More Americans are eating "5 a day" but intakes of dark green and cruciferous vegetables remain low

Orange juice ingestion and supplemental vitamin C are equally effective at reducing plasma lipid peroxidation in healthy adult women

OBJECTIVE

To directly examine the contribution of vitamin C to the antioxidant potential of fruits and vegetables, the antioxidant effect of orange juice consumption (8 and 16 fl. oz.) was compared to the antioxidant effect of supplemental vitamin C (dosage equivalent to that supplied by 8 fl. oz. of orange juice).

METHODS

Subjects (n = 11; 28.6 +/- 2.1 years) received each treatment in a 3 x 3 randomized crossover design, and each two-week treatment was preceded by a two-week washout. During the entire trial, subjects restricted fruit and vegetable consumption to < or =3 servings per day except the vitamin C-rich foods (items containing >20 mg/serving), which were restricted to < or =3 servings per week. A fasting blood sample was collected at the end of each washout and each treatment period.

RESULTS

Following washouts, plasma vitamin C and lipid peroxidation (plasma TBARS) were similar by treatment group and averaged 25.4 +/- 3.6 micromol/L and 3.82 +/- 0.10 nmol/mL respectively. Plasma vitamin C concentrations were similar following each treatment period, 37.9 +/- 8.1, 45.8 +/- 9.4, and 38.3 +/- 12.4 micromol/L for the 8 and 16 fl. oz. orange juice treatments and the supplement treatment, respectively. All intervention treatments reduced plasma TBARS as compared to pretreatment values: -47% (p = 0.013), -40% (p = 0.083), and -46% (p = 0.015) for the 8 and 16 fl. oz. orange juice treatments and supplement treatment respectively.

CONCLUSIONS

These data indicate that the regular consumption of 8 fl. oz. orange juice or supplemental vitamin C ( approximately 70 mg/day) effectively reduced a marker of lipid peroxidation in plasma.

A "contract for change" increases produce consumption in low-income women: a pilot study

This study determined whether a "Contract for Change" goal-setting exercise enhanced the effectiveness of the Expanded Food and Nutrition Education/Food Stamp Nutrition Education programs to increase produce consumption in low-income (<130% of poverty) women after 4 weeks. Thirty-eight participants were randomized in this three-group parallel arm study: (a) control group participants received life-skills lessons, (b) the education group received the Expanded Food and Nutrition Education/Food Stamp Nutrition Education "Food Guide Pyramid" lessons, and (c) the contract group also received the "Food Guide Pyramid" series and completed a "Contract for Change." It was hypothesized that the contract group would have the greatest increases in advancement toward dietary change and produce consumption. Compared with controls, the contract group significantly moved toward acceptance of vegetable consumption (P < or = .05). Compared with the education group, the contract group significantly increased fruit consumption. Results suggest that nutrition professionals can effectively use goal-setting to assist low-income populations with dietary change.

Cruciferae interact with the UGT1A1*28 polymorphism to determine serum bilirubin levels in humans

UDP-glucuronosyltransferase (UGT) 1A1 is a conjugating biotransformation enzyme that plays a role in maintaining levels of endogenous compounds (e.g., bilirubin) and handling exogenous compounds, including carcinogens. The UGT1A1*28 polymorphism results in decreased UGT1A1 promoter activity due to 7 thymine-adenine (TA) repeats instead of the commonly found 6 repeats. Studies indicate that foods from the botanical families Cruciferae (e.g., broccoli), Rutaceae (citrus), Liliaceae (e.g., onions), and Leguminosae (legumes) may increase UGT activity. We investigated, in an observational study, whether foods from these botanical groups were associated with increased UGT1A1 activity as indicated by serum bilirubin concentrations and whether the effect varied by UGT1A1*28 genotype, comparing those homozygous for the [TA](7)-repeat allele (7/7) to homozygous wild-types (6/6) and heterozygotes (6/7) combined. Healthy volunteers completed 3-d food records. Blood samples were drawn for genomic DNA collection and bilirubin measures. For total, direct, and indirect bilirubin measures, there was no significant association with any botanical group independently. There was a significant inverse association between all 3 bilirubin measures and interaction of UGT1A1*28 genotype with Cruciferae intake (P < 0.02 for each measure); individuals with the 7/7 genotype had reduced bilirubin concentrations with increased intake of cruciferous vegetables, whereas individuals with the 6/6 or 6/7 genotype did not. With regard to UGT1A1-conjugated carcinogens (e.g., heterocyclic amines, polycyclic aromatic hydrocarbons), individuals with decreased UGT1A1 activity due to the 7/7 genotype may be at greater risk for carcinogenesis, but our results imply that they also may have greater opportunity to decrease that risk through dietary intervention.

Fruit and vegetable intake in African Americans income and store characteristics

BACKGROUND

The purpose of this study was to examine whether the characteristics of retail food stores where African-American women shopped mediated the association between their income and intake of fruits and vegetables. Food store characteristics included store type (supermarket, specialty store, limited assortment store, independent grocer), store location (suburbs, city of Detroit), and perceptions of the selection/quality and affordability of fresh produce for sale.

METHODS

The analysis drew upon data from a probability sample of 266 African-American women living in 2001 in eastside Detroit, which had no supermarkets. Structural equation modeling was used to calculate a path model of direct and indirect effects.

RESULTS

Women shopping at supermarkets and specialty stores consumed fruit and vegetables more often, on average, than those shopping at independent grocers. More positive perceptions of the selection/quality, but not affordability, of fresh produce at the retail outlet where they shopped was positively associated with intake, independent of store type and location as well as age, per capita income, and years of education. The results suggested an indirect association between income and fruit and vegetable intake; women with higher per capita incomes were more likely to shop at supermarkets than at other grocers, which in turn was associated with intake.

CONCLUSIONS

Previous studies have shown that few supermarkets are located in the city of Detroit, a symptom of economic divestment over the past several decades. Results of this study suggest this may have negative implications for dietary quality, particularly among lower-income women.

Achieving substantial changes in eating behavior among women previously treated for breast cancer--an overview of the intervention

OBJECTIVE

To describe the intervention in a clinical trial examining the effect of a plant-based diet on breast cancer recurrence. To report baseline to 12-month dietary change and investigate whether cooking-class attendance influenced adherence to the study's dietary targets.

DESIGN

A descriptive analysis of baseline and 12-month dietary intake data and other variables from a subcohort of participants in the Women's Healthy Eating and Living Study.

SUBJECTS/SETTING

Seven hundred thirty-nine women (primarily non-Hispanic white and well educated) who had been treated for early stage breast cancer. All were intervention group participants and had adhered to the Women's Healthy Eating and Living Study counseling and dietary assessment protocols. Mean age at study entry was 54 years, and mean body mass index was 26.7.

INTERVENTION

Telephone counseling, complemented by an orientation meeting, cooking classes, and newsletters.

MAIN OUTCOME MEASURES

The change in intake of vegetables, vegetable juice, fruit, fiber, and fat between baseline and 12 months is reported, and the association between cooking classes attended and overall dietary adherence is examined.

STATISTICAL ANALYSES PERFORMED

Mean intake for vegetables, vegetable juice, fruit, fiber, and fat were calculated. Percentage of women meeting select Healthy People 2010 objectives were tabulated.

RESULTS

Total daily vegetable, vegetable juice, fruit, and fiber intake increased significantly (P <.01), while fat decreased significantly (P <.01). The percentage of women meeting the Healthy People 2010 fruit and vegetable objectives increased substantially. Overall dietary adherence was associated with increased cooking-class attendance (P for trend <.01).

CONCLUSIONS

A multimodal approach to dietary modification, based largely on individualized telephone counseling, can substantially change the overall dietary pattern of women previously treated for breast cancer.

Carbohydrates and increases in obesity: does the type of carbohydrate make a difference?

With the prevalence of obesity increasing in the U.S. and elsewhere, the place of carbohydrates in the diet has recently been under closer examination. This has led to the development of methods for analyzing the effects of dietary carbohydrate. Primary among these methods is the glycemic index, a measure of a food's effect on blood glucose levels, which was initially designed as a method for determining suitable carbohydrates for people with diabetes. However, the glycemic index does not address other metabolic issues related to excess sugar consumption. Prominent among these issues is the use of low glycemic index sweeteners, particularly fructose, which is increasingly present in processed food. Fructose is associated with increased adiposity, which may result from its effects on hormones associated with satiety. Other methods of determining "good" carbohydrates have also been developed. The common theme among them is increased nonstarchy vegetables and higher-fiber legumes.

Changes in dietary intake after diagnosis of breast cancer

OBJECTIVE

To quantify change in intake of kilocalories, macronutrients, and fruit and vegetable servings after diagnosis of breast cancer, and to correlate these changes with subject characteristics and with self-reported global change in dietary patterns.

DESIGN

Food frequency questionnaires were completed by women newly diagnosed with breast cancer shortly after diagnosis. They were asked to recall intake 1 year before diagnosis. Two years after the initial interview another food frequency questionnaire was completed recalling intake during the previous year. At the 2-year follow-up interview women were also asked if they had changed their intake of fruit, vegetables, and fat since diagnosis.

SUBJECTS/SETTING

Two hundred sixty New Mexico women with newly diagnosed breast cancer between July 1997 and March 1999.

ANALYSIS

Two-year change scores for kilocalories, macronutrients, and fruit and vegetable servings were calculated and tested for difference from zero using paired t tests or Wilcoxon signed rank tests. Subjects' characteristics were related to change in kilocalories and linear regression was used to determine the relative importance of these characteristics. Amount of change in fruit and vegetable servings and fat intake were calculated using food frequency data for women who reported increasing their intake of fruits and vegetables or decreasing their intake of fat after diagnosis.

RESULTS

Small but significant decreases in intake of total energy and macronutrients were found 2 years postdiagnosis, with younger women reporting the greatest decreases. Fat as a percentage of diet increased over this period. There was no change in mean intake of fruit and vegetable servings. There is agreement between change as measured by food frequency questionnaire and change reported by more global questions on dietary habits; however, the amount of change measured was small. Women reporting an increase in fruit and vegetable intake postdiagnosis described an increase of one-quarter serving of fruit and one-third serving of vegetables per day.

CONCLUSIONS

Breast cancer diagnosis results in modest dietary changes. Small changes in fruit and vegetable consumption suggest that efforts are needed to encourage increased consumption of these foods.

Determination of carotenoid stereoisomers in commercial dietary supplements by high-performance liquid chromatography

A method for the determination of beta-carotene, lutein, and zeaxanthin including their cis-isomers and alpha-carotene in commercial dietary supplements by HPLC has been developed. The study comprises 11 oral dosage forms, including 9 soft gelatin capsules, 1 dragée, and 1 effervescent tablet formulation. The capsule content was extracted with an acetone-hexane mixture, and the gelatin shell was digested with papain to release carotenoids that had migrated into the coat. Sample preparation for tablets and dragées was carried out as described for the capsule content. Extraction recoveries exemplified for all-trans-beta-carotene and all-trans-lutein were 95 +/- 5% and 93 +/- 2%, and 95 +/- 2% and 79 +/- 5% after enzymatic treatment, respectively. Apart from all-trans-beta-carotene, its 9-cis- and 13-cis-isomers were detected in all samples, whereas no evidence for cis-isomerization of lutein and zeaxanthin could be obtained. Migration of carotenoids into the shells was only observed in the case of beta-carotene. With the exception of one preparation, the beta-carotene contents determined exceeded the dosage specified on the label by up to 48%, which results from stability overages necessary to compensate for losses during storage.

Consumption of Carotenoid-Rich Foods and Central Vision Loss

The purpose of this study was to explore the association between consumption of carotenoid-rich foods and risk of central vision loss in 168 rural elders. Food consumption was estimated using a food frequency questionnaire. Median servings per week were used as the cut points for consumption levels. Odds ratios (OR) and 95% confidence intervals (CI) were calculated by using discordant pairs. High consumption of corn bread indicated significant association with central vision loss (OR 0.4; 95% CI 0.2, 0.9). Insignificant inverse associations were observed for seven other foods and the summary index of all selected foods. Prospective studies are needed to further evaluate the potential protective influence of carotenoid-rich foods on central vision loss among older adults.

Vitamin C deficiency and depletion in the United States: the Third National Health and Nutrition Examination Survey, 1988 to 1994

OBJECTIVES

We sought to determine prevalence rates of vitamin C deficiency and depletion in the United States.

METHODS

We used data from the Third National Health and Nutrition Examination Survey to assess intake of dietary, supplemental, and serum vitamin C.

RESULTS

Mean intakes and serum levels of vitamin C were normal; however, vitamin C deficiency and depletion were common (occurring among 5%-17% and 13%-23% of respondents, respectively). Smokers, those who did not use supplements, and non-Hispanic Black males had elevated risks of vitamin C deficiency, while Mexican Americans had lower risks.

CONCLUSIONS

Health professionals should recommend consumption of vegetables and fruits rich in vitamin C and should recommend supplementation for individuals at risk of vitamin C deficiency.

Telephone counseling intervention increases intakes of micronutrient- and phytochemical-rich vegetables, fruit and fiber in breast cancer survivors

Although a large body of evidence suggests that diet may play an important role in cancer prevention, randomized controlled trials reported to date have not achieved sufficient increases in protective micronutrients and phytochemicals to adequately test the hypothesis that diet can reduce cancer risk. The Women's Healthy Eating and Living (WHEL) Study, a randomized controlled trial of the role diet modification may play in future breast cancer events, introduced an innovative theory-based telephone counseling intervention to teach participants to consume a high fiber, low fat diet emphasizing vegetables and fruits rich in carotenoids and other potentially protective phytochemicals. This report examines the baseline to 12-mo changes in dietary intakes of 2970 participants, assessed through 24-h recalls and validated with plasma carotenoid concentrations. At 12 mo, the intervention group reported a significantly increased daily vegetable intake (+vegetable juice) of 7.1 servings (+82%) and fruit intake of 3.9 servings (+18%). Fiber intake increased from 3.04 to 4.16 g/(MJ. d), whereas energy from fat decreased significantly from 28.6 to 23.7%. Plasma carotenoid concentrations increased significantly, i.e., alpha-carotene (+223%); beta-carotene (+87%); lutein (+29%); and lycopene (+17%). In the comparison group, dietary intake and plasma carotenoid concentrations were essentially identical to those of the intervention group at baseline and were unchanged at 12 mo. The WHEL Study showed that a telephone counseling intervention can achieve major increases in micronutrient- and phytochemical-rich vegetables, fruit and fiber intakes, enabling an investigation of the potential cancer preventive effects of these food components.

Carotenoids in health and disease: recent scientific evaluations, research recommendations and the consumer

In addition to his many research achievements, James Allen Olson made important contributions to evaluations of the role of dietary carotenoids in prevention of chronic diseases such as cancer, heart disease and age-related macular degeneration in well-nourished populations. This paper reviews recent scientific evaluations of the role of carotenoids in disease, recommendations for future research, and consumer-related trends of relevance to carotenoids. Authoritative scientific evaluations by key leading thinkers have not been able to ascribe a disease prevention function to carotenoids because of the absence of definitive evidence. These leading thinkers recommend that future research on the role of carotenoids in disease focus on the complexities of diet, genetics and environment in the disease process. This research is important to make it possible for consumers to derive optimal health promoting benefits from fruits and vegetables in the context of changing dietary patterns.

Measuring fruit and vegetable consumption: providing serving size information doubles estimated percent eating five per day

Measuring the extent to which individuals meet the 5 A Day dietary recommendation for fruits and vegetables can provide information on the effectiveness of public health efforts to increase consumption of these foods. However, dietary measurement is complicated by the issue of serving size. We compared two methods of measuring fruit and vegetable consumption using a random-digit-dialed telephone survey of 917 Washington state adults. The survey included two sets of questions about fruit and vegetable consumption, one providing and the other not providing standard definitions of serving size. The specific wording of questions had a large effect on the conclusions about levels of fruit and vegetable consumption. Although only 26% of respondents met the 5 A Day recommendations without serving size information, 50% met these recommendations when using a measure that included a definition of serving size.

Methods to increase fruit and vegetable intake with and without a decrease in fat intake: compliance and effects on body weight in the nutrition and breast health study

Dietary patterns that involve a decrease in fat and an increase in fruit and vegetable (FV) intake have been suggested to decrease cancer risks. In this study, intervention methods to selectively modify dietary fat and/or FV intakes were developed. Compliance to the diets and the effects on body weight are shown, because both of these dietary changes can impact on and be confounded by changes in energy intake. A total of 122 women with a family history of breast cancer were randomized onto one of four diets for 12 mo. Counseling methods were devised to increase amount and variety of FV consumed with or without a decrease in fat intake using modified exchange list diets. Women on the low-fat and combination low-fat/high-FV diet arms decreased their fat intakes to approximately 16% of energy. Women on the high-FV and the combination low-fat/high-FV diet arms increased FV intakes to approximately 11 servings/day. Despite counseling efforts to maintain baseline energy intakes, mean body weight increased significantly by 6 pounds in women in the high-FV diet arm and decreased significantly by 5 pounds in women in the low-fat diet arm. Percent body fat also was increased in the high-FV diet arm and decreased in the low-fat diet arm. Body weight and percent body fat in the combination diet arm did not change significantly. Control of energy intake, therefore, appears to have been achieved only when the addition of FV to the diet was balanced by a decrease in fat intake and both dietary components were enumerated daily. Maintenance of energy intake, therefore, did not appear to be attained intrinsically when individuals were counseled to make changes in the composition of their diets.

Snacking patterns influence energy and nutrient intakes but not body mass index

OBJECTIVE

To study dietary intake and body mass index (BMI) patterns among US adults, stratified by snacking patterns.

DESIGN

The 1994-1996 Continuing Survey of Food Intakes by Individuals (CSFII) provided the study sample. Snacking episodes were defined as a 'food and/or beverage break', and subjects were classified as morning, afternoon, evening, multiple or never snackers.

SUBJECTS/SETTING

Our study included data from 1756 men and 1511 women who provided two nonconsecutive, multiple-pass 24-h dietary recalls.

STATISTICAL ANALYSES

Mean values of each subject's two 24-h recalls were used for analyses, and data were analysed using the Statistical Package for the Social Sciences (SPSS) for Windows and SUDAAN.

RESULTS

Compared with women, men were more likely to be evening, multiple or never snackers. Male multiple snackers had significantly higher energy intakes than did afternoon and never snackers, whereas female multiple snackers had higher energy intakes than did morning, evening and never snackers. At the same time, male and female multiple snackers had more prudent energy-adjusted intakes of protein, cholesterol, calcium and sodium. Coffee, cola, milk, ice cream and fruits were among the most frequently consumed snacks by men and women. The BMI did not differ significantly across snacker categories.

CONCLUSIONS

These data indicate that snacking patterns have some effects on energy and nutrient intakes but not on BMI. Snack food choices remain a concern, especially beverages, including those that are sweetened. Vegetables and fruits as snacks should be encouraged.

An innovative approach to the determination of safety for a dietary ingredient derived from a new source: case study using a crystalline lutein product

Lutein and zeaxanthin are antioxidant carotenoids that occur naturally in the diet. A new source of these carotenoids, a crystalline lutein product, is an extract from the marigold flower (Tagetes erecta) that contains approximately 86% by weight of the carotenoids lutein and zeaxanthin. The safety of consumption of a crystalline lutein product used as an ingredient in food is determined by evaluating the safety of ingestion of the whole product, as well as safety of ingestion of the major constituents, lutein and zeaxanthin. The approach to evaluating the safety of increased lutein and zeaxanthin intake from consumption of crystalline lutein product is based on an evaluation of the incremental increase this ingestion will produce in lutein and zeaxanthin and in total carotenoids, compared to background exposure. In addition, bioavailability of lutein+zeaxanthin from crystalline lutein product, when added to food, is determined and used to adjust the estimated daily intake of lutein and zeaxanthin from this new source and standardize it to the bioavailable dose of these carotenoids from food sources. The proposed level of ingestion of lutein and zeaxanthin from the crystalline lutein product would increase intake of lutein zeaxanthin in the generally vegetable-poor American diet to a level comparable to the mean intake of individuals consuming the recommended number of servings of vegetables per day and is therefore determined to be both prudent and safe. Safety of consumption of the whole product is determined by evaluating the source of the product, production process, nature and quantity of impurities, and product specifications. Corroboration of safety is provided by animal toxicology studies of the crystalline lutein product, as well as human and epidemiologic studies of lutein and zeaxanthin intake. It can be concluded that crystalline lutein is a safe and GRAS source of lutein for its proposed uses in food.

Position of the American Dietetic Association: the role of dietetics professionals in health promotion and disease prevention

In the United States, the leading determinants of morbidity and mortality are rooted in behavioral choices related to eating habits, exercise, tobacco, alcohol consumption, and stress reduction. Scientific data consistently provide evidence that diet plays an important role in health promotion and disease prevention. Healthy eating habits--coupled with other healthful lifestyle behaviors--have the potential to reduce the risk of chronic disease. Health care typically assumes a curative or treatment role in the United States. However, dietetics professionals are shaping an alternate view of health, which includes developing healthy public policies, creating safe and supportive environments, building communities and coalitions, and reorienting health services to include health promotion as a primary approach to delivering health care. Individual-level approaches, such as counseling and group education, have been employed most often in modifying health behaviors. However, population-level approaches that affect availability of or access to healthy foods, opportunities for physical activity, and other healthy lifestyle determinants also are important. Dietetics professionals have pivotal roles in both individual- and population-level approaches.

Increased fruit, vegetable and fiber intake and lower fat intake reported among women previously treated for invasive breast cancer

OBJECTIVE

To describe the dietary intake patterns of women before and after breast cancer diagnosis.

SUBJECTS AND SETTING

3,084 women (age range 27 to 70 years) who had been treated for early-stage breast cancer, who were free of recurrent disease, and who were willing to complete study questionnaires.

DESIGN

A descriptive analysis of baseline demographic and lifestyle questionnaire data, including reported dietary intake data from women who have had breast cancer participating in a randomized, controlled dietary intervention trial. Outcomes include dietary intakes of high- and low-fat foods, fruits and vegetables, and whole grains.

STATISTICAL ANALYSIS PERFORMED

Analyses included frequency of intake of selected food items, chi2 analysis to determine associations between reported intakes and demographic and personal characteristics, and logistic regression to assess odds of making more healthful changes.

RESULTS

Women who have had breast cancer reported higher fruit, vegetable, and fiber-rich food intakes (58%, 60%, 38% more, respectively) and lower intakes of high-fat foods, including fast foods, after diagnosis. Those older than age 60 years were more likely to report no change in intake, including red meat (41%), vegetables (51%), and whole grains (62%). Odds ratios (OR) for more healthful diet choices varied by age and time since diagnosis. The longer the time since diagnosis the more likely women selected low-fat (vs high-fat) foods (OR 1.56, 95% confidence interval [CI] 1.16-2.09 for 3 to 4 years vs <1 year after diagnosis) and reduced added fats (OR 1.47, 95% CI 1.17-1.84 for 3 to 4 years vs <1 year after diagnosis).

APPLICATIONS

Women who have had breast cancer report more healthful diet habits after diagnosis. Through nutrition education and counseling, dietetics professionals may be able to promote healthful and evidence-based eating habits among women previously treated for breast cancer.

Stability of ascorbic acid in commercially available orange juices

OBJECTIVE

To compare the vitamin C content of reconstituted frozen orange juice concentrates at preparation to that of ready-to-drink orange juices purchased 4 to 5 weeks from expiration.

DESIGN

Juices were unsealed and analyzed for reduced and oxidized vitamin C content at the time of purchase and reanalyzed 3 times weekly for 4 to 5 weeks. Same-lot samples of the ready-to-drink juices remained sealed after purchase and were opened for analyses at 3, 2, 1, or 0 weeks before expiration. SAMPLES/SETTING: Orange juices were reconstituted frozen concentrates, ready-to-drink juice packaged in resealable, screw-top containers, or ready-to-drink juice packaged in nonresealable containers. Juices were obtained from local retailers and stored at 4 degrees C in their original containers when appropriate.

STATISTICAL ANALYSES PERFORMED

The reduced vitamin C content of juices analyzed repeatedly, 3 times weekly for 4 weeks, were compared using repeated measures analysis of variance. Linear regression lines were computed for reduced vitamin C in each juice over time, and differences between slopes were analyzed by oneway analysis of variance.

RESULTS

The orange juices from frozen concentrates contained 86 mg reduced vitamin C per fluid cup at initial preparation and 39 to 46 mg/c after 4 weeks of storage. Ready-to-drink juices averaged significantly lower reduced vitamin C: 27 to 65 mg/c at opening and 0 to 25 mg/c at expiration 4 weeks later. Ready-to-drink orange juices had twofold to threefold higher concentrations of oxidized vitamin C vs the orange juices reconstituted from frozen, and the decomposition rate of reduced vitamin C was similar for all juices, about 2% per day once opened.

APPLICATIONS

Ready-to-drink orange juices should be purchased 3 to 4 weeks before expiration date and consumed within 1 week of opening.