A study published in October 2025 in Molecular Nutrition & Food Research found that adults who drank 500 milliliters (about two cups) of pasteurized orange juice every day for 60 days showed altered activity in 1,705 genes inside their immune cells.
Many of the shifts landed on genes tied to inflammation, blood pressure, and fat metabolism, and most of the inflammation-related genes became less active.
The work was a transcriptomic analysis in 20 healthy volunteers, not a clinical trial, so it points to biological patterns rather than proving cause and effect.
The researchers, led by teams at the Food Research Center at the University of São Paulo and North Carolina State University, sequenced RNA from immune cells before and after the two-month juice period.
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The analysis of the 20 healthy participants turned up 3,790 differentially expressed molecules, covering the 1,705 protein-coding genes plus dozens of microRNAs and other regulatory RNAs.
These genes moved
Several of the genes that became less active are ones the body cranks up during inflammation and high blood pressure.
IL1B, the gene for the pro-inflammatory signal interleukin-1 beta, fell sharply, and IL6 and PTGS2, both drivers of the inflammatory response, also dropped.
NAMPT and NLRP3, two genes that tend to be elevated in people with hypertension, were similarly downregulated. Genes involved in fat handling shifted too, including GSK3B, which helps regulate lipid metabolism, and RIPK1.
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Hesperidin and vitamin C as likely drivers
Pasteurized orange juice is a concentrated source of hesperidin and naringenin, two citrus flavanones, along with vitamin C.
The study's molecular docking work pointed to metabolites of hesperidin and naringenin as the most likely molecules interacting with the affected gene networks.
Hesperidin's cardiovascular and anti-inflammatory profile has been documented elsewhere.
A cell-culture study published in September 2025 reported that hesperidin cut production of IL-1β, TNF-alpha and IL-8 in activated immune cells. The paper linked hesperidin's blood pressure effect to its role in the vascular endothelium, the inner lining of blood vessels.
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The response varied by body weight
The pattern was not uniform across the group. In overweight participants, the gene changes clustered around lipid metabolism, with GSK3B, GRK6 and two microRNAs previously linked to body-weight control showing up only in that group.
In the normal-weight participants, the shifts were concentrated in inflammation pathways involving interleukin-4, interleukin-1 and interleukin-9 signaling.
The authors concluded that body weight may shape how the body responds to citrus compounds, opening the door to more personalized nutrition advice.
What it means for your breakfast
The findings add a molecular layer to earlier work linking orange juice to modest reductions in blood pressure, and they may help explain why the effect shows up in some trials.
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But this was a small study, and most of the gene-level changes did not translate into large shifts in the participants' blood biochemistry.
Orange juice also remains a concentrated source of fruit sugar. Public health guidance in most countries recommends favoring whole fruit, which contains the same flavonoids plus fiber.
Anyone with diabetes or on blood pressure medication should talk to a doctor before making a daily glass of juice a regular habit.
The paper is available in open access through the PMC repository, where the full methods, gene lists and statistical results can be read.
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This article is made and published by Ida-Marie Palm Varbæk, who may have used AI in the preparation.