A number of clinical and epidemiological studies have reported positive associations between high sugar or fructose intake and the risk for several chronic diseases or other conditions, including overweight and obesity, diabetes, insulin resistance, metabolic syndrome and hyperlipidaemia( Reference Aller, Abete and Astrup 1 , Reference Samuel 2 ). However, there are also studies that fail to support this relationship, especially when intakes are at levels that mirror typical consumption( Reference Yu, Lowndes and Rippe 3 ). The research on fructose also has implicated this sugar as having possible health risks, although the interpretation of this hypothesis has noteworthy limitations. The results of animal studies are frequently extrapolated to man even though there are metabolic differences related to fructose metabolism, while human clinical studies often suffer from methodological issues that can affect their interpretation and application to the general human population( Reference Sievenpiper 4 , Reference Sievenpiper, de Souza and Kendall 5 ). For example, in most clinical studies fructose levels far exceed those consumed by the general population. Nevertheless, the potential health effects related to the consumption or overconsumption of sugars and fructose have captured the spotlight in scientific journal editorials and commentary( Reference Bray 6 , Reference Lustig 7 ) and the lay press( Reference Cohen 8 – Reference Taubes 10 ), as well as in business/finance institution reports related to global sugar consumption and health impacts( 11 ). While most of the attention has focused on beverages containing added sugars, particularly high-fructose corn syrup, 100 % fruit juices (FJ) have been swept into the discourse because of their sugar and fructose contents( Reference Popkin 12 , Reference Wojcicki and Heyman 13 ), which come not from added sugars but as naturally occurring sugars in the whole fruit. As a result, 100 % FJ is often discussed in a context that focuses solely on its sugar content and neglects the nutritional value and potential health benefits associated with including 100 % FJ in the diet. Moreover, the evidence to date suggests that the adverse effects associated with excess added sugar or fructose intake are not observed with respect to the consumption of 100 % FJ at typical amounts.
Research on 100 % fruit juice
A number of observational studies have investigated the relationship between 100 % FJ intake and anthropometric measures in children and/or adolescents. A comprehensive review article published in 2008 evaluated the results of twenty-one studies (nine cross-sectional and twelve longitudinal)( Reference O’Neil and Nicklas 14 ). Only three out of nine cross-sectional studies and three out of twelve longitudinal studies reported a positive association between 100 % FJ intake and weight status. After critically reviewing the quality of the studies, the authors concluded that there was no systematic association between 100 % FJ intake and body weight in children or adolescents. As analysed in the review, three longitudinal studies reported significant associations between 100 % FJ intake and weight or BMI in adolescent girls in Germany( Reference Libuda, Alexy and Sichert-Hellert 15 ) or low-income children who were overweight or at risk for overweight at baseline in the USA( Reference Faith, Dennison and Edmunds 16 , Reference Welsh, Cogswell and Rogers 17 ). The two latter studies included relatively large sample sizes, yet none of the three studies used a nationally representative sample. Observational studies concerning FJ intake and anthropometric measures in children and adolescents published since the 2008 review are summarized in Table 1. Several cross-sectional and longitudinal studies published since the 2008 review report no association between 100 % FJ consumption and obesity or BMI in children and adolescents, including Mexican-American children in California( Reference Beck, Tschann and Butte 18 ), Swedish adolescents( Reference Vagstrand, Linne and Karlsson 19 ), Greek schoolchildren( Reference Papandreou, Andreou and Heraclides 20 ), Canadian children( Reference Danyliw, Vatanparast and Nikpartow 21 ), children in a California WIC (Special Supplemental Nutrition Program for Women, Infants, and Children)( Reference Davis, Koleilat and Shearrer 22 ), and adolescents in Project EAT (Eating Among Teens)( Reference Vanselow, Pereira and Neumark-Sztainer 23 ) and the National Health and Nutrition Examination Survey (NHANES)( Reference O’Neil, Nicklas and Kleinman 24 ). A multi-year and multi-state analysis of over 272 000 adolescents from the Youth Risk Behavior Survey reported an inverse association between 100 % FJ intake and BMI in girls and a null association in boys( Reference Taber, Stevens and Poole 25 ). These results should be interpreted with caution since height and weight were self-reported and adolescent females tend to under-report their weight( Reference Clarke, Sastry and Duffy 26 , Reference Sherry, Jefferds and Grummer-Strawn 27 ). One longitudinal study reported a significant association between the amount of FJ consumed by children at age 1 year and BMI Z-score during early and mid-childhood( Reference Sonneville, Long and Rifas-Shiman 28 ), while an inverse association was reported between fruit and vegetable juice intake during childhood and waist circumference and skinfold measurements in adolescence( Reference Hasnain, Singer and Bradlee 29 ). Two recent reviews of the literature, including an analysis by a workgroup on behalf of the Academy of Nutrition and Dietetics’ Evidence Analysis Library, concluded that the majority of evidence does not support an association between 100 % FJ consumption and weight status or adiposity in children 2–18 years of age( 30 , Reference O’Neil and Nicklas 31 ). Readers desiring more detailed information about individual studies should consult these reviews.
NHANES, National Health and Nutrition Examination Survey; WIC, Special Supplemental Nutrition Program for Women, Infants, and Children; EAT, Eating Among Teens; fl oz, fluid ounces (1 fl oz=29·57 ml); Ht, height; Wt, weight; WC, waist circumference; FJ, fruit juice; CDC, Centers for Disease Control and Prevention; IOTF, International Obesity Task Force; %BF, percentage body fat; PA, physical activity; SES, socio-economic status; T2, time 2; TV, television; %E, percentage of energy intake.
For adults, no association between 100 % FJ consumption and waist circumference was observed in the Coronary Artery Risk Development in Young Adults (CARDIA) longitudinal cohort( Reference Duffey, Gordon-Larsen and Steffen 32 ), while inverse associations between 100 % FJ and BMI have been reported in other studies( Reference Akhtar-Danesh and Dehghan 33 , Reference Pereira and Fulgoni 34 ). However, a large study using the Nurses’ Health Study I and II, and Health Professionals Follow-Up Study cohorts reported a significant and positive association between the increase in FJ intake and weight gain of about 0·15 kg (0·3 lb) in adults over each 4-year follow-up study period( Reference Mozaffarian, Hao and Rimm 35 ). Demographic, sample size or other differences between cohorts may account for the differences in results. Overall, the results of observational studies in children and adults on 100 % FJ intake and body weight are mixed with the majority of studies reporting no association. Randomized clinical trials are lacking and needed to determine the existence of a causal relationship.
Study results are also mixed for associations between 100 % FJ intake and risk for type 2 diabetes, with the majority of studies reporting no significant effects. 100 % FJ intake was positively associated with risk of type 2 diabetes in several studies, including middle-aged women in the Nurses’ Health Study( Reference Bazzano, Li and Joshipura 36 ), middle-aged Chinese men and women living in Singapore( Reference Odegaard, Koh and Arakawa 37 ), and in an analysis of three large US health professional cohorts (including the Nurses’ Health Study as previously analysed and reported in Bazzano et al.)( Reference Muraki, Imamura and Manson 38 ). However, a systematic review and meta-analysis evaluating four prospective cohort studies representing over 137 000 participants concluded that the intake of 100 % FJ was not significantly associated with the risk for type 2 diabetes( Reference Xi, Li and Liu 39 ). FJ intake was not associated with risk for incident type 2 diabetes in studies in African-American women( Reference Palmer, Boggs and Krishnan 40 ), Japanese-Brazilians( Reference Sartorelli, Franco and Gimeno 41 ), Japanese( Reference Eshak, Iso and Mizoue 42 ), middle-aged women in the Nurses’ Health Study II cohort( Reference Schulze, Manson and Ludwig 43 ), French women( Reference Fagherazzi, Vilier and Sartorelli 44 ) and healthy men in the Health Professionals Follow-Up Study cohort( Reference de Koning, Malik and Rimm 45 ). No association between pre-pregnancy FJ intake and risk for gestational diabetes was reported for women in the Nurses’ Health Study II( Reference Chen, Hu and Yeung 46 ). An analysis of the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort reported no association between the consumption of juices and nectars and the incidence of type 2 diabetes in over 11 000 subjects( 47 ). In this analysis, the juice group also included vegetable juices as well as nectars that may have contained up to 20 % added sugars, so results should be interpreted with some caution. European men and women without diabetes consumed higher amounts of juice compared with those with diabetes( Reference Nothlings, Boeing and Maskarinec 48 ).
Metabolic syndrome is a cluster of risk factors that increase the risk for CVD and diabetes( Reference Alberti, Eckel and Grundy 49 ). Studies using the cross-sectional NHANES( Reference Pereira and Fulgoni 34 ) and longitudinal CARDIA( Reference Duffey, Gordon-Larsen and Steffen 32 ) data sets report no association between 100 % FJ intake and risk for metabolic syndrome. A study of over 1100 adults from the Bogalusa Heart Study reported that 100 % FJ intake was higher in those with no risk factors for metabolic syndrome v. those having one or two risk factors( Reference Yoo, Nicklas and Baranowski 50 ). Substituting sugar-sweetened beverages with moderate amounts of homemade FJ was associated with a 30 % decreased risk for metabolic syndrome among Costa Rican adults( Reference Mattei, Malik and Hu 51 ). An analysis of NHANES 2003–2006 data reported a 36 % reduced odds or likelihood for metabolic syndrome in men who consumed orange juice compared with men who did not consume orange juice, with a null association in women( Reference O’Neil, Nicklas and Rampersaud 52 ). FJ intake has been associated with an increased risk for impaired glucose tolerance in a Japanese-Brazilian population( Reference Sartorelli, Franco and Gimeno 41 ), but has been inversely related to fasting glucose in the Framingham Offspring cohort( Reference Yoshida, McKeown and Rogers 53 ).
Intake of 100 % FJ does not appear to have adverse effects on blood lipids and may be beneficial in some cases. FJ consumption was not associated with significant effects on total cholesterol, LDL-cholesterol or HDL-cholesterol in a meta-analysis of nineteen randomized controlled studies( Reference Liu, Xing and Chen 54 ). A study using the CARDIA cohort reported no association between FJ intake and the CVD risk factors elevated TAG, elevated LDL-cholesterol or low HDL-cholesterol in adults( Reference Duffey, Gordon-Larsen and Steffen 32 ). Substituting sugar-sweetened beverages with moderate amounts of homemade FJ was associated with increases in HDL-cholesterol( Reference Mattei, Malik and Hu 51 ). Clinical studies have reported beneficial effects on blood lipids of some individual juices including orange juice and LDL-cholesterol( Reference Basile, Lima and Cesar 55 , Reference Cesar, Aptekmann and Araujo 56 ) and grapefruit juice and HDL-cholesterol( Reference Silver, Dietrich and Niswender 57 ).
Nutritional and other benefits
100 % FJ are nutrient-dense beverages that provide a variety of vitamins and minerals in varying amounts depending on the juice type, including vitamin C, potassium, thiamin, vitamin B6, folate and vitamin A, as well as calcium and vitamin D in some fortified juices. 100 % FJ are also sources of flavonoids, including polyphenolic compounds that may confer health benefits( Reference Hooper, Kroon and Rimm 58 , Reference Vauzour, Rodriguez-Mateos and Corona 59 ) and are readily found in a variety of 100 % FJ. Consumption of 100 % FJ has been positively associated with the intake of key nutrients, such as vitamin C, folate, potassium and magnesium( Reference O’Neil, Nicklas and Kleinman 24 , Reference Nicklas, O’Neil and Kleinman 60 , Reference O’Neil, Nicklas and Zanovec 61 ), which have been identified as underconsumed nutrients or nutrients of concern (potassium) in the 2010 Dietary Guidelines for Americans( 62 ). Intake of 100 % FJ also has been associated with enhanced diet quality based on Healthy Eating Index scores( Reference O’Neil, Nicklas and Zanovec 63 ). Approximately 60 % of children 4–8 years of age and at least 80 % of older children and adults do not meet fruit intake recommendations( Reference Krebs-Smith, Guenther and Subar 64 ). While whole fruit should be chosen first, 100 % FJ can complement whole fruit and, when consumed in appropriate amounts, is a practical strategy to help Americans meet daily fruit intake recommendations. In fact, 100 % FJ consumers have been reported to have higher intakes of whole fruit than non-consumers( Reference O’Neil, Nicklas and Kleinman 24 , Reference Muraki, Imamura and Manson 38 , Reference Nicklas, O’Neil and Kleinman 60 ), suggesting that 100 % FJ is complementary to, and not a replacement for, whole fruit in the diet.
From strictly an economic standpoint, 100 % FJ can have advantages over whole fresh fruit. Based on data from the US Department of Agriculture’s Agricultural Marketing Service( 65 ), the average price for a non-organic navel orange for the time period 19 September 2014 to 26 December 2014 was $US 0·81. Based on Nielsen Scantrack data, the season-to-date (28 September 2014 to 17 January 2015) price for reconstituted orange juice was $US 4·99/gallon( 66 ), or approximately $US 0·31 for 8 fl oz (237 ml), making an 8 fl oz (237 ml) serving of 100 % orange juice just over one-third the cost of a fresh orange in a practical serving-to-serving comparison. These cost differences could be consequential for lower-income individuals, many of whom have lower intake levels of fruit( Reference Grimm, Foltz and Blanck 67 ), poorer diet quality( Reference Hiza, Casavale and Guenther 68 ) and may be at increased risk for chronic disease( Reference Seligman, Laraia and Kushel 69 ), as well as institutions such as day-care centres, child or adult feeding programmes and schools that purchase and serve food and beverage items in large quantity. The longer shelf-life of 100 % FJ compared with most fresh fruits may also help reduce food waste.
As with any caloric food or beverage, it is important that 100 % FJ be consumed in appropriate amounts that do not contribute to excessive energy intake. The American Academy of Pediatrics( 70 ) and the American Heart Association( Reference Johnson, Appel and Brands 71 ) have suggested guidelines and limits for juice intake in children: 4–6 fl oz/d (118–177 ml/d) for children 1–6 years of age and 8–12 fl oz/d (237–355 ml/d) for older children and adolescents. Juice should not be given to infants 6 months of age and younger and should never be given in a bottle. The Robert Wood Johnson Foundation has issued beverage guidelines for children and adults, with recommended 100 % FJ amounts similar to but slightly more restrictive than those of the American Academy of Pediatrics( 72 ). Some data suggest that sugar-sweetened beverages (not including 100 % FJ) may be displacing milk from the diet( Reference Lasater, Piernas and Popkin 73 , Reference Blum, Jacobsen and Donnelly 74 ). This does not appear to be true with 100 % FJ as children and adolescents who consumed 100 % FJ did not consume significantly less milk compared with non-consumers( Reference O’Neil, Nicklas and Kleinman 24 , Reference Nicklas, O’Neil and Kleinman 60 ). A study examining changes in sweetened beverage, milk and juice consumption in children between the 5th and 8th grades reported that milk and juice were complements to each other, suggesting that 100 % FJ did not displace milk from the diet( Reference Oza-Frank, Zavodny and Cunningham 75 ). Children consuming 100 % FJ may be considered to have healthier diets because they had higher intakes of several vitamins and minerals and lower intakes of total and saturated fat than non-consumers( Reference O’Neil, Nicklas and Kleinman 24 , Reference Nicklas, O’Neil and Kleinman 60 ).
There is no consistent evidence that 100 % FJ is independently associated with adverse impacts on weight; in fact, many studies report null associations or inverse associations between 100 % FJ intake and body weight measures. However, the lack of randomized controlled clinical trials precludes the existence of a cause-and-effect relationship between 100 % FJ intake and weight or body composition measures. Studies related to 100 % FJ and type 2 diabetes are equivocal and reinforce the need for more research in this area. That 100 % FJ intake does not appear to be associated with key risk factors for diabetes such as insulin resistance or metabolic syndrome raises questions about the nature of the positive association between 100 % FJ intake and diabetes risk reported in some studies. Given the complex aetiology of diabetes, cross-sectional studies cannot account for all aspects of diet and lifestyle that could impact the development of these conditions; and further research is warranted. Studies on 100 % FJ intake are often confounded by the nature of the beverages included in the category defined as ‘juice’. For example, studies may combine the intakes of 100 % FJ and juice drinks and beverages that are not 100 % juice, may contain added sugars and have significantly different nutritional profiles compared with 100 % FJ. Self-reported dietary intake data further confound this issue as consumers may not recognize which products are 100 % FJ and which are not, increasing the likelihood that 100 % FJ intake is misreported. Future research should consider and address these issues.
Overall, there appears to be no reported adverse effects of 100 % FJ consumption on health conditions often associated with excess sugar or fructose intake; some studies report benefits. 100 % FJ has been associated with nutritional benefits and with diets that are of higher quality or more nutritionally complete. The amount of 100 % FJ consumed should be balanced with overall energy intake and expenditure. Intake should especially be monitored in children, particularly those who are overweight or obese. Consumption of 100 % FJ can help satisfy several key recommendations in the 2010 Dietary Guidelines for Americans: specifically, a focus on consuming nutrient-dense foods and beverages, increasing fruit intake and achieving nutrient adequacy. Data suggest that the consumption of 100 % FJ in appropriate amounts would be beneficial rather than detrimental to health.
Financial support: The author’s position at the University of Florida is co-supported by the Florida Department of Citrus (contract number 00089708). The Florida Department of Citrus had no role in the design, analysis or writing of this article. Conflict of interest: The author is a member of the Nutrition Working Group of the Juice Products Association. Authorship: G.R. is the sole author. Ethics of human subject participation: Not applicable.