Spinach is an edible flowering plant in the family of Amaranthaceae. It is native to central and southwestern Asia.
It is an annual plant (rarely biennial), which grows to a height of up to 30 cm. Spinach may survive over winter in temperate regions.
The leaves are alternate, simple, ovate to triangular-based, very variable in size from about 2–30 cm long and 1–15 cm broad, with larger leaves at the base of the plant and small leaves higher on the flowering stem.
The flowers are inconspicuous, yellow-green, 3–4 mm diameter, maturing into a small, hard, dry, lumpy fruit cluster 5–10 mm across containing several seeds.
Common spinach, Spinacia oleracea, was long considered to be in the Chenopodiaceae family, but in 2003, the Chenopodiaceae family was combined with the Amaranthaceae family under the family name 'Amaranthaceae' in the order Caryophyllales.
Within the Amaranthaceae family, Amaranthoideae and Chenopodioideae are now subfamilies, for the amaranths and the chenopods, respectively.
Many people are concerned about the nutrient content of delicate
vegetables (like baby spinach) when those vegetables are placed in clear
plastic containers in grocery store display cases and continuously
exposed to artificial lighting. One recent food study has shown that you
don't need to worry about the overall status of antioxidants in baby
spinach that has been stored and displayed in this way. In this
scientific study, the overall nutrient richness of the baby spinach when
exposed to constant light was actually higher than the overall nutrient
richness of baby spinach leaves kept in total darkness. The period of
time in the study was 9 days, and the spinach was kept at 39°F/4°C (a
temperature on the lower end of the scale for most home refrigerators).
These findings are good news for anyone purchasing baby spinach in
"ready-to-eat" containers.
One new category of health-supportive nutrients found in
spinach is called "glycoglycerolipids." Glycoclycerolipids are the main
fat-related molecules in the membranes of light-sensitive organs in most
plants. They're indispensable for the process of photosynthesis carried
out by plants. However, recent lab research in laboratory animals has
shown that glycoglycerolipids from spinach can help protect the lining
of the digestive tract from damage — especially damage related to
unwanted inflammation. You can expect to see more studies about this
exciting new category of molecules in spinach and its potential health
benefits.
In a recent study on the relationship between risk of prostate
cancer and vegetable intake — including the vegetables spinach,
broccoli, cauliflower, cabbage, Brussels sprouts, mustard greens, turnip
greens, collards, and kale — only spinach showed evidence of
significant protection against the occurrence of aggressive prostate
cancer. ("Aggressive prostate cancer" was defined as stage III or IV
prostate cancer with a Gleason score of at least 7. Gleason scores are
based on lab studies of prostate tissue and common tumor-related
patterns.) The study authors did not speculate about specific substances
in spinach that may have been involved in decreased prostate cancer
risk. However, we know that certain unique anti-cancer
carotenoids—called epoxyxanthophylls — are plentiful in spinach, even
though they may not be as effectively absorbed as other carotenoids like
beta-carotene and lutein. You can count on seeing future research on
neoxanthin and violaxanthin — two anti-cancer epoxyxanthophylls that are
found in plentiful amounts in the leaves of spinach.
Foods belonging to the chenopod family—including beets, chard, spinach and quinoa—continue to show an increasing number of health benefits not readily available from other food families. The red and yellow betalain pigments found in this food family, their unique epoxyxanthophyll carotenoids, and the special connection between their overall phytonutrients and our nervous system health (including our specialized nervous system organs like the eye) point to the chenopod family of foods as unique in their health value. While we have yet to see large-scale human studies that point to a recommended minimum intake level for foods from this botanical family, we have seen data on chenopod phytonutrients, and based on this data, we recommend that you include foods from the chenopod family in your diet 1-2 times per week. In the case of a leafy food like spinach, we recommend a serving size of at least 1/2 cup, and even more beneficial, at least one full cup.
This chart graphically details the %DV that a serving of Spinach provides for each of the nutrients of which it is a good, very good, or excellent source according to our Food Rating System. Additional information about the amount of these nutrients provided by Spinach can be found in the Food Rating System Chart. A link that takes you to the In-Depth Nutritional Profile for Spinach, featuring information over 80 nutrients, can be found under the Food Rating System Chart.
Researchers have identified more than a dozen different flavonoid compounds in spinach that function as anti-inflammatory and anti-cancer agents. (Some of these substances fall into a technical category of flavonoids known as methylenedioxyflavonol glucuronides.)
The anticancer properties of these spinach flavonoids have been sufficiently impressive to prompt researchers to create specialized spinach extracts that could be used in controlled laboratory studies.
These spinach extracts have been shown to slow down cell division in human stomach cancer cells (gastric adenocarcinomas), and in studies on laboratory animals, to reduce skin cancers (skin papillomas).
A study on adult women living in New England in the late 1980s also showed intake of spinach to be inversely related to incidence of breast cancer.
Excessive inflammation, of course, typically emerges as a risk factor for increased cancer risk. (That's why many anti-inflammatory nutrients can also be shown to have anti-cancer properties.)
But even when unrelated to cancer, excessive inflammation has been shown to be less likely following consumption of spinach. Particularly in the digestive tract, reduced inflammation has been associated not only with the flavonoids found in spinach, but also with its carotenoids.
Neoxanthin and violaxanthin are two anti-inflammatory epoxyxanthophylls that are found in plentiful amounts in the leaves of spinach. While these unique carotenoids may not be as readily absorbed as carotenoids like beta-carotene or lutein, they still play an important role in regulation of inflammation and are present in unusual amounts in spinach.
Decreased risk of aggressive prostate cancer is one health benefit of spinach consumption that should not be overlooked when talking about the anti-cancer properties of spinach. "Aggressive prostate cancer" is defined as stage III or IV prostate cancer which carries with it a Gleason score of at least
7.(Gleason scores are prostate cancer rating measurements that require lab studies of prostate tissue and evaluation of common tumor-related patterns.)
Interestingly, in a recent study that evaluated possible prostate cancer-prevention benefits from a variety of vegetables including spinach, broccoli, cauliflower, cabbage, Brussels sprouts, mustard and turnip greens, collards, and kale — only spinach showed evidence of significant protection against the occurrence of aggressive prostate cancer.
Given the fact that spinach is an excellent source of other antioxidant nutrients — including vitamin C, vitamin E, vitamin A (in the form of carotenoids), and manganese —as well as a very good source of the antioxidant zinc and a good source of the antioxidant selenium—it's no wonder that spinach helps lower risk of numerous health problems related to oxidative stress.
Our blood vessels, for example, are especially susceptible to damage from oxidative stress, and intake of spinach has been associated with decreased risk of several blood vessel-related problems, including atherosclerosis and high blood pressure.
(Interestingly, the blood pressure benefits of spinach may be related not only to its antioxidants, but also to some of its special peptides.
Peptides are small pieces of protein, and researchers have discovered several peptides in spinach that can help lower blood pressure by inhibiting an enzyme called angiotensin I-converting enzyme.)
Two of the carotenoids that are especially plentiful in spinach — lutein and zeaxanthin — are primary antioxidants in several regions of the eye, including the retina and the macula.
Although we haven't seen specific studies on spinach intake and prevention of eye-related problems like macular degeneration, we have seen studies showing that human blood levels of lutein can be increased by consumption of spinach in everyday amounts.
We've also seen at least one group of researchers suggesting that spinach has a likely role to play in prevention of eye problems, including age-related macular degeneration.
Additionally, friendly bacteria in our intestines convert vitamin K1 into vitamin K2, which activates osteocalcin, the major non-collagen protein in bone.
Osteocalcin anchors calcium molecules inside of the bone. All of these vitamin K-related mechanisms point to the importance of vitamin K-rich foods for bone health, and it is difficult to find vegetables that are richer in vitamin K than spinach.
(On our World's Healthiest Foods list, only kale provides more micrograms of vitamin K per cup.)
Spinach is also an excellent source of other bone-supportive nutrients including calcium and magnesium.
So while spinach probably won't make you super strong the minute you eat it, as it did for Popeye, it will promote your health and vitality in many other ways. It seems like Popeye was pretty smart after all.
Spinach has a high nutritional value, especially when fresh, frozen, steamed, or quickly boiled. It is a rich source (> 20% of the Daily Value) of vitamin A, vitamin C, vitamin K, magnesium, manganese, folate and iron (table, right).
However, spinach contains iron absorption-inhibiting substances, including high levels of oxalate, which can bind to the iron to form ferrous oxalate and render much of the iron in spinach unusable by the body. In addition to preventing absorption and use, high levels of oxalates remove iron from the body.
By way of comparison, the human body can absorb about half of the calcium present in broccoli, yet only around 5% of the calcium in spinach
The older varieties have narrower leaves and tend to have a stronger and more bitter taste. Most newer varieties have broader leaves and round seeds.
The three basic types of spinach are:
The leaves are alternate, simple, ovate to triangular-based, very variable in size from about 2–30 cm long and 1–15 cm broad, with larger leaves at the base of the plant and small leaves higher on the flowering stem.
The flowers are inconspicuous, yellow-green, 3–4 mm diameter, maturing into a small, hard, dry, lumpy fruit cluster 5–10 mm across containing several seeds.
Common spinach, Spinacia oleracea, was long considered to be in the Chenopodiaceae family, but in 2003, the Chenopodiaceae family was combined with the Amaranthaceae family under the family name 'Amaranthaceae' in the order Caryophyllales.
Within the Amaranthaceae family, Amaranthoideae and Chenopodioideae are now subfamilies, for the amaranths and the chenopods, respectively.
WFoods Recommendations
Among the World's Healthiest vegetables, spinach comes out at the top of our ranking list for nutrient richness. Rich in vitamins and minerals, it is also concentrated in health-promoting phytonutrients such as carotenoids (beta-carotene, lutein, and zeaxanthin) and flavonoids to provide you with powerful antioxidant protection. Enjoy baby spinach in your favorite salads or make a salad made exclusively of baby spinach. Spinach is one of only three vegetables that we recommend boiling to help reduce its concentration of oxalic acid. We recommend boiling for just 1 minute to minimize loss of nutrients and flavor. For more on the Healthiest Way of Cooking Spinach, see the How to Enjoy section below.Foods belonging to the chenopod family—including beets, chard, spinach and quinoa—continue to show an increasing number of health benefits not readily available from other food families. The red and yellow betalain pigments found in this food family, their unique epoxyxanthophyll carotenoids, and the special connection between their overall phytonutrients and our nervous system health (including our specialized nervous system organs like the eye) point to the chenopod family of foods as unique in their health value. While we have yet to see large-scale human studies that point to a recommended minimum intake level for foods from this botanical family, we have seen data on chenopod phytonutrients, and based on this data, we recommend that you include foods from the chenopod family in your diet 1-2 times per week. In the case of a leafy food like spinach, we recommend a serving size of at least 1/2 cup, and even more beneficial, at least one full cup.
NutrientDRI/DV
vitamin K987.2%
vitamin A104.8%
manganese84%
folate65.7%
magnesium39.1%
iron35.7%
copper34.4%
vitamin B232.3%
vitamin B625.8%
vitamin E24.9%
calcium24.4%
potassium23.9%
vitamin C23.5%
fiber17.2%
phosphorus14.4%
vitamin B114.1%
zinc12.4%
protein10.7%
choline8.3%
vitamin B35.5%
pantothenic acid5.2%
selenium4.9%
This chart graphically details the %DV that a serving of Spinach provides for each of the nutrients of which it is a good, very good, or excellent source according to our Food Rating System. Additional information about the amount of these nutrients provided by Spinach can be found in the Food Rating System Chart. A link that takes you to the In-Depth Nutritional Profile for Spinach, featuring information over 80 nutrients, can be found under the Food Rating System Chart.
- Health Benefits
- Description
- History
- How to Select and Store
- Tips for Preparing and Cooking
- How to Enjoy
- Individual Concerns
- Nutritional Profile
- References
Health Benefits
We all know that Popeye made himself super strong by eating spinach, but you may be surprised to learn that he may also have been helping to protect himself against inflammatory problems, oxidative stress-related problems, cardiovascular problems, bone problems, and cancers at the same time.Anti-Inflammatory and Anti-Cancer Benefits from Spinach Phytonutrients
Even though virtually all vegetables contain a wide variety of phytonutrients—including flavonoids and carotenoids—spinach can claim a special place among vegetables in terms of its phytonutrient content.Researchers have identified more than a dozen different flavonoid compounds in spinach that function as anti-inflammatory and anti-cancer agents. (Some of these substances fall into a technical category of flavonoids known as methylenedioxyflavonol glucuronides.)
The anticancer properties of these spinach flavonoids have been sufficiently impressive to prompt researchers to create specialized spinach extracts that could be used in controlled laboratory studies.
These spinach extracts have been shown to slow down cell division in human stomach cancer cells (gastric adenocarcinomas), and in studies on laboratory animals, to reduce skin cancers (skin papillomas).
A study on adult women living in New England in the late 1980s also showed intake of spinach to be inversely related to incidence of breast cancer.
Excessive inflammation, of course, typically emerges as a risk factor for increased cancer risk. (That's why many anti-inflammatory nutrients can also be shown to have anti-cancer properties.)
But even when unrelated to cancer, excessive inflammation has been shown to be less likely following consumption of spinach. Particularly in the digestive tract, reduced inflammation has been associated not only with the flavonoids found in spinach, but also with its carotenoids.
Neoxanthin and violaxanthin are two anti-inflammatory epoxyxanthophylls that are found in plentiful amounts in the leaves of spinach. While these unique carotenoids may not be as readily absorbed as carotenoids like beta-carotene or lutein, they still play an important role in regulation of inflammation and are present in unusual amounts in spinach.
Decreased risk of aggressive prostate cancer is one health benefit of spinach consumption that should not be overlooked when talking about the anti-cancer properties of spinach. "Aggressive prostate cancer" is defined as stage III or IV prostate cancer which carries with it a Gleason score of at least
7.(Gleason scores are prostate cancer rating measurements that require lab studies of prostate tissue and evaluation of common tumor-related patterns.)
Interestingly, in a recent study that evaluated possible prostate cancer-prevention benefits from a variety of vegetables including spinach, broccoli, cauliflower, cabbage, Brussels sprouts, mustard and turnip greens, collards, and kale — only spinach showed evidence of significant protection against the occurrence of aggressive prostate cancer.
Antioxidant Benefits of Spinach
Most of the flavonoid and carotenoid nutrients found in spinach that provide anti-inflammatory benefits provide antioxidant benefits as well.Given the fact that spinach is an excellent source of other antioxidant nutrients — including vitamin C, vitamin E, vitamin A (in the form of carotenoids), and manganese —as well as a very good source of the antioxidant zinc and a good source of the antioxidant selenium—it's no wonder that spinach helps lower risk of numerous health problems related to oxidative stress.
Our blood vessels, for example, are especially susceptible to damage from oxidative stress, and intake of spinach has been associated with decreased risk of several blood vessel-related problems, including atherosclerosis and high blood pressure.
(Interestingly, the blood pressure benefits of spinach may be related not only to its antioxidants, but also to some of its special peptides.
Peptides are small pieces of protein, and researchers have discovered several peptides in spinach that can help lower blood pressure by inhibiting an enzyme called angiotensin I-converting enzyme.)
Two of the carotenoids that are especially plentiful in spinach — lutein and zeaxanthin — are primary antioxidants in several regions of the eye, including the retina and the macula.
Although we haven't seen specific studies on spinach intake and prevention of eye-related problems like macular degeneration, we have seen studies showing that human blood levels of lutein can be increased by consumption of spinach in everyday amounts.
We've also seen at least one group of researchers suggesting that spinach has a likely role to play in prevention of eye problems, including age-related macular degeneration.
Helping Your Bone Up
The wealth of vitamin K provided by spinach is important for maintaining bone health. Vitamin K1 helps prevent excessive activation of osteoclasts, the cells that break down bone.Additionally, friendly bacteria in our intestines convert vitamin K1 into vitamin K2, which activates osteocalcin, the major non-collagen protein in bone.
Osteocalcin anchors calcium molecules inside of the bone. All of these vitamin K-related mechanisms point to the importance of vitamin K-rich foods for bone health, and it is difficult to find vegetables that are richer in vitamin K than spinach.
(On our World's Healthiest Foods list, only kale provides more micrograms of vitamin K per cup.)
Spinach is also an excellent source of other bone-supportive nutrients including calcium and magnesium.
So while spinach probably won't make you super strong the minute you eat it, as it did for Popeye, it will promote your health and vitality in many other ways. It seems like Popeye was pretty smart after all.
Nutrition
| Nutritional value per 100 g (3.5 oz) | |
|---|---|
| Energy | 97 kJ (23 kcal) |
|
3.6 g
|
|
| Sugars | 0.4 g |
| Dietary fiber | 2.2 g |
|
0.4 g
|
|
|
2.9 g
|
|
| Vitamins | |
| Vitamin A equiv. |
(59%)
469 μg
(52%)
5626 μg
12198 μg
|
| Vitamin A | 9377 IU |
| Thiamine (B1) |
(7%)
0.078 mg |
| Riboflavin (B2) |
(16%)
0.189 mg |
| Niacin (B3) |
(5%)
0.724 mg |
| Vitamin B6 |
(15%)
0.195 mg |
| Folate (B9) |
(49%)
194 μg |
| Vitamin C |
(34%)
28 mg |
| Vitamin E |
(13%)
2 mg |
| Vitamin K |
(460%)
483 μg |
| Trace metals | |
| Calcium |
(10%)
99 mg |
| Iron |
(21%)
2.71 mg |
| Magnesium |
(22%)
79 mg |
| Manganese |
(43%)
0.897 mg |
| Phosphorus |
(7%)
49 mg |
| Potassium |
(12%)
558 mg |
| Sodium |
(5%)
79 mg |
| Zinc |
(6%)
0.53 mg |
| Other constituents | |
| Water | 91.4 g |
Spinach has a high nutritional value, especially when fresh, frozen, steamed, or quickly boiled. It is a rich source (> 20% of the Daily Value) of vitamin A, vitamin C, vitamin K, magnesium, manganese, folate and iron (table, right).
Iron
Spinach, along with other green leafy vegetables, is considered to be rich in iron. For example, the United States Department of Agriculture states that a 180-g serving of boiled spinach contains 6.43 mg of iron, whereas a 170-g ground hamburger patty contains at most 4.42 mg.However, spinach contains iron absorption-inhibiting substances, including high levels of oxalate, which can bind to the iron to form ferrous oxalate and render much of the iron in spinach unusable by the body. In addition to preventing absorption and use, high levels of oxalates remove iron from the body.
Calcium
Spinach also has a moderate calcium content. However, the oxalate content in spinach also binds with calcium, decreasing its absorption. The calcium in spinach is the least bioavailable of calcium sources.By way of comparison, the human body can absorb about half of the calcium present in broccoli, yet only around 5% of the calcium in spinach
Types of spinach
A distinction can be made between older varieties of spinach and more modern ones. Older varieties tend to bolt too early in warm conditions. Newer varieties tend to grow more rapidly, but have less of an inclination to run up to seed.The older varieties have narrower leaves and tend to have a stronger and more bitter taste. Most newer varieties have broader leaves and round seeds.
The three basic types of spinach are:
- Savoy has dark green, crinkly and curly leaves. It is the type sold in fresh bunches in most supermarkets in the United States. One heirloom variety of savoy is Bloomsdale, which is somewhat resistant to bolting. Other common heirloom varieties are Merlo Nero (a mild variety from Italy) and Viroflay (a very large spinach with great yields).
- Flat- or smooth-leaf spinach has broad, smooth leaves that are easier to clean than Savoy. This type is often grown for canned and frozen spinach, as well as soups, baby foods, and processed foods. Giant Noble is an example variety.
- Semi-savoy is a hybrid variety with slightly crinkled leaves. It has the same texture as Savoy, but it is not as difficult to clean. It is grown for both fresh market and processing. Tyee Hybrid is a common semi-savoy.
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