Most of us think of orange juice as a simple breakfast habit, which you pour without much thought. However, scientists have discovered that this daily drink may be doing more to the body than quenching thirst.
A recent study has shown that regular consumption of orange juice can influence the activity of thousands of genes within our immune cells. Many of these genes help control blood pressure, calm inflammation and regulate the way the body processes sugar, all of which play important roles in long-term heart health.
The study followed adults who drank 500ml of pure orange juice every day for two months. After 60 days, several genes associated with inflammation and high blood pressure were less active.
These include NAMPT, IL6, IL1B and NLRP3, which are normally switched on when the body is under stress. Another gene, known as SGK1, which affects the kidney’s ability to hold sodium (salt), also became less active.
Such changes are consistent with previous findings that drinking daily orange juice can lower blood pressure in young adults.
Previous findings have suggested that daily orange juice can lower blood pressure in young adults (Getty/iStock)
This is noteworthy because it provides a possible explanation for why orange juice has been linked to better heart health in many trials. New work shows that drinking doesn’t just raise blood sugar. Instead, it appears to trigger small changes in the body’s regulatory systems that reduce inflammation and help blood vessels relax.
Natural compounds in oranges, especially 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. Overweight individuals tended to show greater changes in genes involved in fat metabolism, while leaner volunteers showed stronger effects on inflammation.
A systematic review of controlled trials involving 639 participants from 15 studies found that regular orange juice consumption 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 focused on overweight and obese adults found a small decrease in systolic blood pressure and an increase in high-density lipoprotein (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 meaningful difference if maintained over many years.
Additional clues come from studies that examine metabolites, small molecules produced when the body processes food. A recent review found that orange juice affects pathways related to energy use, communication between cells and inflammation. It can also affect the gut microbiome, which is increasingly understood to play a role in cardiovascular health.
About the author
David C. Gage is Senior Lecturer in Chemical Pathology at the University of Westminster.
This article is republished from 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 include high blood pressure, elevated blood sugar and excess body fat, may see particular benefits.
In one study, daily orange juice consumption improved the function of the lining of blood vessels, known as endothelial function, in 68 obese participants. Endothelial function describes how blood vessels relax and widen, and better function is associated with a lower risk of heart attack.
Not all studies report the same results. A broader analysis of blood fat concentrations found that while levels of low-density lipoprotein (LDL), often called bad cholesterol, often decreased, other lipid measures such as triglycerides and HDL may not change much. However, people who drink orange juice regularly can still benefit.
A study of 129 workers at an orange juice factory in Brazil reported lower blood levels of apolipoprotein B, or apo-B, a marker for the number of cholesterol-carrying particles linked to heart attack risk.
Overall, the evidence challenges the idea that drinking citrus fruit juice means eating a glass of sugar. Whole fruit remains a good choice because of its fiber, but a modest daily glass of pure orange juice seems to have effects that build up over time.
These include reducing inflammation, supporting healthy blood flow and improving several blood markers linked to long-term heart health. It’s a reminder that everyday foods can affect the body more than we expect.
