Spinach: Nutrients, What Research Shows and Safety

Spinach (Spinacia oleracea L.) is a leafy vegetable in the amaranth family (Amaranthaceae). The leaves are eaten raw in salads or cooked, and people eat it for its vitamins, minerals and plant pigments. This page keeps the whole food apart from supplements, extracts and hype, and says plainly what research does and does not show.

Read this first

• Warfarin: spinach is very rich in vitamin K, which affects how this blood thinner works. The NHS says you do not need to avoid such foods, but should ask your warfarin clinic for advice. [3] MedlinePlus says sudden changes in vitamin K intake can change how the medicine works. [2] Keep to the clinic's advice and do not change a prescribed medicine on your own.
• Kidney stones: the US kidney institute (NIDDK) names spinach as a high-oxalate food to limit if you have had calcium oxalate stones. [4]
• Kidney disease and potassium: spinach has a lot of potassium (558 mg per 100 g). [1] People with kidney problems, and people taking ACE inhibitors, ARBs or potassium-sparing diuretics, should ask a clinician about potassium-rich foods. [8]
• Allergy: a food allergy is possible with any food. For trouble breathing or swelling of the face or throat, call 911.
• Evidence in one line: eating more green leafy vegetables is linked to lower heart disease in observational studies, but trials of greens have not shown clear effects on blood pressure or artery function. [11]

What is in it (USDA values)

Raw spinach, USDA FoodData Central item 168462 (SR Legacy). [1] USDA household portion: 1 cup of raw leaves = 30 g.

% Daily Value uses the FDA 2016 Daily Values; values vary with variety, ripeness and storage. [1]

Plant compounds. USDA lists beta-carotene (5,626 µg per 100 g) and lutein plus zeaxanthin (12,198 µg per 100 g) in raw spinach. [1] These are yellow-orange plant pigments (carotenoids). Beta-carotene is turned into vitamin A in the body, which is why vitamin A is high in the table. Spinach also contains nitrate, a natural compound that is discussed below and on our nitrate page. The evidence we read for lutein and eye health is from people, and it is mixed (see the table).

What research says

Eaten as food vs taken as a supplement or extract

The heart-health findings above come from people eating greens as part of their diet and cannot show that spinach itself prevents disease. The only spinach-specific trials we read in detail used a concentrated extract, not the vegetable. [15] The lutein trial used a supplement, and it also found that the beta-carotene supplement group had more lung cancers (2.0% versus 0.9%), mostly in former smokers. [14] That finding is about beta-carotene supplements, not spinach, but it shows that a nutrient in food and the same nutrient in a pill are not the same thing. Powders, juices and extracts are different products and are not covered by food evidence.

How much is a normal serving

This is information, not a prescription. The WHO healthy diet fact sheet (January 2026) says at least 400 g of fruits and vegetables a day for people older than 10. [17] The NHS counts 80 g of fresh, canned or frozen vegetables as one portion (last reviewed 9 June 2026). [16] The USDA household portion for raw spinach is 1 cup, or 30 g. [1] Cooked spinach shrinks a lot, so the same weight holds many more leaves. For cooking, freezing and canning effects, proper evidence not found in the sources we read; see fresh, frozen and canned produce.

Safety, allergy and medicines

• Warfarin and vitamin K. Vitamin K helps blood clot, and spinach is a major source. [2] The NHS says foods high in vitamin K such as spinach and other leafy greens can affect how warfarin works; you do not need to avoid them, but should ask your warfarin clinic for advice and speak to a doctor before big diet changes. The NHS also says not to take vitamin K supplements while on warfarin. [3] MedlinePlus adds that steady intake from day to day matters, because sudden changes can change the effect. [2] See foods and medicine interactions.
• Oxalate and kidney stones. NIDDK lists spinach among high-oxalate foods for people who have had calcium oxalate stones, and says drinking enough liquid, mainly water, is the most important step for stone prevention. [4] In a small 2025 study of 21 healthy adults eating 10 oz of spinach, urinary oxalate rose in most people (about 2% to 12% of the oxalate was absorbed), and drinking extra water lowered the spikes in oxalate concentration. [5] Healthy non-stone-formers were studied; the result does not tell a person with stones what to do. Ask a clinician which stone type you have. See foods, kidney disease, potassium and oxalates.
• Potassium, kidney disease and medicines. MedlinePlus says people with kidney problems, particularly on dialysis, should not eat too many potassium-rich foods, and that ACE inhibitors, ARBs and potassium-sparing diuretics (spironolactone, triamterene, amiloride) are common causes of high blood potassium. [8] MedlinePlus does not name spinach on that page, but USDA lists 558 mg of potassium per 100 g. [1, 8]
• Nitrate. Spinach contains natural nitrate. Our nitrate page found mixed blood pressure results for nitrate supplements and beet juice, and a meta-analysis of 16 small trials reported a lower systolic pressure with inorganic nitrate or beetroot juice (-4.4 mm Hg), not spinach. [13] The leafy-greens trials pooled in 2026 showed no significant blood pressure change. [11] Whether nitrate in spinach is a risk for young infants: proper evidence not found in the official sources we could read; we make no claim. A parent worried about homemade baby food can ask a pediatrician.
• Food poisoning from leafy greens. The FDA lists a closed 2024 E. coli O157:H7 outbreak linked to spinach (28 cases) and others linked to romaine lettuce. [7] See the food-safety section below.
• Allergy. The sources we read did not describe spinach allergy specifically, so we give no figures. For trouble breathing or swelling of the face or throat, call 911. See food allergy basics and emergency signs.
• Pregnancy. Folate is found in leafy greens, but MedlinePlus says people thinking about pregnancy should take a folic acid supplement because food alone can be hard. [9] Pregnant people should follow official food-safety advice; see foods in pregnancy.
• Pesticide residues, goitrogens, histamine, FODMAPs: proper evidence not found in the sources we read for spinach, so no claim is made.

Choosing, storing and food safety

• Wash fresh produce under running water, then dry it with a clean towel. Washing reduces bacteria but does not remove all of them. Do not wash with soap, detergent or commercial produce wash. [6]
• Packages labeled "pre-washed" or "ready-to-eat" can be used without more washing. If you rewash them, keep them away from unclean surfaces and utensils. [6]
• Keep leafy greens and all pre-cut or packaged produce in a refrigerator at 40°F (4°C) or below. When buying bagged greens, choose ones kept cold. [6]
• Check the FDA outbreak list if you hear of a recall of bagged greens. [7] Raw sprouts are a separate risk; see raw sprouts, raw milk and undercooked foods.

Related pages

• Leafy greens
• Dietary nitrate in beets and leafy greens
• Foods and medicine interactions: vitamin K, grapefruit and others
• Foods, kidney disease, potassium and oxalates
• Fresh, frozen and canned produce
• Cruciferous vegetables