01,

^‡indicates p<0.001 comparing the difference between the models to the benchmark value on the right-hand side of the table.

Model 1, in which FJ was substituted with the fresh fruit equivalent, showed the largest reduction of energy. For children who had reported consuming FJ, Model 1 showed a mean reduction in energy intake of 2.6% compared to observed diets. Model 2, the cost-sensitive substitution, showed the weakest energy effects, with a reduction of 0.9% compared to observed diets. Fiber effects showed a similar hierarchy across models, with the largest increase in Model 1 (+31.1%) and a more moderate increase in Model 2 (+25.5%). Model 4 had the smallest increase in fiber among juice consumers (+13%). Across the four models, vitamin C was reduced by small amounts in Model 1 (−7.1%) and 4 (−8.3%) and the greatest reduction in Model 3 (−23.3%). However the trend was reversed for potassium, which was reduced the least by Model 4 (−1.5%) and Model 3 (−3.3%) and the most by Model 1 -7.1% from observed), due to the inclusion of bananas in Models 3 and 4. Model 2 affected calcium intake the most (−4.0%) and Model 4 the least (−0.9%) relative to observed.

We further examined the effects of Model 1 on three age strata of children who consumed FJ (3-5, 6-11, 12-18y). Results for Model 1 across the three age groups did not differ markedly. The largest effect on dietary energy, in terms of percentage change, was observed in children 3-5 years, resulting in a mean change of −248 kJ/day (−3.3%) in total dietary energy. Effects were smallest for children 12-18 years, who showed a −2.3% change. Fiber effects were largest for children 12-18 (+34.9%) and smallest for children 6-11 (+27.5%).

Substitution effects on diet cost

All of the substitution models resulted in an increase in estimated diet cost. Of the four models, Model 1 showed the largest monetary effects, with a 13.3% increase in diet cost per day relative to observed diets. Model 2 was specifically designed to minimize the monetary impact of switching from FJ to fruit, resulting in a 1.5% increase. Model 3 showed intermediate effects; with a 6.9% increase in diet cost. Model 4 showed an increase in cost of 3.7%.

The age-specific effects on diet cost differed across the three age strata. Implementing Model 1 for children 12-18 brought the largest increase in diet cost (17.1%). Model 1 effects on diet cost were smallest for children 3-5: 10.0%.

Discussion

The diet simulations presented here indicate that replacing all servings of FJs with fruit has the potential to reduce energy intake and raise intakes of dietary fiber. These findings are consistent with previous analyses commissioned by the Dietary Guidelines Advisory Committee, which showed that replacing FJs with fruit reduced the content of energy and some nutrients in model food patterns¹². Based on the present findings, replacing juice with a variety of fresh whole fruit (Model 1) would have the greatest impact on energy intake, resulting in a reduction in energy intake of 233 kJ (56 kcal) per day. Such a reduction, if sustained, could translate to a reduction in body weight of over 2.3 kg (5 pounds) per year, assuming no compensatory increases in energy intake from other sources¹⁹. This assumption might be realistic given that fresh, whole fruits are low in energy density and high in fiber and are associated with greater satiety than juice ^{11, 20}. This projected energy reduction is roughly half of the estimated 460 kJ (110 kcal) excess in energy intake driving weight gain in children²¹.

Weight and weight gain in children and adolescents were not systematically associated with FJ consumption, according to a recent, comprehensive review²². Irrespective of body weight associations, intake of FJs has been associated with higher overall dietary energy intake² and based on data from 1999-2004 NHANES, FJs contributed between 7 and 9% to the total dietary energy intakes of children who reported consuming fruit juice²³. Replacing FJs with fruit could potentially reduce overall energy intake.

However, this replacement can also reduce intakes of potassium and vitamin C. Vitamin C was not identified as a shortfall nutrient for children by the DGAC, and our analyses indicated that the mean and median level of consumption for juice consumers exceeded the dietary reference intake (25-75mg). Children did fall short of recommended intakes for potassium, and replacing juice with fruit led to a greater shortfall for this nutrient. Potassium decreased because the most frequently consumed FJs (e.g., orange juice and apple juice) contained significantly more potassium per serving than fruits used to replace these juices.

Replacing juice with fruit also in our models led to higher diet costs. Cost is one of several factors that may explain the preponderance of juice in the diets of children. In 2004-05, FJs and juice drinks made up over half of the MyPyramid fruit servings for children²⁴. Fresh, whole fruit (and fresh produce in general) are among the most costly sources of dietary energy²⁵ and FJs provide a lower cost per serving and more nutrients per dollar than many fresh fruits¹³.

Of the three full replacement models (Models 1-3) food costs were best controlled in Model 2, which relied on the lowest-cost fruit equivalent of each juice serving reported. The fruits in this model were typically canned or otherwise processed, indicating that these options provide an avenue for institutions and families switch from juice to fruit while respecting cost constraints. However, it should be noted that Model 2 resulted in the smallest decrease in energy, increase in fiber and largest decrease in calcium.

A minimal cost effect was also observed in Model 4, which conformed to recommendations for limits on FJ from the American Academy of Pediatrics⁶. While this scenario generally resulted in the least reduction of nutrient intakes relative to observed, it also produced the smallest reduction in energy.

This study had a number of limitations. First, the effects of FJ substitution on dietary intakes are entirely projected, based on systematic complete or partial replacement of 100 percent fruit juices with fruit, with quantities scaled using MyPyramid portions sizes. As such, our findings represent an estimation of the maximal efficacy of implementing recommendations to replace juice with fruit. Implementation of nutrition recommendations is often most feasible within institutions such as schools and childcare settings. Based on 2003-2004 NHANES, approximately 9% of fruit servings from FJ were from school cafeteria or childcare settings, indicating that replacing juice with fruit only in these settings is not likely to have a substantial impact at the population level. A second limitation is that our models did not explore other potential substitution scenarios that might have also improved nutrition. For example, replacing juice drinks and other sugar sweetened beverages with fruit would further reduce total energy intake while reducing consumption of added sugars. Third, the monetary cost of substituting fruit for FJ was based on a single, nationally-representative database of food prices that could not account for regional variations in food prices ²⁶ and hence differences in the cost of making the substitutions described here. Finally, other factors that might favor FJs over fruit were not taken into account in these models.

Other factors that might drive a preference for FJs over fruit include ease of storage, preparation and portioning for institutions such as schools and childcare centers²⁷, and the cost of food wasting from fruit that is overripe. FJs may be more convenient for parents and caregivers who have little time to prepare food and look for easy and quick options^{28, 29}.

Conclusions

Complete replacement of juice with variety of whole, fresh fruits has the potential to reduce dietary energy intake and increase intake of dietary fiber by children. These benefits might come at the cost of lower intakes of some vitamins and minerals and higher food costs. Studies using national surveillance data may be useful in assessing the potential benefits- and costs- of dietary recommendations and nutrition policies.