Popeye the Sailor Man built his entire brand around spinach. Every episode, the same routine: Things go sideways, Popeye squeezes open a can, downs the whole thing in one go, and immediately gains the strength to sort out whatever catastrophe Bluto has caused.
As it turns out, Popeye was onto something, though the science is a bit more interesting than a can of spinach giving you instant cartoon muscles. Spinach really is remarkably good for you. It’s just that the reasons why are more nuanced than a sailor’s battle cry would suggest.
So let’s take a look at what spinach actually does, and doesn’t do, for your health — and how to get the most out of it.
Where Is Spinach Grown?
Spinach (Spinacia oleracea L.) likely originated in Asia, in what is now Iran. Its nearest relatives are beets and chard. We have records of spinach cultivation from China in the seventh century and Europe in the fourteenth. The Moors, historical inhabitants of Europe and Rome, introduced it to Spain, a fact reflected in our name for the plant (the etymology of “spinach” is from the Spanish word hispanica). Today, four states — California, Arizona, New Jersey, and Texas — grow 98% of the commercial fresh market spinach in the U.S.
Globally, the U.S. is the second-largest spinach producer after China. It’s not even close, though: China’s spinach production reached almost 28 million tons in recent internationally compiled figures, while the U.S. produces well under half a million tons most years — putting China’s output at roughly 65 to 90 times that of the U.S.
If you like to garden, you don’t have to import your spinach, as it’s easy to grow in many climate zones. It’s a relatively hardy green that can be planted in very early spring, as well as in fall and even winter in some areas.
Types of Spinach
There are three main types of spinach: flat-leaf, savoy, and semi-savoy.
1. Flat-leaf or smooth
This type predominates in grocery stores and restaurants in the U.S. It’s also frequently included in pre-packaged salad mixes, either on its own or mixed with other greens like butter lettuce or arugula. Flat-leaf spinach is sweeter and more tender than other varieties and is delicious (in my opinion! — your mileage may vary) both raw and cooked. Some popular varieties of flat-leaf spinach include Space and Red Cardinal.
2. Savoy
This variety has distinctive wrinkly leaves that are usually around 5–6 inches long. Raw, it’s somewhat bitter, so you may want to cook it. Two popular varieties of savoy spinach are Regiment and Bloomsdale.
3. Semi-Savoy
This type of spinach isn’t as crinkly as savoy but does still have an uneven texture and edges. This makes it easier to clean before eating. Semi-savoy spinach has the same flavor characteristics as savoy, so it’s probably best to cook this one as well. Some popular varieties of semi-savoy spinach include Tyee, Catalina, and Teton.
Spinach Nutrition
While spinach may not give you Popeye-level instant strength, it still has a lot to offer nutritionally. And you don’t have to gulp down a full can of spinach to reap those benefits.
Spinach contains at least 20 different important nutrients. It’s extremely high in antioxidants, containing 13 flavonoids, which are compounds responsible for many of the plant’s health benefits.
A half cup of cooked spinach delivers a striking nutritional payload. It provides more than 400% of your recommended daily vitamin K1, around 58% of your daily vitamin A, and meaningful amounts of magnesium, potassium, iron, and vitamin C. It also provides about 2.6 grams of protein in just 21 calories — which is comparable to the protein-to-calorie ratio of a cooked steak.
Health Benefits of Spinach
The nutrients and potent plant compounds in spinach make it one of the healthiest foods on the planet. Below are some of the known health benefits of making spinach a regular part of your diet.
The nutrients and potent plant compounds in spinach make it one of the healthiest foods on the planet. Below are some of the health benefits of making spinach a regular part of your diet.
1. May have anticancer effects
Some epidemiological studies have observed a protective role of spinach consumption when it comes to cancers of the breast, colon, and esophagus. A 1997 study of more than 17,000 women found that those who ate at least 2 servings of spinach per week had a 45% lower risk for breast cancer. (Carrots had the same effect, in case you prefer orange to green.) Some of the anticancer effects of spinach may be due to its lutein content, a carotenoid that provides a yellow pigment to plants.
In case you’re wondering why spinach isn’t yellow, consider this lesson from kindergarten: yellow and blue combine to make green. Which does make me wonder: If spinach didn’t have so much lutein, would it be blue? We may never know. But what we do know is that regular inclusion of spinach in your diet may be cancer-preventive.
2. May improve metabolic syndrome
Metabolic syndrome refers to a cluster of conditions that raise your risk for chronic diseases like heart disease, cancer, and type 2 diabetes. Some of these conditions include high blood pressure and blood lipids, abdominal obesity, and poor blood sugar management. Eating spinach may help prevent some or all of these conditions.
The effect was first measured in rodents. A 2017 study gave rats metabolic syndrome via a high-fructose diet, then observed the effects of a daily spinach extract. Compared to rats in the control group, the ones on the Popeye diet had lower blood sugar and insulin levels, improved cholesterol numbers, reduced inflammation, healthier hearts, and less cell damage caused by harmful free radicals. And the effects were even more pronounced when the spinach was paired with daily aerobic exercise.
In another animal study, this one using mice, spinach consumption was found to improve insulin resistance, high cholesterol, high triglycerides, and endothelial function. Some of this benefit may be attributed to the dietary nitrates found in spinach. These compounds are converted into nitric oxide, a gas that dilates arteries and improves circulation, which in turn improves heart health.
(Our view on the use of animals in medical research is here.)
Researchers got around to testing the effects of spinach on humans a few years later. In a 2021 case-control study published in the journal BMC Gastroenterology, researchers analyzed 225 patients who had been diagnosed with non-alcoholic fatty liver disease (NAFLD), which is closely linked with metabolic syndrome, and 450 controls. The more spinach (including both raw and cooked) that the study participants ate, the lower their odds of suffering from NAFLD.
3. May help boost your mood
Some people may find that consuming spinach makes them happy. One telltale sign is declaring loudly, publicly, and repeatedly, “I yam what I yam.” And it’s not just a case of wishful thinking; there’s solid scientific evidence that spinach is good for your brain and may actually help boost mood.
In one 2018 study, researchers examined the mental health effects of eating raw versus cooked or canned fruits and vegetables on young adults. They found that eating raw, unprocessed produce predicted significantly better mental health outcomes compared to cooked or canned produce. Spinach was among the top 10 fruits and veggies that improved mental health.
Interestingly, a second 2018 study found antidepressant effects from spinach in a very different form, frozen powder extract, suggesting the mood benefits may not depend entirely on eating it raw. The researchers observed that frozen spinach powder extract increased glutamate and glutamine levels in the prefrontal cortex of the brain. Low levels of these two compounds have been observed among people with depression. (In case you’re wondering, this study was conducted on some very unfortunate mice. It’s not considered ethical to decapitate humans to measure amino acid levels in their brains.)
4. May be good for your brain
In addition to boosting your mood, eating spinach and other leafy greens may have other beneficial effects on your brain.
In a 2018 study published in Neurology, researchers found that consuming green leafy vegetables (including spinach, kale, collards, and lettuce) significantly slowed cognitive decline in dementia-free older adults (average age 81). Even better, these benefits were seen with just one serving of leafy greens per day. But what was the most impressive thing? The rate of cognitive decline among those who consumed the most greens, compared to those who consumed the least, was the equivalent of being a whopping 11 years younger.
5. May increase your strength and athletic performance
Spinach contains a phytosteroid called ecdysterone, which may be responsible for some of its strength benefits. In a 2019 comparative study, researchers concluded that the performance effects of this naturally occurring steroid hormone were so significant that ecdysterone could be added to the list of prohibited substances for sports, along with other anabolic agents. Good thing that Popeye lyricist Sammy Lerner didn’t know this; “I’m strong to the finich ‘cause I get my ecdysterone” just isn’t as catchy as the original.
The nitrates found in spinach may offer other strength benefits. A Swedish study found that adding nitrate to the drinking water of mice for one week resulted in much stronger muscles, compared to those of mice that didn’t get nitrates.
6. May help support eye health
Spinach contains the antioxidant-rich carotenoids lutein and zeaxanthin. These provide pigment to plants and are also responsible for many of their health benefits, particularly to your eyes. Lutein and zeaxanthin have been extensively studied for their association with a reduced risk for cataracts and age-related macular degeneration, a condition that may, over time, result in blurred vision or blindness.
According to a small 2016 study, consistent intake of lutein-rich spinach increased macular pigment optical density, visual acuity, and blood levels of lutein. The 11 healthy participants consumed 75 grams (approximately one-third cup) of frozen spinach containing 10 milligrams of lutein every day for 2 months.
Potential Spinach Health Risks
Despite its numerous health benefits, spinach also comes with a few potential downsides to consider. While for most people its benefits far outweigh its risks, some populations may want to avoid eating large amounts of spinach.
Contains Oxalates
Spinach contains oxalic acid, which your body converts to oxalates. These compounds bind to minerals like iron and calcium, making them less bioavailable for your body to use.
And spinach does contain a higher concentration of oxalates than most other plant foods. Just a half cup of cooked spinach contains around 755 milligrams of oxalic acid.
The good news is, most of this is excreted from your body through urine, and so doesn’t pose a risk for most people at normal levels of consumption.
The less good news is, they may increase the risk of kidney stones in people prone to them. Healthcare providers will sometimes prescribe a low-oxalate diet to people with this susceptibility. Adhering to such a diet generally means eating less than 100 milligrams of oxalic acid per day, which means no spinach (or beet greens or Swiss chard). When this diet is prescribed, it’s usually out of an abundance of caution, because the role of dietary oxalates and kidney stone formation is inconclusive. Also, it’s possible to reduce the risk of kidney stones by drinking a lot of water.
Oxalates may also pose concerns for people who have a history of frequent antibiotic use. This is because some of the oxalates you eat are broken down by bacteria in the gut. People who lack those bacteria may benefit from a lower-oxalate diet.
Despite their ability to reduce absorption of some nutrients, oxalates are not evil. In fact, they are present in almost every food we eat, with high concentrations in some of the healthiest, including rhubarb, spinach, beets, Swiss chard, cacao, peanuts, and sweet potatoes.
The bottom line? Spinach is a highly nutritious food. If you have concerns about your iron or calcium levels and don’t eat a lot of other sources of these nutrients, or if you are prone to kidney stones, you may want to moderate your spinach consumption. But eating a well-balanced diet can give you more of the minerals that oxalates may otherwise inhibit.
Interference with Medications
Spinach contains large amounts of vitamin K1, in both its raw and cooked forms. Vitamin K1 is known to support natural blood clotting and to prevent excessive bleeding. Getting enough is also important for the strength of your teeth and bones, helping to regulate calcium balance and reduce the risk of fractures.
On the other hand, too much vitamin K1 can reduce the effectiveness of blood thinners like Warfarin. If you’re on Warfarin, or a similar medication, there’s probably no need to avoid spinach completely. Rather, maintaining a consistent intake of spinach and other sources of vitamin K1 can help keep blood levels of this nutrient even. And of course, this could be a good thing to discuss with your healthcare provider.
May Contain Pesticides
Spinach remains on the Environmental Working Group’s Dirty Dozen list, where it’s listed as the second most pesticide-contaminated produce item when grown conventionally. To help minimize your consumption of pesticides, choose organically grown spinach whenever possible.
How to Choose & Store Spinach
So perhaps you’ve put spinach on your grocery list. If so, great! Follow these few tips for buying and storage success.
- Choose bunches with vibrant green leaves, and avoid spinach with yellowed leaves, as this shows it’s lost some nutrients.
- Avoid spinach that has wilted or slimy leaves, as this indicates it’s starting to spoil. This deterioration will spread to the rest of the leaves and give that bunch a very short shelf life.
- Choose fresh spinach over bagged if possible, as bagged leafy greens can get soggy. They also have more contact with plastic.
- If fresh spinach isn’t available or you prefer an option that will keep longer, go for frozen spinach. Frozen produce is picked fresh, and the freezing process keeps most of its nutrients intact.
- Canned spinach is also an economical option. But if you buy canned spinach, choose some in a BPA-free can. (And don’t squeeze the sides to open it — use a can opener.)
When you get home, store fresh spinach in the refrigerator in produce bags or in airtight containers. Don’t wash your spinach until you’re ready to eat it, since a moisture-rich environment can promote bacterial growth and premature wilting. If you buy fresh spinach that’s not organic, wash it with water mixed with a bit of baking soda when you’re ready to use it. This combination is more effective for removing pesticides on the surface of produce than water alone, or even commercial produce cleaners. (For our article on how to wash produce to reduce pesticide contamination, click here.)
How to Use Spinach
Now for the part you’ve been waiting for! What are some of the best ways to use the delicious spinach you just brought home, pulled out of the freezer, or picked from your garden?
Many people enjoy spinach washed and raw. It can be used as a foundation for salads, incorporated into dips (like the spinach and artichoke one below), blended into smoothies and homemade juices, or mixed into soups, stews, and curries.
As for cooked spinach, it’s delicious in pasta dishes, sautéed with garlic as a side to just about anything, incorporated into stir-fries and breakfast scrambles, and mixed into soups, stews, and curries. To cook spinach, you can boil and drain it, sauté it with a bit of water or vegetable broth, steam it in a steaming basket, or even microwave it. Be aware that spinach is mostly water, so that giant bunch of fresh greens may end up as a quarter cup if cooked. Don’t be sad; all the good stuff is still there, just concentrated.
Research has shown that there’s more water-soluble B and C vitamins when spinach is steamed or microwaved than when boiled. Cooked spinach can actually be more nutrient-rich than raw, because the cooking process can make certain minerals more bioavailable.
Spinach-licious Recipes
The recipes below provide just a small taste (literally!) of spinach’s diversity. Blend it to make an ooey-gooey tasty appetizer with the Spinach Artichoke Dip. Entice your kids to love their spinach by getting them to help you in the kitchen to make the Superhero Dressing (with spinach as the star ingredient, of course!) that drizzles on top of the Spinach Jeweled Salad. Or, if you want to be super sneaky, make the Cheesy Spinach Lasagna, which is (almost) guaranteed to please even the pickiest eaters.
1. Spinach Artichoke Dip
Something magical happens when you blend spinach with artichokes and cashews — they come together to create an ooey, gooey sea of deliciousness packed with nutrients like vitamin K, iron, magnesium, and zinc. This seemingly indulgent dish is also very simple to prepare. Enjoy it as a veggie dip, spread it on a sandwich, or layer it with potatoes, then bake as a casserole.
2. Spinach Jeweled Salad
If you want to become a real-life superhero, we have just the salad for you. Or, maybe you’re past the superhero phase, but have kids who refuse to eat their greens — entice them with the salad’s Superhero Dressing made with spinach and avocado! There are so many essential nutrients packed into this gem of a meal, including vitamin E, vitamin C, carotenoids, fiber, and much, much more, thanks to the spinach, avocado, nuts, seeds, pomegranate, and radishes. Enjoy it often!
3. Cheesy Spinach Lasagna
Including greens in your daily diet can sometimes be a challenge, and if you have greens-avoidant kids, that’s a whole other level of difficulty. Enter Cheesy Spinach Lasagna — the meal to end all leafy green challenges. This family-friendly meal will most likely satisfy even the pickiest of eaters and may even knock the socks off of some. Feel good knowing that you’re feeding your family a meal filled with nutrient-packed, plant-based ingredients for optimal health and well-being.
Eat Your Spinach, Be Strong to the Finish
Even though he wasn’t on the leading edge of scientific research, it turns out that Popeye was onto something: Spinach is good for you and can make you strong. Plus, it has several other health benefits. Although some people may want to moderate their consumption, most people can safely include spinach as part of a healthy, balanced diet. Whether you go with fresh, frozen, or canned, aim to purchase (or grow) organic if you can, to avoid pesticides. Spinach is a versatile green that deserves your consideration for its excellent nutritional value and, in much of the world, its year-round availability.
Tell us in the comments:
- What are some of your favorite ways to prepare and enjoy spinach?
- If you haven’t been a spinach fan previously, will you try eating more now?
- Have you ever grown spinach at home, or tried any of the less common varieties?
Feature image: iStock.com/Kativ
