Tips about healthiest Vegetables to eat – Kale, Kohlrabi, Leeks, Mushrooms, Okra, Onions


Kale is definitely a superstar vegetable, even though most people don’t even know what it is. (It’s a green, weird-looking leafy vegetable that is actually a form of cabbage. Now you know.) But don’t let its strange looks put you off. This vegetable is a nutritional powerhouse.

Why Kale Is Number One

In fact, in the “rankings” it comes out on top. Currently, there is a testing procedure used by the USDA and others to determine the antioxidant capacity of fruits and vegetables. They look at all the different antioxidants and phytochemicals that are found in a plant food and determine how well everything works together as a team—how much actual ability the “team” has to fight cell-damaging free radicals. The foods are given what’s called an ORAC rating; ORAC stands for oxygen radical absorbance capacity. Though there are different versions of the test, the best known has kale as number one among the vegetables, with an ORAC value of 1770 (the next best vegetable is spinach, with an ORAC value of 1260).

Prevent Cancer As You Chew

Because it’s a cabbage, kale actually has even more benefits than its antioxidant power alone would indicate. Like others in the brassica family, it contains powerful phytochemicals like cancer-fighting indoles, plant compounds that have been found to have a protective effect against breast, cervical, and colon cancer. In addition, kale is high in sulfur and contains something called sulforaphane, which helps give a boost to the body’s detoxification enzymes and may actually help fight cancer as well. Sulforaphane is formed when the vegetables containing it are chopped or chewed, and it triggers the liver to remove free radicals and other chemicals that may cause DNA damage. In fact, a recent study in the Journal of Nutrition demonstrated that sulforaphane helps stop breast cancer proliferation.

Kale is also loaded with calcium, iron, and vitamins A, C, and bone-building vitamin K. It contains seven times the beta-carotene of broccoli and ten times as much lutein and zeaxanthin, eye-protecting carotenoids known to help protect against macular degeneration. And 2 cups of the stuff contain about 4 g of protein and 3 g of fiber.

Secrets to a Great Kale Salad

Tender kale greens can provide a terrific addition to salads, especially when mixed with strong-flavored ingredients like tamari-roasted almonds or red-pepper flakes.

Recently, kale has become one of my favorite foods. The Sherman Oaks Whole Foods deli manager mixes kale leaves with pine nuts and cranberries, then softens the whole mixture by tossing it well in olive oil. It’s become so popular the deli can’t keep it in stock, and because of that recipe, I actually eat kale about five times a week. It’s amazing.


Kohlrabi is a member of the cabbage family and looks like a cross between an octopus and a space capsule. The name comes from the German kohl (cabbage) plus rabi (turnip) because of the resemblance of the cabbagelike stem to the turnip. The stem can be crisp and juicy, almost as sweet as an apple, and similar to a turnip in taste. You can eat it raw (it makes a great crudité) or cooked. It comes in two “flavors,” green and purple, with the purple kind tending to be somewhat spicier. Both the leaves and the stem are edible.

Kohlrabi’s membership in the cabbage family of cruciferous vegetables gains it an automatic place among the world’s healthiest foods. Like its relatives (broccoli, Brussels sprouts, cabbage), kohlrabi contains important phytochemicals such as cancer-fighting indoles, sulforaphane, and isothiocynates. It’s also a good source of vitamin C (83 mg per cup) and an excellent source of potassium (472 mg). And for a measly 36 calories per cup, you get a whopping 5 g of fiber.

In case someone ever asks you, Hamburg Township in Michigan has christened itself the “Kohlrabi Capital of the World.” No, I’m not making this up. At one time, back in the 1980s, they had a kohlrabi festival that actually drew 600 people.


One way to think of a leek is as a sweeter version of an onion. They really are delicious, and most people add them to recipes like stir-fries for their marvelous flavor. But leeks have a serious side as well—they’re members of the allium family, which includes onions, garlic, and shallots. These vegetables contain a whole pharmacy of compounds with health benefits, including thiosulfinates, sulfides, sulfoxides, and other sulfur compounds.

The active substances in leeks, including allyl sulfides, help provide protection against cancers. Allyl sulfides block the action of hormones or chemical pathways within the body that promote cancer. Regular consumption of allium vegetables are associated with a reduced risk of both prostate and colon cancer. The sulfides of the allium family also decrease the tendency for blood clots to form—a significant risk for strokes and cardiovascular events. Plus they lower levels of LDL (“bad”) cholesterol. Allium vegetables have also been shown to lower high blood pressure.

Good Down to the Roots

According to natural-foods expert Rebecca Wood, there is more to the leek than just the flavorful white bulb, which is the part most people use in cooking. Wood also uses the many tiny rootlets that hang from the base of the plant like little mop strings. She claims these mineral-dense filaments add valuable flavor and more nutrients and suggests cutting the cluster of stringy roots from the base, soaking them to loosen any embedded sand, rinsing, mincing, and sautéing in any vegetable dish or soup.

Leeks are also a good source of two of the most important carotenoids for eye health, lutein and zeaxanthin. One 54-calorie leek contains 1,691 mcg of these two superstar nutrients, which are currently the subject of extensive research for their ability to prevent macular degeneration, the number-one cause of blindness in adults. Leeks also have fiber, calcium, iron, magnesium, phosphorus, potassium, vitamin K, and more than 1,400 IUs of vitamin A.


While mushrooms have been used medicinally in Eastern medicine for eons, Western medicine is now beginning to catch up as the healing properties of mushrooms are beginning to be demonstrated scientifically. The three specific types with the greatest health benefits are Maitake, Shiitake, and Reishi. According to Dharma Singh Khalsa, M.D., all three have powerful effects on the immune system, and all three act as medicine.

When you think about it for a minute, it makes an awful lot of sense that mushrooms have medicinal properties. Mushrooms are fungus. They scavenge on organic matter. Where do you find them? Growing on decaying wood, or worse (cow patties, anyone?). That means they are able to absorb—and then safely eliminate—toxins. I don’t know about you, but I’d like to put them to work doing that in my own body, and eating them appears to be a great way to do it.


Maitake comes from the Japanese word meaning “dancing mushrooms”; according to urban legend, foragers danced with joy when they found it. According to some legends, the little mushroom could be traded for its weight in precious metals.

In addition to being loaded with vitamins, maitake has a special polysaccharide component called beta-1,6 glucan, a very close relative of the beta-1,3 glucan in the shiitake (see below). Beta-glucans stimulate the immune system. Many of the compounds in the cell structures of mushrooms are actually classified as HDPs—host defenses potentiators. They’re used as adjunctive cancer treatments throughout Asia. In fact, Maitake is approved by the Japanese government for just this purpose. It’s especially good for counteracting the toxic effects of radiation and chemotherapy, such as extreme fatigue and nausea. According to my friend Robert Roundtree, M.D., author of Immunotics, maitake extract can shrink tumors in mice; Roundtree also points out that a number of studies in Japan showed that maitake and chemotherapy together can boost the effectiveness of standard chemotherapy for several types of cancer. He personally feels that maitake is the most potent of the three medicinal mushrooms discussed here, though he uses all of them for different things.


The shiitake mushroom is one of the most widely cultivated specialty species of mushroom in the world and is deeply valued for its medicinal effects as well as for the fact that it tastes delicious. It contains enzymes and vitamins that do not normally appear in plants, like all eight essential amino acids and one of the essential fatty acids, linoleic acid. The caps contain more nutrients than the stems.

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This superstar mushroom contains a particular chemical component especially worth noting: lentinan, which is approved as an injectable drug in Japan and usually used to prolong survival of patients in cancer therapy. It doesn’t actually work directly against cancer, but it is believed to help prevent some of the damage that results from anticancer drugs. Lentinan is also referred to as beta-1,3 glucan, a polysaccharide that has potent immune-stimulating effects, and a close relative of the beta-1,6 glucan found in maitake (see above). When beta-glucans bind to immune system cells like natural killer (NK) cells, T-cells, and macrophages, the activity of these cells is increased. No one is quite sure why, but Roundtree speculates that the beta-glucans “trick” immune system cells into thinking they’re under attack (mushrooms are, after all, fungus, and maybe the cells think the harmless little critters are dangerous. Who knows? Point is, the immune system is stimulated by them). Many studies have confirmed beta-glucans’ wide range of protective effects, including improved resistance to infections, liver protection, and cardiovascular benefits. It also appears to help inhibit tumor growth in mice.

Japanese researchers have reported that consumption of shiitake mushrooms lowers blood cholesterol by as much as 45 percent, due to an active compound in them called eritadenine.


Sometime in the third century B.C.E., the Chinese emperor Shih Huang was reputed to have sent a fleet of ships to search for a mushroom called the “Elixir of Immortality.” That mushroom? The reishi. Its special chemical makeup was thought to be a tonic for a long and healthy life. In traditional Chinese medicine, reishi is still considered to be among the highest class of tonics.

Now we’re finding out that they may have been on to something. One study at Cornell Medical College found that reishi reduced side effects during chemotherapy while improving the quality of life. Its beneficial components—specifically ganodermic acids classified as triterpenoids, plus a number of polysaccharides—seem to benefit everything from blood pressure to liver detoxification to adrenal function.


Even the conservative and highly regarded Memorial Sloan-Kettering Cancer Center has reishi mushroom listed on the “about herbs” section of its Web site, where it states that reishi mushrooms stimulate the immune system through their positive effect on macrophages and other immune compounds. Sloan-Kettering also references clinical studies showing that reishi increases antioxidant capacity and enhances the immune responses in advanced-stage cancer patients.

And then there’s stress.

Reishi mushrooms appear to be a natural stress-buster. According to Roundtree, reishi is the mushroom of choice for people under extreme physical or emotional stress. He recommends it for endurance athletes as well. Reishi mushrooms also have a very high level of antioxidants, largely due to their ganodermic acid.

Cremini (white button mushrooms)

I almost omitted cremini mushrooms from the list completely—I mean, after all, how could these little prosaic mushrooms possibly hold a candle to the downright medicinal value of their famous siblings? But, my friend, traditional naturopath Regina Wilshire, N.D., sent me this missive, just in time for press. It’s so complete, I’m going to reprint it right here in its entirety: “Cremini mushrooms are superdense with nutrients. One 5-ounce serving (dry weight before cooking) gives you more than 50 percent of the Daily Value for the cancer-fighting trace mineral selenium, 40 percent of the Daily Value for riboflavin, 35 percent of copper, 30 percent of niacin, 20 to 25 percent of pantothenic acid, phosphorus, and zinc, plus 10 to 15 percent Daily Value of manganese and thiamin. They also have trace amounts of magnesium, calcium, folate, B12, and iron.” Now I don’t feel so bad counting mushrooms as a vegetable!

The Mushroom Weight Loss Plan?

Mushrooms in general also contain a powerful antioxidant called L-ergothioneine. L-ergothioneine neutralizes dangerous free radicals called hydroxyl radicals and also increases enzymes with antioxidant activity. In at least two studies, it seems to act as a metabolic energy enhancer, stimulating the breakdown of sugar in red blood cells and mimicking carnitine in its ability to transport fat into the mitochondria of the cells where the fat can be burned for energy. That’s exactly what most over-the-counter weight loss supplements promise but rarely deliver. Three studies also showed L-ergothioneine to be a protector of environmental UV radiation damage. Though shiitake and maitake have much more of it, even our friend the lowly white button mushroom has many times more L-ergothioneine than wheat germ and chicken liver, the other two sources of this incredible antioxidant.


For generations, okra has been a staple of traditional Southern cooking. This nutritious green vegetable arrived in the United States in the mid-1600s and became an important part of the colonial diet. Its seeds were even used to brew a coffee substitute that was consumed by Southern Americans during the Civil War, when they couldn’t obtain coffee beans. Today it’s still very much a part of what is lovingly called “soul food.”

Okra contains a unique combination of valuable nutrients. It’s one of a select group of foods that include naturally occurring glutathione, arguably the most important antioxidant in the body. Optimal amounts of glutathione are necessary for supporting the immune system; in particular, glutathione is required for replication of the lymphocyte immune cells. It also helps the liver detoxify chemicals.

Okra Beats Cereal for Fiber Content

Okra’s also a high-fiber food. People often ask me where they should get their fiber from, since our diet is so deficient in this important compound. My standard answer is fruits, vegetables, and legumes, and okra is a perfect example of what I’m talking about. One cup of cooked okra—which is a tiny 35 calories’ worth—provides 4 g of fiber, way more than the average slice of bread or the average cup of commercial cold cereal. And for a vegetable, it’s also pretty high in protein. That same 35-calorie cup also provides almost 3 g of protein.

Calorie for calorie, okra is high in calcium, magnesium, potassium, vitamin A, vitamin K, and folic acid, which helps prevent neural tube defects in developing fetuses. In Ayurvedic medicine, okra is considered “tridoshic,” meaning it is good for balancing all metabolic types. It can be steamed, pickled, broiled, baked, or even fried and goes well with tomatoes and highly seasoned vegetable dishes. When you boil it, it gives off a kind of viscous substance that adds a lot of smooth thickness to soups and stews, making okra a favorite for gumbo.

NOTE: The larger pods are tough and fibrous. Look for smooth, firm, unblemished, brightly colored pods smaller than 3 inches long.


There are no two ways about it: Onions are a cancer-fighting food. In a number of impressive published studies, the consumption of onions (and other members of the allium vegetable family) demonstrated protective effects against stomach cancer. And in one study published in the Journal of the National Cancer Institute, eating onions (as well as other members of its family like garlic, scallions, chives, and leeks) significantly lowered the risk for prostate cancer. Onions (and their close relatives) have also been shown to have the same effect against esophageal cancer.

In Vidalia, Georgia, where the Vidalia onion comes from and where onions are consumed in large quantities, the death rate from stomach cancer is 50 percent lower than the national mortality rate from stomach cancer. One theory is that onions contain diallyl sulfide, which increases the body’s production of an important cancer-fighting enzyme, glutathione-S-transferase.

Onions Help Build Strong Bones

At least two important studies show that onions help build strong bones. In one, published in the prestigious journal Nature, male rats fed a small amount of dried onion daily had a 17 percent increase in calcium; female rats that had had their ovaries removed (which would rapidly induce bone loss and osteoporosis) had stronger bones when fed onions. And in another study, published in the Journal of Agriculture and Food Chemistry, a compound in onions inhibited the activity of the cells (osteoclasts) that break down bones. The popular drug Fosamax works in a similar way, but onions have no side effects, unless you count the need to have a breath mint before kissing someone!

Onions belong to the allium family, which also includes leeks, garlic, and shallots. They contain a whole pharmacy of compounds with health benefits, including thiosulfinates, sulfides, sulfoxides, and other smelly sulfur compounds. But those same smelly compounds offer a lot of nutrition bang for the relatively small price of a little eye-watering. In a study in the European Journal of Clinical Nutrition, onions are one of a very select group of foods that in combination was found to reduce mortality from coronary heart disease by an impressive 20 percent (the others included broccoli, tea, and apples).

Why Allergy and Asthma Sufferers Benefit from Onions

Onions contain powerful antioxidants and are anti-inflammatory, antibiotic, and antiviral. They are a great source of quercetin, one of my favorite anti-inflammatory compounds and one that is associated with beneficial effects on chronic diseases like cancer and heart disease. The class of chemicals that quercetin belongs to—flavonoids—have antiallergic properties as well, and quercetin in particular is frequently used by nutritionists as part of their arsenal for treating allergies with natural substances. Quercetin can help relieve asthma and hay fever by blocking some of the inflammatory responses in the airways. Our bodies absorb quercetin from onions very easily, though you’ll probably need quercetin supplements if your main interest is using it therapeutically as an anti-inflammatory. Onions also contain a number of sulfides very similar to those in garlic, which may lower blood lipids and blood pressure.

The type of onion affects the content of the health-promoting chemicals, and the stronger-tasting ones have superior properties.


The Environmental Working Group, a consumer advocate and protection nonprofit research organization, put onions on its 2003 list of twelve foods least contaminated with pesticides. Nice to know!

About the author

Many tips are based on recent research, while others were known in ancient times. But they have all been proven to be effective. So keep this website close at hand and make the advice it offers a part of your daily life.