Spinach (Spinacia oleracea) is a leafy green vegetable that originated in Persia.

It belongs to the amaranth family and is related to beets and quinoa. What’s more, it’s considered very healthy, as it’s loaded with nutrients and antioxidants.

Eating spinach may benefit eye health, reduce oxidative stress, help prevent cancer, and reduce blood pressure levels.

There are many ways to prepare spinach. You can buy it canned or fresh and eat it cooked or raw. It’s delicious either on its own or in other dishes.

This article tells you everything you need to know about spinach.

Nutrition facts

The nutrition facts for 3.5 ounces (100 grams) of raw spinach are (1):

Calories: 23

Water: 91%

Protein: 2.9 grams

Carbs: 3.6 grams

Sugar: 0.4 grams

Fiber: 2.2 grams

Fat: 0.4 grams

Carbs

Most of the carbs in spinach consist of fiber, which is incredibly healthy.

Spinach also contains small amounts of sugar, mostly in the form of glucose and fructose (1).

Fiber

Spinach is high in insoluble fiber, which may boost your health in several ways (2).

It adds bulk to stool as food passes through your digestive system. This may help prevent constipation.

SUMMARY

Spinach is low in carbs but high in insoluble fiber. This type of fiber may benefit your digestion.

Vitamins and minerals

Spinach is an excellent source of many vitamins and minerals, including (3):

Vitamin A. Spinach is high in carotenoids, which your body can turn into vitamin A.

Vitamin C. This vitamin is a powerful antioxidant that promotes skin health and immune function.

Vitamin K1. This vitamin is essential for blood clotting. Notably, one spinach leaf contains over half of your daily needs.

Folic acid. Also known as folate or vitamin B9, this compound is vital for pregnant women and essential for normal cellular function and tissue growth.

Iron. Spinach is an excellent source of this essential mineral. Iron helps create hemoglobin, which brings oxygen to your body’s tissues.

Calcium. This mineral is essential for bone health and a crucial signaling molecule for your nervous system, heart, and muscles.

Spinach also contains several other vitamins and minerals, including potassium, magnesium, and vitamins B6, B9, and E.

SUMMARY

Spinach is an extremely nutrient-rich vegetable. It packs high amounts of carotenoids, vitamin C, vitamin K, folic acid, iron, and calcium.

Plant compounds

Spinach contains several important plant compounds, including (4, 5, 6, 7, 8, 9, 10):

Lutein. This compound is linked to improved eye health.

Kaempferol. This antioxidant may decrease your risk of cancer and chronic diseases.

Nitrates. Spinach contains high amounts of nitrates, which may promote heart health.

Quercetin. This antioxidant may ward off infection and inflammation. Spinach is one of the richest dietary sources of quercetin.

Zeaxanthin. Like lutein, zeaxanthin can also improve eye health.

SUMMARY

Spinach boasts many plant compounds that can improve health, such as lutein, kaempferol, nitrates, quercetin, and zeaxanthin.

Health benefits of spinach

Spinach is extremely healthy and linked to numerous health benefits.

It has been shown to improve oxidative stress, eye health, and blood pressure.

Oxidative stress

Free radicals are byproducts of metabolism. They can cause oxidative stress, which triggers accelerated aging and increases your risk of cancer and diabetes (11).

However, spinach contains antioxidants, which fight oxidative stress and help reduce the damage it causes.

One study in eight healthy people found that spinach helped prevent oxidative damage. Although this study was quite small, its findings are backed up by other animal and human research (12, 13, 14).

Eye health

Spinach is rich in zeaxanthin and lutein, which are the carotenoids responsible for color in some vegetables.

Human eyes also contain high quantities of these pigments, which protect your eyes from the damage caused by sunlight (15).

Additionally, several studies indicate that zeaxanthin and lutein work to prevent macular degeneration and cataracts, which are major causes of blindness (16, 17, 18, 19).

These compounds may even be able to reverse existing damage (20, 21).

Cancer prevention

Spinach contains two components, MGDG and SQDG, which may slow down cancer growth.

In one study, these compounds helped slow tumor growth in a person’s cervix. They also decreased the size of the tumor (22, 23).

Several human studies link spinach consumption to a reduced risk of prostate cancer. Eating this leafy green may also help prevent breast cancer (24, 25).

Likewise, one animal study notes that spinach might suppress cancer formation (26).

Additionally, spinach packs high amounts of antioxidants, which may also fight cancer (27).

Blood pressure

Spinach contains high amounts of nitrates, which have been shown to help moderate blood pressure levels and decrease your risk of heart disease (28, 29).

One study in 27 people found that eating spinach effectively lowered blood pressure levels. Several other studies observed similar effects, indicating that spinach boosts heart health (7, 30, 31).

SUMMARY

Spinach has a host of benefits. It may reduce oxidative stress, promote eye health, fight cancer, and regulate blood pressure.

Potential downsides

Spinach is generally considered very healthy. However, it may cause adverse effects in some individuals.

Kidney stones

Kidney stones are caused by acid and mineral salt buildup. The most common variety is calcium stones, which consist of calcium oxalate.

Spinach is high in both calcium and oxalates, so people who are at a high risk of developing kidney stones should limit their intake (32, 33).

Blood clotting

Spinach is high in vitamin K1, which serves several functions in your body but is best known for its role in blood clotting.

As such, it could interfere with blood-thinning medication. People who are taking blood thinners, such as warfarin, should consult with their healthcare practitioner before eating large amounts of spinach (34).

SUMMARY

People who are prone to kidney stones may want to avoid spinach. This leafy green is also very high in vitamin K1, which can be a problem for people on blood thinners.