Citrus fruits like oranges, mandarins, and sweet limes have been part of diets for generations, especially in winter when we crave something refreshing and immune-boosting. But beyond vitamin C, scientists now understand that citrus fruits contain a rich mix of plant compounds called flavonoids, especially a subtype known as flavanones like hesperidin. These compounds are part of the thousands of phytonutrients plants produce to protect themselves, and they’re increasingly showing promise for human health too. Early researchers even imagined a vitamin called “vitamin P” before we knew these flavonoids existed, and modern science has now confirmed they have real biological effects.
One of the ways hesperidin works is by supporting blood vessel health. Healthy vessels dilate (relax) better and allow blood to flow more easily. Studies where participants drank orange juice rich in hesperidin each day have shown improvements in markers of vascular function, including how well arteries widen and how blood pressure behaves, especially for people with mildly elevated blood pressure. This benefit seems to come not just from the vitamin C but also from the flavanones, improving nitric-oxide signalling (a key molecule that helps blood vessels relax) and reducing inflammation.
There’ve also been intriguing clues from studies measuring gene activity in blood cells after orange juice consumption. When people drank real orange juice (not just vitamin C), thousands of genes shifted in their activity patterns, especially those involved in inflammation and blood vessel functioning. This shows that citrus phytonutrients engage with our biology in profound ways beyond just providing calories and a bit of micronutrients.
Research also suggests that people who eat more citrus foods tend to have a slightly lower risk of stroke and other heart diseases. Large cohort studies in Japan and Western countries observed that those with higher citrus intake had lower incidences of ischemic stroke, possibly due to better vascular health and anti-inflammatory effects.
Now about keeping hands warm—the original idea behind the “hands warm with citrus” phrase comes from small experiments where people sensitive to cold had more stable peripheral blood flow after consuming citrus phytonutrients compared with controls, meaning their fingers didn’t cool down as quickly in cold conditions. While modern large-scale trials specifically using cold exposure and citrus flavonoids are limited, the broader science supports the idea that anything improving microvascular blood flow could, in theory, help your hands stay warmer in chillier conditions. Improved blood flow isn’t just nice for fingers and toes—it’s crucial for proper brain, heart, and organ perfusion too.
For people in India, citrus fruits like mosambi (sweet lime), kinnow, nagpur oranges, and mandarins are widely available seasonally and inexpensive compared with many supplements. Eating whole fruits also gives you fibre, potassium, folate, and carotenoids, all of which help overall cardiovascular and metabolic health. In contrast, juices—even 100 % pure orange juice—provide more natural sugars and less fibre, so they should be enjoyed in moderation, especially for those managing blood sugar or weight.
In simple terms, regularly including citrus fruits in your diet can do more than just satisfy your winter craving. The combination of vitamin C and flavonoids like hesperidin may help your blood vessels function better, support healthy blood pressure, and keep peripheral circulation steadier—factors that make your hands warmer and your heart healthier. Eating whole fruits seasonally with local Indian varieties ensures you’re getting these benefits as part of a balanced, traditional diet.