Spinach Health Benefits, Risks & Tips

Spinach is a popular dark green leafy vegetable that can be served either raw or cooked. Contrary to popular belief, spinach is not an especially good source of iron. The myth about its high iron content arose from an analysis in which a decimal point was erroneously displaced. But the vegetable’s dark green leaves do contain many other valuable nutrients. For example, a mere half cup of cooked spinach provides a full day’s supply of vitamin A, and 419 mg of potassium, as well as vitamin C, riboflavin, and vitamin B6.

To avoid losing its vitamin content, don’t overcook spinach. Instead, steam or stir-fry it. These cooking methods also preserve texture and flavor. Although some of these nutrients are lost in cooking, a ½-cup (179 g) serving of the cooked vegetable actually provides more nutrition than 1 cup (28 g) served raw because it takes a full 2 cups of leaves to cook down into a ½-cup serving. In addition, heating makes the protein in spinach easier to break down. The value of raw spinach can be enhanced by serving it with citrus slices for added vitamin C.

Health Benefits

Promotes vision health.
Spinach is rich in carotenoids, plant pigments that are responsible for its dark green color. Among these carotenoids are lutein and zeaxanthin, which help prevent macular degeneration, the leading cause of blindness in older adults. Cooking spinach helps to convert lutein into more bioavailable forms. To enhance the carotenoid absorption, eat spinach with some heart-healthy fat.

Can help prevent cancer.
The antioxidants and bioflavonoids in spinach help block cancer-causing substances and processes.

May help prevent birth defects.
A half cup of cooked spinach provides 105 mcg (micrograms) of folate, more than 25% of the Recommended Dietary Allowance (RDA). Folate is especially important for women who are pregnant or who may be planning a pregnancy, because it helps prevent congenital neurological defects. Folate deficiency can also cause a severe type of anemia.

Boosts bones.
Phylloquinone is the most common form of vitamin K found in dark greens such as spinach. Vitamin K is needed for proper blood clotting and may play a role in preserving bone health. Some research suggests that it may increase bone density and reduce fracture rates. Both the Nurses’ Health Study and the Framingham Heart Study found that people who consume the most vitamin K have a lower risk of hip fractures than those who consume less.

WARNING! FOOD-DRUG INTERACTION
Spinach may interfere with blood-thinning drugs. If your physician has prescribed blood-thinning medication, such as heparin or warfarin (Coumadin), it is wise to moderate your intake of vitamin K–rich foods, such as spinach. Excess vitamin K can counteract the effects of these drugs.
100% of the vitamin A you need every day is in ½ cup cooked spinach.

Health Risks

Mineral absorption.
The nutritional benefits of spinach are somewhat offset by its high concentration of oxalic acid which inhibits the absorption of the iron, calcium, and other minerals found in spinach. To increase mineral absorption eat spinach with other foods that are rich in vitamin C. Oxalic acid can also pose a problem for people susceptible to kidney and bladder stones that form from oxalates.

Eating Tips
• Mix chopped cooked spinach and roasted red pepper into hummus.
• Top crostini with sautéed baby spinach, garlic, and lemon juice.
• Use baby spinach on sandwiches instead of lettuce.

Buying Tips
• Fresh spinach is available in supermarkets year-round, sometimes with the roots attached, sometimes prewashed and bagged.
• Select leaves that are dark green and fresh looking instead of wilted or yellowing.
• If buying frozen spinach, choose brands with no added sauce.

Old School
When it comes to spinach, raw is always better.
New Wisdom
Cooking spinach makes some of its nutrients a bit easier to absorb.

Storing Tips
• Store in a plastic bag in the refrigerator crisper for up to 3 days.
• Wash in plenty of cold water to remove any grit just before using.

QUICK TIP:
Ditch the dirt
Before serving spinach, be careful to remove all the sand and dirt. One effective method is to submerge the spinach in a bowl of cold water and let the sand fall to the bottom, then remove and rinse the leaves. Dry them if making a salad. If you are cooking the spinach, the water left on the leaves may be just about the right amount with which to steam it.