#10. Benefits of Vitamin D

Researchers have long known that the "sunshine vitamin" boosts bone strength by encouraging the body to absorb calcium. But a slew of new studies published in 2007 suggests that the vitamin has a lot of other benefits: Diets high in D may ward off diabetes, gum disease and multiple sclerosis — and maybe even cancer. Though some findings linking vitamin D and cancer showed questionable benefit, the news on colon cancer was promising. In one large trial, men in the Health Professionals Follow-Up Study and women in the Nurses' Health Study with the highest blood levels of vitamin D were half as likely to develop colon cancer as their peers with less circulating vitamin D. To squeeze the most value out of vitamin D, aim for taking a supplement with 1,000 IU daily.