In recent years, the substance hesperidin has come to the forefront. This is a flavonoid, a natural plant protector against damage, found mostly in citrus fruits. Scientists say hesperidin helps with three key things:
- calming inflammation,
- reducing oxidative stress (this is the process when the body is attacked by harmful free radicals),
- and improving blood vessel function.
Grandmothers used to say: an orange drives out inner devils, which was their way to describe reduction of inflammation and better blood flow.
How did researchers even test the effect?
In one of the more recent studies, they included 20 healthy adults, who had one task: for 60 days, drink 500 ml of orange juice every day. The juice was completely natural, pasteurized, and divided into two servings: 250 ml in the morning and 250 ml in the afternoon.
Before starting, they had to remove all other sources of flavonoids from their diet, such as citrus teas, grapefruits, lemons, and even dark chocolate. The goal was simple: let orange juice be the only source of these unique plant compounds.
At the beginning and end of the study, participants had their blood taken, and key parameters measured, such as sugar, fats, cholesterol, and inflammatory markers, and then a technique was used to analyze gene activity. Here, it’s worth explaining the term gene expression, which means how loudly or quietly a specific gene is “speaking” in our body. You can imagine this as the volume of a radio. Some genes are very loud (meaning they work more), others are silenced (meaning they work less).
When researchers compared the results before and after 60 days, they found something that can easily be ranked among the most surprising findings of 2024: 3,790 genes changed their activity.
This is no small thing. For comparison, heart medications typically affect three to ten key genes. Orange juice, almost four thousand.
And which processes did the juice affect the most?
Genes related to high blood pressure were significantly quieter after 60 days. Traditional folk practices also endorsed citrus fruits for better heart health. Some records from the 19th century even mention drying orange peels and using them in teas to calm the heart.
Today’s science confirms this: flavonoids improve blood vessel flexibility, which decreases resistance in blood circulation.
One of the larger meta-analyses from 2023 showed that 500 ml of orange juice daily reduces systolic blood pressure by about 4 mmHg, which is similar to what you can achieve with a 20-minute daily walk.
Inflammations are processes that we don’t feel right away, but can be measured in the blood. Chronic inflammation is linked to more than 50 modern diseases, including type 2 diabetes, fatty liver, cardiovascular disease, and faster aging.
The study showed: genes associated with inflammation were strongly suppressed.
This also means the body actually functioned more calmly, less irritated, and less burdened by internal stressors. This effect was especially noticeable in people with normal body weight, where the reduction in inflammatory markers was most pronounced.
In the world of folk medicine, it’s said that citrus fruits cleanse the blood. In reality, this means they lower markers such as CRP, interleukin-6, and TNF-alpha, which scientists clearly observed here as well.
The juice affects the storage and use of energy
In overweight individuals, the effect was even stronger. Genes involved in how the body stores and uses fats were altered. For these participants, after 60 days, they observed:
- improved regulation of fatty acids,
- lower levels of LDL (bad) cholesterol,
- and higher levels of HDL (good) cholesterol.
In numbers: the average reduction of LDL was 8%, increased HDL by 3-5%. This is very comparable to what other, larger studies have shown. A meta-analysis of 10 studies from 2015-2022 found that regular consumption of orange juice improves the lipid profile by 5-10%, which is surprisingly high.
What about the sugar in orange juice? Is this a problem?
Orange juice contains natural sugar, about 45-50 grams per half-liter. That’s about the same as in a small chocolate bar.
But something else is important: the sugar in juice is wrapped in fiber, vitamins, and flavonoids, which means the body reacts differently than to sugar in sweetened drinks. The study did not observe worsening of blood sugar. Quite the opposite:
- in some people, HOMA-IR (a measure of insulin sensitivity) decreased by 3-4%,
- average glucose levels dropped by about 2%.
Of course, it’s important to understand that this doesn’t mean you can drink a liter or two. Half a liter is the limit that gives the optimal results.
The study also recommends:
- drink 100% natural orange juice, without added sugar,
- drink it in two servings (as in the study and not all at once),
- and make sure it’s a moderate part of your diet, not your main source of sugar.
Folk wisdom says: everything is healthy if it’s in moderation. You can also try this:
- tea from dried orange peels (but the peels must be organic, as others are often waxed),
- water with a few drops of lemon and grated orange peels, which are high in fiber,
- or a simple trick from home kitchens, where as early as 1950, people would mix water with a little orange juice (this drink was once very popular among children).
In all this, it is important to bring flavonoids into the body, which are strongest when part of a natural food (and not in capsules!).
Is half a liter of orange juice a day a good idea?
When we combine all the data, we get a very clear answer: YES, but make it moderate and regular.
In the future, we’ll need even larger and longer-term studies (perhaps those that will follow people for at least a year), but we already know that each day we can take a small step for better health. And sometimes, it’s this very simplicity that helps the most. The orange has been a symbol of health for centuries, from ancient Greek physicians to our grandmothers—and it seems there have always been plenty of reasons for that.
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