Sesame is grown primarily for its oil-rich seeds, which come in a variety of colors, from cream-white to charcoal-black. In general, the paler varieties of sesame seem to be more valued in the West and Middle East, while both the pale and black varieties are prized in the Far East. The small sesame seed is used whole in cooking for its rich nutty flavor (although such heating damages their healthful polyunsaturated fats), and also yields sesame oil. Sesame seeds are sometimes added to breads, including bagels and the tops of hamburger buns. Sesame seeds may be baked into crackers, often in the form of sticks. Sesame seeds are also sprinkled onto some sushi style foods. Whole seeds are found in many salads and baked snacks as well in Japan. Tan and black sesame seed varieties are roasted and used for making the flavoring gomashio. Sesame oil is used for massage and health treatments of the body (abhyanga and shirodhara) and teeth (oil pulling) in the ancient Indian ayurvedic system. Ayurveda views sesame oil as the most viscous of the plant oils and believes it may pacify the health problems associated with Vata aggravation.