Populations are graying in all developed nations, and a lot of people want to stop the aging process. This broad trend provides a lift to companies making products that promise to fight wrinkles or other effects of growing old. Nu Skin Enterprises (NUS), a direct seller of anti-aging skin care and nutrition products, has posted annual profit growth of 16%, 33% and 32% over the past three years. In its latest quarter, the firm's EPS rose 31% to 46