What Happens To Your Body When You Eat Spinach Every Day

While it's generally not a great idea to take nutrition advice from cartoon characters, Popeye's obsession with spinach is definitely worth emulating. This dark leafy green, a member of the cruciferous family (think: broccoli, Brussels sprouts, and kale), has certainly earned its reputation as a superfood. In fact, if you calculate the amount of vitamins and minerals contained in a single serving by adding up the percent daily value (DV) of each micronutrient to create a "total DV," spinach is one of the most nutrient-dense foods you can eat. A one-cup (180-gram) serving of spinach contains 1,938.6% total DV in a mere 41.4 calories, according to My Food Data.

Considering how healthy spinach is, Americans could stand to eat more of the stuff. Although the United States is the world's second-largest grower of spinach, the average American eats only three pounds a year. We might be eating even less if it weren't for Popeye's bulging muscles. The spinach industry saw a 33% increase in American spinach consumption in the 1930s thanks to the popularity of the cartoon character. Spinach comes in several varieties, including the traditional flat-leaf and curly-leaf savoy versions (via the South Florida Reporter).

But what exactly will eating spinach every day do for your body, and are there any downsides to chowing down on this dark leafy green?

Fight free radicals by eating spinach every day

Spinach is an excellent source of antioxidants. In a 2010 paper published in Nutrition Journal, researchers established the total antioxidant content of more than 3,100 foods and beverages, including spinach. According to their findings, frozen spinach contained between 0.89 and 1.35 millimoles (mmol) of antioxidants per 100-gram serving. Live Science noted that the antioxidants in spinach include vitamin C, alpha-lipoic acid, lutein, zeaxanthin, neoxanthin, and violaxanthin.

What, exactly, do antioxidants do, and why are they so important for good health? Antioxidants are chemicals that protect the body against damage from free radicals. Free radicals are highly unstable atoms of oxygen that try to "steal" electrons from other molecules in the body. This destabilizes the molecules and creates a chain reaction that leads to damage throughout the body — a process known as oxidative damage or oxidative stress. Substances that produce free radicals can be found in food and in our environment, and free radicals are also created as the byproduct of natural chemical processes in the body. Antioxidants are able to give free radicals the electrons they want without becoming destabilized themselves (via Live Science).

Eating spinach every day will keep you regular

Including lots of spinach (and other fiber-rich foods) in your diet will ensure that your number twos are number one. According to the Mayo Clinic, "dietary fiber ... includes the parts of plant foods your body can't digest or absorb." It comes in two forms: soluble and insoluble. Soluble fiber absorbs water as it passes through your digestive tract, while insoluble fiber doesn't. Although both types of fiber are beneficial, the insoluble kind is responsible for keeping you regular. It "promotes the movement of material through your digestive system and increases stool bulk." Adult women should aim to get 21 to 25 grams of fiber a day, depending on age, while men should shoot for 30 to 38 grams. But, according to UCSF Health, average consumption is only about 15 grams.

Additionally, the benefits of fiber don't stop at the bathroom. As EatingWell explained, fiber can improve your health in a number of ways. It supports the beneficial bacteria in your digestive tract and can make it easier to lose weight and keep the pounds off over time. It also lowers your risk for heart disease (by reducing cholesterol levels) and type 2 diabetes (by preventing sudden spikes in blood sugar after you eat). Getting adequate fiber reduces your risk of certain cancers and offers a natural way to "detox" your body of potentially harmful compounds. One cup of cooked spinach contains 4.3 grams of fiber (via Nutrition Data).

Fight chronic inflammation by eating spinach every day

Spinach is chock full of quercetin, a flavonoid (plant pigment) found in vegetables, fruits, and grains. Quercetin is a powerful antioxidant that is believed to have anti-inflammatory properties. High levels of free radicals in the body can activate genes that promote inflammation, so by neutralizing these free radicals, quercetin reduces chronic inflammation (via Healthline). Although many plant foods contain quercetin, spinach is a particularly good source. According to a 2019 study published in Nutrients, spinach contains 27.2 milligrams of quercetin per 100 grams of fresh spinach. (For comparison, kale has 22.6 grams and broccoli has 13.7.)

Although it often gets a bad rep, inflammation isn't always a bad thing. According to the Harvard Medical School, acute inflammation occurs immediately after an injury and produces warmth, redness, swelling, and pain. This brings white blood cells to the area, where they can begin the healing process. Problems arise, however, if the inflammatory response becomes chronic. In these cases, the body can get confused and begin attacking healthy tissue. Chronic, low-grade inflammation is believed to cause or worsen a number of conditions, such as heart disease, diabetes, cancer, and arthritis. Chronic inflammation doesn't produce the telltale signs that acute inflammation causes, so it often goes unnoticed and unaddressed. 

If you need to lower your blood pressure, eat nitrate-rich spinach every day

You've heard that nitrates are the ingredient that makes bacon so bad for you, but did you know that there are other nitrates you should be trying to get more of in your diet? Unlike the synthetic nitrates used as preservatives in bacon and other cured meats, the natural nitrates found in some fruits and vegetables appear to be beneficial for health (via Livestrong). A 100-gram serving of raw spinach has 24 to 387 milligrams of nitrate, depending on growing conditions (via WebMD).

WebMD reported on a study published in the New England Journal of Medicine in which researchers examined the effect nitrates had on participants' blood pressure. They found that "average diastolic blood pressure (the bottom number in a blood pressure measurement, representing pressure in the arteries when the heart is resting between beats) was 3.7 mmHg lower after three days of nitrate supplementation." Nitrates appear to help keep blood vessels healthy and adequately dilated, thus reducing blood pressure.

Hypertension, defined as a systolic blood pressure (the top number in a blood pressure measurement, representing pressure in the arteries when the heart is contracting) equal to or greater than 130 mmHg or a diastolic blood pressure equal to or greater than 80 mmHg, affects approximately 45% of American adults and is considered a major risk factor for both heart disease and stroke (via the Centers for Disease Control and Prevention).

Will eating spinach every day prevent cancer?

While a wide variety of genetic, environmental, dietary, and lifestyle factors can affect your risk for various cancers, regularly eating spinach may help your body destroy cancerous cells before they multiply out of control. According to WebMD, spinach boasts a number of micronutrients that can help ward off cancer. The antioxidant carotenoids lutein and zeaxanthin neutralize free radicals before they can cause DNA damage that can turn normal cells cancerous, and research suggests that this powerful duo can protect against mouth, esophageal, stomach, ovarian, endometrial, lung, and colorectal cancers. The folate in spinach also repairs damaged DNA before it can wreak havoc. The 2010 book Bioactive Foods in Promoting Health highlighted two other cancer-fighting compounds in spinach: sulfoquinovosyl diacylglycerol (SQDG) and monogalactosyl diacylglycerol (MGDG). These substances have been shown to suppress the growth of cancer cells in both animal and laboratory studies.

Approximately 39.5% of Americans will be diagnosed with some form of cancer during their lifetime (via National Cancer Institute). Although it may seem like every type of cancer is very different, the process driving all cancers is the same. According to the National Cancer Institute, "In all types of cancer, some of the body's cells begin to divide without stopping and spread into surrounding tissues." Unlike normal body cells, cancer cells are less specialized and can ignore the usual mechanisms that stop cells from dividing out of control.

Give your body the vitamin C is needs by eating spinach every day

Although oranges and other citrus fruits are probably the first foods that come to mind when you think of vitamin C, spinach is no slouch in this department. A one-cup serving of raw spinach has 8.4 micrograms of vitamin C — 14% of your daily needs, according to Nutrition Data. A one-cup serving of cooked spinach packs an even bigger punch: 17.6 micrograms or 29% of the recommended intake.

According to the National Institutes of Health, vitamin C is a water-soluble vitamin that plays a number of important roles in the body. It's essential for the production of collagen, a protein that gives skin and connective tissues their structure. Vitamin C is also needed to produce certain neurotransmitters, metabolize the protein we eat, and absorb iron from plant foods. As a powerful antioxidant, vitamin C fights free radical damage in the body. It may even have the power to "regenerate" other antioxidants in the body. 

Adequate vitamin C is also needed for proper immune function. The recommended dietary allowance (RDA) for vitamin C is 90 micrograms for men, 75 micrograms for non-pregnant women, 80–85 micrograms during pregnancy and 115 to 120 micrograms if breastfeeding. Smokers are advised to up their intake by an additional 35 micrograms a day. While true vitamin C deficiency is rare, 38.9% of American adults don't meet the estimated average requirement (EAR) for vitamin C (via Oregon State University).

Eating spinach every day will help your body get the iron it needs

Iron deficiency is extremely common, affecting approximately 20% of nonpregnant women, 50% of pregnant women, and 3% of men (via WebMD). In fact, according to the Iron Disorders Institute, iron deficiency is the most prevalent nutritional deficiency in the world. It can lead to anemia (low red blood cell count), which can cause fatigue, shortness of breath, dizziness, headaches, and weakness.

The good news for spinach lovers is that this dark leafy green is a double threat when it comes to iron deficiency. First, spinach is an excellent source of iron — one cup of cooked spinach contains 6.4 micrograms, or 36% of your daily needs. Second, the vitamin C in spinach improves absorption of iron from plant-based sources. As the Harvard School of Public Health explained, there are two types of iron: heme (from animals) and non-heme (from plants). While heme iron is easily absorbed by the body, non-heme iron is much less bioavailable and needs help from vitamin C to be metabolized. According to a 2014 paper published in Free Radical Biology and Medicine, In addition to improving iron absorption in the digestive tract, vitamin C plays a number of other roles when it comes to iron, both heme and non-heme. These include influencing cells' uptake of iron from the blood and regulating how much iron is stored in the body.

Avoid easy bruising by eating spinach every day

If just lightly bumping into things leaves you black and blue for days, it could be a sign that you need more spinach in your diet. The vitamin C and vitamin K spinach contains combat easy bruising.

As a 2019 article in Prevention explained, vitamin C is essential for production of collagen, the protein that gives skin its strength and structure. Without enough of it, your blood vessels are out in the open and more likely to rupture. It's this rupturing of small blood vessels under the skin that causes unsightly bruises. Vitamin K may not be as well-known as other vitamins, but it's just as essential for good health. Your body uses vitamin K to produce proteins that oversee blood clotting. This process, also known as coagulation, prevents excessive bleeding both externally and internally. Easy bruising is an early sign of inadequate vitamin K levels. Although our bodies can produce one form of vitamin K, known as K2 (menaquinone), we get most of the vitamin K we need from food in the form of vitamin K1 (via Healthline).

As previously mentioned, spinach is a great source of vitamin C, and it boasts an almost absurd amount of vitamin K. Just one cup of cooked spinach contains an incredible 987 percent of your daily vitamin K needs and 39 percent of your magnesium needs. (via Live Science).

Eating spinach every day protects your joints

If you think arthritis is something you won't have to worry about until you're old, think again. According to the Centers for Disease Control and Prevention (CDC), 54 million Americans are affected by arthritis, and 60% of them are of working age (18 to 64). In fact, arthritis is a leading cause of disability, and 8 million adults aren't able to work because of their arthritis.

Osteoarthritis is the most common form of arthritis and is considered a "wear and tear" condition. Over time, the cartilage that cushions the ends of the bones in a joint wears away, causing bones to rub against one another, leading to pain, stiffness, and inflammation. This can happen simply as a result of getting older or because of injuries or repeated stress on the joint. Women, heavier individuals, and people with certain genetic factors are also more likely to get osteoarthritis (via the Mayo Clinic).

According to a 2013 article published in Science Daily, research suggests that sulforaphane, a compound released when eating cruciferous vegetables, can slow down the destruction of cartilage in joints. Sulforaphane "blocks the enzymes that cause joint destruction by stopping a key molecule known to cause inflammation," the article stated. While broccoli is the best source, all cruciferous veggies, including spinach, contain sulforaphane. Although sulforaphane's joint-preserving effects have only been demonstrated in laboratory-grown tissues and in mice, the results are promising for humans.

Protect your peepers by eating spinach every day

When it comes to eye health, vitamin A is extremely important. According to Healthline, vitamin A is needed to produce rhodopsin, a protein that allows the eyes to function in low light. Vitamin A is also important for maintaining a clear cornea (the outside covering of the eye) and may reduce your risk for cataracts. Not getting enough vitamin A can lead to xerophthalmia, a progressive eye disease that begins with night blindness and, if not corrected, can cause irreversible blindness.

Lutein and zeaxanthin are two other substances crucial to vision. As a 2014 paper published in Nutrition Reviews explained, these carotenoids (plant pigments) are taken up by the eye, where they "may be protective against eye disease because they absorb damaging blue light that enters the eye." In addition to safeguarding the eyes form diseases such as macular degeneration, lutein and zeaxanthin also appear to play a role in visual development and proper functioning of the retina.

Spinach is an excellent source of these micronutrients. One cup of cooked spinach contains 1,8867 IU of vitamin A — 377% of your daily needs (via Nutrition Data). The same serving size contains 20,354 micrograms of lutein and zeaxanthin, making it the richest source of these carotenoids (via My Food Data). To maximize the bioavailability of lutein and zeaxanthin, however, it's best to liquify (blend or juice) raw spinach, according to a 2019 study published in Food Chemistry.

Avoid painful muscle cramps by eating potassium-rich spinach every day

Potassium is a micronutrient that probably isn't on your radar, but it should be. That National Institutes of Health (NIH) recommends that adult men get 3,400 micrograms of potassium daily, while non-pregnant women should aim for 2,600 micrograms. But, average potassium intake among adult men is only 3,016 micrograms, while women get an average of 2,320 micrograms. Potassium is used by every cell in the body and, along with sodium, it plays a key role in regulating fluid balance. The NIH noted that "insufficient potassium intakes can increase blood pressure, kidney stone risk, bone turnover, urinary calcium excretion, and salt sensitivity (meaning that changes in sodium intakes affect blood pressure to a greater than normal extent)."

Sudden, painful muscle cramps are a telltale sign of low potassium levels. As Healthline explained, potassium helps relay signals from the brain to the muscles, causing them to contract. When potassium leaves muscle cells, this causes the muscle contraction to end. But, "when blood potassium levels are low, your brain cannot relay these signals as effectively. This results in more prolonged contractions, such as muscle cramps."

Although bananas are the poster child for potassium, spinach is also an excellent source. According to Live Science, a one-cup serving of cooked spinach has 839 micrograms of potassium — 24% of your daily needs.

Eating spinach every day may be bad for your thyroid

If your metabolism is a factory, where workers (the body's cells) turn food into energy, then the thyroid gland is the foreman, supervising and regulating everything. It does this by producing two hormones: T3 (triiodothyronine) and T4 (thyroxine). These hormones affect every cell in the body and dictate how quickly or slowly that cell uses energy. Iodine is an essential component of these hormones, and the thyroid extracts and stores this mineral. According to EndocrineWeb, thyroid disorders most often occur when the thyroid makes either not enough thyroid hormones (hypothyroidism) or too much thyroid hormones (hyperthyroidism). Goiters are another common thyroid issue and can be caused by hyperthyroidism or iodine deficiency.

According to the Kresser Institute, some foods, including cruciferous vegetables like spinach, are goitrogens, meaning they interfere with the thyroid's ability to take up the iodine it needs. This interference may be particularly problematic for individuals who have a preexisting thyroid disorder. Fortunately, spinach isn't the biggest offender when it comes to cruciferous goitrogens. The institute noted that "certain varieties of kale, collard greens, and Brussels sprouts [are] at the top of the list." Even so, if you have thyroid issues, it's probably not a great idea to be eating lots of raw spinach daily. Cooked spinach is a better option, as "steaming crucifers until fully cooked reduces goitrogens by two-thirds. Boiling crucifers for 30 minutes destroys 90% of the goitrogens."

Eating spinach every day could lead to kidney stones

According to Healthline, oxalate (oxalic acid) is an organic compound found in many plant foods. Oxalate binds to minerals — usually calcium — to create a salt, and these salts leave the body through both stool and urine. In some individuals, however, these salts collect in the kidneys and become kidney stones.

While several substances can concentrate in the kidneys and become stones, the National Kidney Foundation noted that calcium oxalate accounts for the majority of stones. These stones can be extremely painful to pass and may require surgical removal. They're also much more common than you might think: roughly 9% of women and 11% of men will get kidney stones at least once in their lives, and having one kidney stone puts you at much higher risk for additional stones. Kidney stones increase your risk for chronic kidney disease.

The University of Chicago identified spinach, both cooked and raw, as the food with the highest oxalate content per serving. One half-cup serving of cooked spinach contains 755 micrograms of oxalate, while a one-cup serving of raw spinach contains 656 micrograms. For those who need to follow a low-oxalate diet, they recommend getting no more than 100 micrograms a day, which means spinach is off the menu entirely.

Eating spinach everyday might cause allergy-like symptoms

If eating a big helping of spinach leaves you feeling congested and headachey, you may be sensitive to histamine. According to Healthline, histamine is a chemical produced by the body and found in some foods and beverages. It triggers the release of stomach acid to aid digestion and is part of the body's immune response after an injury or allergic reaction. The enzyme diamine oxidase (DAO) breaks down histamine, but some people either have a DAO deficiency or have an imbalance in their gut bacteria that leads to a buildup of more histamine than their DAO levels can handle. These individuals are histamine intolerant and, when histamine levels get too high, it can cause a number of unpleasant allergy-like symptoms, including nasal congestion, sinus problems, headaches or migraines, and hives. Other symptoms include fatigue, nausea, and vomiting. Severe cases of histamine intolerance can lead to dizziness, difficulty regulating body temperature, irregular heartbeat, and high blood pressure.

According to a 2007 study published in The American Journal of Clinical Nutrition, 1% of the population is histamine intolerant. While most fresh vegetables are low in histamine, spinach (along with tomatoes and eggplant) has higher histamine levels and may trigger reactions in sensitive individuals (via Histamine Intolerance Awareness).