Spinach and blood thinners

Spinach is believed to be of Persian origin. By the 12th century, it spread across Europe and became a desirable leafy green known for good health; a reputation that stands firm to this day. The name Florentine is often used to describe dishes containing spinach (and a creamy sauce). It is thought that this name dates back to the 16th century and the Italian wife of France’s Henry II; Catherine de Medici. The unverified tale states that Catherine introduced spinach to the Court of France and to honour her Italian heritage, she then decided to call any dish containing spinach Florentine.

Spinach belongs to the chenopodiaceae family (also known as goosefoot), a family of nutritional powerhouses including beets, chard and quinoa. It shares a similar taste profile with these two other vegetables; the bitterness of beet greens and the slightly salty flavour of chard. There are three different types of spinach generally available: savoy, semi-savoy and smooth leaf.

…The popeye effect
There is much lore regarding spinach, most famously as the source of Popeye’s strength. When faced with the sight of trouble, pipe-smoking sailor-man Popeye would burst open a tin of spinach. Once consumed, his biceps would bulge and his new found strength would see him overcome his enemies. Although there is definitely lots of goodness in those leaves, the legendary status Popeye bestowed on it is slightly inflated.

Nutritional highlights

Spinach is available all year round but is in season during the spring (March – June). It is well known for its nutritional qualities and has always been regarded as a plant with remarkable abilities to restore energy, increase vitality and improve the quality of the blood. There are sound reasons why spinach would produce such results, primarily the fact that it is rich in iron. Iron plays a central role in the function of red blood cells which help in transporting oxygen around the body, in energy production and DNA synthesis. Spinach is also an excellent source of vitamin K, vitamin A, vitamin C and folate as well as being a good source of manganese, magnesium, iron and vitamin B2. Vitamin K is important for maintaining bone health and it is difficult to find vegetables richer in vitamin K than spinach. Others include kale, broccoli and green cabbage.

A 100g serving (raw) provides:

25 calories 2.8g protein 0.8g fat 1.6g carbohydrates 2.8g fibre

…Don’t be shy with your portions when cooking spinach. Its high water content means it reduces in size by about a quarter when cooked.


The dark green colour of spinach leaves indicates they contain high levels of chlorophyll and health promoting carotenoids (beta carotene, lutein and zeaxanthin). These phyto chemicals have anti-inflammatory and anti-cancerous properties and are especially important for healthy eye-sight, helping to prevent macular degeneration and cataracts.

Spinach has good levels of iron, but not quite as much as originally believed as rumour has it researchers placed the decimal point in the wrong place! It is important to note that there are two forms of dietary iron: ‘haem’ iron and ‘non haem’ iron. Haem iron is found in animal products and is the most efficiently absorbed form of iron. Non haem iron is found in plant foods (such as spinach) and is a little harder for the body to absorb in comparison. However vegetarians, those who experience iron-deficiency anaemia and those who are pregnant are encouraged to include green leafy vegetables such as spinach as part of a balanced diet.

How to select and store

Fresh spinach should be medium to dark green, fresh-looking and free from evidence of decay. It should be stored loosely packed in a sealed plastic bag in the fridge where it will keep for about four days. Do not wash spinach before storing, as the moisture will cause it to spoil, although do ensure it is washed properly before consumption as the leaves and stems may collect soil and chemicals. Raw spinach has a milder taste that some describe as metallic once cooked. If cooking, opt for steaming, sautéeing or microwaving spinach rather than boiling to preserve the nutrients.


Frozen baby leaf spinach can be bought and stored. It comes in individual blocks, a handy and tasty alternative to frozen peas.


Spinach contains a high amount of oxalate. Individuals with a history of oxalate containing kidney stones should avoid over consumption. A low oxalate diet is usually defined as containing less than 50 milligrams of oxalate per day. A 100g serving of spinach has more than this and so is best avoided.

The high levels of oxalic acid in spinach has long been thought to inhibit the absorption of important nutrients such as iron and calcium, although some studies suggest that the effects of oxalic acid are minimal. Lightly cooking or wilting spinach is thought to reduce the oxalic acid content.

Recipe suggestions

Due to its excellent taste and nutritional value, spinach is a popular leaf all over the world.

Spinach adores being paired with nutmeg…
Creamed spinach
Buttered spinach with feta

…is best friends with garlic:
Aubergines filled with spinach & mushrooms
Speedy soy spinach

…and really is most versatile with dairy, fish and meat
Spinach & feta-stuffed chicken
Parmesan spring chicken
Smoked mackerel risotto

Simply steam or add to salads and soups:
Zingy courgette & spinach salad
Creamy lentil & spinach soup with bacon
Warm cauliflower salad

Quick & easy super spinach suppers:
Salmon & spinach with tartare cream
Stir-fry prawns with peppers & spinach
Chickpea, tomato & spinach curry
Haddock & spinach cheese melt

And not forgetting lots of pasta dishes!
Bacon, spinach & gorgonzola pasta
Pasta with chilli tomatoes & spinach
Gnocchi with roasted squash & goat’s cheese

Want more? Take inspiration from our latest spinach recipes

This article was updated on 24th September 2018 by Kerry Torrens.

Kerry Torrens is a qualified Nutritionist (MBANT) with a post graduate diploma in Personalised Nutrition & Nutritional Therapy. She is a member of the British Association for Nutrition and Lifestyle Medicine (BANT) and a member of the Guild of Food Writers. Over the last 15 years she has been a contributing author to a number of nutritional and cookery publications including BBC Good Food.

Jo Lewin works as a Community Nutritionist and private consultant. She is a Registered Nutritionist (Public Health) registered with the UKVRN. Visit her website at www.nutrijo.co.uk or follow her on Twitter @nutri_jo.

All health content on bbcgoodfood.com is provided for general information only, and should not be treated as a substitute for the medical advice of your own doctor or any other health care professional. If you have any concerns about your general health, you should contact your local health care provider. See our website terms and conditions for more information.

Since the days of Popeye, spinach has been famous for its ability to make you “strong to the finish.” While this leafy green won’t cause your biceps to inflate like balloons, it is dense in vitamins and minerals, low in calories and versatile in cooking.

Spinach may also help with several health conditions, according to Megan Ware, a registered dietitian nutritionist based in Orlando, Florida. “Eating spinach is beneficial for maintaining healthy skin, hair and strong bones, as well as helping with digestion, lowering the risk for heart disease and improving blood glucose control in diabetics,” she told Live Science.

Spinach is believed to come from Persia, according to Arizona State University. It had arrived in China by the seventh century and reached Europe in the mid-13th century, according to The Agricultural Marketing Research Center. For some time, the English referred to it as the “Spanish vegetable” because it came through Spain via the Moors. According to BBC Good Food, use of the word “Florentine” to describe a dish with spinach can likely be traced to Catherine de Medici, the Italian wife of France’s Henry II. It is believed that Catherine, who loved spinach, brought her own cooks from Florence to cook spinach in her preferred style.

Spinach is a member of the Chenopodiaceae family, which also contains nutritionally powerful foods like beets and Swiss chard, according to Purdue University. There are three types of spinach, according to Bon Appetit:

  • savoy spinach, which has curly or heavily wrinkled, dark green leaves
  • semi-savoy spinach, which is somewhat less wrinkly and good to use in cooking
  • flat-leaf spinach, the popular, smooth-textured variety that works well in salads and is best eaten raw. Baby spinach is a type of flat-leaf spinach.

Nutritional profile

Ware said, “Spinach is one of the best sources of dietary potassium and magnesium, two very important electrolytes necessary for maintaining human health. Spinach provides a whopping 839 milligrams of potassium per cup (cooked). As a comparison, one cup of sliced banana has about 539mg of potassium.”

Ware noted that there are several health benefits to potassium, among them “protection against loss of muscle mass, preservation of bone mineral density and reduction in the formation of kidney stones.” She added, “Only 2 percent of U.S. adults meet the daily 4,700 mg recommendation for potassium.”

The George Mateljan Foundation’s analysis of spinach’s nutritional properties placed it at the top of their nutrient-rich food list. “Spinach is an excellent source of vitamin K, vitamin A (in the form of carotenoids), manganese, folate … copper, vitamin B2, vitamin B6, vitamin E, calcium … and vitamin C,” according to the foundation’s website World’s Healthiest Foods. Spinach’s calcium, however, cannot be as easily absorbed as calcium from dairy, and you should only expect to absorb about 10 percent of it.

Spinach is also a very good source of zinc, dietary fiber, phosphorus, vitamin B1 and choline. It contains a unique and beneficial mixture of phytonutrients, as well as anti-oxidants, flavonoids and carotenoids.

Ware added, “Spinach is also one of the best non-heme (plant-based) sources of iron.” The same is true of spinach’s protein content; most of the calories in spinach come from protein. This makes it a popular food for vegetarians. At only 7 calories per cup of raw spinach and 41 per cup of cooked spinach, it’s also a great choice for dieters.

Here are the nutrition facts for spinach, according to the U.S. Food and Drug Administration, which regulates food labeling through the Nutritional Labeling and Education Act:

Nutrition Facts Spinach Serving size: 1 cup (30 g) Calories 5 Calories from Fat 0 *Percent Daily Values (%DV) are based on a 2,000 calorie diet. Amt per Serving %DV* Amt per Serving %DV*
Total Fat 0g 0% Total Carbohydrate 1g 1%
Cholesterol 0mg 0% Dietary Fiber 1g 4%
Sodium 25mg 1% Sugars 0g
Protein 1g Potassium 167g 5%
Vitamin A 60% Calcium 2%
Vitamin C 15% Iron 4%

Health benefits


The National Osteoporosis Foundation recommends eating spinach for its vitamin K and magnesium content. Just one cup of cooked spinach contains an incredible 987 percent of your daily vitamin K needs and 39 percent of your magnesium ones.

According to the University of Maryland Medical Center, in the past few decades, it has become clear that vitamin K is important to bone health. A review published in Nutrition noted that vitamin K intake might reduce fracture rates, work with vitamin D to increase bone density and positively affect calcium balance. Your body uses vitamin K when building bones, and the effects seem to be especially important for women.

A large 2003 American Journal of Clinical Nutrition study showed that low vitamin K levels were associated with low bone density in women, but not in men. Another study published in the American Journal of Clinical Nutrition in 1999 found that low intakes of vitamin K were associated with an increased risk of hip fractures in middle-aged women. This is especially interesting because the women saw results from eating lettuce, showing that dietary consumption of vitamin K via eating vegetables (not supplements) is beneficial.

When it comes to men, the affects of vitamin K and bone health may become more apparent as they age: A 2000 study saw reduced risk of hip fracture among both elderly women and elderly men who consumed more vitamin K.

The high level of potassium in spinach is also helpful in protecting against bone mineral density loss, said Ware. Additionally, spinach contains calcium, well known to be important for bones. The calcium in spinach is, however, difficult to absorb so the Physicians Committee for Responsible Medicine recommends getting calcium from other vegetable sources, such as broccoli and kale, or dairy.

Iron deficiency anemia

This is the most common type of anemia, and women are its largest risk group. Without sufficient iron, your blood can’t produce enough hemoglobin, a blood protein that gives blood cells their red color and transports oxygen to organs. Eating iron-rich foods is important for those suffering from or at risk of anemia, and with 36 percent of your daily iron needs per cooked cup, spinach is a good option. The National Organization of Women’s Health, as well as the National Heart, Lung and Blood Institute recommends eating spinach as part of an anemia prevention or treatment program.

Skin and hair

“Want healthier-looking hair? Eat more spinach!” raved Ware. “Spinach is high in vitamin A, a nutrient required for sebum production to keep hair moisturized. Vitamin A is also necessary for the growth of all bodily tissues, including skin and hair.”

According to the Linus Pauling Institute at Oregon State University, vitamin A is a compound in retinoids, which are popular in anti-aging skin treatments. Furthermore, vitamin C can help keep skin looking youthful and aids in wound healing. “Adequate intake of vitamin C, which spinach can help to provide, is needed for the building and maintenance of collagen, which provides structure to skin and hair,” said Ware.


Spinach is a standout in terms of its mix of phytonutrient components. According to World’s Healthiest Foods, unlike most other fruits and vegetables, spinach contains cancer-fighting agents called methylenedioxyflavonol glucuronides. It is also an excellent source of antioxidants lutein, zeaxanthin, neoxanthin and violaxanthin. All of these are anti-inflammatories, which can be helpful in cancer prevention.

Spinach’s high levels of chlorophyll may have anti-cancer and anti-carcinogen effects. A review of anti-cancer diet research published in Nutrition Journal explained that this is because chorophyll helps bind together hydrocarbons, aflatoxins and other hydrophobic molecules that may be associated with cancer and expels them. Additionally, a 2001 Japanese study found that spinach leaves contain two powerful antitumor promoters.

Some studies have noted possible anti-cancer effects among prostate, breast and prostate cancers. One study published in the Journal of Nutrition looked at 15 kinds of carotenoids to see if they combatted cancer cells and found only neoxanthin from spinach and fucoxanthin from brown algae to be significantly effective.

One three-year study from the early 1990s found that women who ate raw spinach or carrots more than twice a week had a lower risk of breast cancer, while a more recent study from 2009 looked at the relationship between flavonoid intake and ovarian cancer. Among its many findings, this large-scale study saw a lower risk of ovarian cancer among women who ate the most spinach than those who ate the least.

While most cancer research still focuses on phytonutrients, antioxidants and flavonoids as a whole, and not spinach specifically, spinach’s high flavonoid profile suggests it may have overall cancer-preventative benefits.


“The risks for developing asthma are lower in people who consume a high amount of certain nutrients, one of these being beta-carotene,” said Ware. Beta-carotene may also help asthma sufferers reduce their symptoms. One study from the Annals of Asthma, Allergy & Immunology found that people with exercise-induced asthma did not develop symptoms during a seven-minute intense exercise session after consuming 64 mg of beta-carotene for one week. “Many people automatically think of orange fruits and vegetables when thinking of beta-carotene, but spinach is also an excellent source,” said Ware.

Spinach’s magnesium content may also be good for asthma sufferers. Magnesium can be an effective emergency treatment for asthma attacks. But a literature review of studies involving magnesium and asthma found that only intravenous magnesium is conclusively helpful; oral or vaporized magnesium’s effectiveness is unclear.


“Spinach contains a powerful antioxidant known as alpha-lipoic acid, which has been shown to lower blood sugar levels and increase insulin sensitivity and decrease peripheral neuropathy in patients with diabetes,” said Ware. The University of Maryland Medical Center notes that much of the research has been done with intravaneous alpha-lipoic acid, however, so it’s less clear that consuming the antioxidant by mouth has the same results. One 2006 study published in Diabetes Care found that consuming 600 mg of alpha-lipoic acid by mouth every day for five weeks improved neuropathic symptoms, such as stabbing and burning pain, numbness in feet and paresthesia (a tingling or itching sensation), more than a placebo.


Ware noted that spinach’s potassium levels are heart-healthy. “High potassium intakes are associated with a reduced risk of stroke, lower blood pressure, lower risk of death from heart disease.”

Potassium is an essential part of heart health, according to the American Heart Association. Many studies have linked it with lower blood pressure because it promotes vasodilation (widening of the blood vessels), according to Today’s Dietitian. One study of 12,000 adults, published in Archives of Internal Medicine, showed that those who consumed 4,069 mg of potassium each day lowered their risk of cardiovascular disease and ischemic heart disease (characterized by reduced blood flow to the heart) by 37 percent and 49 percent, respectively, compared to those who took 1,793 mg per day.

Spinach’s astronomical levels of vitamin K are also associated with heart health and blood clotting. According to the Linus Pauling Institute, vitamin K is an essential factor in blood clotting, and lack of it can cause hemorrhages. There are also suggestions that vitamin K might reduce the risk of heart disease because without it, mechanisms that stop the formation of blood vessel calcification may become inactive. Studies are still inconclusive, however, and one review of them, published in Advances in Nutrition, suggested that future research should focus specifically on vitamin-K deficient patients.


The essentiality of folic acid (also known as folate) during pregnancy is well-documented. Folic acid can help prevent neural tube defects—specifically spina bifida and anencephaly—that occur early in pregnancy. Since it’s hard for women to get enough folic acid from food alone, the Centers for Disease Control recommends taking 400 mcg if you are pregnant or might become pregnant. But spinach can also help increase your folic acid intake, with 66 percent of your daily (pre-pregnancy) folate needs per cooked cup.


Spinach is a good source of carotenoids lutein and zeaxanthin, which are associated with helping to prevent age-related macular degeneration and cataracts. According to The Scripps Research Institute, studies have shown that those who ate spinach three times per week had a 43 percent lower risk of developing macular degeneration.

Risks of eating spinach

“Suddenly increasing your consumption of spinach could be harmful if you are taking blood thinners such as Coumadin (warfarin),” said Ware. “It is important that you maintain a consistent intake of foods containing vitamin K (like spinach), which play a large role in blood clotting.”

Spinach ranks number seven on the Environmental Working Group’s 2015 Dirty Dozen list. That means it may be exposed to high levels of pesticides. If possible, you should buy organic spinach, but be sure to wash it thoroughly regardless of what type it is.

“If your kidneys are not fully functional, consuming too much potassium could cause an excess amount of potassium in the blood and even be fatal,” said Ware. Spinach also contains oxalates, which can be harmful to those with kidney or gallbladder problems. Excessive accumulation of oxalates can crystalize and cause problems, according to World’s Healthiest Foods.

Eat more spinach!

Ware provided some tips on how to incorporate more spinach into your diet:

  • Incorporate spinach into recipes you already make at home. Throw a few handfuls into your favorite pasta, soup or casserole.
  • Sautee spinach in a small amount of extra virgin olive oil and season with ground black pepper and freshly grated Parmesan cheese. Serve as a base for grilled chicken or salmon.
  • Add spinach to your wrap, sandwich or flatbread instead of regular lettuce, or use it as a base for your salad.
  • Add spinach to any egg dish, like an omelet, scramble or quiche.
  • Throw a handful of spinach into a smoothie or juice — it will change the color but not the taste!

About that sailor man …

Popeye the Sailor Man made his debut in 1929 in a comic strip called “Thimble Theatre” and jumped to animated cartoons in 1933. According to Comics Kingdom, he was a “good guy underdog with bulging forearms, a mean uppercut and a penchant for canned spinach.”

Popeye’s love for spinach became a common plot device — popping open a can often gave him super-strength. Spinach growers credited Popeye with a 33 percent increase in U.S. spinach consumption and saving the spinach industry in the 1930s, according to Comics Kingdom.

In 1937, Crystal City, Texas, a spinach-growing town, erected a statue to honor Popeye and his creator, E.C. Segar, for their positive influence on America’s eating habits, making Popeye the first cartoon character ever immortalized in public sculpture.

Some sources claim that the reason Segar chose spinach as the source of Popeye’s strength was due to an error in an 1870 study that measured the vegetable’s iron content. The scientist who conducted the research is said to have misplaced a decimal point, giving spinach 10 times the amount of iron it actually has. However, author Mike Sutton says this story is a myth, and that spinach was chosen for its vitamin A content.

Additional resources

4 Side Effects Of Eating Too Much Spinach Ravi Teja Tadimalla Hyderabd040-395603080 December 4, 2019

Though spinach is among the healthiest of vegetables with a powerful nutritional profile, consuming it in excess may lead to issues. Hence, moderation is key. For instance, excess intake of spinach may lead to kidney stones as the vegetable was found to increase urinary calcium excretion (1).

In this post, we will discuss the side effects of excessive intake of spinach.

What Are The Major Side Effects Of Spinach?

Spinach is high in oxalates, and their excess intake over a period may lead to the formation of kidney stones. The vitamin K in spinach may also interfere with blood thinners and certain other medications.

1. May Increase Kidney Stone Risk

Spinach contains oxalates, which are compounds that can form stones in the human system if consumed in excess. These stones are formed by an increase in oxalate content in the urine. The most common types of kidney stones are calcium oxalate stones (1).

A hundred grams of spinach contains 970 milligrams of oxalates (2).

Boiling spinach may reduce the oxalate concentration to some extent. Combining a calcium-based food (like curd or cottage cheese) with spinach can also prevent stone formation (3). However, every individual’s condition is unique, and the reaction may differ from person to person. Hence, please check with your doctor if you can include spinach in your diet.

2. May Interfere With Blood Thinners

Spinach contains high levels of vitamin K, a mineral that reduces the effectiveness of blood thinners. Blood thinners are usually given to prevent the onset of stroke. Hence, susceptible individuals must reduce their spinach intake (4).

Warfarin is a blood thinner that is prescribed for individuals who are at risk of forming harmful blood clots. Vitamin K was found to reduce the effectiveness of Warfarin (5). This is because vitamin K plays a vital role in forming blood clots in your body.

While half a cup of cooked spinach contains 444 mcg of vitamin K, one cup of raw spinach contains 145 mcg of the nutrient (6). Cooked spinach has higher vitamin K levels as heat increases the absorption of the nutrient.

However, you should not eliminate vitamin K from your diet as foods rich in the nutrient, like spinach, contain other essential vitamins and minerals as well. Vitamin K also has a role to play in the prevention of arterial calcifications, coronary heart disease, cancer, and osteoporosis (7). It is best to consult your doctor, who may increase the dosage of your blood thinner.

Eating spinach occasionally, in moderation, could be a safer option (provided the person is stable and not in an acute phase of illness).

3. May Hinder Mineral Absorption

There is some research that the intake of oxalate-rich foods can inhibit mineral absorption. Oxalate is an antinutrient (8).

The oxalates in spinach may also hinder the absorption of minerals like calcium. Spinach contains both oxalates and calcium, and consuming it in large amounts may impair the absorption of calcium in your system (9).

Spinach didn’t seem to have this effect on calcium when it was taken along with milk (9). This is because though spinach contains calcium, the nutrient from the vegetable is absorbed only one-tenth as efficiently as milk calcium (10).

The oxalates in spinach can also react with iron and inhibit its absorption by forming crystals (11).

Spinach is also thought to compromise thyroid function as it contains certain compounds called goitrogens. However, research is mixed in this regard. If you have thyroid issues, please consult your doctor before including spinach in your diet.

4. May Aggravate Symptoms Of Gout

Spinach contains purines, chemical compounds that are thought to contribute to gout. However, there is a lack of a significant association between the intake of purine-rich vegetables and gout (12). Hence, further research is warranted before we can arrive at a definitive conclusion.

But it always is better to stay safe. If you are dealing with gout, please talk to your doctor about your spinach intake. Since the leafy green may also interfere with certain medications, be sure to talk to your doctor if you are on any.

Some anecdotal evidence suggests that excess intake of spinach may cause an individual’s blood pressure and blood sugar levels to drop too low. This could be an issue for those who are on medications for treating high blood pressure and high blood sugar. However, more research is needed to confirm these effects. If you are on blood sugar or blood pressure medication, make sure to consult your doctor before including spinach in your diet.


Spinach is among the most nutritious foods you can find in your kitchen. However, as is the case with any food, moderation is key.

If you have kidney stones, you may have to drastically reduce or even avoid spinach intake (along with other oxalate-containing foods).

Otherwise, spinach is a healthy vegetable, and if you are a generally healthy individual, you should not miss out on its goodness.

Expert’s Answers For Readers’ Questions

How much of spinach is too much?

The lethal oral dose of oxalate in humans is between 15 to 30 grams (13). This could be between 3 to 6 pounds of spinach. It is highly unlikely for anyone to consume so much spinach in a short span of time. However, there is less research to understand if this dose is enough to lead to kidney stone formation.

Can raw spinach be bad for you?

Spinach, raw or cooked, offers great benefits. But if you have kidney stones or are on certain medications (like blood thinners, etc.), you may want to avoid spinach.

Can you eat spinach and tomatoes together?

Like spinach, tomatoes also contain oxalates (14). Hence, if you are someone prone to kidney stones or any drug interactions, you may be required to limit your intake of tomatoes.

Can spinach make your stomach hurt?

Spinach, by itself, may not hurt your stomach. However, eating too much of spinach all too soon may mean a sudden increase in your fiber intake. This may lead to a temporary stomach upset.
On the other hand, pain in the stomach (especially on the side) could be a symptom of kidney stones. If you suspect this could be the case, please visit your doctor.

14 sources

Stylecraze has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical associations. We avoid using tertiary references. You can learn more about how we ensure our content is accurate and current by reading our editorial policy.

  • Effect of dietary oxalate and calcium on urinary oxalate and risk of formation of calcium oxalate kidney stones. Journal of the American Dietetic Association, US National Library of Medicine, National Institutes of Health.
  • Nutritional Management of Kidney Stones (Nephrolithiasis), Clinical Nutrition Research, US National Library of Medicine, National Institutes of Health.
  • Effect of Cooking on Soluble and Insoluble Oxalate Contents in Selected Pakistani Vegetables and Beans, International Journal of Food Properties, Taylor & Francis Online.
  • Medication Interactions: Food, Supplements and Other Drugs, American Heart Association.
  • Warfarin (Coumadin®), Department of Public Health and Human Services, Montana.
  • Why Vitamin K Can Be Dangerous If You Take Warfarin, Cleveland Clinic.
  • The health benefits of vitamin K, OpenHeart, US National Library of Medicine, National Institutes of Health.
  • Expression Analysis of Oxalate Metabolic Pathway Genes Reveals Oxalate Regulation Patterns in Spinach, Molecules, US National Library of Medicine, National Institutes of Health.
  • Oxalate: effect on calcium absorbability, The American Journal of Clinical Nutrition, US National Library of Medicine, National Institutes of Health.
  • Calcium, National Center for Biotechnology Information.
  • Making Spinach with Low Oxalate Levels, United States Department of Agriculture.
  • The Association of Dietary Intake of Purine-Rich Vegetables, Sugar-Sweetened Beverages and Dairy with Plasma Urate, in a Cross-Sectional Study, PLoS One, US National Library of Medicine, National Institutes of Health.
  • Oxalic acid, Centers for Disease Control and Prevention.
  • Determination of total oxalate contents of a great variety of foods commonly available in Southern China using an oxalate oxidase prepared from wheat bran, United States Department of Agriculture.

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Ravi Teja Tadimalla

Ravi Teja Tadimalla is a Senior Content Writer who specializes in writing on Health and Wellness. He graduated from SRM University, Chennai, and has been in the field for well over 4 years now. His work involves extensive research on how one can maintain better health through natural foods and organic supplements. Ravi has written over 250 articles and is also a published author. Reading and theater are his other interests.

TUESDAY, June 11, 2019 (HealthDay News) — Spinach-loving seniors, rejoice. A new study suggests that — despite doctor warnings to the contrary — you can eat leafy greens rich in vitamin K if you are taking the blood thinner warfarin.

In fact, “I think all warfarin-treated patients would benefit from increasing their daily vitamin K intake,” said lead author Guylaine Ferland. She’s a professor of nutrition at University of Montreal in Canada.

The results of the study were scheduled to be presented Tuesday at the annual meeting of the American Society for Nutrition, in Baltimore.

Vitamin K aids clotting, so patients on the anti-clotting drug (or “anticoagulant”) warfarin are often warned by their physicians to limit the amount of foods rich in the nutrient. These foods include green vegetables such as spinach, kale, broccoli, cabbage, Brussels sprouts and many others.

However, Ferland’s team wanted to test the long-held notion that vitamin K really does pose a problem for these patients.

The study involved 46 patients, aged 32 to 85, all of whom had trouble maintaining their anticoagulation levels.

Half attended regular dietary counseling and cooking lessons. The other half went to counseling and cooking classes, but instructors in these classes promoted adding more green vegetables, as well as oils with vitamin K, to the diet.

To their surprise, six months later, 50% of people who’d added more vitamin K to their diets were maintaining stable anticoagulation levels, compared to only 20% of those who did not add more of the vitamin.

These results suggest that taking in more vitamin K, not less, might benefit patients on warfarin (Coumadin).

Based on the new findings, Ferland now recommends a minimum of 90 micrograms of vitamin K per day for women and 120 micrograms per day for men.

“Our hope is that health care professionals will stop advising warfarin-treated patients to avoid green vegetables,” she said in a meeting news release.

“That said, given the direct interaction between dietary vitamin K and the action of the drug, it is important that (higher) daily vitamin K intakes be as consistent as possible,” Ferland said.

If you are a heart patient who is taking blood thinners, such as warfarin (Coumadin®), you need to be careful not to overdo vitamin K.

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Blood thinners are often prescribed for people at risk for developing harmful blood clots.

If you suddenly increase your intake of vitamin K intake in your diet, it can have an unintended consequence. It can actually decrease the effect of warfarin, says cardiologist Leslie Cho, MD.

“This is because vitamin K is an essential part of the chemical process for forming blood clots in your body,” she says.

Don’t cut vitamin K out completely

You don’t want to cut out vitamin K completely, as it is present in a variety of healthy, nutrient-rich foods. These include leafy greens and many vegetables. Instead, be smart about how much vitamin K you consume, be consistent, and work with your doctor to find just the right balance.

For example, if you eat a diet rich in vitamin K, you may need to check your blood a little more frequently or take more warfarin. If you change your diet and eat fewer foods containing vitamin K, you may need to take less warfarin.

Work with your doctor to find the right dose for you.

Here are three tips to help you safely manage your vitamin K intake:

1. Pay attention to food labels to keep your vitamin K intake consistent

“Vitamin K foods can be included in your diet on a regular basis as long as you are mindful of the portion and keep the overall intake of vitamin K-rich foods consistent, says Julia Zumpano, RD, LD.

For instance, you can choose to have a vitamin K rich food every day, every week, or three times in a week — as long as you keep this portion and frequency consistent, she says.

“If necessary, you can discuss including regular sources of vitamin K in your diet with your doctor in case your warfarin dosage would need to be adjusted,” she adds. You will want to tell your physician how often you eat foods high in vitamin K and how much of those foods you eat. Being knowledgeable about vitamin K is a key to managing it in your diet.

There are a variety of vegetables that contain lower amounts of vitamin K. These include:

  • Tomatoes.
  • Peppers.
  • Carrots.
  • Cauliflower.
  • Cucumbers.
  • Potatoes.
  • Sweet potatoes.
  • Squash (both summer and winter).

Iceberg lettuce is low and romaine is also fairly low, so most people can eat either if them daily. In addition, be sure to read labels on multivitamins as they have varying amounts of vitamin K. Talk to your doctor about what vitamins you should take.

2. Beware of herbal supplements and omega-3 supplements (EPA/DHA)

You may need to avoid certain supplements and vitamins to keep your blood values stable. Talk to your doctor about any and all supplements you take to be sure they are not interfering with your blood thinners.

3. Take blood thinners in consistent way

Another way to manage how well your blood thinners work is to take your dose of warfarin at the same time each day, and from day to day, make sure your vitamin K intake is consistent, Dr. Cho says.

To be sure you’re on track, have your blood values checked regularly (usually once per month with your physician; this may be more often during dose adjusting).

Vitamin K in popular foods

Below, find more details on the amount of vitamin K present in different foods, including leafy greens, vegetables and other foods as provided by the U.S. Department of Agriculture.

When it comes to blood thinners, the more you know the better you can manage your diet. Be sure to talk to your doctor if you have any concerns.

What to know about the warfarin diet

Share on PinterestAsparagus is high in vitamin K.

Vitamin K, which is in some foods, has an important role in blood clotting, and how warfarin works.

The liver uses vitamin K to produce clotting factors, which are cells that help to control bleeding and enable blood clots to form.

Warfarin disrupts this clotting process by inhibiting an enzyme in the liver that uses vitamin K to form clotting factors.

Warfarin can reduce the chances of a dangerous blood clot forming by increasing the time it takes for the liver to produce clotting factors.

It is possible that eating a diet rich in vitamin K could reduce the effect of warfarin on clotting factors.

The American Heart Association (AHA) suggest that eating vitamin K-rich foods may counteract the effects of warfarin, and lower the prothrombin time. This is the time it takes for a blood clot to form.

The AHA’a list of 19 foods high in vitamin K includes:

  • amaranth leaves
  • asparagus
  • broccoli
  • Brussels sprouts
  • coleslaw
  • collard greens
  • canned beef stroganoff soup
  • endive
  • garden cress
  • kale
  • kiwifruit
  • lettuce
  • mustard greens
  • soybeans
  • spinach
  • Swiss chard
  • tuna fish in oil
  • turnips
  • vegetable drinks

It is not necessary to cut out foods that contain vitamin K entirely. The foods that contain vitamin K also have other nutritional properties that contribute to a healthful diet.

It is important to note that the guidance varies on how much vitamin K people on warfarin can consume.

For example, a recent systematic review suggests a diet that restricts vitamin K intake is unlikely to improve the efficacy of warfarin. The authors suggest that keeping vitamin K levels consistent may be more beneficial.

The average person only needs a small amount of vitamin K, around 60 to 80 micrograms (mcg) per day. As this amount is so small, it can be easy for vitamin K levels to fluctuate across different days, creating a problem for people on warfarin.

Keeping vitamin K levels stable, and within a normal range, may reduce its effect on the actions of warfarin. Keeping a food diary and being aware of foods that are high in vitamin K can help a person keep track.

Inside Woman

Spinach is generally regarded as a rich source of antioxidants and many vitamins and minerals and has been identified to have substantive healing attributes for critical organ systems including: eyes, skeletal and digestive systems and prostrate gland.
Many of the benefits of spinach are expressed in terms of reducing risk or damage. For example, spinach has been linked to decreased risks of oxidative stress and high blood pressure and other eye-related problems. Recently, spinach has been credited with anti-aging effects in vision, brain and cardiovascular function.
There seems to be solid support for the premise that consuming spinach is generally good for you. However, opinions vary about the health repercussions of including spinach in a daily diet regimen. Here are the three side effects of eating spinach:

  • Spinach is high in oxalic acid, a chemical that can bind with iron and calcium and cause your body to absorb less of these important nutrients. To combat this problem, take in some vitamin C when you eat spinach; you can do this by having a glass of orange juice or a tomato whenever you eat spinach. Vitamin C will help your body better absorb calcium and iron.
  • The oxalates in spinach may interfere with the absorption of calcium, as well as potentially crystallize. People who have kidney or gallbladder problems may want to be careful about eating this green.
  • It’s possible that it can interfere with proper thyroid gland functioning, although cooking may reduce the goitrogenic compounds.
  • Gout-prone people may be affected by the purines in this food.

Remember, you should not eat spinach along with cucumber. This is because that the spinach is rich in vitamin c and cucumbers contain enzymes which can decompose vitamin c. So they should not be consumed together to avoid any interference.

Also, you should avoid having tofu with spinach. The reason for that is because spinach contains a large amount of oxalic acid while tofu has abundant calcium ions in its contents.
Moreover, Spinach should not be eaten with animal liver which is rich in some minor nutrition elements like copper and iron.
Here is the easiest spinach salad:

  • Large portion of fresh baby spinach
  • Tomato
  • Avocado
  • Favourite salad dressing
  • Salt

Cooking spinach increases its health benefits! Just half a cup of cooked spinach will give you thrice as much nutrition as one cup of raw spinach.
Remember, the way best way to get the best from the leaf is to buy it fresh and eat it the same day.

Spinach is one green leafy vegetable that is very rich in nutrition. Most people can relate to having been cooreced to eat spinach as a child because of their parents belief that spinach helps to keep the doctor away. The real truth is that spinach contains a variety of components which help maintain good health and build up immunity against diseases. However, one question remains – which is best, cooked or raw spinach?

Eating raw vegetables of any kind is generally encouraged in any weight loss program. And while that is certainly true, cooked spinach has its own unique advantages over raw spinach. Cooking spinach seems to improve your body’s ability to absorb the beneficial nutrients. Whether you boil, steam or fry, cooking spinach changes the iron into a form that is more readily absorbed into the body. Spinach contains iron in the non-heme form which is not as bio-available as heme iron that is found in foods from animal products. Moreover, spinach in its raw form contains a compound known as oxalic acid which inhibits iron absorption by binding onto it. When you cook your spinach the oxalic acid and other inhibitors will be unlocked and iron will be made more bio-available.

Secondly, cooked spinach releases more lutein. Lutein is a type of phytochemical that protects the eyes from the formation of cataracts and other age related complications like macular degeneration. In raw form, spinach has lower levels of lutein.

On the other side of the argument, raw spinach has more antioxidant properties compared to cooked spinach. The antioxidants are found in the form of vitamins like A and C and also flavanoid polyphenolics. Cooked spinach still contains these antioxidants but in reduced quantities.

Another disadvantage to cooking spinach is that there is a tendency towards overcooking it which greatly reduces the nutrient load. When cooking be careful to keep an eye on it and remove it from the heat right at the moment that it wilts. There is no need to cook it any longer than that.

The one method that I would not recommend is to boil spinach in a pot of water – unless you’re making soup and are boiling the spinach in the broth you’ll end up consuming. Boiling in water that you’ll then throw out means you’ll lose the water soluble vitamins such as the B complex vitamins.

So bottom line – cooked spinach is going to give you a more nutrition packed meal, just be careful not to overcook it and not to boil it and toss out the water.

Garlic Spinach

One of my favorite ways to serve spinach is to saute sliced onion in extra-virgin olive oil. Seasone with sea salt and black pepper and a bit of crushed red pepper if you like. Once the onion starts to soften, add some crushed or sliced garlic and continue sauteing until the onion is soft. Add handfuls of fresh spinach. Turn off the heat and allow the spinach to wilt. Season again with salt and pepper and serve with just about any meat dish or add some more extra virgin olive oil and toss with whole grain pasta.

Spinach Pizza

Pick up a prebaked whole wheat pizza crust. Spread with tomato sauce. Top with 1 bag of baby spinach that’s been steamed, squeezed dry and chopped, then mozzerella, Parmesan cheeses. Sprinkle with sea salt and crushed red pepper flakes. Bake until cheeses are melted and slightly browned.

Cheesy Spinach Eggs

And here’s a recipe from our book “The UnDiet: 2 Weeks of Extremely Low Carb Menus & Recipes” which is only 3 carbs for the entire recipe. You can decide if this is one or two servings.


1 tablespoon extra-virgin olive oil or butter

¼ cup Parmesan cheese, shredded

¼ cup mascarpone cheese

3 large eggs

¼ teaspoon each dried basil and thyme

small pinch each of salt and black pepper

1 – 2 cups fresh spinach, steamed, squeezed dry and chopped


In a medium bowl mix all ingredients except spinach.

Heat oil in a medium skillet over medium heat. Add egg mixture and spinach to pan. Stir once to combine and then allow the eggs to cook without stirring. Lift the edge of the eggs every now and then, tilting the pan to allow the uncooked egg to run to the bottom of the pan. Remove from heat when the eggs are still slightly runny as they’ll continue cooking for a few minutes. This method keeps the eggs nice and moist, rather than dry and overcooked.

Spinach is among the most nutritional things you can consume. On the calorie per calorie basis, spinach has nutrition greatest amount than any other food product in the world. It’s incredibly rich in vitamins and minerals, and is as well packed full of antioxidants and flavonoids. Spinach is packed full of lots of nutrients is such as vitamin B2, vitamin B6, K, potassium, iron, copper, vitamin an or even magnesium, manganese, phosphorus, vitamin B1, vitamin C, calcium as well as fiber. There’re little amounts of protein, omega 3″‘selenium, vitamin B 3 or s.

Lutein and Zeaxanthin are more 2 potent antioxidants that are contained within spinach. They got vital roles in the corps along with protecting the retina from oxidative stress. Now regarding the aforementioned reality. This can help prevent age related challenges such as macular degeneration and other eye issues. Then once again, this oxidative stress is a key reason for a lot of wellbeing troubles such as heart disease, big blood pressure, diabetes or stroke. There’re more than ten unusual flavonoid compounds that are contained in spinach. The compounds have powerful anticancer and ‘antiinflammatory’ properties. As a output, latter studies have shown that spinach can decrease developing incidence breast cancer in girls. Now let me tell you something.a great deal of diseases are either caused or made worse by inflammation. Spinach antiinflammatory properties help relieve inflammation and can help with quite a few those diseases.

As a outcome, heightened blood pressure is an epidemic in our own society. Spinach contains fiber and proteins which are shown to reduce blood pressure over time. Basically, it as well has a rather low rating and is quite low in calories. All combination of this kind of elements help to reduce blood pressure and keep your blood pressure down. Vitamin K is very crucial for decent brain functioning. As a outcome, the brain relies on vitamin K for synthesizing a protective shield throughout the brain. So, vitamin K is absolutely essential for the overall overall well being central nervous scheme.

Due to spinach’s mass amounts of vitamins and minerals, spinach is incredibly significant for humans overall soundness. This is notably real for guys that live in North America as diets have suffered in latest years. On top of this, contained in spinach is vitamin Vitamin A’s role includes protecting mucous membranes and in addition protecting urinary, theintestinal and even respiratory tracts of bodies. Vitamin an is as well immensely significant for whitey development blood cells. On top of that, the whitish blood cells help fight infections and help reduce developing chances colds and also different infections such as strep throat.

Sounds familiar, doesn’t it? Now we see somewhat about spinach supports, we need to get several seconds to talk about methods to store spinach perfectly. Doublecheck if you do not wash spinach until you’re almost ready to prepare. Washing spinach and after all putting it in the refrigerator can lower the spinach life.

Discard any leftovers as cooked spinach shall not keep pretty well and will lose its nutritional value and taste quite quite fast, right after spinach is cooked. That said, this taste absolutely delicious and is perfect means to take spinach. The green smoothies usually taste like the fruit that you put in it. As well, they are really good at masking all the vegetables along with the spinach.

This will ensure I’m getting all the nutrition I need through the week. Needless to say, this will ensure I’m getting all the nutrition I need over the week.

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