How Spinach Helps To Improve Eyesight

Calorie for calorie, leafy green vegetables like spinach with its delicate texture and jade green color provide more nutrients than any other food. Although spinach is available throughout the year, its season runs from March through May and from September through October when it is the freshest, has the best flavor and is most readily available.

This chart below 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

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 protecting himself against osteoporosis, heart disease, colon cancer, arthritis, and other diseases at the same time.

Phytonutrient Flavonoids for Optimal Health

Researchers have identified at least 13 different flavonoid compounds in spinach that function as antioxidants and as anti-cancer agents.

(Many 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 studies. These spinach extracts have been shown to slow down cell division in 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.

Spinach Carotenoid Combats Prostate Cancer

A carotenoid found in spinach and other green leafy vegetables fights human prostate cancer two different ways, according to research published in the the Journal of Nutrition. The carotenoid, called neoxanthin, not only induces prostate cancer cells to self-destruct, but is converted in the intestines into additional compounds, called neochromes, which put prostate cancer cells into a state of stasis, thus preventing their replication.

Spinach Flavonoid Combats Ovarian Cancer

Research calculating flavonoid intake in 66,940 women enrolled in the Nurses Health Study between 1984 and 2002 revealed that women whose diets provided the most kaempferol had a 40% reduction in risk of ovarian cancer, compared to women eating the least kaempferol-rich foods. In addition to spinach, foods richest in kaempferol include tea (nonherbal), onions, curly kale, leeks, broccoli, and blueberries.

A significant 34% reduction in ovarian cancer risk was also seen in women with the highest intake of the flavone luteolin (found in citrus).

Helping You Bone Up

The vitamin K provided by spinach-almost 200% of the Daily Value in one cup of fresh spinach leaves and over 1000% of the Daily Value in one cup of boiled spinach (which contains about 6 times as much spinach)-is important for maintaining bone health. Vitamin K1 activates osteocalcin, the major non-collagen protein in bone. Osteocalcin anchors calcium molecules inside of the bone. Therefore, without enough vitamin K1, osteocalcin levels are inadequate, and bone mineralization is impaired. Spinach is also an excellent source of other bone-building nutrients including calcium and magnesium.

Cardiovascular Protection from Spinach

For atherosclerosis and diabetic heart disease, few foods compare to spinach in their number of helpful nutrients. Spinach is an excellent source of vitamin C and vitamin A, the latter notably through its concentration of beta-carotene. These two nutrients are important antioxidants that work to reduce the amounts of free radicals in the body; vitamin C works as a water-soluble antioxidant and beta-carotene as a fat-soluble one. This water-and-fat-soluble antioxidant team helps to prevent cholesterol from becoming oxidized. Oxidized cholesterol is able to stick to and build up in blood vessel walls, where it can cause blocked arteries, heart attack or stroke. Getting plenty of vitamin C and beta-carotene can help prevent these complications, and a cup of boiled spinach can provide you with 294.8% of the daily value (DV) for vitamin A along with 29.4% of the DV for vitamin C.

Spinach is also an excellent source of folate. Folate is needed by the body to help convert a potentially dangerous chemical called homocysteine that can lead to heart attack or stroke if levels get too high, into other benign molecules. In addition, spinach is an excellent source of magnesium, a mineral that can help to lower high blood pressure and protect against heart disease as well. A cup of boiled spinach contains 65.6% of the daily value for folate and 39.1% of the daily value for magnesium.

In addition to its hefty supply of cardioprotective vitamins and minerals, a study published in the Journal of Agriculture and Food Chemistry has revealed that spinach Rubisco contains four peptides (protein components) that inhibit angiotensin I-converting enzyme-the same enzyme blocked by ACE inhibitor drugs, which are used to lower blood pressure. When given to laboratory animals bred to be hypertensive, spinach produced a blood pressure lowering effect within two to four hours. How much spinach did the animals have to eat to get this beneficial effect? Just 20 to 30 mg of these powerful spinach peptides for each kilogram (2.2 pounds) of their body weight. In human terms, what this suggests is that an entrée-sized spinach salad for lunch or a serving of steamed spinach as part of the evening meal may have a salutary effect on blood pressure two to four hours later.

Promotes Gastrointestinal Health

The vitamin C and beta-carotene in spinach help to protect the colon cells from the damaging effects of free radicals. And the folate in spinach helps to prevent DNA damage and mutations in colon cells, even when they are exposed to cancer-causing chemicals. Studies show that people who eat foods high in vitamin C, beta-carotene, and/or folate are at a much lower risk of getting colon cancer than those who don't.

Anti-Inflammatory Nutrients

The nutrients in spinach can also help with conditions in which inflammation plays a role. For example, asthma, osteoarthritis, and rheumatoid arthritis are all conditions that involve inflammation. Since beta-carotene and vitamin C have anti-inflammatory properties, they can be helpful for reducing symptoms in some patients. In addition, the magnesium and riboflavin in spinach, two nutrients of which it is an excellent source, may help to reduce the frequency of migraine attacks in people who suffer from them.

A Smarter Brain with Spinach

In animal studies, researchers have found that spinach may help protect the brain from oxidative stress and may reduce the effects of age-related related declines in brain function. Researchers found that feeding aging laboratory animals spinach-rich diets significantly improved both their learning capacity and motor skills. Read more about brain benefits of spinach.

Vitamin E-rich Leafy Greens Slow Loss of Mental Function

Mental performance normally declines with age, but the results of Chicago Health and Aging Project (CHAP) suggest that eating just 3 servings of green leafy, yellow and cruciferous vegetables each day could slow this decline by 40%, suggests a study in the journal Neurology (Morris MC, Evans DA, et al.) Compared to people who consumed less than one serving of vegetables a day, people who ate at least 2.8 servings of vegetables a day saw their rate of cognitive decline slow by roughly 40%. This decrease is equivalent to about five years of younger age, said lead author Martha Clare Morris, ScD, with Rush University Medical Center in Chicago.

The prospective cohort study, funded by the National Institute of Aging, used dietary data from 3,718 participants (62% female, 60% African American, average age 74). Mental function was assessed with four different tests: the East Boston Tests of immediate memory and delayed recall, the Mini-Mental State Examination, and the Symbol Digit Modalities Test, taken at the start of the study and then again after 3 and 6 years.

After adjusting the results for potential confounders such as age, sex, race, education, and cardiovascular risk factors, the researchers found that consuming an average of 2.8 vegetable servings each day was associated with a 40% decrease in cognitive decline, compared to those who ate an average of less than one (0.9) serving a day. Of the different types of vegetables, green leafy vegetables had the strongest association, said Dr. Morris.

Surprisingly, no relationship was found between fruit consumption and cognitive decline.

Morris hypothesizes that this may be due to the fact that vegetables, but not fruits, contain high amounts of vitamin E, which helps lower the risk of cognitive decline. Also, vegetables, but not fruits, are typically consumed with a little fat, such as olive oil or salad dressing, which increases the body's ability to absorb vitamin E.

The Rush University researchers plan further research to understand why fruit appears to have little effect and to explore the effects of citrus fruit, specifically, on cognitive decline. Bottomline: If you remember to enjoy at least 3 servings of leafy greens each day, you are much more likely to remember other things as well!

Better Eyesight from Spinach

Lutein, a carotenoid protective against eye diseases such as age-related macular degeneration and cataract, is found in green vegetables, especially spinach, as well as kale and broccoli. But egg yolks, although they contain significantly less lutein than spinach, are a much more bioavailable source whose consumption increases lutein concentrations in the blood many-fold higher than spinach,shows a human study published in the Journal of Nutrition.

Although the mechanism by which egg yolk increases lutein bioavailability is not yet known, it is likely due to the fats (cholesterol and choline) found in egg yolk since lutein, like other carotenoids, is fat-soluble and cannot be absorbed unless fat is also present. To maximally boost your lutein absorption from spinach, we suggest enjoying this vegetable, whether steamed, sautéed or fresh in spinach salad, with a little olive oil and/or a topping of chopped hard-boiled egg to provide your body with some fats to help enhance the bioavailability of this fat-soluble phytonutrient.

Iron for Energy

Cooked spinach is an excellent source of iron, a mineral that it particularly important for menstruating women, who are more at risk for iron deficiency. Boosting iron stores with spinach is a good idea, especially because, in comparison to red meat, a well-known source of iron, spinach provides iron for a lot less calories and is totally fat-free. Iron is an integral component of hemoglobin, which transports oxygen from the lungs to all body cells, and is also part of key enzyme systems for energy production and metabolism. And, if you're pregnant or lactating, your needs for iron increase. Growing children and adolescents also have increased needs for iron. In one cup of boiled spinach, you'll be provided with 35.7% of the daily value for iron.

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.

Description

Spinach belongs to the same family (Chenopodiaceae) as chard and beets. It shares a similar taste profile with these two other vegetables-it has the bitterness of beet greens and the slightly salty flavor of chard.

Popeye popularized spinach, but it's too bad he ate it out of a can. Fresh spinach retains the delicacy of texture and jade green color that is lost when spinach is processed. Raw spinach has a mild, slightly sweet taste that can be refreshing in salads, while its flavor becomes more acidic and robust when it is cooked.

There are three different types of spinach generally available. Savoy has crisp, creased curly leaves that have a springy texture. Smooth-leaf has flat, unwrinkled, spade-shaped leaves, while semi-savoy is similar in texture to savoy but is not as crinkled in appearance. Baby spinach is great for use in salads as it has a sweeter taste, probably owing to its reduced concentration of oxalic acid. Spinacia oleracea is the scientific name of this leafy vegetable.

History

Spinach is thought to have originated in ancient Persia (Iran). Spinach made its way to China in the 7th century when the king of Nepal sent it as a gift to this country. Spinach has a much more recent history in Europe than many other vegetables. It was only brought to that continent in the 11th century, when the Moors introduced it into Spain. In fact, for a while, spinach was known as "the Spanish vegetable" in England.

Spinach was the favorite vegetable of Catherine de Medici, a historical figure in the 16th century. When she left her home of Florence, Italy, to marry the king of France, she brought along her own cooks, who could prepare spinach the ways that she especially liked. Since this time, dishes prepared on a bed of spinach are referred to as "a la Florentine."

Spinach grows well in temperate climates. Today, the United States and the Netherlands are among the largest commercial producers of spinach.

How to Select and Store

Choose spinach that has vibrant deep green leaves and stems with no signs of yellowing. The leaves should look fresh and tender, and not be wilted or bruised. Avoid those that have a slimy coating as this is an indication of decay.

Store fresh spinach loosely packed in a plastic bag in the refrigerator crisper where it will keep fresh for about five days. Do not wash it before storing as the moisture will cause it to spoil. Avoid storing cooked spinach as it will not keep very well.

Tips for Preparing Spinach:

Spinach, whether bunched or prepackaged, should be washed very well since the leaves and stems tend to collect sand and soil. Before washing, trim off the roots and separate the leaves. Place the spinach in a large bowl of tepid water and swish the leaves around with your hands as this will allow any dirt to become dislodged. Remove the leaves from the water, empty the bowl, refill with clean water and repeat this process until no dirt remains in the water (usually two to three times will do the trick). Cut away any overly thick stems to ensure for more even cooking. If you are going to use the spinach in a salad, you can dry it in either a salad spinner or by shaking it in a colander. If you are going to cook it, you do not need to worry about drying it well as the remaining water will serve to help it cook. Spinach is one of the few vegetables we suggest quick boiling (for one minute). That's because boiling will help to reduce the amount of oxalic acids found in spinach, resulting in a sweeter taste.

A Few Quick Serving Ideas:

• Add layers of steamed spinach to your next lasagna recipe.
• Toss steamed spinach with pressed garlic, fresh lemon juice and olive oil. Sprinkle with a little Parmesan cheese.
• Pine nuts are a great addition to cooked spinach.
• Spinach salads are a classic easy and delicious meal or side dish.

Allergic Reactions to Spinach

Although allergic reactions can occur to virtually any food, research studies on food allergy consistently report more problems with some foods than with others. It turns out that spinach is one of the foods most commonly associated with allergic reactions. Other foods commonly associated with allergic reactions include: cow's milk, wheat, soy, shrimp, oranges, eggs, chicken, strawberries, tomato, peanuts, pork, corn and beef. These foods do not need to be eaten in their pure, isolated form in order to trigger an adverse reaction. For example, yogurt made from cow's milk is also a common allergenic food, even though the cow's milk has been processed and fermented in order to make the yogurt. Ice cream made from cow's milk would be an equally good example.

Some of the most common symptoms for food allergies include eczema, hives, skin rash, headache, runny nose, itchy eyes, wheezing, gastrointestinal disturbances, depression, hyperactivity and insomnia. Individuals who suspect food allergy to be an underlying factor in their health problems may want to avoid commonly allergenic foods.

Spinach and Pesticide Residues

Virtually all municipal drinking water in the United States contains pesticide residues, and with the exception of organic foods, so do the majority of foods in the U.S. food supply. Even though pesticides are present in food at very small trace levels, their negative impact on health is well documented. The liver's ability to process other toxins, the cells' ability to produce energy, and the nerves' ability to send messages can all be compromised by pesticide exposure. According to the Environmental Working Group's 2006 report "Shopper's Guide to Pesticides in Produce," spinach is among the 12 foods on which pesticide residues have been most frequently found. Therefore, individuals wanting to avoid pesticide-associated health risks may want to avoid consumption of spinach unless it is grown organically.

Spinach and Oxalates

Spinach is among a small number of foods that contain measurable amounts of oxalates, naturally-occurring substances found in plants, animals, and human beings. When oxalates become too concentrated in body fluids, they can crystallize and cause health problems. For this reason, individuals with already existing and untreated kidney or gallbladder problems may want to avoid eating spinach. Laboratory studies have shown that oxalates may also interfere with absorption of calcium from the body. Yet, in every peer-reviewed research study we've seen, the ability of oxalates to lower calcium absorption is relatively small and definitely does not outweigh the ability of oxalate-containing foods to contribute calcium to the meal plan. If your digestive tract is healthy, and you do a good job of chewing and relaxing while you enjoy your meals, you will get significant benefits - including absorption of calcium - from calcium-rich foods plant foods that also contain oxalic acid. Ordinarily, a healthcare practitioner would not discourage a person focused on ensuring that they are meeting their calcium requirements from eating these nutrient-rich foods because of their oxalate content.

Spinach and Goitrogens

Spinach contains goitrogens, naturally-occurring substances in certain foods that can interfere with the functioning of the thyroid gland. Individuals with already existing and untreated thyroid problems may want to avoid spinach for this reason. Cooking may help to inactivate the goitrogenic compounds found in food. However, it is not clear from the research exactly what percent of goitrogenic compounds get inactivated by cooking, or exactly how much risk is involved with the consumption of spinach by individuals with pre-existing and untreated thyroid problems.

Spinach and Purines

Spinach contain naturally-occurring substances called purines. Purines are commonly found in plants, animals, and humans. In some individuals who are susceptible to purine-related problems, excessive intake of these substances can cause health problems. Since purines can be broken down to form uric acid, excess accumulation of purines in the body can lead to excess accumulation of uric acid. The health condition called "gout" and the formation of kidney stones from uric acid are two examples of uric acid-related problems that can be related to excessive intake of purine-containing foods. For this reason, individuals with kidney problems or gout may want to limit or avoid intake of purine-containing foods such as spinach.

Nutritional Profile

Spinach is an excellent source of vitamin K, vitamin A, manganese, folate, magnesium, iron, vitamin C, vitamin B2, calcium, potassium, and vitamin B6. It is a very good source of dietary fiber, copper, protein, phosphorous, zinc and vitamin E. In addition, it is a good source of omega-3 fatty acids, niacin and selenium.

In addition to the nutrients highlighted in our ratings chart, an in-depth nutritional profile for Spinach is also available. This profile includes information on a full array of nutrients, including carbohydrates, sugar, soluble and insoluble fiber, sodium, vitamins, minerals, fatty acids, amino acids and more. For an in-depth nutritional profile click here: Spinach.

Introduction to Food Rating System Chart

The following chart shows the nutrients for which this food is either an excellent, very good or good source. Next to the nutrient name you will find the following information: the amount of the nutrient that is included in the noted serving of this food; the %Daily Value (DV) that that amount represents; the nutrient density rating; and the food's World's Healthiest Foods Rating. Underneath the chart is a table that summarizes how the ratings were devised.

Content of Nutrients in the Spinach

Spinach, boiled 1.00 cup 180.00 grams 41.40 calories
Nutrient	Amount	DV(%)	Nutrient Density	World's Healthiest Foods Rating
vitamin K	888.50 mcg	1110.6	482.9	excellent
vitamin A	14742.00 IU	294.8	128.2	excellent
manganese	1.68 mg	84.0	36.5	excellent
folate	262.44 mcg	65.6	28.5	excellent
magnesium	156.60 mg	39.1	17.0	excellent
iron	6.43 mg	35.7	15.5	excellent
vitamin C	17.64 mg	29.4	12.8	excellent
vitamin B2 (riboflavin)	0.42 mg	24.7	10.7	excellent
calcium	244.80 mg	24.5	10.6	excellent
potassium	838.80 mg	24.0	10.4	excellent
vitamin B6 (pyridoxine)	0.44 mg	22.0	9.6	excellent
tryptophan	0.07 g	21.9	9.5	excellent
dietary fiber	4.32 g	17.3	7.5	very good
copper	0.31 mg	15.5	6.7	very good
vitamin B1 (thiamin)	0.17 mg	11.3	4.9	very good
protein	5.35 g	10.7	4.7	very good
phosphorus	100.80 mg	10.1	4.4	very good
zinc	1.37 mg	9.1	4.0	very good
vitamin E	1.72 mg	8.6	3.7	very good
omega 3 fatty acids	0.15 g	6.0	2.6	good
vitamin B3 (niacin)	0.88 mg	4.4	1.9	good
selenium	2.70 mcg	3.9	1.7	good

World's Healthiest
Foods Rating Rule

World's Healthiest Foods Rating	Rule
excellent	DV>=75%	OR	Density>=7.6	AND	DV>=10%
very good	DV>=50%	OR	Density>=3.4	AND	DV>=5%
good	DV>=25%	OR	Density>=1.5	AND	DV>=2.5%

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