Most of us think of orange juice as a simple breakfast habit, something we pour without much thought. However, scientists are discovering that this daily drink may be doing much more in the body than quenching thirst.
A recent study showed that regular consumption of orange juice can influence the activity of thousands of genes inside our immune cells. Many of these genes help control blood pressure, calm inflammation and manage the way the body processes sugar, all of which play an important role in long-term heart health.
The study followed adults who drank 500ml of pure pasteurized orange juice a day for two months. After 60 days, many genes associated with inflammation and higher blood pressure had become less active.
These included NAMPT, IL6, IL1B and NLRP3, which are normally turned on when the body is under stress. Another gene known as SGK1, which affects the kidney’s ability to retain sodium (salt), also became less active.
Such changes agree with previous findings that drinking orange juice daily can reduce blood pressure in young adults.
Previous findings have suggested that drinking orange juice daily can lower blood pressure in young adults (Getty/iStock)
This is notable because it offers a possible explanation for why orange juice has been linked to better heart health in several trials. The new work shows that the drink doesn’t just raise blood sugar. Instead, it appears to lead to small changes in the body’s regulatory systems that reduce inflammation and help blood vessels relax.
Natural compounds in oranges, particularly hesperidin, a citrus flavonoid known for its antioxidant and anti-inflammatory effects, appear to influence processes related to high blood pressure, cholesterol balance and the way the body manages sugar.
The response also varies according to body size. People who carried more weight tended to show greater changes in genes involved in fat metabolism, while younger volunteers showed stronger effects on inflammation.
A systematic review of controlled trials involving 639 participants from 15 studies found that regular consumption of orange juice reduced insulin resistance and blood cholesterol levels. Insulin resistance is a key feature of pre-diabetes, and high cholesterol is an established risk factor for heart disease.
Another analysis focusing on overweight and obese adults found a small decrease in systolic blood pressure and increases in high-density lipoproteins (HDL), often called good cholesterol, after several weeks of daily orange juice consumption. Although these changes are modest, even small improvements in blood pressure and cholesterol can make a significant difference when maintained over many years.
More clues come from studies that examine metabolites, the tiny molecules produced as the body processes food. A recent review found that orange juice influences pathways related to energy use, cell communication and inflammation. It can also affect the gut microbiome, which is increasingly understood to play a role in heart health.
About the author
David C. Gaze is Senior Lecturer in Chemical Pathology at the University of Westminster.
This article is republished by The Conversation under a Creative Commons license. Read the original article.
One study showed that drinking blood orange juice for a month increased the number of gut bacteria that produce short-chain fatty acids. These compounds help maintain healthy blood pressure and reduce inflammation. The volunteers also showed improved blood sugar control and lower levels of inflammatory markers.
People with metabolic syndrome, a group of risk factors that includes high blood pressure, high blood sugar and excess body fat, may see particular benefits.
In one study, daily consumption of orange juice improved the function of the blood vessel lining, known as endothelial function, in 68 obese participants. Endothelial function describes how well blood vessels relax and widen, and better function is associated with a lower risk of heart attacks.
Not all studies report the same results. A broader analysis of blood fat concentrations found that although low-density lipoprotein (LDL) levels, often called bad cholesterol, often fall, other lipid measurements such as triglycerides and HDL may not change much. Even so, people who regularly drink orange juice can still benefit.
A study of 129 workers at an orange juice factory in Brazil reported lower blood concentrations of apolipoprotein B, or apo-B, a marker that reflects the number of cholesterol-carrying particles linked to heart attack risk.
Overall, the evidence challenges the idea that drinking citrus fruit juice is simply consuming sugar in a glass. Whole fruit remains the best choice because of its fiber, but a modest daily glass of pure orange juice appears to have effects that build over time.
These include reducing inflammation, supporting healthier blood flow and improving various blood markers linked to long-term heart health. It’s a reminder that everyday food can have more influence on the body than we might expect.