Contents
What it is
The orange is a citrus thought to descend from a cross between the pomelo and the mandarin. It originated in southern China, and Brazil and the United States are now the largest producers. What most distinguishes it from a mandarin is that the peel clings tightly to the flesh and does not come away by hand. The aroma compounds sit in oil glands in the peel, so grated zest smells far stronger than the juice. The white pith carries bitterness along with dietary fibre. Juicing removes most of that fibre.
Scientific name Citrus sinensis
One orange covers an adult's daily vitamin C requirement. But that alone does not describe the fruit.
The white layer around the segments — the albedo — concentrates flavonoids like hesperidin along with pectin. The more carefully you strip it away, the closer what remains gets to plain sugar.
Key benefits
- Nutrition data
Vitamin C for collagen and immunity
53 mg per 100 g. A medium orange (about 140 g) gives roughly 74 mg — close to the daily requirement of 75–90 mg for adults, but one orange does not quite get you there. Vitamin C is an essential cofactor in collagen synthesis and sharply increases absorption of plant-source iron.
- Not established
Hesperidin remains a mixed picture
This citrus flavonoid appears repeatedly in studies of endothelial function, and is concentrated in the pith and peel. But a meta-analysis of randomised trials concluded that hesperidin might not affect lipid profile or blood pressure. The mechanism is plausible; the human results are not yet settled.[1]
- Moderate evidence
Pectin flattens the glucose response
A whole orange raises blood sugar far more slowly than the same amount as juice, because the fibre slows sugar absorption.[2]
- Moderate evidence
Citrate is used to prevent kidney stones
Citrus citrate raises urinary citrate, which inhibits calcium crystal formation. That is why citrus is recommended in diets aimed at preventing stone recurrence.[3]
How to eat it well
- Do not pick off the white pith. The fibre and hesperidin are in it.
- Whole beats juice. Juice has no fibre and a glass carries the sugar of three or four oranges.
- Vitamin C degrades with heat and light. Eat it soon after peeling.
- If you are low on iron, eat it alongside plant-source iron to raise absorption.
- The zest is rich in aroma and flavonoids. Wash well before using, given pesticide residues.
How to read the grades
Each benefit carries a label showing how far research on people supports it. Grades differ between items even within the same ingredient.
- Nutrition data
- A fact verifiable from food composition databases or health authorities. This is a different kind of statement from a clinical effect.
- Strong evidence
- Consistently confirmed across randomised controlled trials or meta-analyses.
- Moderate evidence
- Human studies exist, but effect sizes are small or results are mixed.
- Early research
- Cell or animal work, or small preliminary studies.
- Not established
- Commonly claimed, but not confirmed in studies on people.
What to watch out for
- With acid reflux, the acidity can worsen symptoms.
- Unlike grapefruit, sweet oranges barely interact with medication — but Seville (bitter) oranges behave more like grapefruit, so take care.
- Juice is concentrated in sugar: if you manage blood glucose, choose the whole fruit.
- The acid means brushing right after eating can damage enamel.
Nutrition
Approximate values per 100 g edible portion.
- Calories
- 47 kcal2%
- Carbohydrates
- 11.8 g4%
- Fiber
- 2.4 g9%
- Sugars
- 9.4 g
- Protein
- 0.9 g2%
- Vitamin C
- 53 mg59%
- Folate
- 30 µg8%
- Potassium
- 181 mg4%
Percentages are of the US FDA Daily Value for adults and children 4 and over. National reference intakes differ by sex and age.
Calculate this alongside other ingredients →
Key nutrients
By health concern
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Sources
The databases and health authorities this article's nutrition figures and health statements draw on.
- 1Hesperidin, a major flavonoid in orange juice, might not affect lipid profile and blood pressure: A systematic review and meta-analysis of randomized controlled clinical trialsMeta-analysisMohammadi M, et al. Phytother Res 2019PMID 30632207
- 2Addition of Orange Pomace Attenuates the Acute Glycemic Response to Orange Juice in Healthy AdultsClinical trialGuzman G, et al. J Nutr 2021PMID 33704466
- 3Randomized double-blind study of potassium citrate in idiopathic hypocitraturic calcium nephrolithiasisClinical trialBarcelo P, et al. J Urol 1993PMID 8230497
- 4USDA FoodData CentralFood composition database
- 5NIH Office of Dietary SupplementsHealth authority
- 6PubMedResearch literature
