The Citrus Industry’s Future in Health and Wellness

American consumers have long had a love affair with orange juice as part of the iconic breakfast table. Eighty-seven percent of consumers surveyed like 100% orange juice, and 79% say they feel good about serving orange juice to their families, according to 2016 information from Porter Novelli. More than half of the orange juice enjoyed by Americans comes from Florida, whereas most varieties of edible oranges come from California.

Interestingly, in the face of such a strong affinity for 100% orange juice, consumption has declined year over year from 5.7 gallons per capita in 1998 to about 3 gallons per capita in 2014, according to U.S. Dept. of Agriculture (USDA) data. There appear to be two prime factors that contribute to this decline: perceived negative nutritional contributions (e.g., simple sugars and calories) and decreased production. This latter factor is due to huanglongbing (HLB) or citrus greening disease caused by the motile bacterium Candidatus Liberibacter asiaticus.

Orange juice has long been accepted and valued as a nutritious beverage and part of an overall healthy lifestyle, and rightly so, because 100% orange juice contains no added sugars (like the fruit, it contains natural sugars) and provides many key nutrients, such as vitamin C, potassium, folate, thiamin, magnesium, and vitamin B6. In addition, thanks to food science and nutrition, fortified orange juice is a source of biologically available calcium and vitamin D. Consumption of 100% orange juice is associated with a greater likelihood that adults and children meet fruit intake recommendations (O’Neil et al. 2012, O’Neil et al. 2011, Yang et al. 2013).

The 2015 Dietary Guidelines for Americans (DGA) states that 100% juice such as orange juice counts as a fruit choice; one cup equates to one cup equivalent of fruit. The DGA also recommends that at least half of fruit servings should come from whole fruit to increase fiber and reduce overconsumption of juice (USDA 2015). As for young children, the American Academy of Pediatrics recommends that intake of fruit juice should be limited to 4–6 ounces/day for children aged 1 to 6 and to 8–12 ounces/day for children aged 7 to 18 (AAP 2001). Following these recommendations reduces the likelihood of unbalanced consumption of calories.

The calories in beverages like a glass of 100% orange juice have raised concerns that consumption increases the risk of weight gain (Drewnowski and Bellisle 2007, Mattes 2006). However, in observational studies, no associations have been found with consuming 100% fruit juice and body weight.

In a cross-sectional study using NHANES 2003–2006 recall data, researchers reported no significant difference in body mass index (BMI), waist circumference, or percentage of body fat in children and adolescents who consumed 100% orange juice compared to nonconsumers (Wang et al. 2012). A study in preschool children aged 24–36 months reported no statistically significant differences in children’s height, BMI, or ponderal index related to fruit juice intake (Skinner et al. 1999).

Furthermore, a longitudinal study of 72 children aged 2–6 years reported no statistically significant associations between juice intake and children’s height, weight, or BMI. Researchers also noted that as juice consumption decreased, intakes of less nutritious beverages increased (Skinner and Carruth 1999). A systematic review based on 22 studies concluded that the data do not support an association between consumption of 100% fruit juice and weight or adiposity in children (Crowe-White et al. 2016). These and other reports indicate consumers of 100% fruit juice and orange juice can benefit from the wealth of nutrients in a serving of juice while maintaining a healthy weight.

Beyond the vitamins and nutrients in 100% orange juice, emerging research suggests that hesperidin, a flavanone in oranges and orange juice, may help maintain healthy blood pressure, blood vessel function, and reduced total and LDL cholesterol (Morand et al. 2011, O’Neil et al. 2012, Asgary et al. 2013, Basile et al. 2010). A meta-analysis of 19 randomized controlled trials demonstrated a significant reduction in diastolic blood pressure among adults who consumed 65.2–2,660 mg polyphenols/day fruit juice from 2 weeks to 3 months (Liu et al. 2013).

Emerging research suggests inflammation is a contributor to chronic disease development. Orange juice has been implicated in helping to reduce some biomarkers of inflammation (Dourado and Cesar 2015, Sanchez-Moreno et al. 2003). Two clinical studies (n=30 healthy adults) demonstrated that the consumption of orange juice (500 mL) helped attenuate selected inflammatory responses, such as myeloperoxidase, platelet P-selectin, C-reactive protein, and prostaglandin E2 (PGE2), following the consumption of a high carbohydrate (~36% en) and/or high fat (~53% en) meal or a normal meal (Cerletti et al. 2015, Ghanim et al. 2010).

History of Citrus Greening

History of Citrus Greening

One area potentially related to inflammation is cognition. An interesting 8-week clinical study investigated whether the daily intake of flavanone-rich orange juice was beneficial to cognitive function in 37 healthy older adults. It reported that compared to the control drink, adults who consumed 100% orange juice (500 mL juice, 305 mg flavanone) scored better on global cognitive function (Positive and Negative Affect Scale), a result that seemed to persist over time (Kean et al. 2015).

Disease and pestilence is often an issue with crop production, and Florida and California citrus are no exception. HLB was first identified in China in 1919. It is caused by a bacterium (Candidatus Liberibacter asiaticus) that infects the tree and reduces the flow of nutrients through the phloem of the tree’s circulatory system; it is spread by a tiny insect, the citrus psyllid (Diaphorina citri). In 2005, the disease was first confirmed in South Florida when symptoms of citrus greening—yellow mottled leaves, yellow stems, small, misshaped fruit—were identified. Greening has since spread to infect every citrus growing county in Florida, reducing production by more than half (Bové 2006).

The citrus industry has focused efforts and resources on treating, mitigating, and ultimately curing citrus greening. The industry has invested more than $52 million in research focused on four areas: preventing the spread of HLB, sustaining tree health, reducing HLB in trees, and improving fruit quality and loss, according to information from the Citrus Research and Development Foundation. In addition, since 2014 the USDA has committed more than $20 million to coordinate the federal, state, and industry’s immediate response to the effects of HLB on the citrus industry in the United States.

The citrus industry has explored unique approaches to knocking back the Asian citrus psyllid. One approach has been to enhance tree nutritionals to support a tree’s overall vitality and natural immunity. When a tree’s health is supported, it can continue to produce while still being infected. Additionally, researchers from the University of Florida studied metalized polyethylene mulch, or reflective mulch, which confuses the psyllid and reduces the bacterial impact on trees. This approach shows promise, but more research is necessary before it can be employed on a wide-scale level (Croxton and Stansly 2014).

Bacteria tend to be heat sensitive. Tents or chambers are created with plastic material as heat is applied either from the sun or by the introduction of steam. Research has shown that temperature-controlled growth chambers significantly decreased the bacteria population and improved tree health (Hoffman et al. 2013).

There is no cure for HLB at this time. Additional research is underway to explore new varieties of citrus trees resistant to HLB through traditional crossbreeding and biotechnology. Trees are being tested, but none are in production for commercial use.

What was once viewed as a staple part of a nutritious breakfast and an easy choice has now become more complex and challenged. Orange juice is unquestionably nutrient rich. Contemporary research shows that there are many benefits to consuming 100% orange and other juices as part of overall fruit consumption (Clemens et al. 2015). Concern over sugar content and calories are allayed by the evidence that consistently shows that body weight is not associated with consumption of 100% orange juice.

Faced with the added challenge of citrus greening, the industry has redoubled research efforts to support robust production levels while ensuring the same nutritional quality. The use of tested and approved methods of disease mitigation will help protect tree, environmental, and human health until a cure is found.

Roger Clemens, DrPH, CFS, Contributing Editor
Adjunct Professor, Univ. of Southern California School of Pharmacy, Los Angeles, Calif.
[email protected]

Gail Rampersaud, RDN, LDN, is associate in nutrition research and education, Food Science and Human Nutrition Dept., Institute of Food and Agricultural Sciences (UF/IFAS), University of Florida ([email protected]).