Spices are rich in more than just savory compounds: They are loaded with potential disease-combating substances. A study of 27 cooking herbs from the U.S. Department of Agriculture found that most had greater antioxidant power per gram than various fruits and vegetables. Other studies show that spices often contain substances that fight inflammation and infection, inhibit cancer-causing enzymes and tumor-stimulating hormones, and slow the life cycle of cancer cells or promote their destruction.
Most of the research has been done with concentrated spices on laboratory animals or in test tubes, often with larger doses than used for cooking. Whether smaller amounts of the dried cooking spices can boost human health is not known, but here is a rundown on some of the most promising research:
Turmeric. Based on encouraging animal evidence, scientists have launched several studies in humans to test the benefits of curcumin, the substance that gives turmeric its yellow-orange color.
* Researchers at the Alzheimer's Disease Research Center at the University of California, Los Angeles, are testing curcumin's ability to treat the early stages of the disease. Studies have shown that curcumin may both inhibit and break up the accumulation of destructive proteins in the brain, a hallmark of Alzheimer's disease, and also fight the inflammation that may contribute to the condition.
* The Cystic Fibrosis Foundation is funding a clinical trial on whether curcumin can block the buildup of mucus in the digestive system of cystic fibrosis patients.
* Scientists at M.D. Anderson Cancer Center in Houston are studying curcumin as a possible treatment for multiple myeloma and pancreatic cancer, based on research showing that it may stop cancer cells from proliferating and cause malignant tumors to self-destruct.
Cinnamon. Another USDA study, this one in humans, found that consuming cinnamon for 40 days reduced blood levels of sugar and triglycerides, a potentially artery-clogging fat, by about 25%; it also cut the "bad" LDL-cholesterol level by nearly 20%. It did not take much — just under half a teaspoon per day.
Oregano. In the USDA study of antioxidants, oregano had three to 20 times more power than other culinary herbs, and more than vitamin E, too. One tablespoon of oregano has about the same antioxidant capacity as an entire apple or banana or a cup of string beans or one half cup of steamed carrots. The runner-up herbs: bay leaf, coriander, dill, rosemary, and savory.
Sage. As Alzheimer's disease progresses, the brain produces less and less acetylcholine, a crucial chemical for memory and thinking. Sage appears to inhibit the chemical's breakdown; its high antioxidant content may further help preserve cognition. A British clinical trial of two dozen healthy young adults found that sage oil taken in pill form boosted memory, alertness, and calmness. An earlier, smaller trial by British and New Zealand researchers found evidence that the oil may improve the memory and attention of people with Alzheimer's disease.