Spicing up a vegetarian diet: chemopreventive effects of phytochemicals.

Thousands of chemical structures have been identified in plant foods. Many are found in spices. Typically, spices are the dried aromatic parts of plants-generally the seeds, berries, roots, pods, and sometimes leaves-that mainly, but not invariably, grow in hot countries. Given the wide range of botanical species and plant parts from which spices are derived, they can contribute significant variety and complexity to the human diet. In the past, the medicinal uses of spices and herbs were often indistinguishable from their culinary uses, and for good reason: people have recognized for centuries both the inherent value, as well as the potential toxicity, of phytochemicals in relation to human health. Plants have the capacity to synthesize a diverse array of chemicals, and understanding how phytochemicals function in plants may further our understanding of the mechanisms by which they benefit humans. In plants, these compounds function to attract beneficial and repel harmful organisms, serve as photoprotectants, and respond to environmental changes. In humans, they can have complementary and overlapping actions, including antioxidant effects, modulation of detoxification enzymes, stimulation of the immune system, reduction of inflammation, modulation of steroid metabolism, and antibacterial and antiviral effects. Embracing a cuisine rich in spice, as well as in fruit and vegetables, may further enhance the chemopreventive capacity of one's diet.