5 Reasons to Avoid Eating Too Much Spinach
Updated on July 31, 2025
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Versatile, low calorie, nutrient dense, and delicious, leafy green spinach is an excellent source of various vitamins and minerals. It’s also a good way to get fiber and protein in your diet.
Eating too much spinach won’t cause issues for the average healthy adult. But it may cause some rare adverse effects under certain circumstances.
For some people, eating lots of spinach can reduce calcium intake or increase the risk of kidney stones. Feeding very young infants spinach can raise their risk of health problems. And filling up on spinach can trigger reactions for people with histamine intolerance.
Spinach’s Oxalic Acid Can Block Calcium Absorption
Calcium is essential for building bones and teeth, as well as for supporting muscle movement, nerve function, blood vessels’ ability to move blood, and hormone release. Getting as much of your calcium intake from food as you can is vital, and you want to ensure that your body absorbs as much as it can.
A compound called oxalic acid may reduce calcium absorption. This compound occurs naturally in many greens, including spinach. Oxalic acid can bind with calcium in your intestines to form oxalates, which are insoluble salts. These salts may interfere with how your gut can absorb calcium, making it less available.
Discarding the water after steaming or boiling spinach may reduce the amount of oxalate you consume. Vitamin D can also help your body absorb calcium, and you can get this from sun exposure. Vitamin D and calcium supplements are also available to boost intake when necessary.
Potential for Kidney Stones
Spinach has one of the highest contents of oxalic acid among green vegetables. For this reason, eating too much spinach may also play a part in the formation of calcium oxalate, which forms the most common type of kidney stones.
In rare cases, eating extreme amounts of oxalate-rich foods, like spinach, can lead to dietary hyperoxaluria, which is the excessive excretion of oxalate in the urine. This can lead to kidney stone formation. It’s also vital to avoid excessive intake of high-oxalate foods if you have a type of hyperoxaluria that can develop due to an underlying health condition. Examples include primary hyperoxaluria (a genetic disorder) and enteric hyperoxaluria (a digestive issue that means your body absorbs too much oxalate).
But in healthy people, only 10 to 15 percent of the oxalate in the urine comes from what you eat. You don’t need to cut out oxalate-rich foods like spinach completely. Instead, eat foods that are high in oxalate alongside those that are high in calcium in a meal. This way, they bind together in the stomach and intestines and are less likely to form kidney stones.
The Danger of Spinach’s Nitrates for Babies
Nitrates are a natural part of plant foods and, they don’t cause any real issues in healthy adults. But babies under 4 months of age have a high risk of adverse health consequences from exposure to nitrates.
No indication exists to support adding whole foods to a healthy infant’s diet before 4 to 6 months of age. Even if you’re considering it, avoid adding home-prepared foods that include nitrate-rich vegetables like spinach until your baby is at least 3 months old. Other nitrate-rich vegetables include beets, green beans, squash, and carrots.
But even up to 12 months, infants who eat high-nitrate foods or drink water with high nitrate content have a higher risk of developing a condition called methemoglobinemia, or blue baby syndrome. It can mean that babies don’t have enough oxygen in their blood, giving their skin a bluish tint.
Does Spinach Increase the Risk of Gout?
Some plant foods, such as spinach, contain natural purines. People with gout — a form of arthritis in which uric acid forms painful crystals in the joints — have hyperuricemia, or excess uric acid in the bloodstream.
Your body converts purines into uric acid. The increased uric acid volume in the blood, after your body converts it from excessive amounts of high-purine foods, may trigger gout attacks if your body struggles to remove it in the urine.
But if you’re a spinach fan, you can breathe a sigh of relief. Studies suggest that high-purine vegetables, including spinach, don’t increase your gout risk.
Spinach Can Interact With Some Medications
Spinach has a very high vitamin K content that can affect certain medications in harmful ways.
For example, doctors advise against eating lots of spinach if you take an anticoagulant medication (also called a blood thinner) to treat a heart condition. The vitamin K promotes blood clotting, which might decrease the activity of medications like warfarin (Jantoven) that aim to reduce blood clotting.
If your doctor prescribes a medication for you, ask what foods it might interact with — even those foods that are otherwise very nutritious.
Spinach Contains Histamines, Which Can Trigger Reactions
Reactions to spinach are rare. But spinach has high amounts of a chemical called histamine, which some people are sensitive to. In these people, the digestive system doesn’t make enough of an enzyme called diamine oxidase that supports the breakdown of histamine in the gut. This causes a buildup of histamine, and the effects of this can resemble allergy symptoms.
Symptoms of histamine intolerance differ between people, but they often appear between 30 minutes to several hours after eating. They may include:
- Headaches or migraine attacks
- Hives
- Itching
- Skin rashes
- Swelling of the lips, eyes, or face
- A runny or blocked nose
- Wheezing
- Breathlessness
- A rapid or irregular heartbeat
- Nausea
- Vomiting
- Abdominal pain
- Diarrhea
Spinach is a high-histamine vegetable. So, if a doctor or a dietitian recommends that you try a low-histamine diet to diagnose histamine intolerance, you may need to avoid spinach and other high-histamine vegetables like tomato, avocado, eggplant, and squash. You shouldn’t cut out all high-histamine foods permanently, though, as this could lead to malnutrition. But a low-histamine diet can help you work out which foods are triggering a reaction.
Nutrition in Spinach
One hundred grams (g) of raw spinach contains 27 calories and provides around 6 percent of the daily value (percent DV) of both fiber and protein. The U.S. Food and Drug Administration’s recommended intakes have guided the percent DV here, but these may vary depending on your age, sex, and pregnancy status.
Spinach also provides good or excellent amounts of several vitamins and minerals, including:
- Vitamin K: 483 micrograms (mcg), or 403 percent DV.
- Vitamin A: 283 mcg, or 31 percent DV.
- Vitamin C: 26.5 milligrams (mg), or 29 percent DV.
- Folate: 116 mcg, or 29 percent DV.
- Magnesium: 93 mg, or 22 percent DV.
- Riboflavin: 0.194 mg, or 15 percent DV.
- Vitamin E (alpha-tocopherol): 2.03 mg, or 14 percent DV.
- Potassium: 582 mg, or 12 percent DV.
- Vitamin B6: 0.195 mg, or 11 percent DV.
- Copper: 0.082 mg, or 9 percent DV.
- Iron: 1.26 mg, or 7 percent DV.
- Thiamin: 0.077 mg, or 6 percent DV.
- Calcium: 68 mg, or 5 percent DV.
In short: Spinach is highly nutritious. Its antioxidant content can protect against free-radical molecules linked to cancer, Alzheimer’s disease, and autoimmune disease development. Spinach’s high potassium also supports lower blood-pressure levels. And its folate, antioxidants, and vitamin K content might reduce age-related memory changes.
The vitamin A content in spinach can help protect the eyes against sun damage and reduce the risk of eye conditions like age-related cataracts or macular degeneration.
But spinach has a few drawbacks that mean moderation may be key to reaping its benefits for some.
The Takeaway
- Eating moderate amounts of spinach can be a healthful part of your diet. But eating too much may contribute to the formation of kidney stones due to spinach’s high oxalic acid levels.
- If you take anticoagulant medications, you should monitor your spinach intake, as its high vitamin K content can interfere with the effectiveness of these drugs in preventing blood clots.
- Although nitrate-rich vegetables like spinach bolster health in adults, they pose risks for infants under 12 months, potentially leading to methemoglobinemia, or blue baby syndrome.
- While high-purine foods are typically a gout concern, supportive research suggests that spinach, though high in purines, may not increase the risk of gout flare-ups.
EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
- Calcium: Fact Sheet for Consumers. National Institutes of Health Office of Dietary Supplements. September 14, 2023.
- Joshi V et al. Regulation of Oxalate Metabolism in Spinach Revealed by RNA-Seq-Based Transcriptomic Analysis. International Journal of Molecular Sciences. May 18, 2021.
- Oxalate. Vegan Health. March 2023.
- Dietary Advice for Stone Formers. National Health Service. December 14, 2022.
- Calcium Oxalate Stones. National Kidney Foundation.
- Hyperoxaluria. Cleveland Clinic. July 8, 2024.
- Kidney Stones. Cedars-Sinai.
- Who Is at Most Risk of Adverse Health Effects from Overexposure to Nitrates and Nitrites? Agency for Toxic Substances and Disease Registry. May 24, 2023.
- Infant Methemoglobinemia (Blue Baby Syndrome). Wisconsin Department of Health Services. January 3, 2025.
- Gout Diet: What's Allowed, What's Not. Mayo Clinic. April 2, 2025.
- Medication Interactions: Food, Supplements and Other Drugs. American Heart Association. January 18, 2024.
- Histamine Intolerance. Allergy UK.
- Low Histamine Diet. Johns Hopkins Medicine.
- Spinach, Raw. U.S. Department of Agriculture. October 31, 2024.
- Daily Value on the Nutrition and Supplement Facts Labels. U.S. Food and Drug Administration. March 5, 2024.
- 7 Reasons You Should Eat More Spinach. Cleveland Clinic. February 16, 2024.
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Kayli Anderson has over a decade of experience in nutrition, culinary education, and lifestyle medicine. She believes that eating well should be simple, pleasurable, and sustainabl...
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