Green & Vegetable Juices: Nutrients, What Research Shows and Safety

"Green juice" and "vegetable juice" cover very different drinks: juice squeezed at home or at a juice bar from kale, spinach, celery and cucumber, and canned or bottled mixed-vegetable juice. The ingredients, the amounts and the salt vary a lot from one glass to the next, so this page looks at both and says which one a study actually used. It keeps these drinks apart from whole vegetables, from "cleanse" claims and from supplements, and it says plainly what the research does not show.

Read this first

• There is no single "green juice" to measure. USDA has no entry for homemade green juice in our data, so we show the raw vegetables that go into it instead. [1] [2] [3] [4] Real glasses depend on what and how much was juiced.
• Oxalate can hurt the kidneys in some people. Case reports describe sudden kidney failure after green juice and smoothie "cleanses" in people with risk factors such as bowel surgery, antibiotics, diabetes or kidney disease. [6] [7] NIDDK lists spinach among foods to avoid for people prone to calcium oxalate stones. [8]
• Warfarin: leafy greens such as kale and spinach are rich in vitamin K, and MedlinePlus says people on warfarin should keep vitamin K intake steady, because sudden changes can change the medicine's effect. [5]
• Kidney disease: leafy greens contain a lot of potassium; ask a clinician or dietitian before drinking them regularly if you have kidney disease. [2] [15]
• Juice cleanses and "detox" claims are not supported. A critical review found very little clinical evidence for detox diets. [16] See Detox foods and juice cleanse claims.
• Evidence in one line: a few small trials of commercial vegetable juice show it can help people eat more vegetables and may lower blood pressure in some, but those trials were partly industry-funded and small.
• Emergency: for trouble breathing or swelling of the face or throat after any food, call 911 (or your local emergency number).

What is in it (USDA values)

USDA has no value for green juice made at home or at a juice bar, so there is no row for the drink itself. [1] The table shows the raw vegetables often used (USDA FoodData Central, SR Legacy) per 100 g. Juicing does not keep every part: the amount in a glass depends on how many vegetables were used and on how much pulp was strained out. We did not read a source that measured home-made juice.

For comparison, one commercial mixed vegetable juice used in a trial listed, per 8 fluid ounces: 50 calories, 480 mg sodium, 470 mg potassium, 8 g sugars and 2 g fiber. [10] USDA's canned tomato juice lists 253 mg sodium per 100 g with salt added and 10 mg without. [19] [20] Canned and bottled juices can therefore carry a lot of salt, so check the label.

The FDA 2016 Daily Values for these nutrients are 120 mcg vitamin K, 4,700 mg potassium and 2,300 mg sodium, so 100 g of raw kale or spinach already holds several times the vitamin K Daily Value. We did not find an official serving size for home-made green juice. Plant compounds: the sources we read for this page did not measure them in the juice, so we make no antioxidant or polyphenol claim.

What research says

Both vegetable juice trials were supported by a soup and juice company, and company employees are among the authors. [9] [10] The nitrate trial was a small pilot. [11] Observational findings about people who drink vegetable juice cannot prove cause, and we did not read one.

Eaten as food vs taken as juice or supplement. The trials used juice drinks, not whole vegetables and not powders or capsules. We did not read a source that compares the same vegetables eaten whole and juiced. The NHS counts vegetable juice as at most one portion of 5 A DAY, with juice and smoothies together limited to 150 ml a day. [12]

How much is a normal serving

There is no official serving size for green juice. The NHS counts fruit juice, vegetable juice and smoothies as one 5 A DAY portion at most, and advises a combined 150 ml a day, partly because crushing produce releases sugars that can harm teeth. [12] WHO says people over 10 should aim for at least 400 g of fruit and vegetables a day. [14] The trials used 8 or 16 fluid ounces of commercial juice [9] [10] and 250 ml of a green leafy juice [11]. That is what the studies tested, not a prescription.

Safety, allergy and medicines

• Oxalate and kidney injury: a case report describes a 65-year-old woman with acute oxalate nephropathy linked in time to a juice "cleanse" made from oxalate-rich leafy greens and fruit; her risk factors included gastric bypass and recent antibiotics, and her condition progressed to end-stage kidney disease. [6] Another case report describes a diabetic man who developed kidney injury needing dialysis after a week-long juice diet. [7] These are case reports, not proof that juice causes the injury, but the authors warn people with risk factors. [6] [7] NIDDK says to avoid spinach if you form calcium oxalate stones and to ask a health care professional about other oxalate sources. [8]
• Warfarin and other medicines: kale, spinach, collards, Swiss chard and romaine are rich in vitamin K. [5] Keep intake steady and tell your prescriber if you start a juice routine. See Foods and medicine interactions.
• Kidney disease and potassium: raw spinach has 558 mg of potassium per 100 g and kale 348 mg. [1] [2] The National Kidney Foundation says people with kidney disease can have potassium levels outside their goal range and may be advised to limit high-potassium foods. [15]
• Sodium: canned and bottled vegetable juices can contain several hundred milligrams of sodium per serving. [10] [19]
• Unpasteurized juice: the FDA says untreated juice must carry a warning label and that children, older adults, pregnant women and people with weakened immune systems can become seriously ill from it. Juice sold by the glass, as at a juice bar, may not carry a label. [13] [17] Pregnant women should avoid unpasteurized juice. [17]
• Pregnancy and breastfeeding: besides juice safety above, the FDA says to rinse raw produce under running water without soap and to avoid raw sprouts of any kind. [17] We did not read a source on specific green juice ingredients in pregnancy.
• Children: the American Academy of Pediatrics says unpasteurized juice should be strongly discouraged for children of all ages. [18]
• Diabetes: we did not find a trial of green juice and blood sugar. Juices with fruit, carrots or beets add sugar; check what is in the glass. Canned tomato juice lists 2.58 g of sugars per 100 g. [20] Ask a clinician or dietitian.
• Allergy: we did not find a source we read describing a common allergy to the vegetables in green juices. Any food can cause a reaction; for trouble breathing or swelling of the face or throat, call 911. See Food allergy basics and emergency signs.

Choosing, storing and food safety

• Wash vegetables under running water (no soap or produce wash), scrub firm produce with a brush, cut away damaged areas and wash your hands for at least 20 seconds. [13]
• At a juice bar, ask whether the juice has been treated; look for the warning label on refrigerated bottles. [13]
• We did not read a source on how long fresh juice keeps; keep it cold and drink it soon, following the label for bottled juice.

Related pages

• Dietary nitrate in beets and leafy greens
• Beet juice
• Tomato juice
• Detox foods and juice cleanse claims
• Foods, kidney disease, potassium and oxalates
• Foods and medicine interactions: vitamin K, grapefruit and others
• Kale and Spinach