U.S. scientists have found that substances and compounds found in natural orange juice have beneficial effects on the body, reducing oxidative stress and inflammation. The study was published in the journal Advances in Nutrition. Despite the fact that the benefits of fruits, vegetables and drinks made from them have long been proven, in most developed countries, people do not consume half of the established dietary standards and, therefore, do not receive the necessary compounds for health. Researchers from Tufts University and George Mason University decided to find out how important orange juice consumption is for humans. To do so, they reviewed 21 studies involving 307 healthy adults and 327 adults at risk for chronic inflammatory diseases such as heart disease and diabetes. They added to the resulting summary the results of 16 systematic reviews that measured the six most commonly described biomarkers associated with inflammation and oxidative stress in the body, as well as ten meta-analysis studies that examined the association between orange juice intake and markers of inflammation or oxidation in healthy adults and those at risk for chronic disease.
Clinical and observational studies of any duration were included in the review, and C-reactive protein (CRP), interleukin IL-6, TNF-α, malone dialdehyde (MDA), oxidized LDL (oxLDL), and total antioxidant capacity were used as markers.
The researchers concluded that 100 percent sugar-free orange juice significantly reduced levels of interleukin 6, a well-known marker of inflammation, in both healthy and at-risk adults, as well as two additional markers of inflammatory and oxidative stress.
Scientists attribute the positive effect to ascorbic acid and flavonoids, compounds that can modulate the body's oxidative and inflammatory systems. Some papers also report the positive effects of hesperidin, another biologically active compound found in oranges. The authors note that the results of absolutely all of the articles analyzed indicate positive or neutral, but not negative, effects of orange juice on oxidative stress or inflammation, but more research is needed to determine numerical rates.