How much spinach per day is too much?

No nutrient here reaches an NIH upper limit, the FDA caffeine figure or a Dietary Guidelines limit within 60 of these servings a day. One cup = 1 cup (1.1 oz, 30 g). USDA FoodData Central, Spinach, mature. Limits count everything you eat and drink that day, so other foods and supplements use up part of each one.

• Level B In a 12-week RCT of 48 women with obesity and PCOS on a calorie-restricted diet, 5 g a day of spinach thylakoids led to about 15 lb (7 kg) weight loss versus about 6.6 lb (3 kg) with placebo. Nutr J, 2020
• Level B Eating 6 oz (170 g) of spinach in a warm meal every day for 11 days left kidney, liver, cardiovascular, inflammation and iron markers unchanged in healthy adults. Plant Foods Hum Nutr, 2022
• Level C In patients stable on warfarin, 250 g spinach once kept Thrombotest in range, but daily spinach for one week tended to push it above the therapeutic limit and required dose adjustment. Acta Med Scand, 1986

Only studies that give the amount eaten. Levels: A is a meta-analysis of trials, B a randomized trial, C an observational study. How we grade evidence.

• Level C In people on warfarin, vitamin K began to shift the INR at 150 micrograms a day, and meals of spinach produced only a short-lived response that pointed to poor absorption from the leaf. Blood, 2004
• Level C Where crops were irrigated with untreated wastewater, spinach held a pooled mean of 2.86 mg of cadmium per kg, more than 9 times the EU limit of 0.2 to 0.3 mg per kg. Environ Monit Assess, 2026
• Level C Observational data link eight or more spinach servings a month with about 30% higher kidney stone risk in men and older women. J Am Soc Nephrol, 2007
• Level C A systematic review of 149 reports names spinach among the herbs, foods and other items reported to interact with warfarin. Br J Clin Pharmacol, 2021

If you have kidney disease, take blood thinners or other medicines, or are pregnant, the right amount for you is a question for your clinician.

Spinach has no nutrient near an upper limit. One cup raw is 1.1 oz (30 g) and 6 calories. The 11-day trial was small and short, and spinach was the comparison vegetable there, so it says little about long-term safety.

With warfarin, a change in the amount is what the studies flag. In patients stable on warfarin, one 8.8 oz (250 g) serving kept the clotting test in range, but spinach every day for a week tended to push it out of range, toward weaker anticoagulation, and needed a dose change (Level C). In another study, vitamin K began to lower the INR at 150 mcg a day, while spinach meals gave only a short-lived response (Level C). A systematic review lists spinach among foods reported to interact with warfarin (Level C).

Observational data link eight or more spinach servings a month with about 30% higher kidney stone risk in men and older women (Level C). This is an association, and it does not show that spinach causes stones.

The weight-loss trial on this page tested 5 g a day of thylakoids, an extract made from spinach, in women with PCOS on a calorie-restricted diet. It does not show that eating spinach leaves causes weight loss.

Evidence behind this note

1. Level B Eating 6 oz (170 g) of spinach in a warm meal every day for 11 days left kidney, liver, cardiovascular, inflammation and iron markers unchanged in healthy adults. Plant Foods Hum Nutr, 2022
2. Level C In patients stable on warfarin, 250 g spinach once kept Thrombotest in range, but daily spinach for one week tended to push it above the therapeutic limit and required dose adjustment. Acta Med Scand, 1986
3. Level C In people on warfarin, vitamin K began to shift the INR at 150 micrograms a day, and meals of spinach produced only a short-lived response that pointed to poor absorption from the leaf. Blood, 2004
4. Level C A systematic review of 149 reports names spinach among the herbs, foods and other items reported to interact with warfarin. Br J Clin Pharmacol, 2021
5. Level C Observational data link eight or more spinach servings a month with about 30% higher kidney stone risk in men and older women. J Am Soc Nephrol, 2007
6. Level B In a 12-week RCT of 48 women with obesity and PCOS on a calorie-restricted diet, 5 g a day of spinach thylakoids led to about 15 lb (7 kg) weight loss versus about 6.6 lb (3 kg) with placebo. Nutr J, 2020

Written from the data and studies on this page, reviewed by the Bioma editorial system. How we verify.

• Spinach: what the research says