Espinaca

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By Nikola · Precision Nutrition L1 · Updated 4 November 2026

Spinach (Spinacia oleracea) is a leafy green with very few calories, 23 kcal per 100 g raw, and a lot of vitamin K, folate, vitamina A and potassium. Its iron is non-heme iron, which the body absorbs less well than iron from meat, but vitamin C at the same meal helps. Two practical cautions matter more than any “superfood” headline: the high vitamin K if you take warfarin, and the oxalate if you have had calcium oxalate kidney stones.

Spinach nutrition per 100 g and per portion

Nutritivo	Raw spinach, 100 g	Portion: 30 g raw
Energía	23 kcal	7 kcal
Proteína	2.9 g	0.9 g
Fat	0.4 g	0.1 g
Carbohydrate	3.6 g	1.1 g
of which fibre	2.2 g	0.7 g
of which sugars	0.4 g	0.1 g
Vitamina K	483 µg	145 µg
Vitamin A (RAE)	469 µg	141 µg
folato	194 µg	58 µg
Vitamina C	28.1 mg	8.4 mg
Hierro	2.7 mg	0.8 mg
Magnesio	79 mg	24 mg
Potasio	558 mg	167 mg
Calcio	99 mg	30 mg
Manganese	0.9 mg	0.27 mg

Source: USDA FoodData Central, SR Legacy, “Spinach, raw” (FDC 168462), checked 4 November 2026. The 30 g portion is calculated from the same record; NIH lists 145 µg of vitamin K for one cup of raw spinach, which matches about 30 g. Values rounded.

Spinach shrinks dramatically in the pan: a large bowl of raw leaves becomes a few spoonfuls once wilted. That is why a portion of cooked spinach usually carries several times more of everything in the raw column, vitamin K and oxalate included.

Glycemic index of spinach

Spinach is not listed in the international GI tables. With 3.6 g of carbohydrate per 100 g, of which 2.2 g is fibre, it has very little effect on blood sugar.

Health benefits: what the evidence says

• Vitamin K. 100 g of raw spinach gives 483 µg, about four times the adequate intake of 120 µg a day for men and more than five times the 90 µg for women (NIH Office of Dietary Supplements). The EU accepts that vitamin K contributes to normal blood clotting and to the maintenance of normal bones (Regulation (EU) No 432/2012). NIH reports no adverse effects from vitamin K in food; the issue is medicines (see below).
• Folate. 194 µg per 100 g. Permitted EU claims include that folate contributes to normal blood formation and to maternal tissue growth during pregnancy.
• Iron, with a condition. Spinach has 2.7 mg of iron per 100 g, all of it non-heme. NIH explains that the body absorbs non-heme iron from plants less well than heme iron from animal foods, and absorbs it better when the meal also contains vitamin C (citrus, sweet pimientos, Tomates, brócoli) or some meat, poultry or seafood. The EU claim “vitamin C increases iron absorption” says the same. Raw spinach brings 28 mg of its own vitamin C; a squeeze of lemon adds more.
• Potassium and magnesium. 558 mg of potassium and 79 mg of magnesium per 100 g raw.

Ayurveda: spinach in the traditional system

In Usha and Vasant Lad’s food guidelines spinach is favourable for Kapha and for Vata, cooked or raw, in moderation. For Pitta it is a different story: cooked spinach only rarely, and raw spinach is on the list to avoid. This is a traditional view, not a clinical finding.

Raw or cooked: what changes

• Crudo spinach keeps all of its vitamin C, which helps with iron absorption, and works well in salads, wraps and smoothies.
• Boiled spinach loses part of its oxalate. In a study of nine vegetables, boiling reduced soluble oxalate by 30-87% and steaming by 5-53%; almost all of the lost oxalate was found in the cooking water (Chai and Liebman, 2005). If you watch oxalate, boil, drain and discard the water. The trade-off: water-soluble vitamins such as C and folate can also go into that water.
• Sautéed or wilted spinach is the quickest option, but without draining it keeps its oxalate.
• Leftovers: cool cooked spinach quickly and keep it in the fridge. EFSA notes that storing cooked leafy vegetables badly, especially at room temperature for long periods, converts nitrate into nitrite.

How to buy, cook and use spinach

• Buying: choose crisp, deep green leaves without slime or yellowing. Baby spinach suits salads; frozen spinach is handy for stews.
• Washing: spinach often carries sand. Soak the leaves in a bowl of cold water, lift them out, and repeat until no grit remains.
• Quick side: wilt spinach in a pan with ajo and a little extra virgin olive oil, then finish with lemon juice and black pepper.
• Stews and soups: stir a few handfuls into chickpea o lentil dishes at the end of cooking.
• Desayuno: scrambled eggs or an omelette with spinach and feta, or a handful of baby spinach in a green smoothie with fruit.
• Pair for iron: serve with Tomates, peppers or a lemon dressing.
• Storage: keep fresh spinach dry and cold in the fridge and use it within a few days.

Who should be careful

• People taking warfarin. NIH advises people on warfarin (Coumadin) to keep their vitamin K intake from food and supplements consistent, because sudden changes can increase or decrease the effect of the medicine. Spinach is one of the richest sources. You do not have to avoid it, but keep the amount steady from week to week and talk to your doctor before big changes.
• People with calcium oxalate kidney stones. NIDDK lists spinach among the foods people with calcium oxalate stones may want to avoid to lower the oxalate in their urine. It also says that in the right amounts calcium can block substances in the digestive tract that may cause stones, so do not cut calcium on your own; ask your doctor or a dietitian.
• Babies and young children. EFSA concluded in 2010 that nitrate levels in leafy vegetables are not of health concern for most children, but for children aged 1-3 who eat large amounts of spinach (over 200 g in a day) a risk of methaemoglobinaemia, a condition that reduces oxygen supply to the body, cannot be excluded. EFSA also advises not giving spinach to children with a bacterial gastrointestinal infection, notes that puréeing speeds up the conversion of nitrate to nitrite, and warns against storing cooked leafy vegetables at room temperature.

Related entries and articles

• col rizada – another dark leafy green
• garbanzos – the classic partner in chickpea and spinach stew
• lentejas – plant iron and fibre in one pot
• Tomates – vitamin C for better iron absorption
• Ajo
• Plant-based meals for weight loss
• Which foods reduce inflammation naturally?

FAQ

Is spinach a good source of iron?

Spinach has 2.7 mg of iron per 100 g raw, but it is non-heme iron, which the body absorbs less well than iron from meat or fish. Eating spinach with vitamin C foods, such as lemon, peppers or tomatoes, improves absorption.

Is spinach healthier raw or cooked?

Both have a place. Raw spinach keeps all its vitamin C; boiled and drained spinach has much less soluble oxalate; cooked spinach of any kind lets you eat a larger amount in one portion.

Can I eat spinach if I take warfarin?

Usually yes, as long as the amount stays roughly the same from day to day. NIH advises a consistent vitamin K intake on warfarin, because sudden changes can alter how the medicine works. Discuss any big diet change with your doctor.

Sources

1. USDA FoodData Central, SR Legacy: Spinach, raw (FDC 168462). fdc.nal.usda.gov
2. NIH Office of Dietary Supplements: Vitamin K, Fact Sheet for Health Professionals, updated 22 October 2026. ods.od.nih.gov
3. NIH Office of Dietary Supplements: Iron, Fact Sheet for Consumers, updated 17 August 2023. ods.od.nih.gov
4. Commission Regulation (EU) No 432/2012, list of permitted health claims (vitamin C and iron absorption, vitamin K, folate). EUR-Lex
5. NIDDK: Eating, Diet, & Nutrition for Kidney Stones. niddk.nih.gov
6. Chai W, Liebman M. Effect of different cooking methods on vegetable oxalate content. J Agric Food Chem 2005. PubMed
7. EFSA: EFSA assesses possible health risk for children from nitrate in leafy vegetables, 9 December 2010. efsa.europa.eu
8. Lad U, Lad V. Food Guidelines for Basic Constitutional Types, from Ayurvedic Cooking for Self-Healing, 2nd ed. The Ayurvedic Institute. ayurveda.com

This page is for information only and is not medical or dietary advice.