Orange and watermelon: nine times the vitamin C, and juice trials that trim LDL

A meta-analysis of 10 randomized trials in adults found that orange juice lowered LDL cholesterol by 9.14 mg/dl (95% CI 2.49 to 15.79) and fasting glucose by 2.92 mg/dl (95% CI 0.53 to 5.33) against control. That result is about juice, not the whole fruit, and the effect held in trials giving 17 fl oz (500 mL) a day or more. That volume is a trial dose, not advice: the US guidelines ask for 100% juice in limited portions or diluted with water. Watermelon has its own meta-analysis of 9 randomized trials. It found lower systolic pressure and lower total and LDL cholesterol, alongside a rise in fasting blood sugar, and the abstract gives no size for any of them. A 4-week pilot trial in 39 adults with elevated blood pressure then found no significant change in 24-hour pressure from one or two cups of watermelon a day. On composition the two fruits are far apart. Across 8 USDA samples each, raw navel oranges averaged 59.1 mg of vitamin C per 3.5 oz (100 g) and seedless watermelon 6.5 mg. The UK table gives 52 mg against 8 mg.

How much is actually in it

• Raw navel oranges averaged 59.1 mg vitamin C per 3.5 oz (100 g) in USDA Foundation Foods, against 6.5 mg for seedless watermelon flesh, about nine times more. — Oranges, raw, navels (8 samples); Watermelon, seedless, flesh only, raw (8 samples) (n = 16) Evidence E source
  Orange 59.1 mg/100 g (51.8-65.6); watermelon 6.458 mg/100 g (5.02-8.67)
• In USDA Foundation Foods watermelon flesh holds 90.9 g water and 117 mg potassium per 3.5 oz (100 g), orange 86.7 g water and 166 mg potassium. — Oranges, raw, navels (8 samples); Watermelon, seedless, flesh only, raw (8 samples) (n = 16) Evidence E source
  Water 90.91 vs 86.7 g/100 g; potassium 117.3 (76.2-145.0) vs 166.0 (147.0-188.0) mg/100 g
• The UK CoFID 2021 lists 52 mg vitamin C and 36 calories per 3.5 oz (100 g) for orange flesh against 8 mg and 31 calories for watermelon flesh, a second independent figure. — CoFID 14-327 Oranges, flesh only; CoFID 14-296 Melon, watermelon, flesh only (n = -) Evidence E source
  Vitamin C 52 vs 8 mg/100 g; energy 36 vs 31 calories; carotene 55 vs 116 ug; sugars 8.2 vs 7.1 g

What a real portion looks like

• In the US FNDDS one raw orange weighs 5.4 oz (154 g) and a cup 180 g, while a cup of watermelon is 155 g and a small wedge 218 g. — FNDDS 61119010 Orange, raw; FNDDS 63149010 Watermelon, raw (n = -) Evidence E source
  Orange 1 fruit 154 g, 1 cup 180 g; watermelon 1 cup 155 g, small wedge 218 g, medium wedge 325 g
• The 2025-2030 US Dietary Guidelines advise eating whole fruits in their original form, with a goal of 2 fruit servings a day on a 2,000-calorie pattern. — US population, federal dietary guidance Evidence E source
  Fruits 2 servings/day at 2,000 calories; whole fruit in original form
• In the guidelines' serving guide one fruit serving is 1 cup raw or half a cup dried, and the fruit group includes fresh, frozen, canned, juiced and dried fruit. — US population, federal dietary guidance Evidence E source
  1 fruit serving = 1 cup raw or 1/2 cup dried
• The 2025-2030 US Dietary Guidelines say 100% fruit or vegetable juice should be drunk in limited portions or diluted with water. — US population, federal dietary guidance Evidence E source
  100% juice: limited portions or diluted; no volume given

What your body absorbs

• In a randomized crossover trial in 37 overweight men, 11 fl oz (330 mL) orange juice daily gave hesperetin metabolite exposure comparable to 210 mg pure hesperidin over 6 weeks. — 37 centrally overweight men, three 6-week crossover periods (n = 37) Evidence B source
  Plasma AUC0-6h and 24 h urinary excretion comparable for juice and hesperidin

What cooking and storage change

• By the USDA retention table for Fruits and Fruit Juices, cooked citrus keeps 95% of vitamin C and 70% of folate, while frozen fruit keeps 70% of vitamin C. — food group Fruits and Fruit Juices (group factors, not product-specific) (n = -) Evidence E source
  R6:270 citrus cooked vitamin C 95%, folate 70%; R6:156 frozen fruit vitamin C 70%

What it does to your health

• A meta-analysis of 10 RCTs found orange juice lowered LDL cholesterol by 9.14 mg/dl and fasting glucose by 2.92 mg/dl versus control. — adults in 10 randomized controlled trials of orange juice (n = 10 RCTs) Evidence A source
  LDL-C WMD -9.14 mg/dl (95% CI -15.79 to -2.49); glucose WMD -2.92 mg/dl (95% CI -5.327 to -0.530)
• A meta-analysis of 9 RCTs found watermelon lowered systolic pressure, total and LDL cholesterol but raised fasting blood sugar, with no change in diastolic pressure or BMI. — participants of 9 randomized controlled trials of watermelon supplementation (n = 9 RCTs) Evidence A source
  SBP, TC, LDL decreased; FBS increased; size not reported in abstract
• In a crossover RCT in 18 healthy young adults, 17 fl oz (500 mL) watermelon juice daily for 2 weeks preserved heart rate variability (pNN50) during a glucose challenge versus placebo. — 18 healthy young men and women, 2-week crossover periods (n = 18) Evidence B source
  PNN50 higher with watermelon juice (treatment effect p = 0.009); no effect on metabolic parameters
• In a 4-week randomized trial in 39 adults with elevated blood pressure, eating one or two cups of watermelon a day did not change 24-hour blood pressure compared with no watermelon. — 39 adults (41 ± 14 y, BMI 31) with elevated BP; 0, 152 or 304 g watermelon flesh a day for 4 weeks (n = 39) Evidence B source
  Mean 24 h ambulatory BP 130.2 (control), 130 (1 cup), 124.9 mm Hg (2 cups), p > 0.05; plasma L-arginine and L-arginine/ADMA up
• In a 4-week randomized trial in 62 adults with fatty liver disease, 14 oz (400 g) of whole oranges a day left 70.9% with liver steatosis against 100% of those eating other fruit, without weight change. — 62 adults aged 30-65 with MASLD (CAP > 275 dB/m); 400 g whole oranges vs non-citrus fruit daily, 4 weeks (n = 62) Evidence B source
  Steatosis prevalence 70.9% vs 100% (p < 0.004); GGT down; fibrosis, other liver enzymes, weight, lipids, glucose unchanged

Safety, limits and interactions

• In an RCT of 128 women discharged after hyperemesis gravidarum, adding watermelon kept body weight stable at 2 weeks (+0.55 lb (0.25 kg)) while controls lost 1.1 lb (0.5 kg). — 128 pregnant women after hospitalization for hyperemesis gravidarum, Malaysia (n = 128) Evidence B source
  Weight change week 2 median +0.55 vs -1.1 lb (0.25 vs -0.5 kg) (P = 0.001); rehospitalization not different
• A 2026 case report describes a 40-year-old man with normal kidneys who reached serum potassium of 9.4 mmol/L after weeks of drinking large volumes of dried orange juice powder. — one 40-year-old man with normal renal function (n = 1) Evidence D source
  Serum potassium 9.4 mmol/L, ICU admission
• A meta-analysis of 51 pharmacokinetic studies found that orange and apple juice have comparable effects on certain medications. — humans in 51 pharmacokinetic studies, mostly open-label crossover (n = 51 studies) Evidence A source
  Orange and apple juice: comparable effects on certain drugs; drugs and effect size not given in the quoted sentence

What people believe that the data does not support

• A meta-analysis of 21 RCTs found citrulline or watermelon supplementation had no overall effect on body weight, BMI, fat mass or waist circumference. — participants of 21 randomized controlled trials (n = 21 RCTs) Evidence A source
  No substantial effect on BMI, body weight, FM, WC, BFP, FFM
• The EU did not authorize claims that watermelon extract helps weight loss or improves carbohydrate and fat metabolism. — EU market (n = -) Evidence E source
  -
• The EU did not authorize the traditional claim that orange supports blood circulation in small vessels or relieves heavy legs. — EU market (n = -) Evidence E source
  -

Who this works differently for

• A meta-analysis of 15 RCTs with 415 middle-aged and older adults found L-citrulline or watermelon lowered systolic pressure by 4.02 mmHg and diastolic by 2.54 mmHg. — 415 middle-aged and elderly participants, 15 RCTs, 24 datasets (n = 415) Evidence A source
  SBP -4.02 mmHg (95% CI -6.54 to -1.50); DBP -2.54 mmHg (95% CI -4.27 to -0.81)
• A meta-analysis of 8 RCTs with 176 middle-aged and older adults found watermelon did not improve arterial stiffness or flow-mediated dilation, unlike L-citrulline (FMD +1.81). — 176 middle-aged and older adults in 8 RCTs, ages 54 to 72 (n = 176) Evidence A source
  L-citrulline FMD 1.81 (95% CI 0.76 to 2.85); watermelon: no significant change in PWV or FMD
• In 15 people with well-controlled type 2 diabetes, a breakfast with whole orange pieces, 8.5 fl oz (250 mL) orange juice or a sugary orange drink of equal sugar gave the same blood glucose and insulin rise. — 15 adults with well-controlled T2DM (60 ± 6 y, HbA1c 6.6%), single test meals (n = 15) Evidence B source
  No difference in glucose or insulin AUC or peaks between whole orange, 100% juice and sugar-sweetened drink (p > 0.05)

The bottom line

The trials of whole oranges are short. In 62 adults aged 30 to 65 with fatty liver disease, 14 oz (400 g) of whole oranges a day for 4 weeks left 70.9 percent with liver steatosis against 100 percent of those eating other fruit, with no change in weight. Those were exploratory outcomes from a single center. In 15 people with well-controlled type 2 diabetes, one breakfast with whole orange pieces, 8.5 fl oz (250 mL) of orange juice or a sugary orange drink of equal sugar produced the same rise in blood glucose and insulin. That was a single meal in a small group. In 37 centrally overweight men, 11 fl oz (330 mL) of orange juice a day gave hesperetin levels in the blood comparable to 210 mg of pure hesperidin. Much of the watermelon evidence is really about citrulline. A meta-analysis of 15 randomized trials in 415 middle-aged and older adults found L-citrulline or watermelon lowered systolic pressure by 4.02 mmHg (95% CI 1.50 to 6.54) and diastolic by 2.54 mmHg (95% CI 0.81 to 4.27), with the two pooled and no separate figure for the fruit. Another meta-analysis of 8 trials in 176 adults aged 54 to 72 found that watermelon did not significantly improve arterial stiffness or flow-mediated dilation, while L-citrulline raised dilation by 1.81 points. In 18 healthy young adults, 17 fl oz (500 mL) of watermelon juice a day for 2 weeks kept heart rate variability higher during a glucose challenge than placebo did. That is a small, short trial on a surrogate marker. The trials do not show watermelon helping weight loss. A meta-analysis of 21 randomized trials, mostly of citrulline supplements, found no substantial effect on body weight, BMI, fat mass or waist size. The EU did not authorize weight-loss claims for watermelon extract, nor the traditional claim that orange relieves heavy legs. A refused claim means the evidence was not accepted, which is weaker than proof of no effect. Who should be careful. A meta-analysis of 51 pharmacokinetic studies found that orange and apple juice have comparable effects on certain medicines, and the sentence we hold does not name which medicines or how large the effect is. Most of those studies were open-label, and their clinical importance was not assessed. If you take regular medicines, that is a question for your pharmacist, not a reason to assume orange juice is neutral. A 2026 case report describes a 40-year-old man with normal kidneys whose serum potassium reached 9.4 mmol/L after weeks of drinking large volumes of dried orange juice powder, a single case involving a powder and not fresh fruit. The US guidelines ask for 100 percent juice in limited portions or diluted with water, without naming a volume. In pregnancy we have one trial, and it measured weight, not safety. After hospital treatment for severe pregnancy sickness, 128 Malaysian women who added watermelon gained a median 0.55 lb (0.25 kg) over 2 weeks while controls lost 1.1 lb (0.5 kg), in an unblinded trial at one hospital that saw no difference in readmissions. We found no other safety data for watermelon. Per 100 g, orange carries 166 mg of potassium and watermelon 117 mg, with watermelon samples ranging from 76 to 145 mg, and watermelon is 90.9 percent water. The US survey counts one raw orange as 154 g and a cup of watermelon as 155 g. By USDA group factors from 1975, cooked citrus keeps 95 percent of its vitamin C and frozen fruit 70 percent, figures never measured on these two fruits.

Sources

1. orwm-daily-r4-01 · composition dataset
   Oranges, raw, navels (USDA FoodData Central, Foundation Foods, release 2026-04-30): Vitamin C, total ascorbic acid 59.1 MG, range 51.8-65.6 (median 58.0), samples 8, spread 23%; Watermelon, seedless, flesh only, raw: Vitamin C, total ascorbic acid 6.458 MG, range 5.02-8.67 (median 5.995), samples 8, spread 57%
   USDA FoodData Central, Foundation Foods, release 2026-04-30 (Oranges, raw, navels; Watermelon, seedless, flesh only, raw) · checked 2026-09-29
2. orwm-daily-r4-02 · composition dataset
   Oranges, raw, navels (USDA FoodData Central, Foundation Foods, release 2026-04-30): Water 86.7 G, range 85.5-87.9, samples 8; Potassium, K 166.0 MG, range 147.0-188.0, samples 8; Watermelon, seedless, flesh only, raw: Water 90.91 G, range 89.55-93.1, samples 8; Potassium, K 117.3 MG, range 76.2-145.0, samples 8
   USDA FoodData Central, Foundation Foods, release 2026-04-30 (Oranges, raw, navels; Watermelon, seedless, flesh only, raw) · checked 2026-09-29
3. orwm-daily-r4-03 · composition dataset
   CoFID 2021 14-327 Oranges, flesh only: Vitamin C (mg) 52, Energy (kcal) 36, Carotene (ug) 55, Total sugars (g) 8.2; CoFID 2021 14-296 Melon, watermelon, flesh only: Vitamin C (mg) 8, Energy (kcal) 31, Carotene (ug) 116, Total sugars (g) 7.1
   CoFID 2021, Public Health England, codes 14-327 and 14-296 (OGL v3.0) · checked 2026-09-29
4. orwm-daily-r4-05 · portion dataset
   FNDDS 61119010 Orange, raw (fdc_id 2709171, Citrus fruits): 1 fruit 154 g, 1 cup 180 g; FNDDS 63149010 Watermelon, raw (fdc_id 2709270, Melons): 1 cup 155 g, 1 small wedge/slice 218 g, 1 medium wedge/slice 325 g
   USDA FNDDS (fdc_id 2709171, 2709270) · checked 2026-09-29
5. orwm-dga-01 · agency guideline
   Eat whole vegetables and fruits in their original form. ... Vegetables and fruits serving goals for a 2,000-calorie dietary pattern, adjusting as needed based on your individual caloric requirements: - Vegetables: 3 servings per day - Fruits: 2 servings per day
   Dietary Guidelines for Americans, 2025-2030 (HHS, USDA), January 2026 · checked 2026-09-29
6. orwm-dga-02 · agency guideline
   Fruits 1 cup raw; ½ cup dried ... Fruits: Fruits of all types, including fresh, frozen, canned, juiced, and dried fruits.
   Dietary Guidelines for Americans, 2025-2030: Daily Servings by Calorie Level (HHS, USDA) · checked 2026-09-29
7. orwm-dga-03 · agency guideline
   100% fruit or vegetable juice should be consumed in limited portions or diluted with water.
   Dietary Guidelines for Americans, 2025-2030 (HHS, USDA), January 2026 · checked 2026-09-29
8. orwm-daily-r4-06 · RCT
   Plasma exposure to phase II hesperetin metabolites (AUC0-6 h) and 24 h urinary excretion were comparable after OJ and HESP, indicating effective hesperidin delivery and limited matrix effects on bioavailability.
   Food Funct, 2026 · checked 2026-09-29
9. orwm-daily-r4-04 · retention dataset
   USDA-RETN-R6:270 FRUITS,CITRUS,CKD, group Fruits and Fruit Juices: vitamin_c_mg 95% retained, folate_total_ug 70% retained; USDA-RETN-R6:156 FRUITS,FROZEN: vitamin_c_mg 70% retained
   USDA Table of Nutrient Retention Factors, Release 6 (2007), codes 270 and 156 · checked 2026-09-29
10. orwm-daily-r4-07 · meta-analysis
    Pooled results demonstrated a significant effect of orange juice on glucose (WMD: -2.92 mg/dl, 95% CI: -5.327, -0.530, p = 0.017), insulin (WMD: -1.229 μU/ml, 95% CI: -2.083, -0.374, p = 0.005), HOMA-IR (WMD: -0.464, 95% CI: -0.747, -0.181, p = 0.001), total cholesterol (WMD: -9.84 mg/dl, 95% CI: -15.43, -4.24, p = 0.001), LDL-C (WMD: -9.14 mg/dl, 95% CI: -15.79, -2.49, p = 0.007), and CRP (WMD: -0.467 mg/l, 95% CI: -0.815, -0.120, p = 0.008) compared to control group.
    Crit Rev Food Sci Nutr, 2022 · checked 2026-09-29
11. orwm-daily-r4-08 · meta-analysis
    Of the 8962 identified studies, 9 RCTs were included in the final analysis. Watermelon consumption significantly decreased systolic blood pressure (SBP), totalcholesterol (TC) and low-density lipoprotein (LDL). In addition, watermelon consumption led to a significant increase in fasting blood sugar (FBS).
    Diabetes Res Clin Pract, 2023 · checked 2026-09-29
12. orwm-daily-r4-11 · RCT
    Subsequently, participants were randomized to complete 2 weeks of daily WMJ supplementation (500 mL) or a placebo drink (PLA)...We studied 18 healthy young men and women...The percentage of successive differences that differ by more the 50 ms (pNN50) was increased during WMJ treatment (treatment effect p = 0.009).
    Nutrients, 2023 · checked 2026-09-29
13. orwm-ws12-01 · RCT
    After 4 weeks, mean 24 h ambulatory BP was 130.2 ± 3.9 mm Hg (control), 130 ± 3.2 mm Hg (WM-1 cup), and 124.9 ± 3.9 mm Hg (WM-2 cups), with no statistically significant differences between study interventions (p > 0.05).
    Nutrients 2025;17(19):3073 · checked 2026-09-29
14. orwm-ws12-02 · RCT
    After 4 weeks of orange supplementation, liver steatosis decreased in the treatment group, with 70.9% showing steatosis compared to 100% in controls (p < 0.004), indicating a 30% reduction in liver disease prevalence.
    Nutrients, 2024 · checked 2026-09-29
15. orwm-daily-r4-12 · RCT
    Weight change (kg) at end of week 1, median[interquartile range] -0.05[-0.775 to + 0.50] vs. -0.5[-1.4 to + 0.1] P = 0.014 and to the end of week 2, + 0.25[-0.65 to + 0.975] vs. -0.5[-1.3 to + 0.2] P = 0.001 for watermelon and control arms respectively.
    BMC Pregnancy Childbirth, 2023 · checked 2026-09-29
16. orwm-daily-r4-14 · case report
    Further history revealed excessive daily consumption of large volumes of a dried orange juice powder reconstituted as a beverage over several weeks.
    Cureus, 2026 · checked 2026-09-29
17. orwm-daily-r4-15 · meta-analysis
    Apple and orange juices have comparable effects on certain medications.
    Complement Ther Med, 2025 · checked 2026-09-29
18. orwm-daily-r4-13 · meta-analysis
    Twenty-one RCTs were included. Overall, CIT supplementation had no substantial effects on body mass index (BMI), body weight, fat mass (FM), waist circumference (WC), body fat percentage (BFP), and fat-free mass (FFM).
    Nutrients, 2025 · checked 2026-09-29
19. orwm-daily-r4-16 · EU claim register
    POL-HC-6935 Citrullus lunatus (Watermelon) extract - ACTI-08 Helps to improve carbohydrate and fat metabolism of the body Used to facilitate the weight loss Helps to loose weight Contributes to loose weight Used to facilitate the weight loss Helps in weight control Contributes to body weight management. Non-authorised
    EU Register on nutrition and health claims, claim POL-HC-6935, snapshot 2026-09-21 · checked 2026-09-29
20. orwm-daily-r4-17 · EU claim register
    POL-HC-6941 Citrus sinensis - common name : Orange Traditionally used for the good circulation of blood in microvessels / "Traditionally used to decrease the sensations of heavy leggs" / "Used for the good circulation of blood in microvessels" / "Helps to decrease the sensations of heavy leggs" Non-authorised
    EU Register on nutrition and health claims, claim POL-HC-6941, snapshot 2026-09-21 · checked 2026-09-29
21. orwm-daily-r4-09 · meta-analysis
    A total of 15 randomized controlled trials (RCTs) investigating the effects of l-citrulline supplementation and watermelon intake on BP in middle-aged and elderly individuals were included, comprising 24 datasets involving 415 participants. The results indicate that l-citrulline supplementation and watermelon intake significantly reduced SBP (-4.02 mmHg [95 % CI: -6.54 to -1.50], P = 0.002) and DBP (-2.54 mmHg [95 % CI: -4.27 to -0.81], P = 0.004) in the elderly.
    Clin Nutr ESPEN, 2025 · checked 2026-09-29
22. orwm-daily-r4-10 · meta-analysis
    The results showed that L-citrulline supplementation significantly improved FMD [1.81 (95% CI: 0.76 to 2.85), p = 0.0007]...However, watermelon supplementation did not significantly improve PWV and FMD in middle-aged and older adults.
    Front Nutr, 2025 · checked 2026-09-29
23. orwm-ws12-03 · RCT
    Following a single intake, no significant differences were found in acute glucose or insulin responses (expressed as total or incremental area under the curve or peak values; ptreatment > 0.05, respectively) when either whole orange pieces, orange juice or a sugar-sweetened control beverage were consumed with a standard high carbohydrate meal.
    Nutr Diabetes 2025 · checked 2026-09-29