Be Smart When Cooking with Turmeric

More than any other spice, turmeric marries health benefits to zesty taste. Numerous recent scientific studies–not to mention millennia of experience–suggest the breadth of turmeric’s therapeutic potential, while its flavoring potential is equally broad for adding clean, camphorous, and peppery notes to myriad ­savory dishes.

The most exciting research indicates that this brilliant yellow spice may inhibit several types of cancers. Other data show that it inhibits inflammation, ulcers, gallstones, and the growth of various microbes. It may also aid wound healing, muscle regeneration, and the cardiovascular system as well as modestly decrease total cholesterol while increasing HDL cholesterol.

The main medicinal components in turmeric are antioxidant molecules called curcuminoids. But cooking easily destroys these fragile molecules. The recipes below are designed to retain the best of both the taste and health benefits of this spice. Here are a few of many possible dishes in which turmeric gives a flavorful, health-promoting lift to already nutritious foods.

Recipes with Turmeric:

• Honey-Mustard Vinaigrette
• Barbecue Sauce
• Roasted Onions
• Green Beans with Turmeric Glaze
• Ras Al Hanout
• Spicy Tomato-Olive Soup
• Masoor Dahl
• Apricot-Rice Pilaf

In the Kitchen

A fat-soluble molecule, curcumin constitutes roughly 1 to 6 percent of turmeric’s dry weight. Curcumin is extremely sensitive to light, moisture, and heat. Roughly 85 percent is destroyed when turmeric is boiled for 15 to 30 minutes. Furthermore, it degrades rapidly (within 30 minutes or so) at a neutral pH. The rate of destruction increases sharply as the pH increases (becomes more alkaline). In laboratory situations, some proteins stabilize curcumin. Whether the same happens in the kitchen with proteins such as the albumin in milk has yet to be determined.

Protect it from the elements. Store turmeric in a dark, cool place, away from light. A foil-wrapped, tightly capped bottle stored in the refrigerator is ideal.

Minimize heat exposure. In cooking, add the spice when you’ve finished heating the dish.

Stabilize it with acids. Whenever possible, use turmeric in acid-containing recipes such as salad dressings and tomato-based dishes. Or add a little vinegar or lemon juice to stews or vegetables, just enough to lend a faint, pleasing tartness that will stabilize the curcumin as well.

Marinate. If you barbecue meat, there’s another way turmeric inhibits cancer potential. A recent study conducted at the Cancer Research Center of Hawaii indicates that steaks soaked in a turmeric-garlic marinade prior to grilling had lower levels of two potent carcinogens.

Turmeric’s Health Benefits

Turmeric (Curcuma longa), belongs to the ginger family and is a rhizome native to the tropics of Southeast Asia, where its medicinal use dates back at least 3,000 years.

Turmeric is loaded with antioxidant molecules called curcuminoids which are responsible for turmeric’s yellow color and much of its medicinal value. Although some scientific studies are based on whole turmeric, others rely on standardized preparations of curcumin (the major curcuminoid in turmeric).

A note of caution: The quantities of curcumin used in some of the studies discussed below equal eating 1/3 to 1/2 cup or more of turmeric a day, an unpalatable amount. And while there is little evidence for turmeric toxicity, some studies report that high turmeric intake reduces growth rate in rats, mice, and pigs, and liver toxicity in the latter animals. So use common sense when you cook with turmeric. It’s a health-protective condiment, not a cure-all potion.

Accumulated data shows that turmeric inhibits inflammation, ulcers, gallstones, platelet aggregation, oxidation of lipids and LDL cholesterol (which plays an important role in atherosclerosis), and the growth of various microbes. In addition, it may modestly decrease total cholesterol while increasing HDL cholesterol, and aid wound healing and muscle regeneration.

Most promising, it may inhibit several types of cancers, probably by inhibiting tumor formation in both the early (initiation) phase and later stages of promotion and progression. ­Curcumin inhibits free-radical production, stimulates enzymes that detoxify chemical carcinogens, decreases the activity of molecules that activate pro-carcinogens and inhibits production of inflammatory compounds that are over produced in tumors. In some cell types, it appears to inhibit the copying of several genes ­involved in cell growth and halts the division of some cell types.

Oral Cancers

Both whole turmeric and standardized curcumin appear to inhibit cancerous growths of the gastrointestinal tract from mouth to colon. Studies in India, where oral cancers are prevalent, demonstrate turmeric’s potential to reverse premalignant lesions in smokers’ mouths. In one study, smokers who ate about 1/2 teaspoon of turmeric daily for nine months showed significant regression of such lesions. Another study in smokers found that eating about 3/4 teaspoon of turmeric for thirty days reduced the cigarette-related mutagens excreted in the subjects’ urine.

An animal study supports this data. Hamsters with chemically induced tumors of the buccal pouch (analogous to human mouths) exhibited less damage to DNA and developed fewer tumors when fed turmeric or curcumin.

Digestive Cancers

In the United States, colon cancer is the third most common type of malignancy. Curcumin appears to inhibit forms of this type of cancer, at least in animal model systems.

In one study, rats treated with a chemical carcinogen who also ingested curcumin had 45 percent fewer aberrant colonic crypts (an early measure of colon cancer). The rats were fed a diet containing 0.2 percent curcumin; in human terms, this is roughly equal to 1/3 cup of turmeric. Although this is an ­unpalatable amount of the spice, the animals’ tumors were ­induced with massive doses of carcinogens unseen in real human experience.

A second study demonstrated decreases of 25 to 77 percent in the numbers of mice developing tumors of the forestomach, duodenum, and colon following treatment with chemical carcinogens. Even mice that did develop malignancies had fewer of them and they were smaller.

Despite curcumin’s potential, it can’t reach everywhere in the body. Several studies indicate it is poorly absorbed from the small intestine, that little circulates in the blood, and that most is rapidly excreted in feces. This may explain turmeric’s effectiveness in inhibiting malignancies of the GI tract–the whole length is exposed to any consumed spice. However, at least some curcumin reaches the liver where it stimulates production of enzymes that detoxify many carcinogens. Presumably this ­accounts for its ability to reduce the incidence of chemically caused tumors. Poor absorption in no way negates curcumin’s potential in clinical settings where the compound can be injected, rather than eaten.

Breast Cancer

Curcumin may inhibit some breast cancers resulting from exposure to estrogen-like compounds such as DES, chlordane, and DDT. In two studies, curcumin inhibited the growth of cultured human breast-cancer cells. Genistein (an estrogen-like compound found in soybeans) acted synergistically with curcumin.

In a third study conducted in gamma-irradiated rats, mammary tumor formation following DES treatment (which promotes malignant cell development) was reduced from 85 percent of the animals to only 28 percent in those animals simultaneously fed curcumin.

At least two tissue culture studies suggest that curcumin may inhibit the growth of various lymphomas. Ninety-five percent of Epstein-Barr virus lymphoma cells died when grown in the presence of curcumin, as compared to 24 percent of cells grown in the absence of curcumin. This study has particular relevance to immune-compromised patients (such as those with organ transplants or HIV infection), who are particularly susceptible to Epstein-Barr infection. A second study ­con­ducted in immature B cell lymphoma cells shows similar growth ­inhibition.

Other laboratory studies suggest that curcumin inhibits the spread of melanoma cells to the lungs, a frequent site of secondary tumors. Mice treated with curcumin developed 90 ­percent fewer lung tumors than untreated control animals.

Cornelia Carlson holds a doctorate in biochemistry and is an avid grower and user of herbs. She writes frequently for Herbs for Health and is the author of The Practically Meatless Gourmet (Berkley, 1996). She writes from her home in Arizona.

If you would like to obtain a reference list for this article, please e-mail herbsforhealth@hcpress.com.